city of umatilla standard specifications

city of umatilla standard specifications
CITY OF UMATILLA
STANDARD SPECIFICATIONS
WATER & SEWER UTILITIES
JANUARY 2013
Adopted October 1, 2013 - Ordinance 2013 - M
Table of Contents
Section 1 – Introduction
Sec. 1.1
General
Sec. 1.2
Definitions
Sec. 1.3
Transfer to the City of On-Site Water and Sewer Facilities in
Developments
Section 2 – Water Supply System Design
Sec. 2.1
General
Sec. 2.2
Plan Review, Approval, Construction, and Acceptance of Water
and Wastewater Improvements
Section 3 – Sanitary Sewage Facilities Design
Sec. 3.1
General
Sec. 3.2
Plan Review, Approval, Construction and Acceptance of
Wastewater Improvements
Section 4 – Wellfields and Water Supply
Sec. 4.1
General
Sec. 4.2
Surface Water Intake Facilities Design
Sec. 4.3
Water Wells and Wellfields
Sec. 4.4
Water Well Design Standards
Standard Drawing Index
Standard Drawings
General
Water
Sewer
APPENDIX A
APPENDIX B
APPENDIX C
APPENDIX D
APPENDIX E
General Construction Requirements for Water Distribution and
Wastewater Collection
Gravity Sewers, Force Mains, and Pump Stations
Water Distribution
Reclaimed Water Transmission/Distribution
Interim Package and Subregional Wastewater Treatment
Facilities Design Criteria
SECTION 1
INTRODUCTION
1.1
1.2
1.3.
GENERAL
DEFINITIONS
TRANSFER TO THE CITY OF ON-SITE WATER AND SEWER FACILITIES IN
DEVELOPMENTS
City of Umatilla Standard Specifications
Water & Sewer Utilities
Section 1
January 2013
SECTION 1
INTRODUCTION
1.1
GENERAL
The information set forth in this document is intended to provide minimum standards for
improving design and construction of water supply and treatment facilities, wastewater treatment
facilities, and transmission, collection and distribution systems. Questions regarding
interpretations of the provisions in this document shall be addressed to Umatilla City Hall Utilities Department .
1.2
DEFINITIONS
Except where specific definitions are used within a specific section, the following terms, phrases,
words, and their derivation shall have the meaning given herein when consistent with the context.
Words used in the present tense include the future tense, words in the plural number include the
singular number and words in the singular number include the plural number. The word "shall"
is mandatory, and the word "may" is permissive.
A.
AASHTO - means American Association of State Highway and Transportation
Officials. Any reference to AASHTO standards shall be taken to mean the most
recently published revision unless otherwise specified.
B.
ANSI - means American National Standards Institute. Any reference to ANSI
standards shall be taken to mean the most recently published revision unless
otherwise specified.
C.
As-Built/Record Drawings - means completed construction drawings (one set of
reproducible drawings), documenting the actual construction work as it exists in the
field, including any changes made from the originally approved drawings and certified
by an Engineer, not necessarily the Engineer-of -Record. The Engineer(s) shall be
registered in the State of Florida and all drawings shall have the Engineer(s) seal,
signature, date and the words "As-Built/Record Drawings" affixed to each sheet of the
drawing. Also includes electronic copy of drawings in AutoCadd or DXF format.
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D.
ASTM - means American Society for Testing Materials. Any reference to ASTM
standards shall be taken to mean the most recently published revision unless
otherwise specified.
E.
AWWA - means American Water Works Association. Any reference to AWWA
Standards shall be taken to mean the most recently published revision unless
otherwise specified.
F.
Contractor - means the person, firm, or corporation with whom the contract for work
has been made by the Owner, the Developer, City, or the County.
G.
City - means the City of Umatilla, Florida or its designated representative.
H.
Cross Connection - means any unprotected actual or potential connection or structural
arrangement between a public or a customer's potable water system and any other
source or system through which it is possible to introduce into any part of the potable
water system any used water, industrial fluid, gas, or substance other than the
intended potable water with which the system is supplied.
I.
Developer - means the person, firm, or corporation engaged in developing or
improving real estate for use or occupancy.
J.
Developer's Engineer - means an Engineer or Engineering firm registered with the
State of Florida, Department of Professional Regulation, retained by the Developer to
provide professional engineering services for a project.
K.
DIPRA - means Ductile Iron Pipe Research Association.
L.
Director - means the Director of Public Works for the City of Umatilla, Florida acting
directly or through an assistant or other representative authorized by him.
M.
Drawings - means engineering drawings prepared by an Engineer to show the
proposed construction.
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N.
Dryline Permit - means a construction permit for water and/or sewer lines issued with
certain special conditions applied. All such permitted projects cannot be put into
service until all special conditions attached to the permit have been met.
O.
Engineer - means an Engineer or Engineering firm registered with the State of Florida
Department of Professional Regulation.
P.
Fire Line - Piping from the water main to point of delivery for exclusively providing
fire protection.
Q.
FDEP - means State of Florida Department of Environmental Protection.
R.
FDOT - means State of Florida Department of Transportation.
S.
Geotechnical/Soils Engineer - means a Registered Florida Engineer who provides
services related to terrain evaluation and site selection, subsurface exploration and
sampling, determination of soil and rock properties, foundation engineering,
settlement and seepage analysis, design of earth and earth retaining structures, the
design of subsurface drainage systems and the improvement of soil properties and
foundation conditions, and testing and evaluation of construction materials.
T.
Manual On Uniform Traffic Control Devices - means the United States Department of
Transportation Manual on Uniform Traffic Control Devices, latest edition.
U.
Lake County - means Lake County, Florida.
V.
NEMA - means National Electrical Manufacturers Association. Any reference to
NEMA Standards shall be taken to mean the most recently published revision unless
otherwise specified.
W.
NSF - means National Sanitation Foundation. Any reference to NSF Standards shall
be taken to mean the most recently published revision unless otherwise specified.
X.
OSHA - means the Federal Occupational Safety and Health Administration.
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Y.
Owner - means the person, firm, corporation, or governmental unit holding right of
possession of the real estate upon which construction is to take place.
Z.
Plans - means drawings as defined herein above.
A.A.
Point of Connection - shall mean, for potable water and/or reclaimed water, to be the
outlet side of the meter designated to serve the customer. For unmetered reclaimed
water the point of connection shall be at the property line.
B.B.
Public Potable Water Supply Systems shall mean wells, treatment systems,
disinfection systems, reservoirs or other storage and high service pumping, pipes,
lines, valves, meters, water mains and services, used or having the present capacity
for future use in connection with the obtaining and supplying of potable water for
domestic consumption, fire protection, irrigation, consumption by business, or
consumption by industry. Without limiting the generality of the foregoing definition,
the system shall embrace all necessary appurtenances and equipment and shall include
all property, rights, easements and franchises relative to any such system and deemed
necessary or convenient for the operation thereof.
C.C.
Reclaimed Water - means water that has received at least advanced secondary
treatment, high level disinfection and is reused after flowing out of the wastewater
treatment facility. Water receiving additional treatment may be used in public access
areas, when in compliance with the FDEP requirements pursuant to Chapter 62-610,
FAC.
D.D.
Right-of-Way - means the City, County or FDOT Right-of-Way
E.E.
Road Construction Specifications – means City, County or FDOT Road Construction
Standard Specifications
F.F.
Specifications - means the specifications contained in the Appendix of this Code.
G.G.
Standard Drawings - means the detailed drawings in the Appendix of this Code.
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H.H.
Standard Specifications - means the Department of Transportation, State of Florida,
Standard Specifications for Road and Bridge Construction, latest edition.
I.I.
Traffic Control and Safe Practices Manual- means the State of Florida Department of
Transportation Manual on Traffic Control and Safe Practices for Street and Highway
Construction, Maintenance and Utility Operation, latest edition.
J.J.
Utility Accommodation Guide - means the State of Florida Department of
Transportation Utility Accommodation Guide, latest edition.
K.K.
Water Mains - means water transmission mains, distribution mains, pipes, fittings,
valves, hydrants, services, meters and miscellaneous related appurtenances.
L.L.
Water Meter - means that device which registers water flow to a customer with all
appurtenances.
M.M.
Water Service Line - The pipe from the water main to the point of connection.
N.N.
Wastewater Mains - means wastewater gravity sewers, manholes, force mains, pump
stations, fittings, valves, service laterals, and miscellaneous related appurtenances.
O.O.
Wastewater Service Lateral - means those service laterals or force mains from the
customer's property line to the wastewater main and all appurtenances.
P.P.
Work - means the labor, materials, equipment, supplies, services and other items
necessary for the execution, completion and fulfillment of the contract.
1.3.
TRANSFER TO THE CITY OF ON-SITE WATER AND SEWER FACILITIES IN
DEVELOPMENTS
A.
Dedication to City - This subsection shall apply to all proposed water and wastewater
mains to be owned, operated or maintained by the City. All new water mains or
wastewater mains in subdivisions shall be dedicated to City in areas where the City
presently can provide service or could provide service through a pipeline or
contractual arrangement with another utility.
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New water mains or wastewater mains located within Florida Public Service
Commission (FPSC) certificated areas, areas where the City will not provide service,
or in areas where services are provided by a not-for-profit or quasi-governmental
entity will not be dedicated to the City.
B.
Prior to water and sewer plan approval by the City Engineer and execution of water
and sewer main extension applications to state agencies by the City, the builder or
developer shall be required to execute a developer's agreement. This agreement shall
run with the land and be binding on the developer, its successors, assigns and any
other subsequent owner of the land, setting forth such reasonable provisions
governing developer and City responsibility pertaining to the installation of service
facilities; the interconnection of plumber's lines with the facilities of the City; the
manner and method of payment of contributions, fees and charges; guaranteed
revenue provisions; standards of construction or specifications; regulations, policies,
practices and procedures of the City; prohibitions against improper use of the City's
facilities; and other matters normally associated with and contained in developer
agreements. Developer agreements shall only apply to specific parcels of property
and are not assignable or transferable in any manner to any other parcel of property.
C.
Each developer who has constructed a portion of the water mains and wastewater
mains on the developer's own property prior to interconnection with the City's
existing or proposed facilities shall convey such component parts of the water mains
and wastewater mains to the City by “bill of sale” in form satisfactory to the City
Attorney, together with such evidence as may be required by the City; that the water
and wastewater mains proposed to be transferred to the City are free of all liens and
encumbrances; that the City Engineer has approved the construction of said lines and
accepted the tests to determine that such construction is in accordance with the
criteria established by the City and that the City Council has evidenced its acceptance
of such lines for the City's ownership, operation and maintenance.
D.
The developer shall maintain accurate cost records establishing the construction costs
of all utility facilities constructed by the developer and proposed to be transferred to
the City. Such cost information shall be furnished to the City concurrently with the
“bill of sale”, and such cost information shall be a prerequisite for the acceptance by
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the City of the portion of the water and wastewater mains constructed by the
developer.
E.
The City may refuse connection and deny the commencement of service to any
consumer seeking to be connected to portions of the water and wastewater mains
installed by the developer until such time as the provisions of this section have been
fully met by the developer or the developer's successors or assigns.
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SECTION 2
WATER SUPPLY SYSTEM DESIGN
2.1
GENERAL
2.2
PLAN REVIEW, APPROVAL, CONSTRUCTION, AND ACCEPTANCE OF
WATER AND WASTEWATER IMPROVEMENTS
A.
Plans and Specifications
1.
Master Plan
2.
Plan and Profile
3.
Details
4.
Scale
General Criteria
1.
City Utility Service Area
a.
General
b. Service Criteria
2.
Rural Land Area
3.
Approval
4.
Submittals
a.
Drawings
b. Permits
c.
Prepared by Engineer
5.
Testing
Subdivision Related Water and Wastewater Mains
1.
General
2.
Design and Plan Review
3.
Construction Inspection
4.
Maintenance Materials, and Workmanship Warranty Bond
5.
Certificate of Completion/Approval for Maintenance and Acceptance
6.
Miscellaneous Water and Wastewater Mains
7.
Compliance With Other Regulatory Requirements
8.
As-Built/Record Drawings
a.
Drawings
b. Actual Locations
c.
Field Changes
B.
C.
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D.
d. Details
e.
Manhole & Valve Boxes
f.. Dimensions
g. Signed & Sealed
h. Electronic Data
Water Mains
1.
System Design Criteria
a.
Type of Water Mains
b. Design Period
c.
Location
2.
3.
4.
Design Basis
a.
Average Daily Flow and Peak Flows
b.
Fire Flow Requirements
General:
Single-Family or Duplex Residential Dwellings:
Multi-Family, Commercial, Industrial, Institutional, and All Other
Types:
Fire Flow Duration:
c.
Design Calculations
Details of Design and Construction
a.
Pressure
b.
Diameter
c.
Fire Hydrant Location and Spacing
d. Dead Ends
e.
Valves
f.
Separation of Water Mains and Sewers
g. Surface Water Crossings
h. Air Relief Valves
i.
Chamber Drainage
j.
Disinfection Following Repair or Replacement
Water Services and Connections
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5.
Water Metering
a.
General
b. Single-Family, Duplex, and Multi-Family Subdivisions with Public Rights
of Way
c.
Single Family and Duplex Subdivisions with Private Streets
d. Commercial, Industrial, and Institutional Projects Without Private Fire
Lines
e.
Commercial, Industrial, Institutional, Multi-Family with Private Streets,
Apartments, and Condominium Projects with Private Fire Lines
f.
Shopping Centers
g. Meter Installation
h. Meter Sizing
i.
Meter Type
6.
7.
8.
Material, Installation and Testing
Location and Identification
Cross Connection Control
a.
General
b. Commercial, Industrial, and Multi-Family Residential
c.
Irrigation Systems
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SECTION 2
WATER SUPPLY SYSTEM DESIGN
2.1
GENERAL
This section sets forth the general requirements for the design of the water supply
system.
2.2
PLAN REVIEW, APPROVAL, CONSTRUCTION, AND ACCEPTANCE OF
WATER AND WASTEWATER IMPROVEMENTS
A.
Plans and Specifications
1.
Master Plan
Whenever possible, the entire water and wastewater systems shall be shown on
a single Master Plan. The Master Plan shall indicate the general locations of all
mains, manholes, valves, hydrants, services and service laterals with respect to
the proposed development improvements and the existing water and wastewater
systems. Main sizes shall be indicated on the Master Plan. The city shall
require (7) sets of drawings for review.
2.
Plan and Profile
All gravity sewers, all wastewater force mains, and off-site water mains shall be
drawn in plan and profile. On-site water mains may be shown in plan view only.
Whenever possible, on-site water and wastewater systems shall be shown on the
same drawing sheet. As a minimum, the plan and profile drawings shall include
the following information:
a.
General information such as north arrow, names of designer and Engineer,
revision block with dates, graphic scale(s) and sheet number.
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3.
b.
Profile with elevations at one (1) foot interval, or more frequently if
required by good design practice.
c.
Development layout with horizontal and vertical controls.
d.
All potential conflicts with other utility and drainage systems.
e.
All manhole locations and rim elevations for manholes either in or outside
of paved areas.
f.
Pipe data including size, lengths, material, and slopes.
g.
Size, type, and locations of fittings, valves, hydrants, air release/vacuum
relief, and other related appurtenances.
h.
Limits of pipe deflection not generally included on drawings.
i.
Description and limits of special exterior coatings.
j.
Description and limits of special bedding requirements.
k.
Pipe restraint requirements.
l.
Details of connection to existing systems.
m.
Separate site plan(s) showing location(s) and general layout of wastewater
pumping stations with details, working elevations and schedules.
n.
Construction notes regarding cover, horizontal and vertical control, special
construction requirements, and references to standard and special details.
Details
The Drawings shall include all applicable Standard Drawings. Special details
shall be prepared by the Developer's Engineer for aerial and underwater
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crossings of rivers, streams, canals and ditches. Other special details shall be
prepared by the Developer's Engineer as required the City Engineer.
4.
Scale
The master plan shall be prepared at a scale not to exceed 1" to 400'. Plan and
profile sheets shall not exceed a horizontal scale of 1" to 50'. Special details
shall be of sufficiently large scale to show pertinent construction information.
B.
General Criteria
1.
City Utility Service Area
a.
General
Where available, the owner of every lot or parcel of land within the city
utility service area developed for residential, public, commercial office,
industrial, warehousing or multifamily use shall connect the premises or
cause the premises to be connected with the City’s water distribution
system.
b.
Service / Criteria
Availability of water and sewer will be as defined in the City Land
Development Regulations.
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2.
3.
Rural Land Area
a.
In the rural land area where an existing public or privately-owned water
system has the capacity and desire to expand and provide service to a
proposed development, the standards in Paragraph 1.b., Service Criteria,
above shall apply.
b.
When there is no existing public or privately-owned water system
available with expansion capability, the proposed development shall either
develop and provide a central water system or if the project density cannot
support such a system, individual wells may be provided, subject to the
rules and regulations of the State of Florida, Department of Health and
Rehabilitative Services and the appropriate water management district
rules and regulations.
Approval
All construction drawings for water supply systems shall require approval of the
City Engineer and Public Works Department.
4.
Submittals
Requirements for submittal of construction drawings for water supply systems:
a. Drawings
Plans shall meet same scale and size requirements as Improvement Plans
and shall be integrated into Improvement Plans when applicable.
b. Permits
Permits for construction of water supply facilities shall be obtained by
the developer from City, County, and from Florida Department of
Environmental Protection, prior to commencing construction.
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c. Prepared by Engineer
Drawings for water supply facilities shall be prepared by a Florida
registered professional engineer and submitted to the City. Submit the
same number of copies of drawings as required for Improvement Plans.
5.
C.
Testing
Hydrostatic testing of water systems shall be certified and conform to the
current requirements of the Florida Department of Environmental Protection.
Subdivision Related Water and Wastewater Mains
1.
General
This section shall apply to all proposed community water and wastewater
systems and mains to be owned, operated or maintained by the City, or in the
City rights-of-way. These improvements shall be constructed in compliance
with this Manual unless a waiver is granted by the City Council in accordance
with City of Umatilla Land Development Code.
2.
Design and Plan Review
Design of water and wastewater mains associated with City approved
subdivisions shall be in compliance with the design standards in this article, and
the specifications outlined in the City Land Development Regulations.
Drawings will be reviewed and approved by the City Engineer and the City
Public Works Department as part of the subdivision review and approval
process.
3.
Construction Inspection
Inspection of water and wastewater mains shall be in accordance with criteria
established in the City Land Development Regulations. The City Engineer,
Public Works Director, or their designated representative shall inspect the water
and wastewater mains to ensure their compliance with requirements in the
Appendix.
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After all required water or wastewater mains have been installed, the
Developer's Engineer shall submit certification to the City that the water and
wastewater mains have been constructed in substantial conformance with the
approved drawings and specifications. Non-compliance with approved plans or
specifications or evidence of faulty materials or workmanship shall be called to
the attention of the Developer or Developer's Engineer and if not corrected in an
expeditious manner, all work on the project will be suspended and/or certificate
of occupancy withheld. Laboratory tests may be required when appropriate.
4.
Maintenance Materials, and Workmanship Warranty Bond
A bond shall be posted by the Developer and executed by a company authorized
to do business in the State of Florida that is satisfactory to the City, payable to
City in the amount of twenty (20) percent of the estimated construction cost of
all required water and wastewater mains to be owned and maintained by the
City. Such bond shall guarantee maintenance of all water and wastewater mains
intended to be owned and maintained by the City for a two (2) year period, and
the materials, workmanship and structural integrity of water and wastewater
systems, and miscellaneous related facilities, excluding mechanical equipment
for a one (1) year period, commencing after a Certificate of Completion has
been issued by the City. The manufacturer's warranty will be acceptable for
mechanical equipment. As an alternative to the provision of a surety bond, the
Developer may provide for the deposit of cash in an escrow account or a letter
of credit acceptable to the City.
5.
Certificate of Completion/Approval for Maintenance and Acceptance
After successful completion of all water and wastewater mains, and after receipt
of the required documents outlined in this Section, the City will provide a
"Certificate of Completion" verifying the satisfactory construction of all water
and wastewater mains intended to be owned and maintained by the City. After
the one (1) year Warranty Period, verification by the City of satisfactory
performance of all water and wastewater mains construction and compliance
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with The Developer's Agreement, the City will issue the "Approval for
Maintenance", thereby releasing the Developer from further responsibilities.
Approval and acceptance of water and wastewater mains shall be in accordance
with the criteria established in this Section.
6.
Miscellaneous Water and Wastewater Mains
All water and wastewater mains constructed which are intended to be owned,
operated or maintained by the City, shall be designed, reviewed, inspected and
accepted in strict compliance with the criteria established hereinabove.
7.
Compliance With Other Regulatory Requirements
It shall be the responsibility of the Developer to obtain and comply with all
applicable Federal, State and Local regulatory permits.
8.
As-Built/Record Drawings
The Developer's Engineer shall submit one (1) Reproducible Original and four
(4) certified sets of As-Built/Record Drawings to the City prior to issuance of
Certificate of Completion for the improvements. The Developer's Engineer shall
be responsible for recording information on the approved Drawings
concurrently with construction progress. As-Built/Record Drawings submitted
to the City as part of the project acceptance shall comply with the following
requirements:
a. Drawings
Drawings shall be legibly marked to record actual construction.
b. Actual Locations
Drawings shall show actual location of all underground and above ground
water and wastewater piping and related appurtenances. All changes to
piping location including horizontal and vertical locations of utilities and
appurtenances shall be clearly shown and referenced to permanent surface
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improvements. Drawings shall also show actual installed pipe material,
class, etc.
c.
Field Changes
Drawings shall clearly show all field changes of dimension and detail
including changes made by field order or by change order.
d. Details
Drawings shall clearly show all details not on original contract drawings
but constructed in the field. All equipment and piping relocation shall be
clearly shown.
D.
e.
Manholes & Valve Boxes
Location of all manholes, hydrants, valves, and valve boxes shall be
shown. All valves shall be referenced from at least two and preferably
three permanent points.
f.
Dimensions
Dimensions between all manholes shall be field verified and shown. The
inverts and grade elevations of all manholes shall be shown.
g.
Signed and Sealed
Each sheet of the Drawings shall be signed, sealed and dated by the
Developer's Engineer as being "As-Built/Record Drawings." Construction
Drawings simply stamped "As Built" or "Record Drawings" and lacking in
above requirements will not be accepted, and will be returned to the
Developer's Engineer. The "Certificate of Completion" will not be issued
until correct "As-Built/Record Drawings" have been submitted.
h.
Electronic Data
The Developer's Engineer shall also submit on an Auto cad Disc or DXF
File the required As-Built/Record Drawings. The engineer's seal with his
signature shall be on the letter of transmittal.
Water Mains
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January 2013
1.
System Design Criteria
a.
Type of Water Mains
The City will approve Drawings for water supply mains and extensions
only when such mains are designed and constructed in accordance with
the criteria set forth in this Manual.
b.
Design Period
Water mains should be designed for a 30 year life span and for the
estimated ultimate tributary population, as delineated in the approved City
Water Master Plan (latest edition) except in considering parts of the
system that can be readily increased in capacity. Water systems shall be
designed to satisfy the domestic water demand and fire protection
requirements for the area.
c.
Location
Water mains shall be located in dedicated rights-of-way or dedicated
utility easements. When installed in rights-of-way, water mains shall, in
general, maintain a consistent alignment with respect to the centerline of
the road. All water mains located outside of dedicated rights-of-way shall
require a minimum 20' easement. If a water main is located adjacent to a
road right-of-way, a minimum 10' easement shall be provided. Additional
easement widths shall be provided if the pipe size or depth of cover so
dictate. All easements are subject to the approval and acceptance by the
City. Water mains shall not be placed under retention ponds, retention
pond berms, tennis courts, or any vertical structures. Water mains shall not
be located along side or rear lot lines.
2.
Design Basis
a.
Average Daily Flow and Peak Flows
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Average daily water flow shall be calculated by referencing the Equivalent
Residential Connection (ERC) flow rates as outlined in Appendix . The
Appendix is subject to revision by amendment to this Manual. Maximum
daily and peak hourly water flow rates shall be calculated by referencing
the service area peaking factors to be determined by the City Utility
Department.
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b.
Fire Flow Requirements
General: Water distribution systems and/or water main extensions shall be
designed and constructed in accordance with the requirements of the City
Fire Codes, the Insurance Services Offices (National Board of Fire
Underwriters), as stated in their Fire Protection Rating Schedule "Needed
Fire Flow" section and state codes.
Single-Family or Duplex Residential Dwellings: For single family or
duplex residential development, not exceeding two (2) stories in height, a
central water system shall be used for fire protection water supply which
meets the requirements in Table 2-1 with a minimum residual system
pressure of 20 psi.
Multi-Family, Commercial, Industrial, Institutional, and All Other Types:
For multi-family residential developments, commercial or industrial
developments, institutional or other types of structures the fire protection
requirements shall be in accordance with the requirement of the City Fire
Codes, the Insurance Services Office (National Board of Fire
Underwriters), as stated in the Fire Protection Rating Schedule "Needed
Fire Flow" section and state codes. In all cases, the minimum fire flows
shall not be less than required for single family or duplex residential
dwellings in Table 2-1.
Fire Flow Duration: Fire flow duration shall be 2-hours for fire flow
demands up to 2,500 gallons per minute (gpm) and 3-hours for fire flow
demands in excess of 2,500 gpm.
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TABLE 2-2
MINIMUM FIRE FLOW REQUIREMENTS
FOR RESIDENTIAL DWELLINGS
1. Using the peak hourly demand rate, calculated by the Project Engineer, determine from
Table 2-1 the minimum required fire flow rates in gallons per minute (to be used in
designing water distribution system). For single family, multi-family and manufactured
home developments in areas having less than 9 units per acre, fire flow rates, times and
storage shall be based on the Table 2-1.
Table 2-1
PEAK HOURLY
MINIMUM
AVAILABLE STORED
DOMESTIC DEMAND REQUIRED FIRE TOTAL FLOW
OR PUMPABLE
RATE IN GPM
FLOW IN GPM TIME IN HOURS
WATER(1)
0 to 50
500
0.50
*
10,000
51 to 100
500
1.00
**
20,000
101 to 200
750
1.50
**
40,000
201 to 300
1,000
2.00
**
75,000
301 to 400
1,250
2.50
**
120,000
401 to 500
1,500
3.00
**
175,000
501 to 600
1,500
3.25
200,000
601 to 750
1,750
3.50
250,000
751 to 1,000
2,000
4.00
350,000
1,251 to 1,500
2,500
5.00
600,000
(3)
***
Over 1,500
City of Umatilla Standard Specs
Water & Sewer Utilities
(3)
2-12
January 2013
2.
For areas having 9 or more units per acre, multi-family residential areas and commercial,
institutional or industrial areas fire flow rates, times and storage shall be based on the
table below.
Table 2-2
PEAK HOURLY
MINIMUM
AVAILABLE STORED
DOMESTIC DEMAND REQUIRED FIRE TOTAL FLOW
OR PUMPABLE
RATE IN GPM
FLOW IN GPM TIME IN HOURS
WATER(1)
0 to 50
1,000
1.00
**
50,000
51 to 100
1,500
2.00
**
100,000
101 to 200
1,500
2.50
**
125,000
201 to 300
1,500
3.00
**
160,000
301 to 400
1,500
3.50
**
200,000
401 to 500
1,500
3.75
**
225,000
501 to 600
1,500
4.00
250,000
601 to 750
1,750
4.00
300,000
751 to 1,000
2,000
4.00
350,000
1,001 to 1,250
2,250
4.50
450,000
1,251 to 1,500
2,500
5.00
600,000
Over 1,500
(3)
(3)
***
Notes: ** This does not include hydropneumatic tank storage capacity.
** Where two wells are provided and total pump capacity exceeds 100% of combined
peak hourly domestic demand rate and required fire flow demand rate, fire flow
storage tanks are not required.
*** To be calculated by project engineer.
c.
Design Calculations
Developer's Engineer shall submit signed, sealed and dated design
calculations with the Drawings for all water distribution projects.
Calculation shall show the water mains will have sufficient hydraulic
capacity to transport peak hourly flows and the combination of maximum
daily flows and fire flows while meeting the pressure requirements of
Section 2.2.C.3.,. Head losses through meters and backflow devices shall
also be included in calculations.
City of Umatilla Standard Specs
Water & Sewer Utilities
2-13
January 2013
3.
Details of Design and Construction
a.
Pressure
All water mains shall be designed in accordance with Section 2.2.B.2
above. The system shall be designed to maintain a minimum pressure of
20 psi at all points in the distribution system under all conditions of flow.
Higher pressures may be required at commercial, industrial and high
density residential areas. The normal working pressure in the distribution
system should be approximately 65 psi, but in no case less than 35 psi on
the downstream side of a meter. For pressures greater than 80 psi special
provisions such as pressure reducers may be required at the service
connection. Surge protection shall be provided. Design friction losses for
water mains shall be as specified as to this manual.
b.
Diameter
Only 4", 6", 8", 10", 12", 16", 20", 24", 30", 36", 42", 48", and 54"
diameter water mains shall be permitted. In cul-de-sac areas with a
maximum length of 500 feet of pipe, a 4" looped connection may be
permitted to prevent dead ends. As a minimum, 6" looped systems shall
be required in low density residential projects. Where looping of mains is
not practical, minimum 8" mains shall be required, unless detailed
calculations are submitted to substantiate the sufficiency of a 6" main. In
commercial, industrial, and high density residential areas, minimum 8"
looped mains shall be required. Larger size mains shall be required if
necessary to allow the withdrawal of the required fire flow while
maintaining the minimum residual pressure specified in Section 2.2.C.3.a
above.
c.
Fire Hydrant Location and Spacing
As a minimum, specifications outlined herein and applicable City Fire
Codes shall apply. In addition, flushing hydrants shall be placed at 1000
feet intervals to provide for proper flushing for all off-site mains.
City of Umatilla Standard Specs
Water & Sewer Utilities
2-14
January 2013
d.
Dead Ends
In order to provide increased reliability of service and reduce head loss,
dead ends shall be minimized by making appropriate tie-ins whenever
practical, as determined by the City Engineer.
Where dead-end mains occur, they shall be provided with a fire hydrant or
with an approved flushing hydrant or blow-off (should meter all water
used for flushing) for flushing purposes. Flushing devices shall be sized
to provide flows which will give a velocity of at least 2.5 feet per second
in the water main being flushed. No flushing device shall be directly
connected to any sewer.
e.
Valves
Sufficient valves shall be provided on water mains so that inconvenience
and sanitary hazards will be minimized during repairs. Valves shall be
located at not more than 300 foot intervals in commercial, industrial and
high density residential areas and at not more than 500 foot intervals in all
other areas. Appropriate valves shall also be provided at all areas where
water mains intersect to ensure effective isolation of water lines for repair,
maintenance or future extension.
f.
Separation of Water Mains and Sewers
Refer to the horizontal and vertical separations and to the FDEP Rules and
Regulations. The more stringent requirements shall apply. No water pipe
shall pass through or come in contact with any part of a sanitary sewer
manhole.
Extreme caution should be exercised when locating water mains at or near
certain sites such as sewage treatment plants or industrial complexes.
Individual septic tanks must be located and avoided.
g.
Surface Water Crossings
City of Umatilla Standard Specs
Water & Sewer Utilities
2-15
January 2013
The City shall be consulted before final Drawings are prepared.
Requirements outlined in Sections 3.2.D.3.f and 3.2.D.3.g shall apply. All
above ground pipe shall be painted as specified in Appendix C for water
mains.
h.
Air Relief Valves
At high points in water mains where air can accumulate, provisions shall
be made to remove the air by means of hydrants or automatic air relief
valves. Automatic air relief valves shall not be used in situations where
flooding of the manhole or chamber may occur. See Standard Drawings
i.
Chamber Drainage
Chambers, pits or manholes containing valves, blow-offs, meters, or other
such appurtenances to a distribution system shall not be connected directly
to any storm drain or sanitary sewer, nor shall blow-offs or air relief
valves be connected directly to any sewer.
j.
Disinfection Following Repair or Replacement
Any part of the City water system which has direct contact with finished
water and has been out of service for repair, alteration, or replacement
shall be disinfected as outlined in Appendix C.2.f. of this Manual.
4.
Water Services and Connections
Water services and connections shall conform to the applicable provisions of
the Appendices and the Standard Drawings. Only 1", 1-1/2", 2", 4", 6", 8" and
12" services will be permitted. Where water services greater than 12" are
required, dual services shall be provided. Water services and connections to
existing City systems up to 4" are available from the City after payment of
applicable fees and charges. Services and connections to new water systems
and to existing systems, sizes 6" and larger shall be made by the Contractor.
5.
Water Metering
City of Umatilla Standard Specs
Water & Sewer Utilities
2-16
January 2013
a.
General
All water service connections shall be metered. In general, the method of
metering will follow the guidelines listed below. However, the
Developer's Engineer must obtain approval before finalizing the design of
the metering system. Meters for irrigation or reuse must be provided.
b.
Single Family, Duplex, and Multi-Family Subdivisions with Public Rights
of Way
Each unit shall be individually metered. Single and double services shall
be installed at property lines as indicated by the Standard Drawings.
c.
Single Family and Duplex Subdivisions with Private Streets
Individual meters may be permitted in accordance with Sub-Section
2.2.C.5.b above, if the private streets are designed to City Standards and
easements are dedicated over the entire private street common areas. In
addition, sufficient area must be available outside of paved areas to locate
water mains, services, and meters.
d.
Commercial, Industrial, and Institutional Projects Without Private Fire
Lines
In general, each building shall be individually metered. Meter(s) shall be
located in the public rights of way at the property line.
City of Umatilla Standard Specs
Water & Sewer Utilities
2-17
January 2013
e.
Commercial, Industrial, Institutional, Multi-Family with Private Streets,
Apartments, and Condominium Projects with Private Fire Lines
In general all such projects shall require installation of a fire line master
meter or dual system. Dual systems shall require installation of a detector
check valve or double detector check valve as determined by the City
Engineer. Individual meters to each unit must be provided subject to the
Developer executing a Meter Installation and Easement Agreement.
f.
Shopping Centers
In general, shopping centers shall require installation of a fire line master
meter or a detector check valve. Individual meters to each unit may be
considered on a case-by-case basis subject to the Developer executing a
Meter Installation and Easement Agreement.
g.
Meter Installation
All meters in a City maintained system will be installed and inspected by
the City after payment of applicable fees and charges. All meters less than
2" in size will be installed underground in an approved meter box. Meters
2" and larger may be installed above ground. In general, meters larger
than 4" shall be located in a meter easement located adjacent to the public
right of way.
h.
Meter Sizing
Size of all meters shall be determined by the City Engineer and the City
Public Works Department. The Developer's Engineer shall provide
sufficient information on estimated peak flows and low flows so that
meter size can be determined. The Developer's Engineer shall include
head losses through metering device when designing the water system.
Refer to Head Loss Tables in manufacturer's literature.
City of Umatilla Standard Specs
Water & Sewer Utilities
2-18
January 2013
i.
Meter Type
All meters shall be radio-read meters. All meters shall be compatible with
all Neptune meter reading equipment and billing software.
6.
Material, Installation and Testing
Applicable provisions of the City Land Development Regulations shall apply.
7.
Location and Identification
A means for locating and identifying all water mains and valves shall be
provided in accordance with Details
8.
Cross Connection Control
a.
General
In order to protect the public water supply system from contamination due
to cross-connections, the Developer shall install City approved backflow
prevention devices where there is the potential of a non potable substance
coming into contact with or connected to the public water system. Some
of the common instances requiring installation of cross connection control
devices are listed below. However, the Developer's Engineer must obtain
City approval before finalizing the design of a Cross Connection Control
Device.
b.
Commercial, Industrial, and Multi-Family Residential
All commercial and industrial projects shall, as a minimum, require
installation of city approved double check valve type backflow prevention
device. Projects with a higher degree of hazard may be required to install
an approved reduced pressure principle device or other approved device.
City of Umatilla Standard Specs
Water & Sewer Utilities
2-19
January 2013
All projects with fire sprinkler and standpipe systems, and projects with
extensive on-site water systems shall be required, as a minimum, to install
an approved double check valve type backflow assembly.
c.
Irrigation Systems
The appropriate type of back flow preventer device shall be determined by
the city on a case by case basis. A backflow prevention device of the
correct type shall be utilized on all potable water lines supplying irrigation
systems.
City of Umatilla Standard Specs
Water & Sewer Utilities
2-20
January 2013
SECTION 3
SANITARY SEWAGE FACILITIES DESIGN
3.1
3.2
GENERAL
PLAN REVIEW, APPROVAL, CONSTRUCTION AND ACCEPTANCE OF
WASTEWATER IMPROVEMENTS
A.
General Requirement
1.
City Utility Service Area
a.
Availability
b. Exemptions
2.
Rural Land Area
3.
Construction Plans Submittal
4.
Requirements For Submittal
5.
Requirements for Submittal of As-Built Drawings:
B.
Definitions
C.
Design of Gravity Sewers
1.
General Considerations
a.
Type of Sewers
b. Design Period
c.
Location
2.
Design Basis
a.
Average Daily Flow
b. Peak Design Flow
c.
Design Calculations
3.
Details of Design and Construction
a.
Minimum Size
b. Minimum Cover
c.
Slope
d.
Size and Alignments
e.
Additional Requirements
4.
Manholes
i
January 2013
5.
6.
7.
D.
a.
Location
b. Type
c.
Diameter
d. Flow Channel
e.
Materials
f.
Castings
g. Inflow Prevention Lids
Service Connections
a.
General
b. Size and Length
c.
Slope
d. Connection
Grease Traps
a.
General
b. Sizing Procedures
c.
Fast Food Restaurants
d. General Restaurants
e.
24-Hour Restaurants
f.
Convention Center/Manufacturing Cafeterias
g. Miscellaneous Food Preparation/Service Establishments
Materials, Installation and Testing
Design of Wastewater Force Mains
1.
General Considerations
a.
Design Period
b. Location
2
Design Basis
a.
Average Daily Flow
b. Peak Design Flow
c.
Design Calculations
3.
Details of Design and Construction
a.
Velocity and Diameter
b. Design Friction Losses
c.
Design Pressure and Restraint
d. Termination
e.
Air Release and Vacuum Relief Valves
ii
January 2013
f.
4.
5.
6.
E.
Aerial Crossings
i.
Structural support
ii. Expansion Protection
iii. Flood Clearance
iv. Pipe Material and Joints
v.
Valves
vi. Guards
vii. Permits and Requirements of Other Agencies
g. Underwater Crossings
i.
Pipe Material and Cover
ii. Valves
iii
Permits
h.
Valves
Material, Installation and Testing
Location and Identification
Additional Requirements
Wastewater Pump Stations
1.
General Considerations
2.
Design Basis
a.
Design Flows
b.
Number of Pumps
c.
Pump and Motor Selection
d. Design Calculations
3.
Details of Design and Construction
a.
Flooding
b. Accessibility
c.
Buoyancy
d. Pump Requirements
e.
Wet Well Requirements
f.
Pump Station Water System
g. Electrical equipment, Power Supply and Power Cords
h.
Controls
i.
Site Sizing and Easement Requirements
j.
Site Fencing
4.
Flow Meters
iii
January 2013
5.
Emergency Operation
iv
January 2013
SECTION 3
SANITARY SEWAGE FACILITIES DESIGN
3.1
GENERAL
This section includes the general requirements for the design of a sanitary sewage facility.
3.2
PLAN REVIEW, APPROVAL, CONSTRUCTION AND ACCEPTANCE OF
WASTEWATER IMPROVEMENTS
For information regarding submittal of construction plans for a sanitary sewer system, refer to
Section 2.2. For information regarding requirements for the submittal of As-Built Record
Drawings, refer to Section 2.2.C.8. Definitions applicable to this section can be found in the
City of Umatilla Land Development Regulations.
A.
General Requirement
1.
City Utility Service Area
a.
Availability
Where available, the owner of every lot or parcel of land within the city
utility service area developed for residential, public, commercial office,
industrial, warehousing or multifamily use shall connect the premises or
cause the premises to be connected with the City sewer and reclaimed
water distribution system.
If an existing sewage treatment facility is not available and all lots are
greater than one (1) acre in size, the proposed development shall either
design and construct a central sewage system or construct individual septic
tank systems subject to the rules and regulations of the State of Florida,
Department of Health and Rehabilitative Services.
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-1
January 2013
b.
2.
Exemptions
(1)
Any domestic wastewater facility having a design capacity of 2,000
gallons, average daily flow or less, which serves the complete
wastewater treatment and disposal needs of a single establishment or
development.
(2)
Septic tanks drain field systems and other on-site commercial
sewage systems with sub-surface disposal of a design capacity of
less than 5,000 gallons average daily flow, which serves the
complete wastewater disposal needs of a single establishment. This
exception does not include restaurant facilities with greater than
3,000 gallons average daily flow, industrial facilities, or commercial
laundry facilities.
Rural Land Area
a.
When an existing sewage treatment facility with excess capacity is not
located within one quarter (1/4) mile, the proposed development shall
design and construct a central sewage system. The lines will remain dry
until city sewer is available. Individual septic tank systems may be
provided subject to the rules and regulations of the State of Florida,
Department of Health and Rehabilitative Services. Once sewer is provided
the septic tanks shall be pumped, collapsed and backfilled. A sewer stub
out with a utility easement shall be in place for the tie-in. After review of
drawings by the city engineer it is deemed that a wastewater pump will be
required for the development, then land for the station will be provided by
the owner and deeded to the city.
3.
Construction Plan Submittal
All construction drawings for sanitary sewer systems including sewage
treatment plants shall require approval of the City Engineer and the City Utility
Department.
4.
Requirements for Submittal
Requirements for submittal of construction drawings for sanitary sewer systems:
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-2
January 2013
5.
a.
Drawings shall meet same scale and size requirements as Improvement
Plans and shall be integrated into Improvement Plans when applicable.
b.
Permits for construction of sewer facilities shall be obtained by the
developer from City, County, and from Florida Department of
Environmental Regulation, prior to commencing construction.
c.
Drawings for sewer facilities shall be prepared by a Florida registered
professional engineer and submitted to the City Engineer. Submit the same
number of copies of plans as required for Improvement Plans.
d.
Testing shall be certified and conform to the City specifications.
Requirements for Submittal of As-Built Drawings:
As-built Reproducible Original plan and profile views of the sewer system shall
be prepared by the engineer of record at the completion of each phase of the
project and submitted to the City.
The plan view shall clearly indicate manhole number, size and material of pipe
and location of materials relative to manholes. Location of proposed or existing
force main shall also be indicated on plan view. Profile views shall indicate
manhole number, rim and invert elevations (if more than one, invert label
North, South, etc.) and distance between manholes on center.
B.
Definitions
Design Flow - The flow of water in a pipe when either half full or full and expressed
in gallons per minute, gallons per day, or cubic feet per second.
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-3
January 2013
C.
Design of Gravity Sewers
1.
General Considerations
a.
Type of Sewers
The City will approve drawings for new sewer systems and/or new sewer
extensions only when designed as a separate sanitary system in which
precipitation, runoff and groundwater are excluded.
b.
Design Period
Sewer systems should be designed for a 30 year life span, and for the
estimated ultimate tributary population, as delineated in the approved City
Wastewater Master Plan (latest edition) except in considering parts of the
systems that can be readily increased in capacity.
c.
Location
Gravity sewers shall be located in dedicated rights-of-way or utility
easements. Whenever possible, sewers shall be located under pavement in
dedicated rights-of-way.
All sewers located outside of dedicated
rights-of-way shall require a minimum 20' easement. Where the proposed
sewer exceeds 8 feet in depth, additional easement may be required. If a
gravity sewer is located adjacent to a road right-of-way, a minimum 10'
easement (or more depending on sewer depth) shall be provided.
Additional easement widths shall be provided if the pipe size or depth of
cover so dictate. All easements are subject to the approval and acceptance
by the City. Gravity sewers shall not be placed under retention ponds,
retention pond berms, tennis courts, or any vertical structures. Gravity
sewers shall not be located along side or rear lot lines.
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-4
January 2013
2.
Design Basis
a.
Average Daily Flow
The gravity sewer design shall be based on full ultimate development as
known, or projected. Average daily wastewater flow shall be calculated
by the ERC method as outlined in City Land Development Regulations.
The regulations are subject to revision by amendment to this Manual.
b.
Peak Design Flow
Gravity sewers shall be designed on the basis of ultimate development
maximum rates of flow, which shall be the product of selected peak
factors times the accumulative average daily flow as calculated above. In
general, the following minimum peak factors shall be applicable for the
range of average daily flow rates.
Flow Range
Peak Factor
Flows to 100,000 GPD
100,000 GPD to 250,000 GPD
250,000 GPD to 1,000,000 GPD
Flows greater than 1,000,000 GPD
4.0
3.5
3.0
2.5
For design, average daily flows above 2,000,000 GPD, peaking factors
less than 2.5 may be considered if substantiated by extensive data. Under
no circumstances shall peaking factors less than 2.0 be allowed.
c.
Design Calculations
Developer's Engineer shall submit signed, sealed and dated design
calculations with the Drawings for all sewer projects. Calculations shall
show that sewers will have sufficient hydraulic capacity to transport all
design flows. Gravity sewers shall be designed to flow ½ full @ peak
flow.
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-5
January 2013
3.
Details of Design and Construction
a.
Minimum Size
No gravity sewer main conveying wastewater shall be less than 8" in
diameter.
b.
Minimum Cover
The minimum cover over gravity sewers shall be no less than 3' calculated
from the finished grade. Exceptions to this requirement may be made for
a short length of pipe where structural considerations are incorporated in
the design.
c.
Slope
All sewers shall be designed and constructed to give minimum velocities,
when flowing full, of not less than 2.0 feet per second, based on
Manning's formula using an "n" value of 0.013. The following minimum
slopes shall be provided; however, slopes greater than these are desirable:
Minimum Slope
in feet per 100'
0.40
0.28
0.22
0.17
0.15
0.14
0.12
0.11
0.10
0.08
Sewer Size
8"
10"
12"
14"
15"
16"
18"
20"
21"
24"
and larger
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-6
January 2013
Note: Based upon Mannings Formula using an "n" value of 0.013.
Under special conditions, if detailed justifiable reasons are given, slopes
slightly less than those required for the 2.0 feet per second velocity when
flowing full may be permitted. Such decreased slopes will only be
considered where the depth of flow will be 0.3 of the diameter or greater
for design average flow. Whenever such decreased slopes are selected,
the Developer's Engineer must furnish his computations of the depths of
flow in such pipes at minimum, average, and peak rates of flow.
Where design velocities greater than 10 feet per second (only for peak
instantaneous flows) are attained, due to topography or other reasons,
special provisions shall be provided for sewer protection. Refer to
Subsection 3.2.C.2.a and b above.
Sewers shall be laid with uniform slope between manholes.
d.
Size and Alignments
Size conversion between manholes shall not be allowed. All sewers shall
be laid with straight alignments between manholes.
e.
Additional Requirements
Main pool drains and back wash systems, spas, and storm drain systems
shall not connect to any gravity sanitary sewer system.
In general, all sewer extensions for future connections shall terminate at a
manhole. The City may allow such extensions without a terminal manhole
on a case by case basis subject to all of the following conditions:
(1)
Total sewer extension length shall be limited to 50'.
(2)
Sewer extension location at the initiating manhole shall be plugged
to the satisfaction of the City.
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-7
January 2013
4.
(3)
Such sewer extensions shall not be a part of the accepted sewer
facilities. This shall be clearly delineated on the Drawings.
(4)
All such sewer extensions shall be inspected and accepted as part of
the future construction phase.
Manholes
a.
Location
Manholes shall be installed at the end of each gravity sewer; at all changes
in grade, size or alignment; at all sewer intersections; and at distances not
greater than 400'.
b.
Type
An outside drop pipe shall be provided for a sewer entering a manhole
where its invert elevation is 24" or more above the manhole invert.
Where the difference in elevation between the incoming sewer invert and
the manhole invert is less than 24" the manhole invert shall be filleted to
prevent solids deposition.
c.
Diameter
For sewers 24" in diameter and smaller, the minimum inside diameter of
manholes shall be 48". For sewers between 24" and 36", the minimum
inside diameter shall be 60". For sewers larger than 36" in diameter, a 72"
inside diameter manhole shall be provided.
A minimum access cover diameter of 22" shall be provided.
d.
Flow Channel
The flow channel through manholes shall be made to conform in shape
and slope to that of the sewers. Flow direction changes in excess of 90º
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-8
January 2013
shall not be included in sewer alignments without special consideration.
When directional changes exceeding 45º degrees occur, an additional flow
line elevation drop of 0.1' across manholes shall be provided. Benching
shall be provided which shall have a minimum slope of 2" per foot.
e.
Materials
Manholes shall be constructed of precast units as specified in Appendix B.
Brick manholes shall not be permitted. Cast-in-place manholes may be
accepted on a case by case basis for conflict resolution.
High density polyethylene (manholes) (HDPE) shall be designed with
anti-flotation anchors when applicable and may be allowed upon the
specific written approval of the City Engineer.
Fiberglass manholes may be allowed upon the approval of the City
Engineer.
f.
Castings
Cast iron frames and covers shall be as specified in Appendix B. Bolt
down and/or gasketed covers shall be provided where manholes are
located in areas subject to ponding or flooding.
g.
Inflow Prevention Lids
Inflow prevention lids acceptable to the City shall be provided for
manholes not in the crown or center of the roadway or in areas subject to
ponding or flooding.
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-9
January 2013
5.
Service Connections
a.
General
Service connection shall be through a lateral and miscellaneous
appurtenances, all as shown on Shop Drawing Details to connect the
gravity sewer to the house or establishment being served.
b.
Size and Length
Service laterals and fittings shall be a minimum of 6" in diameter. All
service laterals shall be less than 100' in length.
c.
Slope
Service laterals shall have a minimum slope of 1%.
d.
Connection
In general, service laterals shall not be allowed to discharge into sanitary
manholes, except at terminal manholes. A case by case exception to this
requirement may be allowed if the lateral discharges at the same elevation
as the manhole invert.
6.
Grease Traps
a.
General
All Food Preparation/Service Establishments shall have outside grease
traps sized as discussed herein, although a minimum capacity shall be 750
gallons.
All wastewater flow from the kitchen areas of these
establishments must flow through approved grease traps prior to entering
the City system.
b.
Sizing Procedures
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-10
January 2013
Once the gallon per day usage for an establishment has been determined,
use that figure to determine the appropriate sized grease trap as noted
below.
Grease Trap
Capacity - Gallons
Gallons Per Day
2,600
750*
4,900
1,200
7,200
1,600
9,500
2,000**
11,800
2,400
14,100
2,800
* Minimum Size
** Above 2,000 gallons, multiple tanks in series may be used, but in all
cases, tanks shall be of same size.
c
Fast Food Restaurants
Single grease trap capacity shall be sized at the rate of 10 gallons per seat.
If two (2) grease traps are used in series, total capacity of the grease traps
shall be based on 5 gallons per seat.
d.
General Restaurants
Single grease trap capacity shall be sized at the rate of 20 gallons per seat.
If two (2) grease traps are used in series, total capacity of the grease traps
shall be based on 10 gallons per seat.
e.
24-Hour Restaurants
Single grease trap capacity shall be sized at the rate of 30 gallons per seat.
If two (2) grease traps are used in series, total capacity of the grease traps
shall be based on 15 gallons per seat
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-11
January 2013
f.
Convention Center/Manufacturing Cafeterias
Single grease trap capacity shall be sized at the rate of 3 gallons per meal.
If two (2) grease traps are used in series, total capacity of the grease traps
shall be based on 1.5 gallons per meal.
g.
Miscellaneous Food Preparation/Service Establishments
Developer's Engineer shall consult with the City Engineer personnel
before finalizing the design.
7.
Materials, Installation and Testing and Reporting
Applicable provisions of City Land Development Regulations shall apply.
D.
Design of Wastewater Force Mains
1.
General Considerations
a.
Design Period
Force main systems shall be designed for a 30 year life span and the
estimated ultimate tributary population, as delineated in the approved City
Wastewater Master Plan (latest edition) except in considering parts of the
systems that can be readily increased in capacity.
b.
Location
Force mains shall be located in dedicated rights-of-way or utility
easements. When installed in rights-of-way, force mains shall maintain a
consistent alignment with respect to the centerline of the road where
possible. All force mains located outside of dedicated rights-of-way shall
require a minimum 20' easement. If a force main is located adjacent to a
road right-of-way, a minimum 10' easement shall be provided. Additional
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-12
January 2013
easement widths shall be provided if the pipe size or depth of cover so
dictate. All easements are subject to approval and acceptance by the City.
Force mains shall not be placed under retention ponds, retention pond
berms, tennis courts, or any vertical structures. Force mains shall not be
located along side or rear lot lines.
2
Design Basis
a.
Average Daily Flow
Provisions of Section 3.2.C.2.a shall apply.
b.
Peak Design Flow
Provisions of Section 3.2.C.2.b shall apply.
c.
Design Calculations
Developer's Engineer shall submit signed, sealed and dated design
calculations with the Drawings for all force main projects. Calculations
shall show that force mains will have sufficient hydraulic capacity to
transport all design flows.
3.
Details of Design and Construction
a.
Velocity and Diameter
At design pumping rates, a cleansing velocity of at least 2.5 feet per
second should be maintained. Maximum velocity at design pumping rates
should not exceed 8 feet per second for ductile iron pipe or 5 feet per
second for PVC pipe. The minimum force main diameter shall be 4".
Only 4", 6", 8", 10", 12", 16", 20", 24", 30", 36", 42", 48", and 54",
diameter force mains shall be permitted.
b.
Design Friction Losses
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-13
January 2013
Friction losses through force mains shall be based on the Hazen and
Williams formula. In the use of Hazen and Williams formula, the value
for "C" shall be 120. "C" values greater than 130 shall not be allowed.
When initially installed, force mains may have a significantly higher "C"
factor. The higher "C" factor should be considered only in calculating
maximum power requirements and duty cycle time of the motor.
c.
Design Pressure and Restraint
The force main and fittings, including all restrained joint fittings and thrust
blocking, shall be designed to withstand pump operating pressures and
pressure surges, but not less than 100 psi.
d.
Termination
Force mains shall not terminate directly into a gravity sewer line. Force
mains should enter the gravity sewer system at a point not more than 1'
above the flow line of the receiving manhole. For instance where force
mains terminate into a manhole, then that manhole must be fiberglass
lined.
e.
Air Release and Vacuum Relief Valves
Air release valves, or air/vacuum relief valves, shall be provided, as
necessary, to prevent air locking and vacuum formation. All such valves
shall be clearly delineated on the force main profile in the drawings. The
Developer's Engineer shall submit calculations to the City justifying the
valve sizing. See additional requirements in Appendix B.
f.
Aerial Crossings
i.
Structural support
City of Umatilla Standard Specifications
Water & Sewer Utilities
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January 2013
Support shall be provided for all joints in pipes utilized for aerial
crossings. The supports shall be designed to prevent overturning and
settlement.
ii.
Expansion Protection
Expansion joints shall be provided between the aerial and buried
sections of the pipe.
iii.
Flood Clearance
For aerial stream crossings, the impact of flood waters and debris
shall be considered. The bottom of the pipe shall be placed no lower
than 1' above the 100 year flood elevation.
iv.
Pipe Material and Joints
Flanged joints shall be used. Pipe and flange material shall be
ductile iron, minimum class 53. All above ground pipe shall be
painted as specified in Appendix B.6.d. above ground wastewater
force mains. Use of epoxy coated steel pipe may be allowed on a
case by case basis.
v.
Valves
Underground plug valves shall be provided at both ends of the
crossing so that the section can be isolated for testing or repair. The
valves shall be easily accessible and not subject to flooding. An air
release/vacuum relief valve shall be installed at the high point of the
crossing.
vi.
Guards
Appropriate guards shall be installed at both ends of the crossing to
prevent public access to the pipe.
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-15
January 2013
vii. Permits and Requirements of Other Agencies
It shall be the responsibility of the Developer to obtain all applicable
regulatory permits. When the Aerial Crossing is accomplished by
attachment to a bridge or drainage structure, the Developer shall
meet all requirements of the Agencies who own or have jurisdiction
over such structures.
g.
Underwater Crossings
i.
Pipe Material and Cover
A minimum cover of 3' plus a 6" concrete slab or concrete bag
stabilization shall be provided over the pipe. The pipe material shall
meet appropriate AWWA Standards for use in submerged
conditions.
ii.
Valves
Valves shall be provided at both ends of the water crossings so that
the section can be isolated for testing or repair. The valves shall be
easily accessible, and not subject to flooding. Both valves shall be
provided in a manhole or a valve vault.
iii.
Permits
It shall be the responsibility of the Developer to obtain all applicable
regulatory permits.
h.
Valves
Sufficient plug valves shall be provided on force main systems to
facilitate effective isolation of the pipe system for repairs and
maintenance. On straight runs of force mains, valve spacing shall not
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-16
January 2013
exceed 1000'. Additional valves shall be provided where force mains
intersect or to facilitate isolation of pipe segments.
4.
Material, Installation and Testing
Applicable provisions of Appendix B shall apply.
5.
Location and Identification
A means for locating and identifying all force mains and valves shall be
provided in accordance with the provisions in Appendix B.6.n. and the Standard
Drawings.
6.
Additional Requirements
While designing force main systems, consideration shall be given to possible
future connecting pumping stations. If applicable, this requirement shall be
reviewed with the City prior to finalization of the design.
E.
Wastewater Pump Stations
1.
General Considerations
The design standards outlined in this section apply to wastewater pump stations
discharging 3,000 gallons per minute or less. All such pump stations shall be
submersible type stations. For designing pump stations discharging more than
3,000 gallons per minute, the type of pump station and the basis of design shall
be reviewed with the City and approval obtained before proceeding with the
design.
2.
Design Basis
a.
Design Flows
Design flows shall be based upon the total ultimate development flow
from all contributory areas to the pump station. The design average daily
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-17
January 2013
flow shall be computed as outlined in Section 3.2.C.2.a. The design
pumping capability of the station shall be based upon the Peak Design
Flow which shall be calculated by multiplying the design average flow
with the applicable minimum peaking factors as outlined below:
Minimum
Peaking Factor
for Peak Design Flow
Design Average
Daily Flow
Flows to 100,000 GPD
100,000 GPD to 250,000 GPD
250,000 GPD to 1,000,000 GPD
Flows greater than 1,000,000 GPD
4.0
3.5
3.0
2.5
For design average daily flows above 2,000,000 GPD, peaking factors less
than 2.5 may be considered if substantiated by extensive data. Under no
circumstances shall peaking factors less than 2.0 be allowed.
b.
Number of Pumps
For pump stations with a peak design flow of 1,000 GPM or less, a
minimum of two (2) pump units shall be provided. Where the peak design
flow exceeds 1,000 GPM, three (3) or more units shall be provided. See
Section 3.2.C.2.c. for standby requirements.
c.
Pump and Motor Selection
Pump station shall be capable of pumping the peak design flow with the
largest pumping unit out of service. Pumps shall be capable of meeting all
system hydraulic conditions without overloading the motors. In addition a
minimum 5 HP motor will be required. Head capacity curves shall be
prepared and submitted to the City along with the pump station drawings.
Such curves shall be based upon the friction losses outlined in Section
3.2.D.3.b of this Manual. Head capacity curves shall verify that the
pumps are operating at peak or near peak efficiency and are suitable for
the design flow application. Pump and motor selection and head capacity
curves shall reflect hydraulic conditions in cases where receiving force
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-18
January 2013
main systems are interconnected to additional pumping stations. If
justifiable, smaller motor sizes will be considered by the City Engineer.
d.
Design Calculations
Developer's Engineer shall submit signed, sealed and dated design
calculations for all wastewater pump stations. Calculations shall include
head capacity curves with copies of manufacturers pump curves, hydraulic
analysis of force main system, operating cycle calculations with wet well
sizing, and buoyancy calculations.
3.
Details of Design and Construction
a.
Flooding
Wastewater pumping station structures and electrical and mechanical
equipment shall be protected from physical damage by the 100 year flood.
Wastewater pumping stations should remain fully operational and
accessible during the 100 year flood. Regulations of Local, State and
Federal agencies regarding flood plain obstructions shall be considered.
b.
Accessibility
The pumping station shall be readily accessible by, maintenance vehicles
during all weather conditions. The access road to the pumping station
shall be paved. The facility shall not be located in road rights-of-way. In
a phased development, a stabilized access road may be accepted during the
initial phase with paving to be accomplished in the later phase.
c.
Buoyancy
Buoyancy of the pump station structures shall be considered and adequate
provisions shall be made for protection.
d.
Pump Requirements
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-19
January 2013
Submersible wastewater pumps shall comply with the requirements
spelled out in Appendix B.7.e.
Only approved pumps listed in
Appendix B shall be allowed. Submersible pumps and motors shall be
designed specifically for raw sewage use, including totally submerged
operation during a portion of each pumping cycle. Submersible pumps
shall be readily removable and replaceable without dewatering the wet
well or disconnecting any piping in the wet well.
Pumps shall be capable of handling raw sewage and passing spheres of at
least 3" in diameter. Pump suction and discharge openings shall be at
least 4" in diameter.
e.
Wet Well Requirements
Wet well shall be minimum 6' diameter and shall have a minimum 4.5'
depth below the lowest invert. Additional depth shall be provided based
on station design and cycle time.
Pumping levels shall be set to provide a minimum capacity between
operational water levels sufficient to allow a minimum of five (5) minutes
between successive starts of the pumps.
Pump-off water levels shall provide adequate submergence to preclude
pump inlet vortexing, or air binding. Operational maximum water levels
shall not exceed the invert elevation of the influent pipe.
The wet well floor shall have a minimum slope of 1 to 1 to the hopper
bottom. The horizontal area of the hopper bottom shall be no greater than
necessary for proper installation and function of the pump inlet.
The wet well shall be coated or lined as specified by the City.
No interior ladders shall be permitted in the wet well.
f.
Pump Station Water System
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-20
January 2013
All wastewater pump stations shall be provided with a water system with
adequate capacity and pressure for station wash down and other
requirements. The station water system shall be completely separated
from the potable water supply by means of a reduced pressure type
backflow preventer or other City approved system.
g.
Electrical equipment, Power Supply and Power Cords
Requirements in Appendix B.7.f. shall apply.
h.
Controls
Requirements in Appendix B.7.f. shall apply.
i.
Site Sizing and Easement Requirements
Pump station sites shall be sized as delineated on the "Pump Station Site
Plan" in the Standard Drawings. The Developer shall dedicate pump
station site by warranty deed or plat to the City. Dedicated easements
shall also be required around the site as delineated on the "Pump Station
Site Plan" in the standard drawings. In general, the site for the paved
access road shall also be dedicated to the City by Warranty deed or plat.
An exception to this requirement may be allowed on a case by case basis
in the form of an ingress/egress easement for the access road.
j.
Site Fencing
Fencing at the pump station site perimeter shall comply with the technical
criteria established in Appendix B.7.q. In general, all pump station sites
shall be fenced. However, exception to this requirement may be made for
pump stations serving residential areas only, on a case by case basis as
approved by the City and subject to adequate landscape screening. Refer
to the City Land Development Regulations.
4.
Flow Meters
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-21
January 2013
Indicating, totalizing and recording flow measurement shall be provided at
pumping stations designed to handle peak flows of 1,000 GPM or more.
Applicable provisions of Appendix B shall apply.
Bypass piping around the meter shall be provided for all stations with flow
meters to facilitate meter maintenance.
5.
Emergency Operation
All pump stations shall be provided with a riser, with appropriate coupling
device and valving, to the discharge pipe in order to connect portable pumps
and appurtances. In addition, stand-by emergency generators shall be provided
at all wastewater pumping stations in the sewer system. Such stand-by
generator facilities shall comply with the requirements spelled out in Appendix
B.7.f. All such generators shall be rated and designed to operate the pump
station under design conditions.
City of Umatilla Standard Specifications
Water & Sewer Utilities
3-22
January 2013
SECTION 4
WELLFIELDS AND WATER SUPPLY
4.1
GENERAL
A. Protection of Water Resources
4.2
SURFACE WATER INTAKE FACILITIES DESIGN
A. Required Reference:
B. Additional Design Standards:
4.3
WATER WELLS AND WELLFIELDS
A. General
1. Scope
a.
Purpose of Section.:
b.
Not A Specification:
2. Definitions
3. Developer Submittals
4. Permits
a.
Responsibilities
b.
Governmental Requirements:
5. Protection of Groundwater Resources
B. Investigation of Geologic/Hydrologic Conditions and Groundwater Quality
1. The Standard Conditions
a.
Well Efficiencies:
b.
Test Boreholes:
c.
Drawdown Test:
d.
Drawdown Test Data:
2. Formation Sampling
a.
Formation Samples:
b.
Additional Samples:
c.
Sample Preservation:
d.
Storage:
e.
Delivery:
3. Geophysical Logging
4. Water Sampling and Analyses When Designated
City of Umatilla Standard Specifications
Water & Sewer Utilities
Section 4
January 2013
5.
6.
4.4
a.
Water Sampling.
b.
Analyses.
Reports
a.
Driller's Log.
b.
Rate of Penetration
c.
Stratigraphic Log
Identification of Principal Aquifers
a.
Identification
b.
Differentiation:
WATER WELL DESIGN STANDARDS
A. Well Casings
1. General
a.
Permanent Casing:
b.
Types of Well Cased:
2. Casing Diameter
3.
Casing Wall Thickness
a.
Minimum Thickness:
b.
Plastic Casings:
4. Casing Material
a.
Manufacturing Standards for Single-Ply Carbon-Steel Well Casing
b.
Manufacturing Standards for Alternative Single-Ply Well-Casing
Materials
c.
Two-Ply Steel Casing Material Properties
1. Chemical Composition, Present:
2. Physical Properties:
5. Joints
6. Drive Shoes
7. Well-Casing Installation
8. Seating or Sealing of Well Casing
9. Completion of Well Site
a.
Temporary Capping:
b.
Height of Casing Above Ground:
c.
Equipment Placement:
d.
Site Grading:
B. Well Screens
1. General
2. Screen Diameter
3. Screen Length
a.
Length:
b.
Other Design Factors:
City of Umatilla Standard Specifications
Water & Sewer Utilities
Section 4
January 2013
4.
5.
6.
7.
Screen-Aperture Size
a.
Naturally Developed Wells
b.
Gravel-Packed Wells.
c.
Total Aperture Area
Material
Screen Strength
Screen Construction
a.
Punched- or Louvered-Pipe Screens
b.
Wire-Wound, Continuous-Slot Screens
8.
C.
Screen Joints and Spacers
a.
Joints:
b.
Spacers:
c.
Joining Screens To Casings:
d.
Screen Casing Seals:
e.
Continuous Casing And Screen:
9. Sealing Bottom of Screen
a.
Threaded Or Welded Plate:
b.
Self-Closing Valve:
Gravel Pack
1. General
2. Gravel-Pack Thickness and Location
a.
Gravel-Pack Thickness.
b.
Gravel-Pack Location
3. Material and Impurities
a.
Specific Gravity:
b.
Minimum Specific Gravity:
c.
Non-round Pieces:
d.
Acid Solubles:
e.
Washed Material:
f.
Iron And Manganese:
4. Gradation
a.
Gravel-Pack Gradation:
b.
Gravel-Pack To Formation-Sand Ratio:
c.
Uniformity Coefficient:
City of Umatilla Standard Specifications
Water & Sewer Utilities
Section 4
January 2013
D.
E.
F.
d.
Distribution Curve:
5. Gravel-Pack Samples
a.
Labeling Of Samples:
b.
Method Of Sampling:
6. Delivery and Storage
7. Method of Installation
a.
Placement:
b.
Drilling Fluid:
c.
Unusual Drilling Conditions:
8. Disinfection
Grouting and Sealing
1. General
2. Sealing Requirements
a.
Surface Of Sanitary Seal
b.
Sealing Of Uncompleted Bore Hole
c.
Sealing Of Select Zones
d.
Sealing Of Production Casing
3. Materials
a.
Neat-Cement Grout:
b.
Pozmix-Cement Grout:
c.
Portland Cement-Concrete Grout:
d.
Sand-Cement Grout:
4. Methods of Placement
Plumbness and Alignment
1. General
2. Tolerances
a.
Plumbness:
b.
Alignment:
3. Depth of Applied Tolerances
Well Development
1. General
2. Development Test
a.
Test Pump Capacity:
b.
Discharge Piping:
c.
Completing Development:
City of Umatilla Standard Specifications
Water & Sewer Utilities
Section 4
January 2013
3.
G.
H.
I.
J.
Measurement of Operating Parameters During Development
a.
Discharge Rate:
b.
Water Elevations:
c.
Measurement Of Sand Content:
4. Development Records
a.
Quantity Of Gravel:
b.
Data To Record:
Performance Testing
1. General
2. Testing Methods
a.
Step-Drawdown Test:
b.
Constant-Rate Tests:
3. Water-Level Measurements:
4. Pumping-Test Interruption:
5. Records and Reports:
Well Disinfection
1. General
2. Disinfectant
3. Disinfection Procedure
a.
Overdosing Requirement:
b.
Contractor's Responsibility:
4. Disinfection of Gravel Pack Wells
a.
Single Aquifer:
b.
Multi-Aquifer :
Water Quality Testing
1. General Considerations
2. Sampling Procedures
a.
Field Tests:
b.
Samples For Local-Regulation Test:
c.
Analytical Procedures:
Abandonment of Test Holes, Partially Completed Wells, and Completed Wells
1. General
a.
Need For Sealing Of Wells:
b.
Restoration Of Geological Conditions:
2. Sealing Requirements
City of Umatilla Standard Specifications
Water & Sewer Utilities
Section 4
January 2013
a.
b.
c.
3.
Liner-Pipe Removal:
Exception To Removing Liner Pipe:
Sealing Materials And Placement:
Records of Abandonment Procedures
a.
Depths Sealed:
b.
Quantity Of Sealing Material:
c.
Changes Recorded:
City of Umatilla Standard Specifications
Water & Sewer Utilities
Section 4
January 2013
SECTION 4
WELLFIELDS AND WATER SUPPLY
4.1
GENERAL
This section covers the withdrawal of surface waters or groundwater for potable water treatment
and provides for minimum requirements for design and construction of surface water intake
structures or groundwater wells. It is designed to meet the needs for sub-regional or regional
water supply facilities.
A. Protection of Water Resources
1.
4.2
The contractor shall take all precautions necessary, or other actions as may be
required, to permanently prevent contaminated water or water having
undesirable physical or chemical characteristics from entering the water body
from which the structure is to draw its supply. The contractor shall also take all
necessary precautions during the construction period to prevent contaminated
water, gasoline, or any other contaminant from entering the water body, either
through the opening or by seepage through the ground surface.
SURFACE WATER INTAKE FACILITIES DESIGN
A. Required Reference: Facilities shall comply with the design and installation
requirements as established by the Florida Department of Environmental Protection.
The criteria set forth in the "Ten State Standards - Recommended Standards for Water
Works" should be used as a design guide for the intake structures.
B. Additional design Standards: Additional design standards and standard requirements
stated in this Manual shall also apply.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4-1
January 2013
4.3
WATER WELLS AND WELLFIELDS
A. General
1.
Scope
The scope of this section covers public water supply well diameters ranging
from 8" through 30" (203 mm through 762 mm).
2.
a.
Purpose of section. This section provides minimum requirements for the
construction of a potable water supply well and simplifies the writing of
specifications by permitting direct reference to specific sections, tables,
figures, or appendices.
b.
Not a specification. It is not the purpose of this section to serve as a
specification nor is it written in such a manner that a set of well
specifications can be properly developed by stating that the well should
conform to AWWA Standard A100-84 without using additional
specification criteria.
Definitions
The following definitions apply to this section:
i.
Abandoned well: A well whose purpose and use have been
permanently discontinued or a well that is in such a state of
disrepair that its purpose cannot be reasonably achieved.
ii.
Absorption: The penetration of molecules or ions of one
substance into the interior of a solid or liquid.
iii.
Acidizing: The process of introducing acid into a well or
surrounding geological formations.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4-2
January 2013
iv.
Adsorption:
Attachment of gases, liquids, or dissolved
substances on the surface of solids.
v.
Air line: A small-diameters pipe installed in the well and
charged with air for the purpose of measuring the water level.
vi.
Alignment: The variation of the well centerline from true
straightness.
vii.
Anion: A negatively charged ion or radical.
viii.
Annular space: The space between the inner well casing and the
outer well casing or bore hole.
ix.
Apparent specific gravity: The ratio of the weight of a given
volume of material to an equal volume of water under standard
conditions.
x.
Aquitard: A body of earth material of low permeability that can
absorb water but cannot transmit it at a rate sufficient for
economic extraction by wells. (An aquiclude is defined as a
formation that will not transmit any water. An aquiclude is never
found in nature).
xi.
Aquifer: A geologic formation, group of formations, or part of a
formation that contains water in its void or pores that may be
removed economically and used as a source of water supply.
Unconsolidated alluvial deposits of sand and gravel and
consolidated sandstone are examples of water-bearing strata.
xii.
Artesian well: A well in an aquifer where the groundwater is
confined under pressure and the water level stands above the top
of the confined aquifer it tops.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4-3
January 2013
xiii.
Bailer: A long, narrow bucket made of pipe with a valve in the
bottom used to remove cuttings from the hole.
xiv.
Bailer (flat bottom): A type of bailer (or sampler) that is fitted
with a flat bottom check valve for removing earth materials from
the bottom of the hole.
xv.
Bentonite: A highly plastic, highly absorptive, colloidal clay
composed largely of the mineral montmorillonite.
xvi.
Cake thickness: The thickness of filter cake deposited against
porous media by the drilling fluid.
xvii.
Capillarity: The action by which the surface of a liquid, where it
contacts a solid, is elevated or depressed because of the relative
attraction of the molecules of the liquid for each other and for
those of the solid.
xviii.
Capillary fringe: The zone immediately above the water table in
which water is held by capillarity.
xix.
Casing: A tubular retaining structure that is installed in the hole
to maintain the well opening (for example, steel, PVC,
fiberglass).
xx.
Centralizer: A tool used to center the casing in the hole.
xxi.
Coefficient of viscosity: The force required to maintain a unit
difference in velocity between two layers of water a unit distance
apart.
xxii.
Cone of depression (confined aquifers): The depression, roughly
conical in shape, produced in the pressure surface (piezometric
surface) by a well, or wells, pumping in a confined aquifer.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4-4
January 2013
xxiii.
Cone of depression (water table or phreatic aquifers): The
depression, roughly conical in shape, produced in the water level
by a well, or wells, pumping in an unconfined aquifer.
xxiv.
Confined groundwater: Groundwater under pressure greater than
atmospheric pressure.
xxv.
Consolidated formation: Strata of sedimentary, igneous, or
metamorphic type rock, which can be porous and permeable to
provide an aquifer.
xxvi.
Deep well: The term deep has no real significance relative to the
actual depth of a well. Such use is eliminated from technical and
legal applications in factor or specific depths.
xxvii.
Dogleg: Used to describe abrupt deflection in the straightness of
the well within a short distance.
xxiii.
Drawdown: The difference in elevation between the static water
elevation the water elevation under pumped conditions.
xxix.
Drilling fluid: A medium, typically composed of a mixture of
bentonite clay and water, used to hydraulically remove the drill
cuttings from the hole as drilling takes place.
xxx.
Drive shoe: A special steel collar, with a cutting edge, fastened
onto the bottom of the casing to protect the lower edge of the
casing as it is driven.
xxxi.
Effective size: The sieve-size opening that will pass 10 percent
of a representative sample of the filter material; for example, if
the size distribution of the particles is such that 10 percent of a
sample is finer than 0.45 mm, the filter material has an effective
size of 0.45 mm.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4-5
January 2013
xxxii.
Electrolyte: A chemical that dissociates into positive and
negative ions when dissolved in water, increasing the electrical
conductivity of the water.
xxxiii.
Filtration properties: Ability of the drilling fluid to form a
controlled filter cake on the side of the hole under static
conditions.
xxxiv.
Gravel-packed well: A well in which gravel filter material is
placed in the annular space of the well (also known as filter
pack).
xxxv.
Groundwater: Water that occupies all the voids within a
geologic stratum. Commonly referred to as the zone of
saturation.
xxxvi. Groundwater divide: A line on a potentiometric surface on each
side of which the groundwater flow is downward in a direction
away from the line.
xxxvii. Grout: A fluid mixture of Portland cement and water (neat
cement) of a consistency that can be forced through a pipe and
placed as required. Various additives, such as sand, bentonite,
and hydrated lime, are included in the mixture to meet certain
requirements.
xxxviii. Heterogeneous: Pertaining to a substance having different
characteristics at different locations. A synonym is non-uniform.
xxxix.
Homogeneous: Pertaining to a substance having the same
characteristics at different locations. A synonym is uniform.
xl.
Hydraulic gradient: The change in static head per unit of
distance in a given direction.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4-6
January 2013
xli.
Hydrologic properties: The properties of a geologic stratum that
control the movement and storage of groundwater or surface
water.
xlii.
Laminar flow: Movement of fluid particles in essentially parallel
paths.
xliii.
Liner: A casing, screen, or other device inserted into a larger
casing, screen, or open hole as a means of sealing off undesirable
material or maintaining the structural integrity of the well.
xliv.
Packer: A device placed in a well that plugs or seals the well at a
specific point.
xlv.
Perched groundwater: Groundwater in a saturated zone that is
separated from the main body of groundwater by semipermeable
material.
xlvi.
Perforations: A series of opening in a well casing.
xlvii.
Permeability: The capacity of a porous medium for transmitting
water.
xlviii.
Plumbness: The drift, inclination, or horizontal deviation of the
well centerline from vertical.
xlix.
Potentiometric surface (Potentiometric head): The level to which
water would rise in a tightly cased well penetrating an aquifer.
The water table and artesian pressure surfaces are particular
potentiometric surfaces.
l.
Pumping level: The water level in the well when pumping is in
progress.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4-7
January 2013
li.
Recovery level: The water level in the well at a measured point
in time after the pump has been stopped.
lii.
Safe yield: The overage annual amount of groundwater that
could be extracted from a groundwater basin (or reservoir) over a
long period of time without causing a long term reduction of
groundwater quantity, quality, or other undesirable impacts.
liii.
Specific capacity: The ratio of well discharge to the drawdown
produced, measured inside the well (gpm/ft of drawdown).
liv.
Semiconfined aquifer: An aquifer that receives recharge in the
form of leakage through underlying or overlying semipermeable
formations (aquitards).
lv.
Static level: The stabilized water level in a nonpumped well.
lvi.
Storage coefficient: The volume of water that an aquifer releases
from or takes into storage per unit surface area of aquifer per unit
change in the component of head normal to that surface. In a
water table aquifer the storage coefficient is essentially the some
as its porosity.
lvii.
Telescoping: A method of fitting or placing one casing inside
another or introducing screen through a casing diameter larger
than the diameter of the screen.
lviii.
Test hole: Hole used only to obtain information on groundwater
quality and/or geologic or hydrologic conditions.
lix.
Test well: Completed well for pumping used to obtain
information on capacity, groundwater quality, geologic and
hydrologic conditions, and related information.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4-8
January 2013
lx.
Transmissivity: The rate at which water is transmitted through a
unit width of an aquifer under G unit hydraulic gradient.
lxi.
Tremie pipe: A device that carries materials to a designated
depth in the hole.
lxii.
Unconsolidated formation: Loose, soft rock-material strata of
sedimentary, igneous, or metamorphic type rock, which includes
sand, gravel, and mixtures of sand and gravel.
lxiii.
Uniformity coefficient: A ratio of the sieve-size opening that
will just pass 60 percent of a representative sample of the filter
material divided by that sieve-size opening that will just pass 10
percent of the material.
lxiv.
Water table: The upper surface of the zone of saturation in an
unconfined formation at which the pressure is atmospheric.
lxv.
Well efficiency (E): The formation loss (head loss required to
produce flow) divided by the total drawdown observed in the
well. This quotient is expressed as the percentage (from Jacob's
method).
lxvi.
Well screen: A special form of slotted or perforated well casing
that admits water from an aquifer consisting of unconsolidated
granular material while preventing the granular material from
entering the well.
lxvii.
Zone of aeration: The zone above the water table in which the
interstices are partly filled with air. The term is replaced by
unsaturated zone. It includes the capillary fringe.
lxviii.
Zone of saturation: The zone below the water table in which all
interstices are filed with groundwater.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4-9
January 2013
3.
Developer Submittals
The developer shall submit certifications and reports as required in this code.
4.
5.
Permits
a.
Responsibility: Unless otherwise specified, it shall be the responsibility of
the Developer or City to provide and sign all permits required by local,
state or federal agencies.
b.
Governmental Requirements: It shall be the responsibility of the
contractor or bidder to meet applicable governmental requirements that are
in existence on the date of the bid opening and that are designated as the
responsibility of the contractor, unless otherwise provided for in the
project specifications.
Protection of Groundwater Resources
The contractor shall take all precautions necessary, or other actions as may be
required, to permanently prevent contaminated water or water having
undesirable physical or chemical characteristics from entering, through the
opening made by the contractor in construction of the well, the stratum from
which the well is to draw its supply. The contractor shall also take all necessary
precaution during the construction period to prevent contaminated water,
gasoline, or any other contaminant from entering the well, either through the
opening or by seepage through the ground surface.
B.
Investigation of Geologic/Hydrologic Conditions and Groundwater Quality
1.
Standard Conditions: The standards set forth in this section for evaluating and
reporting the data pertinent to the investigation of geologic/hydrologic
conditions and groundwater quality can be applied to exploratory test-hole or
test-well drilling in addition to production wells.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 10
January 2013
2.
a.
Well Efficiencies: Pumped well efficiencies and transmissibility, storage
capabilities of aquifers, and groundwater quality may be determined
through data acquired from test bore holes and test wells.
b.
Test Boreholes: Test boreholes provide geo-hydrologic information on
aquifers and, may serve as observation wells.
c.
Draw down Tests: Step-draw down tests conducted in test wells serve to
facilitate the design of production wells.
d.
Draw down Test Data: The data obtained from both interference and step
draw down testing shall be used to determine the amount of water that can
be safely withdrawn from or added to aquifer storage during any given
time period.
Formation Sampling
a.
Formation Samples: Formation samples shall be taken every 10' (3.05 m)
and at each change in formation. Particular care shall be taken in
collecting samples from expected producing zones.
b.
Additional Samples: At the direction of the City, the contractor shall
obtain additional samples from water-bearing formations for laboratory
analysis. Duplicate samples shall be retained until the results of the
analysis are received.
c.
Sample Preservation: Samples shall be collected, dried, and preserved in
separate jars, bags, or other containers of at least 500-gram capacity for
each interval. Containers shall be plainly marked with well designation,
owner, location, depth interval, and date and time the sample was taken.
d.
Storage: The contractor shall be responsible for the safe storage of
formation samples until such time as they are accepted by the City.
e.
Delivery: Time, place, and mode of delivery shall be directed by the City.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 11
January 2013
3.
Geophysical Logging
Various geophysical logs are commercially available and may be required at the
discretion of the City. The geophysical bore-hole logs shall provide qualitative
and quantitative information on aquifer types and characteristics.
4.
5.
Water Sampling and Analyses When Designated
a.
Water Sampling: Water samples shall be taken for purposes of chemical
analyses from each aquifer designated as a possible source of
development.
The method used to collect the sample shall not
contaminate the aquifer.
b.
Analyses: The analyses of the water shall be done in accordance with the
requirements of all governing regulatory agencies. Temperature, pH, and
dissolved gases shall be determined by field test and recorded.
Reports
a.
Driller's Log: During drilling and completion of the well, the contractor
shall maintain a complete log, as applicable, setting forth the following
items:
i.
The reference point for all depth measurements.
ii.
The depth at which each change of formation occurs.
iii.
The depth at which the first water was encountered.
iv.
The location and thickness of each aquifer.
v.
The identification of the material of which each aquifer is composed.
vi.
The depth interval from which each water and formation sample was
taken.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 12
January 2013
vii. The depth at which the bore-hole diameter changes.
viii. The depth to the static water level (SWL) and observable changes in
SWL with well depth.
ix.
Total depth of completed well.
x.
Location limits of lost circulation zones.
xi.
The depth of the surface or sanitary seal, if applicable.
xii. The nominal hole diameter of the well bore above and below the
casing seal.
xiii. The quantity of cement installed for the seal, if applicable.
xiv. The depth and description of the well casing.
xv.
Data regarding well-screen type, size, and placement in the well
bore.
xvi. The sealing off of water-bearing strata,, if any, and the exact location
thereof.
xvii. Any and all other pertinent information required by the well
specifications.
b.
Rate of Penetration: During the drilling of the hole, a time log shall be
maintained showing rate of penetration as well as types of bits used in
each portion of the hole.
c.
Stratigraphic Log: A Stratigraphic log shall be prepared to accompany the
set of drilling samples, noting (1) depth; (2) strata thickness; (3) lithology,
including: size, range, and shape of constituent particles, as well as
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 13
January 2013
smoothness, rock type, and rate of penetration; and (4) such special notes
as might be helpful. The material shall be described according to the
USGS standard size grade scales.
6.
4.4
Identification of Principal Aquifers
a.
Identification: Principal aquifers occurring throughout the depth of a well
shall be identified using interpretation of results generated by geophysical
bore-hole, logging devices. Identification shall be made by a qualified
engineer, hydrogeologist, or well-drilling contractors.
b.
Differentiation: Differentiation of principal aquifers in a well shall be
determined on the basis of formation samples obtained.
WATER WELL DESIGN STANDARDS
A.
Well Casings
1.
General
This section sets forth standards applicable to permanent casings for water
wells. Selection of temporary casings used only for construction is left to the
contractor unless otherwise specified by the City.
a.
Permanent Casing: Permanent well casings shall be continuous and
watertight from top to bottom of the casing except for well screens.
b.
Type of Wells Cased: Permanent protective casings shall be provided for
all types of well construction.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 14
January 2013
2.
Casing Diameter
Casings shall meet the minimum diameter requirements given in Table 4-1.
TABLE 4-1
STANDARD WELL CASING/SIZES OF WELLS
Casing Diameter Required
Maximum Horizontal
Dimension on Pump Assembly
4"
5"
6"
8"
10"
12"
14"
16"
3.
Minimum Inside Diameter (ID)
of Well Casing
(101.6 mm)
(127.0 mm)
(152.4 mm)
(203.2 mm)
(254.0 mm)
(304.8 mm)
(355.6 mm)
(406.4 mm)
5"
6"
8"
10"
12"
14"
16"
18"
(127.0 mm)
(152.4 mm)
(203.2 mm)
(254.0 mm)
(304.8 mm)
(355.6 mm)
(406.4 mm)
(457.2 mm)
Casing Wall Thickness
Well-casing wall thickness shall be sufficient to withstand anticipated formation
and hydrostatic pressures imposed on the casing during its installation, well
development, and use.
a.
Minimum Thickness: The minimum wall thickness for carbon steel and
black iron pipe casing shall be in accordance with Table 4-2 for standard
casing or Table 4-3 for two-ply casing, whichever is applicable.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 15
January 2013
TABLE 4-2
MINIMUM THICKNESS FOR STEEL WELL CASING - SINGLE CASING
Depth of
Casing
ft (m)
8
(203)
10
(254)
NOMINAL CASING DIAMETER - INCHES (MM)
12
14
16
18
20
22
(305)
(356)
(406)
(457)
(508)
(559)
0-100
1/4
1/4
1/4
1/4
1/4
1/4
1/4
(0-30)
(6.35)
(6.35)
(6.35)
(6.35)
(6.35)
(6.35)
100-200
1/4
1/4
1/4
1/4
1/4
(30-60)
(6.35)
(6.35)
(6.35)
(6.35)
200-300
1/4
1/4
1/4
(60-90)
(6.35)
(6.35)
300-400
1/4
(90-120)
24
(610)
30
(762)
5/16
5/16
5/16
(6.35)
(7.94)
(7.94)
(7.94)
1/4
1/4
5/16
5/16
5/16
(6.35)
(6.35)
(6.35)
(7.94)
(7.94)
(7.94)
1/4
1/4
5/16
5/16
5/16
5/16
3/8
(6.35)
(6.35)
(6.35)
(7.94)
(7.94)
(7.94)
(7.94)
(9.52)
1/4
1/4
1/4
5/16
5/16
5/16
5/16
3/8
3/8
(6.35)
(6.35)
(6.35)
(6.35)
(7.94)
(7.94)
(7.94)
(7.94)
(9.52)
(9.52)
400-600
1/4
1/4
1/4
1/4
5/16
5/16
5/16
3/8
3/8
7/16
(120-180)
(6.35)
(6.35)
(6.35)
(6.35)
(7.94)
(7.94)
(7.94)
(9.52)
(9.52)
(11.11)
600-800
1/4
1/4
1/4
5/16
5/16
5/16
3/8
3/8
3/8
7/16
(180-240)
(6.35)
(6.35)
(6.35)
(7.94)
(7.94)
(7.94)
(9.52)
(9.52)
(9.52)
(11.11)
800-1000
1/4
1/4
1/4
5/16
5/16
5/16
3/8
7/16
7/16
1/2
(240-300)
(6.35)
(6.35)
(6.35)
(7.94)
(7.94)
(7.94)
(9.52)
(11.11)
(11.11)
(12.70)
1000-15000
1/4
5/16
5/16
5/16
3/8
3/8
3/8
7/16
*
*
(300-450)
(6.35)
(7.94)
(7.94)
(7.94)
(9.52)
(9.52)
(9.52)
(11.11)
---
---
1500-2000
1/4
5/16
5/16
5/16
3/8
3/8
7/16
7/16
*
*
(450-600)
(6.35)
(7.94)
(7.94)
(7.94)
(9.52)
(9.52)
(11.11)
(11.11)
---
---
* As specified by the purchaser
mm- Millimeter
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 16
January 2013
TABLE 4-3
MINIMUM THICKNESS FOR TWO-PLY STEEL WELL CASING*
Depth of
Casing
ft (m)
10
(254)
12
(305)
14
(356)
DIAMETER - INCHES (MM)
16
18
20
22
(406)
(457)
(508)
(559)
0-100
12
12
12
12
10
10
(0-30)
(2.66)
(2.66)
(2.66)
(2.66)
(3.42)
100-200
12
21
12
10
(30-60)
(2.66)
(2.66)
(2.66)
200-300
12
12
(60-90)
(2.66)
300-400
24
(610)
30
(762)
10
10
8
(3.42)
(3.42)
(3.42)
(4.18)
10
10
10
8
8
(3.42)
(3.42)
(3.42)
(3.42)
(4.18)
(4.18)
10
10
10
10
8
8
8
(2.66)
(3.42)
(3.42)
(3.42)
(3.42)
(4.18)
(4.18)
(4.18)
12
12
10
10
10
8
8
8
8
(90-120)
(2.66)
(2.66)
(3.42)
(3.42)
(3.42)
(4.18)
(4.18)
(4.18)
(4.18)
400-600
10
10
10
10
8
8
8
8
8
(120-180)
(3.42)
(3.42)
(3.42)
(3.42)
(4.18)
(4.18)
(4.18)
(4.18)
(4.18)
600-800
10
10
10
8
8
8
6
6
6
(180-240)
(3.42)
(3.42)
(3.42)
(4.18)
(4.18)
(4.18)
(4.94)
(4.94)
(4.94)
More than 800
10
8
8
8
8
6
6
6
6
(More than 240
(3.42)
(4.18)
(4.18)
(4.18)
(4.18)
(4.94)
(4.94)
(4.94)
(4.94)
* Values are United States Standard Steel Thickness Gauge (mm).
mm- Millimeter
b.
4.
Plastic Casings: Plastic well-casing thickness, where used, shall conform
with the requirements stated in ASTM F480.
Casing Material
All casing material shall be new and shall conform to one of the material
standards listed in Table 4-4.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 17
January 2013
TABLE 4-4
WATER-WELL CASING MATERIALS
a.
Manufacturing Standards for Single-Ply Carbon-Steel Well Casing
ANSI/AWWA C200
API Spec. 5L
ASTM A53
ASTM A139
.
b.
Manufacturing Standards for Alternative Single-Ply Well-Casing Materials:
Casing Material
Carbon Steel
High Strength, Low-Alloy Steel
Stainless Steel
Plastic
c.
Mfg. Standard
ASTM A211
ASTM A714
ASTM A409
ASTM F480
Two-Ply Steel Casing, Material Properties
1.
Chemical Composition, Present:
Carbon
Manganese
Phosphorus
Sulfur
Silicon
Copper
2.
0.20-0.30
0.85-1.30
0.05 maximum
0.05 maximum
0.12 maximum
0.20 maximum
Physical Properties:
Yield Strength, psi (MPa)
Ultimate Strength, psi (MPa)
Elongation, percent in 8 in. (200 mm)
Rockwell "B" Hardness
Elastic Ratio
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 18
55,000-70,000 (378-483)
80,000-95,000 (552-655)
17-25
80-90
69-73
January 2013
5.
Joints
Casing joints shall be of the type listed in Table 4-5.
TABLE 4-5
WELL-CASING JOINT STANDARDS
Casing Material
Steel
Plastic
Two-Ply
6.
Type of Joint
Welded or threaded
Treaded or solvent-welded
Welded
Standard
AWWA C206
ASTM F480
AWWA C206
Drive Shoes
Special, steel drive shoes shall be heat treated (Rockwell C Hardness 30-32)
SAE 1040 steel ring or equal.
7.
Well-Casing Installation
The method of installation shall be at the option of the drilling contractor,
provided the installation process does not alter the shape, size, configuration, or
strength of the casing as called for in this section.
8.
Seating or Sealing of Well Casing
Seating or sealing of well casings shall conform to FDEP regulations.
9.
Completion of Well Site
At all times during the progress of the work, the contractor shall use reasonable
precautions to prevent either tampering with the well or the entrance of foreign
material or surface water into the well.
a.
Temporary Capping: Temporary capping of well. On completion of the
well, the contractor shall install a suitable threaded, flanged, or welded cap
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 19
January 2013
or compression seal to prevent any surface pollutants from entering the
well.
B.
b.
Height of Casing Above Ground: The watertight casing of any well shall
extend not less than 24" (610 mm) above the final ground level elevation
and not less than 24" (610 mm) above the hundred year flood level of
record, whichever is higher.
c.
Equipment Placement: Any equipment that will permit direct open access
to the well shall also meet the height requirements and shall be sealed or
screened to prevent entrance of foreign matter, surface water, or
contaminants into the well.
d.
Site Grading: The ground immediately surrounding the top of the well
casing shall be sloped away from the well to prevent surface runoff from
entering the completed well.
Well Screens
1.
General
This section sets forth standards for screens to be used for water wells.
2.
Screen Diameter
The diameter of the well screen selected shall be the minimum size permitted
that will maintain an aperture (slot) entrance velocity of 0.1 -1.5 fps (0.03-0.45
m/s) or less and a vertical velocity not greater than 5 fps (1.52 m/s), as
determined in conjunction with the screen-length formula below, based on the
maximum flow in gallons per minute specified. In the event it is anticipated
that the pump setting will be into or through the screen, the minimum inside
diameter of the screen shall conform to Table 4-1. The actual design aperture
entrance velocity shall be subject to approval of state and local regulatory
agencies.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 20
January 2013
3.
Screen Length
a.
Length:. The minimum length of a well screen shall be determined by the
following formula:
L =
Q
AcVc(7.48)
Where:
L
Q
Ac
Vc
b.
= length of screen (feet)
= quantity specified (gpm)
= effective aperture area per foot of screen in square feet (The
effective aperture area shall be taken as one half the total aperture
area) (square feet/foot)
= design entrance velocity (fpm)
Other Design Factors: Other factors must be considered specifically for
each individual well installation.
i.
All available information on the character of the water-bearing
formation must be evaluated for proper well design.
ii.
When cost factors have limited the acquisition of additional aquifer
data, a more conservative design criteria for entrance velocities is
recommended.
iii.
Consideration, such as approach velocities, turbulent versus laminar
flow, and velocity distribution, both into the screen and through the
aquifer, are not automatically taken into account by the usual screen
design criteria.
iv.
Screen length for a highly efficient well is determined by thickness
and hydrogeologic character of the aquifer.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 21
January 2013
4.
Screen-Aperture Size
a.
5.
Naturally Developed Wells: In naturally developed wells, screen apertures
shall be sized in accordance with the following criteria:
i.
Where the uniformity coefficient of the formation is greater than 6,
the aperture size shall be that which retains 30%-40% of the aquifer
sample.
ii.
Where the uniformity coefficient of the formation is less than 6, the
aperture size shall be that which retains 40%-50% of the aquifer
sample.
iii.
If the water in the formation is corrosive or the accuracy of the
sample is in doubt, select a size that will retain 10% more than is
indicated in the preceding paragraphs.
iv.
Where fine sand overlies coarse sand, use the fine-sand-size aperture
for the top 2' (0.61m) of the underlying coarse sand. The coarse-size
aperture shall not be larger than twice the fine-sand size.
b.
Gravel-packed Wells: For gravel-packed wells, the screen-aperture
openings shall be of such size to retain between 85% and 100% of
gravel-pack material.
c.
Total Aperture Area: The total aperture area of the well screen shall be
that which will result in entrance velocities equal to or less than those set
forth in Section 4.4.B.2.
Material
To reduce the possibility of corrosion, the well screen and its fittings shall be
fabricated of Type 304 stainless steel unless otherwise specified.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 22
January 2013
6.
Screen Strength
Screens shall be designed to minimize the possibility of damage during
installation, development, and use. The contractor shall submit screen strength
specifications (for example, collapse and tensile strength) as well as supporting
drawings and data to the owner.
7.
Screen Construction
Unless a specific type of construction is required by the City's specifications or
is dictated by strength requirements, well screens shall be constructed by one of
the methods described below.
a.
Punched- or Louvered-Pipe Screens: Openings shall be punched in pipe in
such a way that no material is removed from the pipe wall. The spacing
and size of openings shall be uniform.
b.
Wire-Wound, Continuous-Slot Screens: Continuous-slot well screen shall
be of all-welded construction.
i.
Special shaped wire shall be helically longitudinal rods and welded
at each point of intersection.
ii.
The inlet-slot openings between adjacent turns of the outer wire shall
widen inwardly so as to be nonclogging.
iii.
Screen end fittings shall be made of the some material as the screen
body and shall be securely welded to each screen section.
iv.
Perforated-pipe base screens. Pipe conforming to the requirements
for well-casing specified in Table 4-2 shall be perforated with
uniformly spaced and size round hole openings. Telescoped over
this shall be a continuous-slot, Type 304 stainless steel screen.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 23
January 2013
8.
Screen Joints and Spacers
a.
Joints: Joints between screen sections and blank pipe spacers shall be
welded or threaded and shall be sand tight, straight, and as strong as the
screen itself.
b.
Spacers: Spacers between screen sections shall be of the some material as
that used for the casing if greater than 5' (1.52m) long. If less than 5'
(1.52m) in length they shall be made of the same material as the screen.
c.
Joining Screens to Casings: The joint between the well screen and the
casing shall be made by any one of the methods described herein and shall
be sand tight.
d.
Screen Casing Seals.:
i.
A nonmetallic seal of neoprene or rubber made to fit the casing
surrounding the screen shall be attached to the screen or screen
casing to affect the seal, and the screen or screen casing shall extend
at least 2' (0.61m) into the exterior casing.
ii.
A lead packer shall be expanded to fill the space between the screen
and the casing. This lead packer shall be manufactured for this
purpose and be attached to the screen or screen casing.
iii.
The space between the screen casing and the casing shall be filled
with neat cement to form a seal at least 1/2" (38mm) thick and 3'
(0.91m) in length.
iv.
Where the construction of the well is of the gravel-packed type and
the screen casing overlaps at least 50' (15.2m) into the casing above
and the space between the two is filled with gravel, no other seal will
be required unless specified by state or federal regulations.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 24
January 2013
e.
9.
Continuous Casing and Screen: When the screen and casing are one
continuous unit from the bottom of the well to the top of the well, joints
may be of any of the types approved for casing in Table 4-5.
Sealing Bottom of Screen
The bottom of the deepest screen or screen casing shall be sealed by any one of
the methods described below.
C.
a.
Threaded or Welded Plate: A threaded or welded plate shall be installed at
the bottom of the screen or well-casing extension. The plate shall be made
of the some material as that used for the screen or the well casing to which
the plate is attached.
b.
Self-Closing Valve: A self-closing valve shall be installed at the bottom
of the screen or casing and shall then be covered by a cement plug at least
1' (0.30m) deep.
Gravel Pack
1.
General
This section refers to those applications in water-well construction where the
gravel-pack material is installed in the annular space between the screen (and
casing) and bore hole for the purpose of stabilizing the aquifer material.
2.
Gravel-Pack Thickness and Location
a.
Gravel-Pack Thickness:
Selection of the gravel-pack thickness
surrounding the screen is dependent on individual aquifer characteristics.
i.
Minimum thickness to allow for proper placement of gravel pack
shall be 4" (102 mm).
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 25
January 2013
ii.
b.
3.
4.
The maximum grovel-pack thickness usually does not exceed 12"
(305 mm).
Gravel-Pack Location: Placement of the gravel filter shall be made in
locations adjacent to the well screens and shall extend above the screen at
least 20' (6.10m).
Material and Impurities
a.
Specific Gravity: The gravel-pack material shall have an overage specific
gravity of not less than 2.5.
b.
Minimum Specific Gravity: Not more than 1%, by weight, of the material
shall have a specific gravity of 2.25 or less.
c.
Non-round Pieces: Thin, flat, or elongated pieces, the maximum length
dimension of which shall not exceed three times the minimum width, shall
not be in excess of 2%, by weight.
d.
Acid Solubles: Not more than 5% of the gravel shall be soluble in
hydrochloric acid.
e.
Washed Material: The material shall be washed and free of shale, mica,
clay, dirt, loam, and organic impurities of any kind.
f.
Iron and Manganese.: The materials shall contain no iron or manganese in
a form or quantity that will adversely affect the well water supply.
Gradation
Tests for gradation of gravel-pack material shall be in accordance with the
method of testing as specified in ASTM C136.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 26
January 2013
5.
a.
Gravel-Pack Gradation: Gravel-pack gradation shall be determined by
taking the 50th percentile (for example, 50% of the grains having
diameters greater than d50) of the finest aquifer material to be filtered.
b.
Gravel-Pack to Formation-Sand Ratio: Gravel-pack to formation-sand
ratio at the 50th percentile point shall fall within the range of 6:1 or 4:1.
c.
Uniformity Coefficient: The uniformity coefficient of the gravel pack
shall not exceed 2.5.
d.
Distribution Curve: The gravel-pack size-distribution curve shall parallel
the main part of the formation-sand distribution curve for formation sands
having a uniformity coefficient less than 2.5.
Gravel-Pack Samples
Samples of gravel-pack, including sieve analysis shall be approved by the City
in advance of delivery and placement,
6.
a.
Labeling of Samples: All samples shall be plainly labeled to indicate the
source of the material, the date, and the name of the supplier.
b.
Method of Sampling: Methods of sampling shall be in accordance with
ASTM D75.
Delivery and Storage
The gravel-pack material shall be delivered to the well site upon approval by the
City.
The material may be delivered in bags or in bulk.
i.
Materials delivered in bags shall be protected from weather until
installed.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 27
January 2013
7.
Materials delivered in bulk shall be stored on a surface covered with
a 2-mil plastic sheet.
iii.
Contaminated material. Material for the gravel-pack that comes in
contact with the ground shall not be used and all materials shall be
protected from contamination until installed.
Method of Installation
a.
Placement: Gravel shall be placed to ensure continuity of the gravel pack
without bridging, voids, or segregation.
b.
Drilling Fluid: Before the introduction of gravel-pack, the drilling fluid
shall be reconditioned, unless different properties are needed to protect the
well, until it has the following properties;
c.
8.
ii.
i.
Weight - maximum of 68 lb/cu. ft. (1083 kg/m3)
ii.
Viscosity - maximum of 30x, API Marsh-Funnel test
iii.
Sand content of fluid in the system - maximum of 1%, by volume
Unusual Drilling Conditions: Where aquifer conditions make it necessary
to continue drilling operations with drilling fluid that does not meet these
standards, the drilling contractor shall be responsible for the complete
removal of drilling mud and development of the well.
Disinfection
The gravel-pack shall be disinfected in accordance with Section 4.4.H as it is
installed.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 28
January 2013
D.
Grouting and Sealing
1.
General
Grouting consists of sealing by filling the annular space between the casing and
bore hole with a substance that hardens.
2.
Sealing Requirements
The well shall be sealed to prevent the entrance of any water from any source
other than from the aquifers selected.
3.
a.
Surface of Sanitary Seal: The annular space around the conductor and/or
well casing, from surface to designated depth, shall be grouted and shall
not be less than 1.5" (38 mm).
b.
Sealing of Uncompleted Bore Hole: Sealing of an uncompleted bore hole
shall be performed in accordance with the requirements set forth in
Section 4.4.J.
c.
Sealing of Select Zones: All zones containing water of undesirable quality
or zones to be protected but excluded from final well completion shall be
grouted from a point at least 5' (1.52m) above the zone to a point at least 5'
(1.52m) below the zone.
d.
Sealing of Production Casing: Requirements of Section 4.4.J. shall apply
to the sealing of production casing if no other sealing has occurred.
Materials
a.
Neat-Cement Grout: Grout shall consist of a mixture of API Spec. 10,
Class G cement (or Class B similar to ASTM C150 Type II) and water in
the ratio of 0.67 cu ft [5.0 gal (19.0 L)] of water per 94 lb (42.6 kg) sack of
cement weighing approximately 118 lb/cu ft (1880 kg/m3). A maximum
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 29
January 2013
of 6%, by weight, bentonite and 2%, by weight, calcium chloride may be
added.
b.
Pozmix-Cement Grout: Grout shall consist of a mixture of 50%, by
volume, Pozzolan A 74 lb/cu ft 1179 kg/m3 and 50%, by volume, API
Spec. 10, Class G cement with 0.77 cu ft (21.8 L) of water per 84 pound
(38.1 kg) of mixture. To this mixture may be added a maximum of 2%, by
weight, bentonite and a maximum of 2%, by weight, calcium chloride, at
the discretion of the contractor.
c.
Portland Cement-Concrete Grout: Grout shall contain 5.3 sacks of
portland cement, ASTM C150 Type II, per cubic yard (0.76m3) of
concrete and a maximum of 7 gallons (26.5 L) of water per 94 pound
(42.6kg) sack of cement. The maximum slump shall be 4" (102 mm). The
aggregate shall consist of 47% sand and 53% coarse aggregate,
conforming to ASTM C33.
d.
4.
i.
The maximum size aggregate should be 0.75 " (19 mm).
ii.
Concrete seal shall not be placed in an annulus of less than 3 " (75
mm).
Sand-Cement Grout: Grout shall consist of a mixture of portland cement
(ASTM C 150 Type II), sand, and water in the proportion of not more than
2 parts, by weight, of sand to 1 part of cement with not more than 6
gallons (22.7L) of water per 94 pound (42.6kg) sack of cement.
Methods of Placement
Grouting shall be performed to ensure a complete seal of the annulus
designated.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 30
January 2013
E.
Plumbness and Alignment
1.
General
The completed well shall be constructed round, plumb, and true to line as
defined in this section. Tests for plumbness and alignment shall be made after
completed construction of the well.
2.
Tolerances
The following tolerances shall be maintained by the contractor:
a.
Plumbness: The maximum allowable horizontal deviation (drift) of the
well from the vertical shall not exceed two thirds of the smallest inside
diameter of that part of the well being tested per 100' (30.5M) of depth.
b.
Alignment: The alignment must be satisfactory for the successful
operation of the permanent pumping equipment.
i.
Alignment shall be tested by lowering into the well a section of pipe
or a dummy 40' (12.2m) long.
ii.
This pipe or dummy shall move freely throughout the tested interval.
iii.
The outside diameter of the pipe or dummy shall not be more than
0.5" (12.7mm) smaller than the diameter of that part of the casing or
hole being tested.
iv.
If a dummy is used, it shall consist of a rigid spindle with a
minimum of three truly cylindrical rings, each ring being a minimum
of 12" (305mm) wide.
v.
The rings shall be located one at each end and one in the center.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 31
January 2013
vi.
Alternate-alignment tolerance. Alternate-alignment tolerance may
be required for shallower wells after consideration of depth,
formations, casing straightness, well diameter versus pump diameter,
and local experience.
vii. The maximum allowable horizontal distance between the actual well
centerline and a straight line representing the proposed pump
centerline (this line being constructed to minimize the horizontal
distance between the centerlines) shall not exceed one half the
difference between the inside diameter of the casing or hole in that
part of the well being tested and the desired maximum outside
diameter of the proposed pump indicated in Table 4-1, to be
installed.
3.
Depth of Applied Tolerances
The tolerances set forth in Section 4.4.E.2 above shall apply from the top of the
well to the maximum depth specified for the tolerance requirements in the well
specifications.
F.
Well Development
1.
General
Well development consists of the application of appropriate techniques designed
to bring the well to its maximum production capacity with attendant optimizing
of well efficiency, specific capacity, stabilization of aquifer material, and
control of suspended solids.
2.
Development Test
The well shall be tested for development using a well pump.
a.
Test Pump Capacity: The pump and prime mover shall have a capacity in
excess of the anticipated lift, and final production capacity of the well and
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 32
January 2013
the pump shall be set to a depth in excess of the anticipated pumping level.
The method used shall permit adjustable flow rates for the pumping.
3.
b.
Discharge Piping: Discharge piping shall be provided of sufficient
diameter and length to conduct water to a point designated by the City,
together with orifices, meters, or other devices that will accurately measure
the flow rate.
c.
Completing Development:
Development shall continue until the
following conditions have been met:
i.
Sand contents shall average not more than 5 mg/L for a complete
pumping cycle of 2 hours duration when pumping at the designated
capacity.
ii.
Not less than 10 measurements shall be taken at equal intervals to
permit plotting of sand content as a function of time and production
rate and determination of average content for each cycle.
iii.
There shall be no increase in specific capacity during at least 24
continuous hours of pumping and surging.
Measurement of Operating Parameters During Development
a.
Discharge Rate: The device used to measure the pump discharge rate shall
have a minimum accuracy of 95%.
b.
Water Elevations: Water elevations in the well shall be measured to the
accuracy specified at each of the various pumping rates.
c.
Measurement of Sand Content: Sand content shall be measured with a
centrifugal sand sampler as described in Rossum, John R., Control of Sand
in Water Systems; Journal American Water Works Association, 46:2:123
(Feb. 1954).
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 33
January 2013
4.
Development Records
Complete records of all development work shall be maintained.
a.
Quantity of Gravel: For gravel-pack wells, the quantity of gravel added
during development shall be recorded.
b.
Data to Record: The following data shall be included in the work record:
i.
Quantity and description of material brought into the well
ii.
Static and pumping water levels
iii.
Methods of measurement
iv.
Duration of each operation
v.
Observation of results
vi.
Production rates and specific capacity
vii. Sand content as a function of production rate and time
viii. Sand content as a function of production rates and specific capacity
ix.
G.
All other pertinent information
Performance Testing
1.
General
Tests for well performance are necessary to secure water samples for analysis
and to determine well capacity, drawdown, and production on a long-term basis.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 34
January 2013
2.
Testing Methods
a.
b.
3.
Step-Drawdown Test: A step-drawdown test shall be conducted to
determine pumped-well capacity and to obtain data from which to design
the permanent production pump.
i.
The well shall be pumped at progressively increasing fractions of the
maximum discharge capacity as determined during the final
development phase.
ii.
The length of each discharge step shall be long enough to plot a
straight-line trend of drawdown versus logarithm of time since
pumping began.
Constant-Rate Tests: After the step-drawdown test, a constant-rate test
shall be conducted at a designated capacity to determine time draw-down
characteristics of the pumped well and any observation wells.
i.
The well shall be pumped at a constant rate until a straight-line trend
is observed on a plot of water level versus logarithm of time.
ii.
Recovery time of the pumping well and any observation wells to be
used in the test should be such that a straight-line trend is observed
in all of the wells on a plot of water level versus the logarithm of
time.
Water-Level Measurements
Water-level measurements shall be obtained prior to, during, and after the
pumping test in order to acquire background information (static water levels),
the effects of pumping (pumping water levels), and a profile of the recovery of
the water level from pumping level to original state. The measurement
frequency of water levels during pumping shall be such that adequate definition
of the time drawdown data is made available.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 35
January 2013
4.
Pumping-Test Interruption
The contractor shall conduct any specified pumping tests without any
interruptions or fluctuations that may affect the accuracy of the required
pumping results.
5.
Records and Reports
The contractor shall maintain all records and shall submit to the City accurate
written reports regarding water levels, pumping rates, time intervals, and other
pertinent details on testing of the production well and all observation wells used
in the test period.
H.
Well Disinfection
1.
General
The well shall be disinfected to remove bacteriological contamination that may
cause the well-water supply to be unsafe for human consumption.
2.
Disinfectant
A chlorine solution of water and available chlorine compounds shall be used for
disinfecting the well.
3.
Disinfection Procedure
The chlorine solution used for disinfecting the well shall be of such volume and
strength and shall be so applied that a concentration of at least 50 mg/L of
available chlorine shall be obtained for the entire water depth of the well. The
chlorine solution shall be prepared and applied to produce a contaminant-free
sample.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 36
January 2013
4.
a.
Overdosing Requirement: If the samples continue to show bacteriological
contamination, the contractor shall prepare and apply to the entire depth of
the well a total volume of the chlorine solution equal to at least four (4)
times the volume of water in the well and shall allow this solution to
remain in the well for a period of at least 2 hours.
b.
Contractor's Responsibility: The contractor's responsibility will be
fulfilled on completion of the above disinfection requirements.
Disinfection of Gravel Pack Wells
During the addition of the gravel to a gravel-pack well, the material shall be
disinfected.
I.
a.
Single Aquifer: In single aquifer wells, the gravel-pack material shall be
disinfected by maintaining and circulating a solution containing a chlorine
residual of at least 50 mg/L. The circulating fluid shall be sampled at
suitable intervals and tested for chlorine residual.
b.
Multi-Aquifer: In multi-aquifer wells, the gravel shall be disinfected by
adding 0.5 pound (0.23 kg) of calcium hypochlorite tablets per ton of
gravel. The tablets shall be distributed as uniformly as practical.
Water Quality Testing
1.
General Considerations
Water quality (physical, biochemical, and chemical composition) shall be
determined by analysis of water samples collected from the well.
2.
Sampling Procedures
The procedures outlined in the latest edition of Manual of Methods for
Chemical Analysis of Water and Wastes, US Environmental Protection Agency,
shall be followed.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 37
January 2013
J.
a.
Field Tests: Water temperatures, pH, and dissolved gases shall be
determined on samples collected and analyzed in the field.
b.
Samples for Local-Regulation Test: Water samples shall be taken at the
end of the pumping test for chemical analyses as required by the city or
state.
c.
Analytical Procedures: All analyses performed shall be in accordance with
methods as prescribed by regulatory agencies having jurisdiction over the
well construction, or potable supply standards.
Abandonment of Test Holes, Partially Completed Wells, and Completed Wells
1.
General
Abandoned test holes, including test wells, uncompleted wells, and completed
wells shall be sealed.
a.
b.
Need for Sealing of Wells:
i.
Eliminate physical hazard
ii.
Prevent contamination of groundwater
iii.
Conserve yield and hydrostatic head of aquifers
iv.
Prevent intermixing of desirable and undesirable waters.
Restoration of Geological Conditions: The guiding principle to be
followed by the contractor in the sealing of abandoned wells is the
restoration, as for as feasible, of the controlling geological conditions that
existed before the well was drilled or constructed.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 38
January 2013
2.
Sealing Requirements
A well shall be measured for depth before it is sealed to ensure freedom from
obstructions that may interfere with effective sealing operations.
3.
a.
Liner-Pipe Removal: Removal of liner pipe from some wells may be
necessary to ensure placement of an effective seal.
b.
Exception to Removing Liner Pipe: If the liner pipe cannot be readily
removed, it shall be perforated to ensure the proper sealing required.
c.
Sealing Materials and Placement: Concrete, cement grout, or neat cement
shall be used as primary sealing materials and shall be placed from the
bottom upward by methods that will avoid segregation or dilution of
material.
Records of Abandonment Procedures
Complete accurate records shall be kept of the entire abandonment procedure to
provide detailed records for possible future reference and to demonstrate to the
governing state or local agency that the hole was properly sealed.
a.
Depths Sealed. The depth of each layer of all sealing and backfilling
materials shall be recorded.
b.
Quantity of Sealing Material Used: The quantity of sealing materials used
shall be recorded. Measurements of static water levels and depths shall be
recorded.
c.
Changes Recorded: Any changes in the well made during the plugging,
such as perforating casing, shall be recorded in detail.
City of Umatilla Standard Specifications
Water & Sewer Utilities
4 - 39
January 2013
APPENDIX A
GENERAL CONSTRUCTION REQUIREMENTS
FOR WATER DISTRIBUTION AND WASTEWATER COLLECTION
1.
GENERAL REQUIREMENTS
a.
Grades, Survey Lines, and Protection of Monuments
(1)
Grade
(2)
Surveys
(3)
Monument Preservation
b.
Utility Coordination
(1)
Location of Utilities
(2)
Deviations Occasioned by Structures or Utilities
(3)
Test Pits
c.
Maintenance of Traffic and Closing of Streets
d.
Protection of Public and Private Property
(1)
Barricades, Guards and Safety Provisions
(2)
Protection of Utility Structures
(3)
Open Excavation
(4)
Protection of Trees and Shrubs
(5)
Protection of Lawn Areas
(6)
Restoration of Fences
(7)
Protection Against Siltation and Bank Erosion
e.
Access to the Public Services
f.
Public Nuisance
g.
Construction Hours
h.
Construction in Easements And Rights-of-way
(1)
Construction in Easements
(2)
Construction in Florida Department of Transportation Right-of-way
(3)
Construction in Lake County Right-of-way
(4)
Construction in City Right-of-way
i.
Suspension of Work Due to Weather
j.
Use of Chemicals
k.
Cooperation with Other Contractors and Forces
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix A
April 2013
l.
m.
n.
o.
Subsurface Exploration
Cleaning
(1)
During Construction
(2)
Final Cleaning
Salvage
Shop Drawings and Samples
2.
SITE, PREPARATION, SURFACE REMOVAL AND RESTORATION
a.
General
b.
Clearing and Grubbing
(1)
Clearing
(2)
Grubbing
(3)
Stripping
(4)
Disposal of Cleared and Grubbed Material
c.
Dust Control
d.
Surface Removal
e.
Restoration
3.
EXCAVATION, BACKFILL, COMPACTION AND GRADING
a.
General
b.
Soil Borings and Subsurface Investigations
c.
Existing Utilities
d.
Materials
(1)
General
(2)
Structural Fill
(3)
Common Fill
(4)
Select Common Fill
(5)
Bedding Rock
e.
Sheeting and Bracing in Excavations
(1)
General
(2)
Miscellaneous Requirements
f.
Dewatering, Drainage and Flotation
(1)
General
(2)
Additional Requirements
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix A
April 2013
g.
h.
i.
j.
k.
l.
4.
Excavation
(1)
General
(2)
Excavation for Structures
(3)
Trench Excavation
Bedding and Backfill
(1)
General
(2)
Bedding and Backfill for Structures
(3)
Bedding and Backfill for Pipes
Compaction
(1)
General
(2)
Percentage of Maximum Density Requirements
(3)
Compaction Tests
Grading
Maintenance
Inspection and Quality Assurance
(1)
Inspection
(2)
Quality Assurance
BORING AND JACKING
a.
General
b.
Pipe Material
(1)
Steel Casing
(2)
Carrier Pipe
(3)
Inspection
c.
Pipe Handling
d.
Construction Requirements
(1)
Work Coordination
(2)
Dewatering
(3)
Carrier Pipe Support
(4)
Jacking Pits
(5)
Miscellaneous Requirements
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix A
April 2013
5.
HORIZONTAL DIRECTIONAL BORES (DIRECTIONAL DRILL)
a.
General
b.
Pipe Material
c.
Qualification Requirements
d.
Warranty
e.
Submittals
(1)
Contractor’s Experience Record
(2)
Material
(3)
Work Plan
(4)
Bore Plan
(5)
Equipment
f.
Horizontal Directional Drilling Equipment
(1)
General
(2)
Drill Rig
(3)
Drill Head
(4)
Mud Motors
(5)
Drill Pipe
g.
Guidance System
(1)
General
(2)
Components
(3)
Operation
h.
Drilling Fluid (Mud) System
(1)
Mixing System
(2)
Drilling Fluid
(3)
Delivery System
i.
Other Equipment
(1)
Pipe Rollers
(2)
Restrictions
j.
Execution
(1)
General
(2)
Directional Drilling Operations
(3)
Handling Pipe
(4)
Testing
(5)
Site Restoration
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix A
April 2013
(6)
Record Keeping
6.
PRESSURE PIPE RESTRAINT
a.
General
b.
Restrained Joint Construction
c.
Mechanical Restraining Devices
(1)
General
(2)
Joint Restraint Device
d.
Thrust Block Construction
7.
PRESSURE CONNECTION
a.
General
b.
Tapping Sleeves
(1)
General
(2)
Mechanical Joint Sleeves
(3)
Steel Tapping Sleeves
(4)
Tapping Valves
c.
Notification and Connection to Existing Mains
d.
Installation
(1)
Excavation, Backfill, Compaction and Grading
(2)
Construction Details
8.
GREASE TRAPS
a.
Shape
b.
Material of Construction
c.
Wall Thickness
d.
Accessibility
e.
Clean outs
f.
Rings & Covers
g.
Minimum Pipe Size
h.
Minimum Slope
i.
Openings
j.
Manhole Insert
k.
Inspection
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix A
April 2013
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix A
April 2013
APPENDIX A
GENERAL CONSTRUCTION REQUIREMENTS
FOR WATER DISTRIBUTION AND WASTEWATER COLLECTION
1.
GENERAL REQUIREMENTS
a.
Grades, Survey Lines, and Protection of Monuments
(1)
Grade
All work shall be constructed in accordance with the lines and grades
shown on the Drawings. The full responsibility for keeping alignment and
grade shall rest upon the contractor.
Bench marks and base line controlling points shall be established prior to
beginning work. Reference marks for lines and grades as the work
progresses will be located to cause as little inconvenience to the
prosecution of the work as possible. The contractor shall so place
excavation and other materials as to cause no inconvenience in the use of
the reference marks provided. Contractor shall remove any obstructions
placed contrary to this provision.
(2)
Surveys
The contractor shall furnish and maintain, at his own expense, stakes and
other such materials, and give such assistance, including qualified helpers,
for setting reference marks to the satisfaction of the City and the Engineer.
The contractor shall check such reference marks by such means as he may
deem necessary and, before using this, shall call the City's attention to any
inaccuracies. The contractor shall, at his own expense, establish all
working or construction lines and grades as required from the reference
marks, and shall be solely responsible for the accuracy thereof. The
contractor shall, however, be subject to the check and review of the City.
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(3)
Monument Preservation
Property corners and survey monuments shall be preserved using care not
to disturb or destroy them. If a property corner or survey monument is
disturbed or destroyed during construction, whether by accident, careless
work, or required to be disturbed or destroyed by the construction work,
said property corner or survey monument shall be restored by a
Professional Surveyor and Mapper registered in the State of Florida. All
costs for this work shall be paid for by the contractor.
b.
Utility Coordination
(1)
Location of Utilities
Prior to proceeding with trench excavation the contractor shall contact all
utility companies in the area to aid in locating their underground services.
It shall be the contractor's responsibility to contact utility companies or
sunshine state one call at least three (3) normal working days before
starting construction. The contractor shall proceed with caution in the
excavation and preparation of the trench so that the exact location of
underground utilities may be determined.
The contractor shall take all reasonable precautions against damage to
existing utilities. However, in the event of a break in an existing water
main, gas main, sewer, underground cable, or other utility, the contractor
shall immediately notify the responsible official of the organization
operating the interrupted utility. The contractor shall lend all possible
assistance in restoring services and shall assume all cost, charges, or
claims connected with the interruption and repair of such services.
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(2)
Deviations Occasioned by Structures or Utilities
Wherever obstructions are encountered during the progress of the work
and interfere to such an extent that an alteration in the location shown on
the Drawings is required, the City with the concurrence of the engineer of
record shall have the authority to order a deviation from the line and grade
or arrange with the owners of the structures for the removal, relocation or
reconstruction of the obstructions. Where gas, water, telephone, electrical,
hot water, steam or other existing utilities are an impediment to the
vertical or horizontal alignment of the proposed pipe line, the City shall
order a change in grade or alignment or shall direct the contractor to
arrange with the owners of the utilities for their removal. If a change in
line or grade of a gravity sewer is necessary, the City will require the
addition of any necessary manholes required to maintain the integrity of
the sewer system.
(3)
Test Pits
Test pits for the purpose of locating underground pipeline, utilities, or
structures in advance of the construction shall be excavated and backfilled
by the contractor. Test pits shall be backfilled immediately after their
purpose has been satisfied and maintained in a manner satisfactory to the
City. The costs for such test pits shall be borne by the contractor.
c.
Maintenance of Traffic and Closing of Streets
The contractor shall carry on the work in a manner which will cause a minimum
of interruption to traffic. Where traffic must cross open trenches at street
intersections and driveways, the contractor shall provide suitable bridges. The
contractor shall post suitable signs indicating that a street is closed and necessary
detour signs for the proper maintenance of traffic. Prior to the closing of any
street the contractor shall notify and obtain the approval of responsible authorities
and the City.
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Unless permission to close a street is received in writing from the proper authority
(City, County, FDOT, etc.), all excavated material shall be placed so that
vehicular and pedestrian traffic may be safely maintained at all times. If the
Contractor's operations cause traffic hazards, the contractor shall repair the road
surface, provide temporary ways, erect wheel guards or fences, or take other
measures for safety that are satisfactory to the City.
Detours around construction will be subject to the approval of the authority
having jurisdiction and the City. Where detours are permitted, the contractor shall
provide all necessary barricades and signs as required to divert the flow of traffic.
While traffic is detoured the contractor shall expedite construction operations.
Periods when traffic is being detoured will be strictly controlled by the City.
It shall be the sole responsibility of the contractor to take precautions to prevent
injury to the public due to open trenches. Night watchmen may be required where
special hazards exist, or police protection provided for traffic while work is in
progress. The contractor shall be fully responsible for damage or injuries whether
or not police protection has been provided.
d.
Protection of Public and Private Property
(1)
Barricades, Guards and Safety Provisions
The contractor shall be solely responsible for adhering to the rules and
regulations of Occupational Safety and Health Administration (OSHA)
and appropriate authorities regarding safety provisions. To protect
persons from injury and to avoid property damage, adequate barricades,
construction signs, lights and guards as required shall be placed and
maintained by the contractor at his expense during the progress of the
work and until it is safe for traffic to use the roads and streets. All
material piles, equipment and pipe which may serve as obstructions to
traffic shall be enclosed by fences or barricades and shall be protected by
proper lights when the visibility is poor.
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All signage and barricades shall be in accordance with the Manual on
Uniform Traffic Control Devices and the Traffic Control and Safe
Practices Manual.
(2)
Protection of Utility Structures
Temporary support, adequate protection and maintenance of all
underground and surface utility structures including drains, sewers,
manholes, hydrants, valves, valve covers, power poles and miscellaneous
other utility structures encountered in the progress of the work shall be
furnished by the contractor at his expense. Any such structures which
may have been disturbed shall be restored upon completion of the Work.
(3)
Open Excavation
All open excavations shall be adequately safeguarded by providing
temporary barricades, caution signs, lights and other means to prevent
accidents to persons and damage to property. The contractor shall, at his
own expense, provide suitable and safe bridges with hand railings and
other crossings for accommodating travel by pedestrians and workmen.
Bridges provided for access to private property during construction shall
be removed when no longer required. The length of open trench will be
controlled by the particular surrounding conditions, but shall be limited to
300 feet unless otherwise specifically approved by the City. If the
excavation becomes a hazard, or if it excessively restricts the flow of
traffic at any point, the City may require special construction procedures
such as limiting the length of open trench, fencing, prohibiting excavated
material in the street and requiring that the trench shall not remain open
overnight. The contractor shall take precautions to prevent injury to the
public due to open trenches. All trenches, excavated material, equipment
or other obstacles which could be dangerous to the public shall be well
lighted at night.
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(4)
Protection of Trees and Shrubs
All trees and shrubs not shown to be removed on the Drawings shall be
protected by the contractor at his own expense. No excavated materials
shall be placed so as to injure such trees or shrubs. Trees or shrubs
destroyed by negligence of the contractor or his employees shall be
replaced by him with new stock of similar size and age at the sole expense
of the contractor.
(5)
Protection of Lawn Areas
Lawn areas shall be left in as good or better condition as before starting of
the Work. Where sod is to be removed it shall be carefully restored with
new sod of the same type.
(6)
Restoration of Fences
Any fence, or part thereof, that is damaged or removed during the course
of the Work shall be replaced or repaired by the contractor and shall be
left in as good a condition as before the starting of the Work. The manner
in which the fence is repaired or replaced and the materials used shall be
subject to the approval of the City.
(7)
Protection Against Siltation and Bank Erosion
The contractor shall arrange his operations to minimize siltation and bank
erosion on construction sites and on existing or proposed water courses
and drainage ditches. The Contractor, at his own expense, shall remove
any siltation deposits and restore to original grade.
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e.
Access to the Public Services
Neither the materials excavated nor the materials or equipment used in the
construction of the Work shall be so placed as to prevent free access to public
services. All excavated material shall be piled in a manner that will not endanger
the Work and that will avoid obstructing streets, sidewalks and driveways.
Excavated material suitable for backfilling shall be stockpiled separately on the
site. No material shall be placed closer than 2'0" from the edge of an excavation.
Fire hydrants under pressure, valve pit covers, valve boxes, curb stop boxes, or
other utility controls shall be left unobstructed and accessible until the Work is
completed. Gutters shall be kept clear or other satisfactory provisions made for
street drainage. Natural water courses shall not be obstructed or polluted. Surplus
material and excavated material unsuitable for backfilling shall be transported and
disposed of off the site in disposal areas obtained by the contractor.
f.
Public Nuisance
The contractor shall not create a public nuisance including but not limited to
encroachment on adjacent lands, flooding of adjacent lands, or excessive noise or
dust. The contractor shall eliminate noise to as great an extent as practicable at all
times.
g.
Construction Hours
No Work shall be done between the hours of 7:00 p.m. and 7:00 a.m., or on
Saturdays, Sundays and City holidays unless the proper and efficient prosecution
of the Work requires operations during the night or weekend. Written notification
for proceeding with the Work, during on-working hours, shall be provided to the
City a minimum 24 hours before starting such items of the Work.
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h.
Construction in Easements And Rights-of-way
(1)
Construction in Easements
In easements across private property, the contractor shall confine all
operations to areas within the easement and shall be responsible and liable
for all damage occurring outside of the easement area. Trees, fences,
shrubbery or other type of surface improvements located in easements will
require protection during construction. Precautions shall be taken by
adequate sheeting or other approved method to prevent any cave-in or
subsidence beyond the easement limits or damage to existing
improvements within the easement. In general, the easement area is
intended to provide reasonable access and working area for efficient
operation by the contractor. Where easement space for efficient operation
is not provided, the contractor shall be responsible for organizing the
necessary operations to perform within the restrictions shown on the
Drawings.
(2)
Construction in Florida Department of Transportation Right-of-way
The contractor shall strictly adhere to the requirements of the Florida
Department of Transportation where construction work is in a
right-of-way under the jurisdiction of the State of Florida, and shall take
care to avoid any unreasonable traffic conflicts due to the Work in road
right-of-way.
(3)
Construction in Lake County Right-of-way
The contractor shall strictly adhere to the requirements of Lake County
where construction work is in right-of-way under the jurisdiction of Lake
County, and shall take care to avoid any unreasonable traffic conflicts due
to the work in road right-of-way.
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(4)
Construction in City Right-of-way
Work shall be governed by the requirements in the City of Umatilla Land
Development Regulations, Utilities, Pavement Cuts and Right-of-Way
Construction.
i.
Suspension of Work Due to Weather
During inclement weather, all Work which might be damaged or rendered inferior
by such weather conditions shall be suspended. During suspension of the Work
from weather or any other cause, the Work shall be suitably covered and protected
so as to preserve it from injury.
j.
Use of Chemicals
All chemicals used during project construction or furnished for project operation,
whether herbicide, pesticide, disinfectant, polymer, reactant, or of any other
classification, must show approval of either United States Environmental
Protection Agency or United States Department of Agriculture. Use of all such
chemicals and disposal of residues shall be in strict conformance with label
instructions.
k.
Cooperation with Other Contractors and Forces
During construction progress, it may be necessary for other contractors and
persons employed by the City to work in or about the site. The City reserves the
right to allow such other contractors to work and to afford such access to the
construction site and at such times as the City deems proper. The contractor shall
not impede or interfere with the work of such other contractors and shall
cooperate with the other contractors for proper prosecution of the work.
l.
Subsurface Exploration
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The contractor shall make such subsurface explorations as he believes necessary
to perform the Work.
m.
Cleaning
(1)
During Construction
During construction the contractor shall, at all times, keep the construction
site and adjacent premises as free from material, debris and rubbish as is
practicable and shall remove the same from any portion of the site if, in
the opinion of the City, such material, debris, or rubbish constitutes a
nuisance or is objectionable.
(2)
Final Cleaning
At the conclusion of the Work, all tools, temporary structures and
materials belonging to the contractor shall be promptly taken away. The
contractor shall remove and promptly dispose of all water, dirt, rubbish or
any other foreign substances.
n.
Salvage
Any existing City owned equipment or material including but not limited to
valves, pipes, fittings, couplings, etc., which is removed or replaced as a result of
construction may be designated as “salvage” by the City, and if so, shall be
carefully excavated or removed and delivered to the City at a specified location
within the City.
o.
Shop Drawings and Samples
If requested by the City, prior to commencing construction the contractor shall
submit seven (7) copies of all required shop drawings, signed by the Developer's
Engineer, to the City. The data shown on the shop drawings shall be complete
with respect to dimensions, design criteria, materials of construction and the like
to enable review of the information as required.
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The contractor shall, if requested by the City, furnish certificates, affidavits of
compliance, test reports, or samples for analysis and review for any of the
materials specified hereafter in this Appendix.
2.
SITE, PREPARATION, SURFACE REMOVAL AND RESTORATION
a.
General
This Section covers clearing, grubbing, and stripping of the construction sites.
The contractor shall clear and grub all of the area within the limits of construction
as shown on the Drawings and approved by the City prior to beginning any work.
All site work shall conform to the requirements of in the City of Umatilla Land
Development Regulations, Landscape Standards and Tree Preservation in the City
Land Development Regulations, Utilities, Pavement Cuts and Right-Of-Way
Construction.
b.
Clearing and Grubbing
(1)
Clearing
The surface of the ground for the area to be cleared and grubbed shall be
completely cleared of all timber, brush, stumps, roots, grass, weeds,
rubbish and all other objectionable obstructions resting on or protruding
through the surface of the ground. However, trees and shrubs shall be
preserved as specified in Appendix A, paragraph 1.d.(4). Clearing
operations shall be conducted so as to prevent damage to existing
structures and installations and to those under construction, and so as to
provide for the safety of employees and others.
(2)
Grubbing
Grubbing shall consist of the complete removal of all stumps, roots larger
than 1-1/2" in diameter, matted roots, brush, timber, logs and any other
organic or metallic debris not suitable for foundation purposes, resting on,
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under or protruding through the surface of the ground to a depth of 24 "
below the subgrade. All depressions excavated below the original ground
surface for or by the removal of such objects shall be refilled with suitable
materials and compacted to a density conforming to the surrounding
ground surface.
(3)
Stripping
In areas so designated, top soil shall be stripped and stockpiled. Topsoil
so stockpiled shall be protected until it is placed as specified. Any topsoil
remaining after all work is in place shall be disposed of by the contractor.
(4)
Disposal of Cleared and Grubbed Material
The contractor shall at his expense dispose of all material and debris from
the clearing and grubbing operation in accordance with all applicable
ordinances or codes.
c.
Dust Control
Contractor shall control dust resulting from clearing and grubbing operations to
prevent nuisance to adjacent property owners and the general public. Contractor
shall use dust control methods and materials approved by the City.
d.
Surface Removal
Along the proposed pipe lines as indicated on the Drawings, the contractor shall
remove the surface materials only to such widths as will permit a trench to be
excavated which will afford sufficient room for proper efficiency and proper
construction. All applicable City, County and FDOT regulations shall be
followed. Where sidewalks, driveways, pavements and curb and gutter are
encountered, care shall be taken to protect against fracture or disturbance beyond
reasonable working limits. All fractured, broken or disturbed surfaces shall be
restored to their original condition prior to completion of the Work.
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e.
Restoration
Restoration of all surfaces including road subbase, soil cement, limerock base,
asphaltic concrete surface, portland cement concrete pavement and driveways,
sidewalks and concrete curbs shall be in strict accordance with Road Construction
Specifications. All grassing and mulching shall be done as specified in the Road
Construction Specifications. Solid sodding shall be placed on all slopes greater
than 4:1, within 10 feet of all proposed structures and where existing sod is
removed or disturbed during progress of the work. In addition, contractor shall
restore all storm drains, culverts, inlets and storm manholes to equal or better
condition in accordance with the Road Construction Specifications.
3.
EXCAVATION, BACKFILL, COMPACTION AND GRADING
a.
General
This section covers excavation, backfill, fill and grading associated with utility
trench and structural construction. All such work shall be performed by the
contractor concurrently with the work specified herein. The contractor shall
furnish all labor, materials, equipment and incidentals necessary to perform all
excavation, backfill, fill, compaction, grading and slope protection required to
complete the work shown on the drawings and specified herein. The work shall
include, but not necessarily be limited to: pump stations, manholes, vaults,
conduit, pipe, roadways and paving; all backfilling, fill and required borrow;
grading; disposal of surplus and unsuitable materials; and all related work such as
sheeting, bracing and water handling.
b.
Soil Borings and Subsurface Investigations
The contractor shall carefully examine the site and undertake whatever subsurface
investigations, including soil borings, if necessary, before commencing the work.
The City will not be responsible for presumed or existing subsurface conditions in
the work area.
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c.
Existing Utilities
Contractor shall locate existing utilities in the areas of work. If utilities are to
remain in place, the contractor shall provide adequate means of protection during
earthwork operations. Should uncharted or incorrectly charted piping or other
utilities be encountered during excavation, the contractor shall consult the owner
of such piping or utility immediately for directions. Payment for damage and
repair to such piping or utilities is the Contractor's responsibility. Refer to
Appendix A, paragraph l.b. for utility coordination requirements.
The City shall not be responsible for uncharted or incorrectly charted water and
wastewater mains or other utilities. It is the contractor's responsibility to ensure
that such facilities exist at the presumed point prior to commencing construction.
d.
Materials
All materials used in the backfill and/or grading of utility trenches or structures
shall conform to the classification as identified in the Unified Soils Classification
System (ASTM D2487-11).
(1)
General
Materials for use as bedding and backfill, whether in-situ or borrow, shall
be as described under this section. The contractor shall upon request by
the City, make an appropriate sample of this material available for testing
by the City or its designated representative.
(2)
Structural Fill
Materials for structural fill shall be bedding rock or select common fill as
specified herein or other suitable material as approved by the City.
(3)
Common Fill
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Common fill shall consist of mineral soil, substantially free of clay,
organic material, loam, wood, trash and other objectionable material
which may be compressible or which cannot be compacted properly.
Common fill shall not contain stones larger than 6" in any dimension,
asphalt, broken concrete, masonry, rubble, or other similar materials. It
shall have physical properties such that it can be readily spread and
compacted during filling. Additionally common fill shall be no more than
12% by weight finer than the No. 200 mesh sieve unless finer material is
approved for use in a specific location by the City.Material falling within
the above specifications, encountered during the excavation may be stored
in segregated stockpiles for reuse. All material which, in the opinion of
the City, is not suitable for reuse, shall be spoiled as specified herein for
disposal of unsuitable materials.
(4)
Select Common Fill
Select common fill shall be as specified above from common fill, except
that the material shall contain no stones larger then 1-1/2" in largest
dimension, and shall be no more than 5% by weight finer than the No. 200
mesh sieve.
(5)
Bedding Rock
Bedding rock shall be 3/16" to 3/4" washed and graded stone (FDOT #67).
This stone shall be graded so that 90 to 100% percent will pass a 3/4"
screen and 95 to 100% will be retained on a No. 8 screen. No stones
larger then 1" in any dimension shall be accepted.
e.
Sheeting and Bracing in Excavations
(1)
General
If required to support the sides of excavations, to prevent any movement
which could in any way diminish the width of the excavation below that
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necessary for proper construction and to protect adjacent structures,
existing piping and/or foundation material from disturbance, undermining
or other damage, the contractor shall construct, brace and maintain
cofferdams consisting of sheeting and bracing. Care shall be taken to
prevent voids outside of the sheeting, but if voids are formed, they shall be
immediately filled and rammed.
(2)
Miscellaneous Requirements
For trench sheeting for pipes, no sheeting is to be withdrawn if driven
below mid-diameter of any pipe and no wood sheeting shall be cut off at a
level lower than one foot above the top of any pipe unless otherwise
directed by the City. If during the progress of the Work, the City decides
that additional wood sheeting should be left in place, it may direct the
contractor to do so. If steel sheeting is used for trench sheeting, removal
shall be as specified above, unless written approval is given by the City for
an alternate method of removal. All sheeting and bracing not left in place
shall be carefully removed in such a manner as not to endanger the
construction of other structures, utilities, existing piping or property.
Unless otherwise approved or indicated on the Drawings or in the
Specifications, all sheeting and bracing shall be removed after completion
of the substructure. All voids left or caused by withdrawal of sheeting
shall be immediately refilled with sand by ramming with tools specially
adapted to that purpose, by watering or otherwise compacting as may be
directed.
The right of the City to order sheeting and bracing left in place shall not be
construed as creating any obligation on its part to issue such orders and its
failure to exercise its right to do so shall not relieve the contractor from
liability for damages to persons or property occurring from or upon the
work occasioned by negligence or otherwise, growing out of a failure on
the part of the contractor to leave in place sufficient sheeting and bracing
to prevent any caving or moving of the ground.
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The contractor shall construct the cofferdams and sheeting outside the neat
lines of the foundation unless indicated otherwise or to the extent he
deems it desirable for his method of operation. Sheeting shall be plumb
and securely braced and tied in position. Sheeting, bracing and
cofferdams shall be adequate to withstand all pressures to which the
structure will be subjected. Pumping, bracing and other work within the
cofferdam shall be done in a manner to avoid disturbing any construction
already performed. Any movement or bulging which may occur shall be
corrected by the contractor at his own expense so as to provide the
necessary clearances and dimensions.
f.
Dewatering, Drainage and Flotation
(1)
General
The contractor shall excavate, construct and place all pipelines, concrete
work, fill, and bedding rock, in-the-dry. In addition, the contractor shall
not make the final 24" of excavation until the water level is a minimum of
1" foot below proposed bottom of excavation. For purposes of these
specifications, "in-the-dry" is defined to be within 2% of the optimum
moisture content of the soil. The City reserves the right to ask the
contractor to demonstrate that the water level is a minimum of one foot
below proposed bottom of excavation before allowing the construction to
proceed.
Water discharged from the dewatering operations shall be clear, with no
visible soil particles. Discharge from dewatering shall be disposed of in
such a manner that it will not interfere with the normal drainage of the
area in which the Work is being performed, create a public nuisance, or
form ponding. The operations shall not cause injury to any portion of the
Work completed, or in progress, or to the surface of streets, or to private
property. The dewatering operation shall comply with the requirements of
appropriate regulatory agencies. Additionally, where private property will
be involved, advance permission shall be obtained by the contractor.
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(2)
Additional Requirements
The contractor shall, at all times during construction, provide and maintain
proper equipment and facilities to remove promptly and dispose of
properly all water entering excavations and keep such excavations dry so
as to obtain a satisfactory undisturbed subgrade foundation condition until
the fill, structure, or pipes to be built thereon have been completed to such
extent that they will not be floated or otherwise damaged by allowing
water levels to return to natural elevations.
Dewatering shall at all times be conducted in such a manner as to preserve
the natural undisturbed bearing capacity of the subgrade soils at proposed
bottom of excavation.
It is expected that in some cases, well points will be required for
dewatering of the soils prior to final excavation for some of the deeper
in-ground structures, or piping and for maintaining the lowered
groundwater level until construction has been completed to such an extent
that the structure, pipeline or fill will not be floated or otherwise damaged.
Well points shall be surrounded by suitable filter sand and negligible fines
shall be removed by pumping.
The contractor shall furnish all materials and equipment and perform all
work required to install and maintain the drainage systems for handling
groundwater and surface water encountered during construction of
structures, pipelines and compacted fills.
During backfilling and construction, water levels shall be measured in
observation wells located as directed by the City.
Continuous pumping will be required as long as water levels are required
to be below natural levels.
g.
Excavation
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(1)
General
Excavation consists of removal, storage and disposal of material
encountered when establishing required grade elevations and in
accordance with the notes shown on the Drawings.
Authorized earth excavation includes removal and disposal of pavements
and other obstructions visible on ground surface, underground structures
and utilities indicated to be demolished and removed, and other materials
encountered that are not classified as rock excavation or unauthorized
excavation. Unauthorized excavation consists of removal of material
beyond the limits needed to establish required grade and subgrade
elevations without specific direction of the City. Unauthorized excavation,
as well as remedial work directed by the City shall be at the Contractor's
expense. Such remedial work shall be performed as directed by the City.
If requested by the City, when excavation has reached required subgrade
elevations, a Geotechnical/Soils Engineer shall make an inspection of
conditions. If the subgrade is unsuitable, contractor shall carry excavation
deeper and replace excavated material with select common fill or bedding
rock, as directed by the City.
If the contractor excavates below, grade through error or for his own
convenience or through failure to properly dewater the excavation or
disturbs the subgrade before dewatering is sufficiently complete, the
contractor may be directed by the City to excavate below grade and refill
the excavation using select common fill or bedding rock.
Slope sides of excavations shall comply with local codes and ordinances,
and with OSHA requirements. Contractor shall shore and brace where
sloping is not possible due to space restrictions or stability of the material
excavated. Sides and slopes shall be maintained in a safe condition until
completion of backfilling.
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Contractor shall stockpile satisfactory excavated materials at a location
approved by the City until required for backfill or fill. When needed in
the Work, material shall be located and graded at the direction of a
Geotechnical/Soils Engineer.
Stockpiles shall be placed and graded for proper drainage. All soil
materials shall be located away from the edge of excavations. All surplus
and/or unsuitable excavated material shall be legally disposed of by the
contractor. Any permits required for the hauling and disposing of this
material shall be obtained by the contractor prior to commencing hauling
operations.
(2)
Excavation for Structures
All such excavations shall conform to the elevations and dimensions
shown on drawing within a tolerance of plus or minus 0.10' and extending
a sufficient distance, as shown on the Drawings, from footings and
foundations to permit placing and removing form work, installation of
services and other construction or inspection. In excavating for footings
and foundations, care shall be exercised not to disturb the bottom of the
excavation. Bottoms shall be trimmed to required lines and grades to
leave a solid base to receive concrete.
(3)
Trench Excavation
Excavation for all trenches required for the installation of utility pipes
shall be made to the depths indicated on the Drawings and in such manner
and to such widths as will give suitable room for laying the pipe within the
trenches, for bracing and supporting and for pumping and drainage
facilities.
The bottom of the excavations shall be firm and dry and in all respects
acceptable to the City.
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Excavation shall not exceed normal trench width as specified in the
standard drawings. Any excavation which exceeds the normal trench
width, shall require special backfill requirements as determined by the
City.
Where pipes are to be laid in bedding rock, select common fill or encased
in concrete, the trench may be excavated by machinery to or just below the
designated subgrade provided that the material remaining in the bottom of
the trench is no more than slightly disturbed.
Where the pipes are to be laid directly on the trench bottom, the lower part
of the trenches shall not be excavated to grade by machinery. The last of
the material being excavated shall be done manually in such a manner that
will give a shaped bottom, true to grade, so that pipe can be evenly
supported on undisturbed material, as specified in the Standard Drawings.
Bell holes shall be made as required.
h.
Bedding and Backfill
(1)
General
Material placed in fill areas under and around structures and pipelines
shall be deposited within the lines and to the grades shown on the
drawings or as directed by the City, making due allowance for settlement
of the material. Fill shall be placed only on properly prepared surfaces
which have been inspected and approved by the City. If sufficient select
common or common fill material is not available from excavation on site,
the contractor shall provide fill as may be required.
Fill shall be brought up in substantially level lifts starting in the deepest
portion of the fill. The entire surface of the Work shall be maintained free
from ruts and in such condition that construction equipment can readily
travel over any section.
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Fill shall be placed and spread in layers by a backhoe or other approved
method, unless otherwise specified. Prior to the process of placing and
spreading, all materials not meeting those specified under Appendix A,
paragraph 3.d. shall be removed from the fill areas. The contractor shall
assign a sufficient number of employees to this Work to insure satisfactory
compliance with these requirements.
If the compacted surface of any layer of material is determined to be too
smooth to bond properly with the succeeding layer, it shall be loosened by
harrowing or by another approved method before the succeeding layer is
placed.
All fill materials shall be placed and compacted "in-the-dry". The
contractor shall dewater excavated areas as required to perform the work
and in such manner as to preserve the undisturbed state of the natural
inorganic soils.
Prior to filling, the ground surface shall be prepared by removing
vegetation, debris, unsatisfactory soil materials, obstructions and
deleterious materials. Contractor shall plow strip or break up sloped
surfaces steeper than one vertical to four horizontal so that fill material
will bond with the existing surface. When existing ground surface has a
density less than that specified under Appendix A, paragraph 3.i. for the
particular area classification, contractor shall break up the ground surface,
pulverize, moisture-condition to the optimum moisture content and
compact to required depth and percentage of maximum density.
Before compaction, material shall be moistened or aerated as necessary to
provide the optimum moisture content. Material which is too wet shall be
spread on the fill area and permitted to dry, assisted by harrowing if
necessary, until the moisture content is reduced to allowable limits. If
added moisture is required, water shall be applied by sprinkler tanks or
other sprinkler systems, which will insure uniform distribution of the
water over the area to be treated and give complete and accurate control of
the amount of water to be used. If too much water is added, the area shall
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be permitted to dry before compaction is continued. The contractor shall
supply all hose, piping, valves, sprinklers, pumps, sprinkler tanks, hauling
equipment and all other materials and equipment necessary to place water
in the fill in the manner specified. Contractor shall compact each layer to
required percentage of maximum dry density or relative dry density in
accordance with Appendix A, paragraph 3.i. Backfill or fill material shall
not be placed on surfaces that are muddy, frozen or contain frost or ice.
(2)
Bedding and Backfill for Structures
Bedding rock shall be used for bedding under all structures as indicated on
the standard drawings. The contractor shall take all precautions necessary
to maintain the bedding in a compacted state and to prevent washing,
erosion or loosening of this bed. Structural fill shall be used as backfill
against the exterior walls of the structures. Fill shall be compacted
sufficiently in accordance with Appendix A, paragraph 3.i.(2) of these
specifications. If compaction is by rolling or ramming, material shall be
wet down as required.
Backfilling shall be carried up evenly on all walls of an individual
structure. No backfill shall be allowed against walls until the walls and
their supporting slabs, if applicable, have attained sufficient strength.
In locations where pipes pass through building walls, the contractor shall
take precautions to consolidate the fill up to an elevation of at least 1'
above the bottom of the pipes. Structural fill in such areas shall be placed
for a distance of not less than 3' either side of the center line of the pipe in
level layers not exceeding 8" in depth.
The surface of filled areas shall be graded to smooth true lines, strictly
conforming to grades indicated on the drawings. No soft spots or
uncompacted areas will be allowed in the work.
Temporary bracing shall be provided as required during construction of all
structures to protect partially completed structures against all construction
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loads, hydraulic pressure and earth pressure. The bracing shall be capable
of resisting all loads applied to the walls as a result of backfilling.
(3)
Bedding and Backfill for Pipes
Bedding for pipe shall be as shown on the drawings and detailed on the
Standard Drawings. The contractor shall take all precautions necessary to
maintain the bedding in a compacted state and to prevent washing, erosion
or loosening of this bed.
Backfilling over and around pipes shall begin as soon as practicable after
the pipe has been laid, jointed and inspected. All backfilling shall be
prosecuted expeditiously and as detailed on the Standard Drawings.
Any space remaining between the pipe and sides of the trench shall be
carefully backfilled and spread by hand or approved mechanical device
and thoroughly compacted with a tamper as fast as placed, up to a level of
1' above the top of the pipe. The filling shall be carried up evenly on both
sides. Compaction shall be in accordance with the Standard Drawings and
Appendix A, paragraph 3.i.
The remainder of the trench above the compacted backfill, as just
described above, shall be filled and thoroughly compacted in uniform
layers. Compaction shall be in accordance with the Standard Drawings
and Appendix A, paragraph 3.i.
i.
Compaction
(1)
General
The contractor shall control soil compaction during construction to
provide the percentage of maximum density specified. The contractor
shall provide the City copies of all soils testing reports, prepared by a
Geotechnical/Soil Engineer, demonstrating compliance with these
specifications.
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When existing trench bottom has a density less than that specified under
Appendix A, paragraph 3.i.(2) the contractor shall break up the trench
bottom surface, pulverize, moisture-condition to the optimum moisture
content and compact to required depth and percentage of maximum
density.
(2)
Percentage of Maximum Density Requirements
Fill or undisturbed soil from the bottom of the pipe trench to 1' above the
pipe shall be compacted to a minimum density of 98% of the maximum
dry compacted as determined by AASHTO T-180.
Backfill from 1' above utility pipes to grade shall be compacted to a
minimum density of 95% of the maximum dry density as determined by
AASHTO T-180.
Fill under and around structures, and to the extent of the excavation shall
be densified to a minimum density of 95% of the maximum dry density as
determined by AASHTO T-180.
(3)
Compaction Tests
One compaction test location shall be required for each 300 linear feet of
pipe and for every 100 square feet of backfill around structures as a
minimum. The City may determine that more compaction tests are
required to certify the installation depending on field conditions. The
locations of compaction tests within the trench shall be in conformance
with the following schedule:
a.
One test at the spring line of the pipe.
b.
At least one test for each 12" layer of backfill within the pipe
bedding zone for pipes 24" and larger.
c.
One test at an elevation of one foot above the top of the pipe.
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d.
One test for each 2' of backfill placed from 1' above the top of the
pipe to finished grade elevation.
If based on Geotechnical/Soils Engineer testing reports and inspection, fill
which has been placed is below specified density, contractor shall provide
additional compaction and testing prior to commencing further
construction.
j.
Grading
All areas within the limits of construction, including transition areas, shall be
uniformly graded to produce a smooth uniform surface. Areas adjacent to
structures or paved surfaces shall be graded to drain away from structures and
pavement. Ponding shall be prevented. After grading, the area shall be
compacted to the specified depth and percentage of maximum density.
No grading shall be done in areas where there are existing pipelines that may be
uncovered or damaged until such lines have been relocated.
k.
Maintenance
Contractor shall protect newly graded areas from traffic and erosion and keep
them free of trash and debris. Contractor shall repair and reestablish grades in
settled, eroded and rutted areas.
Where completed compacted areas are disturbed by subsequent construction
operations or adverse weather, contractor shall scarify surface, and reshape and
compact to required density prior to further construction.
l.
Inspection and Quality Assurance
(1)
Inspection
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Contractor shall examine the areas and conditions under which excavating,
filling and grading are to be performed, and not proceed with the work
until unsatisfactory conditions have been corrected.
Contractor shall examine existing grade prior to commencement of work
and report to the City if elevations of existing grade vary from elevations
shown on drawings.
(2)
Quality Assurance
All work shall be performed in compliance with applicable requirements
of governing authorities having jurisdiction.
The contractor, at his own expense, shall engage soil testing and
inspection services for quality control testing during earthwork operations.
The testing and inspection service shall be subject to the approval of the
City.
Quality control testing shall be performed during construction to ensure
compliance with these Specifications. Contractor shall allow the testing
service to inspect and approve fill materials and fill layers before further
construction is performed. The contractor shall give copies of all test
results in a report form to the City to demonstrate compliance with
compaction requirements stipulated in this Manual.
4.
BORING AND JACKING
a.
General
Jack and bore shall be required under all state, county and city roads inside the
city. Horizontal directional bores may be considered with approval from the city
engineer and the city utilities department. (Refer to Section 5 below)
The installation of a casing pipe by the method of boring and jacking is covered
herein. The overall work scope shall include, but not be limited to, boring and
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jacking pits and equipment, sheeting, steel casing pipe, skid, stainless steel straps,
coatings, location signs as required, miscellaneous appurtenances to complete the
entire work as shown on the Standard Drawings, and restoration. Applicable
provisions of these specifications shall apply. Boring and jacking operations shall
be performed within the right-of-way and/or easements shown on the drawings.
b.
Pipe Material
(1)
Steel Casing
Steel casings shall conform to the requirements of ASTM Designation
A139 (straight seam pipe only) Grade "B" with a minimum yield strength
of 35,000 psi. The casing pipes shall have the minimum nominal diameter
and wall thickness as shown on the following table:
Carrier Pipe
Nominal Diameter
Casing
Outside Diameter
Casing
Wall Thickness
4"
6"
8"
10"
12"
16"
20"
24"
30"
36"
42"
16"
18"
20"
24"
30"
30"
36"
42"
48"
54"
60"
0.250"
0.250"
0.250"
0.250"
0.312"
0.312"
0.375"
0.500"
0.500"
0.500"
0.500"
Field and shop welds of the casing pipes shall conform with the American
Welding Society (AWS) standard specifications. Field welds shall be
complete penetration, single-bevel groove type joints. Welds shall be
airtight and continuous over the entire circumference of the pipe and shall
not increase the outside pipe diameter by more than 3/4".
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(2)
Carrier Pipe
The carrier pipe shall be minimum class 250 or 350 ductile iron pipe with
restrained joints depending on size of pipe. Refer to following sections.
Ductile iron pipe shall comply with the specification outlined in
Appendices B, paragraph 1.b.(2), B, paragraph 6.d.(1) and C, paragraph
1.d.(1).
(3)
Inspection
All casing pipe to be installed may be subject to be inspected at the site of
manufacture for compliance with these Specifications by an independent
laboratory selected and paid for by the City. The manufacturer's
cooperation shall be required in these inspections.
All casing pipe shall be subjected to a careful inspection prior to being
installed. If the pipe fails to meet the specifications it shall be removed
and replaced with a satisfactory replacement at no additional expense to
the City.
c.
Pipe Handling
Care shall be taken in loading, transporting, and unloading to prevent injury to the
pipe or coatings. Pipe shall not be dropped. All pipe shall be examined before
laying, and no piece shall be installed which is found to be defective. Any
damage to the pipe or coatings shall be repaired to the satisfaction of the City.
d.
Construction Requirements
(1)
Work Coordination
It shall be the contractor's responsibility to perform the boring and jacking
work in strict conformance with the requirements of the agency in whose
right of way or easement the work is being performed. Any special
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requirements of the agency such as insurance, flagmen, etc., shall be
strictly adhered to during the performance of work. The special
requirements shall be performed by the contractor at no additional cost to
the city.
(2)
Dewatering
Dewatering through the casing during construction shall not be permitted.
All dewatering methods shall be approved by the city before construction
work begins.
(3)
Carrier Pipe Support
The carrier pipes shall be supported within the casing pipes so that the
pipe bells do not rest directly on the casing. The load of the carrier pipes
shall be distributed along the casing by wooden skids or casing spacers.
The wooden skids shall be constructed as shown on the Details of
Standard Drawings. Casing spacers shall be bolt on style split shells made
of either T-304 stainless steel or fusion coated steel (a minimum 0.010"
thick coating of PVC shall be provided over the entire band). The shell
shall be lined with a PVC liner 0.090" thick with 85-90 Durometer. All
nuts and bolts shall be high strength, low alloy meeting AWWA Clll.
Runners shall be made of a high molecular weight polymer with inherent
high abrasion resistance and a low coefficient of friction.
(4)
Jacking Pits
Excavation adjacent to the roads shall be performed in a manner to
adequately support the roads. Bracing, shoring, sheeting or other supports
shall be installed as needed. Contractor shall install suitable reaction
blocks for the jacks as required. Jacking operations shall be continuous
and precautions shall be taken to avoid interruptions which might cause
the casing to "freeze" in place. Upon completion of jacking operations,
the reaction blocks, braces, and all other associated construction materials
shall be completely removed from the site.
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(5)
Miscellaneous Requirements
Correct line and grade shall be carefully maintained. Earth within the
casing shall not be removed too close to the cutting edge in order to
prevent the formation of voids outside the casing. If voids are formed,
they shall be satisfactorily filled with grout by pumping.
The sections of steel casing shall be field welded in accordance with the
applicable portions of AWWA C206 and AWS D7.0 for field welded pipe
joints. Contractor shall wire brush the welded joints and paint with Inertol
Quick-Drying Primer 626 by Koppers Company or approved equal. After
completion of jacking, contractor shall clean the interior of the casing of
all excess material.
The annular space between the carrier pipe and casing shall be filled with
clean sand, if required in the Bore and Jack permit. Masonry plugs are to
be installed at each open end of the casing. Plugs shall be suitable for
restraining the earth load while allowing drainage of the casing.
5.
HORIZONTAL DIRECTIONAL BORES (DIRECTIONAL DRILL)
a.
General
Horizontal Directional Bores (directional drilling) may be permitted under all
state, county, and city roads with approval of the City Engineering Department.
Furnish all labor, materials, tools, and equipment required to install a new water
main using the horizontal directional drilling method to the sizes and limits as
shown on the drawings, and as specified by these technical specifications herein.
Work includes, but not limited to, proper installation, testing, restoration of
underground utilities and environmental protection and restoration.
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The directional drilling method involves first drilling a pilot hole as shown on the
approved pilot bore plan, and then enlarging the pilot hole no larger than 1.5 times
the outer diameter of the pull-in pipe, pipe joint coupling and pull back the pipe
through the enlarged hole.
b.
Pipe Materials
Unless otherwise specified in the plans and/or specifications, one of the following
pipes can be considered for horizontal directional drilling contingent upon
approval by the Owner:
•
•
Fusible Polyvinylchloride (PVC) Water Pipe as manufactured by
Underground Solutions, Inc.
Restrained Joint Polyvinylchloride (PVC) Water Pipe as manufactured by
CertainTeed Corporation
The pipe to be used must be certified for use as a pressure-rated water delivery
system and fire protection piping applications conforming to all standards and
procedures, and meeting all testing and material properties as described in
applicable pipe specifications.
c.
Qualification Requirements
All horizontal directional drilling operations shall be performed by a qualified
directional drilling company who has at least three (3) years experience involving
work of a similar nature. The company must have installed a minimum of 25,000
linear feet of pipe (6-inch diameter or greater) using directional drilling operations
or supply a list of project references, prior to job commencement.
•
•
•
Schedule all work through the City. Notify the City a minimum of ten (10)
working days in advance of the start of work.
Perform all work in the presence of the City, or their representative.
All applicable permits and applications must be in place prior to start of work.
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d.
Warranty
A one-year warranty for the pipe shall be included from the Contractor, and shall
cover the cost of replacement pipe and freight to project site, should the pipe have
any defects in material or workmanship.
In addition to the standard pipe warranty, the fusing contractor shall provide in
writing a warranty for a period of one year for all the fusion joints, including
formation, installation, and pressure testing, if applicable.
Unless otherwise specified, the warranty periods shall begin after the Certificate
of Acceptance is issued for the Contract.
e.
Submittals
The Contractor shall make the following submittals:
(1)
Contractor’s Experience Record:
Furnish document(s) supporting the directional drilling Contractor’s
qualifications and experience.
(2)
Material:
Submit all applicable pre and post-construction pipe submittals as per
applicable technical specifications of the pipe to be used for this project.
(3)
Work Plan:
Prior to beginning work, submit a Work Plan detailing the procedure and
schedule to be used to execute the project. The Work Plan is to include
a description of all equipment to be used, down-hole tools, a list of
personnel and their qualification and experience (including backup
personnel in the event that an individual is unavailable), list of
subcontractors, a schedule of work activity, a safety plan (including
MSDS of any potentially hazardous substances to be used), an
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environmental protection plan, and contingency plans for possible
problems. Work Plan should be comprehensive, realistic and based on
actual working conditions for this particular project. The plan should
document the thoughtful planning required to successfully complete the
project.
(4)
Bore Plan:
Prior to beginning work, submit a signed and sealed, scaled drawing of
the pilot bore plan for review and approval (Max Vertical Scale 1” = 2’
and Max Horizontal Scale 1” = 20’). Show finished grade, deflection
and radiuses of the pilot bore, all existing utilities with minimum vertical
and horizontal clearances. Address the location of the drill rig setups
and for multiple bores, the lengths of each bore based on soil condition,
equipment used, topography, etc. The proposed vertical and horizontal
clearances between the bored pipe and any existing/proposed conflicting
pipes, conduits or obstructions can not exceed the guidance system
accuracy tolerance by a minim of 100%.
(5)
Equipment:
Submit specifications on directional drilling equipment to be used to
ensure that the equipment will be adequate to complete the project.
Equipment is to include but not be limited to: drilling rig, mud system,
mud motors (if applicable), down-hole tools, guidance system, and rig
safety systems. Include calibration records for guidance equipment.
Submit any qualifications for any drilling fluid additives that might be
used.
f.
Horizontal Directional Drilling Equipment
The Contractor shall provide directional drill equipment as follows:
(1)
General:
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The directional drilling equipment is to consist of a directional drilling
rig of sufficient capacity to perform the bore and pull back the pipe, a
drilling, fluid mixing, delivery and recovery system of sufficient
capacity to successfully complete the installation, a drilling fluid
recycling system to remove solids from the drilling fluid so that the fluid
can be reused (if required), a Magnetic Guidance System (MGS) or
“walkover” system to accurately guide boring operations, a vacuum
truck of sufficient capacity to handle the drilling fluid volume, and
trained and competent personnel to operate the system. All equipment
must be in good, safe condition with sufficient supplies, materials and
spare parts on hand to maintain the system in good working order for the
duration of this project.
(2)
Drilling Rig:
The drilling shall consist of a hydraulically powered system to rotate and
push hollow drilling pipe into the ground at a variable angle while
delivering a pressurized fluid mixture to a guidable drill (bore) head.
Anchor machine to the ground sufficiently to withstand the pulling,
pushing and rotating pressure required to complete the installation. The
hydraulic power system must be self-contained with sufficient pressure
and volume to power drilling operations. Hydraulic system must be free
of leaks. The rig is to have a system to monitor and record maximum
pullback pressure during pull-back operations. A system to detect
electrical current from the drill string must be in place with an audible
alarm that automatically sound when an electrical current is detected.
(3)
Drill Head:
The drill head shall be steerable by changing its rotation with the
necessary cutting surfaces and drilling fluid jets.
(4)
Mud Motors (if required):
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The mud motor shall have adequate power to turn the required drilling
tools.
(5)
Drill Pipe:
The drill pipe shall be constructed of high quality 4130 seamless tubing,
grade D or better, with threaded box and pins. Tools joints should be
hardened to 32 – 36 RC.
g.
Guidance System
(1)
General:
Use an electronic “walkover” tracking system or a Magnetic Guidance
System (MGS) probe or proven (non-experimental) gyrospopic probe
and interface for a continuous and accurate determination of the location
of the drill head during the drilling operation. The guidance system
must be capable of tracking at all depths up to fifty feet and in any soil
condition, including hard rock. If should enable the driller to guide the
drill head by providing immediate information on the tool face, azimuth
(horizontal direction) and inclination (vertical direction). The guidance
system has to be accurate and calibrated to manufacturer’s specifications
of the vertical depth of the borehole at sensing position at depths up to
fifty feet and accurate to 2-feet horizontally.
(2)
Components:
Supply all components and materials to install, operate, and maintain the
guidance system.
(3)
Operation:
Set up and operate the Magnetic Guidance System (MGS) with
personnel trained and experienced with the system. Be aware of any
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geo-magnetic anomalies and consider such influences in the operation of
the guidance system.
h.
Drilling Fluid (Mud) System
(1)
Mixing System:
A self-contained, closed, drilling fluid mixing system of sufficient size
to mix and deliver drilling fluid composed of bentonite clay, potable
water, and appropriate additives. The mixing system must be able to
molecularly shear individual bentonite particles from the dry powder to
avoid clumping and ensure thorough mixing. The drilling fluid reservoir
tank must be a minimum of 1,000 gallons. Agitate the drilling fluid
during drilling operations
(2)
Drilling Fluids:
Use drilling fluid composed of potable water and bentonite clay. Supply
water from an authorized source with a pH of 8.5-10. Treat any water of
a lower pH or with excessive calcium with the appropriate amount of
sodium carbonate or equal. No additional material may be used in
drilling fluid without prior approval from the Owner. The bentonite
mixture used must have the minimum viscosities as measured by a
March funnel:
Rocky Clay
60 seconds
Hard Clay
40 seconds
Soft Clay
45 seconds
Sandy Clay
90 seconds
Stable Sand
80 seconds
Loose Sand
110 seconds
Wet Sand
110 seconds
These viscosities may be varied to best fit the soil conditions
encountered, or as determined by the operator. No additional fluid shall
be used without prior approval from the Owner.
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(3)
i.
Delivery System:
Fluid pumping system with a minimum capacity of 35-500 GPM and
capable of delivering drilling fluid at a constant minimum pressure of
1200 psi. Employ filters on the delivery system in-line to prevent solids
from being pumped into drill pipe. Contain all used drilling fluid and
drilling fluid spilled during operations convey to the drilling fluid
recycling system or remove by vacuum trucks or other methods
acceptable to the Owner. Maintain a berm, minimum of 12-inches high,
around drill rigs drilling fluid mixing system, entry and exit pits and
drilling fluid recycling system to prevent spills into the surrounding
environment. Furnish pumping equipment and/or vacuum truck(s) of
sufficient size to convey drilling fluid from containment areas, to storage
and recycling facilities or disposal.
Other Equipment:
(1)
Pipe Rollers:
Use pipe rollers for pipe assembly during final product pull back.
(2)
Restrictions:
Do not use other devices or utility placement systems for providing
horizontal thrust other than those previously defined in the preceding
sections unless approved by the Owner prior to commencement of the
work. Consideration for approval will be made on an individual basis for
each specified location. The proposed device or system will be evaluated
by the Owner without undue delay and maintain line and grade within
the tolerances prescribed by the particular conditions of the project.
j.
Execution
(1)
General
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Notify the City a minimum of ten (10) working days in advance of
starting work. All necessary permits and approvals must be in place
prior to commencement of work. Do not begin the directional drilling
until the City is present at the job site and agrees that proper preparations
for the operation have been made. The City’s approval for beginning the
installation does not in any way relieve the Contractor of the ultimate
responsibility for the satisfactory completion of the work as authorized
under the Contract.
All equipment used on the City’s property and right-of-ways may be
inspected by the City or their representatives and removed if considered
unsatisfactory.
(2)
Directional Drilling Operation
Provide all material, equipment, and facilities required for directional
drilling. Maintain proper alignment and elevation of the borehole
throughout the directional drilling operation. The method used to
complete the directional drill must conform to the requirements of all
applicable permits.
Survey the entire drill path with entry and exit stakes placed in the
appropriate locations within the areas indicated on drawings. If using a
magnetic guidance system, survey drill path for any surface geomagnetic variations or anomalies. In addition, open cut, "pothole" or
"daylight" areas along the proposed alignment at 200 foot intervals
before and during the drilling operation to make sure proper alignment
and grade are maintained. It may become necessary, if so determined by
the City, to open excavate, "pothole" or "daylight" other areas to
determine location of existing facilities and utilities. Costs of open
cutting, “potholing" or "daylighting" for the purposes of determining
proper alignment and grade are considered incidental to the base bid
item for horizontal drill.
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Stabilize the open bore hole by means of bentonite drilling slurry
pumped through the inside diameter of the drill rod and through
openings in the reamer. The drilling slurry must be in a homogenous/
flowable state serving as an agent to carry the loose cuttings to the
surface through the annulus of the borehole. Calculate the volume of
bentonite mud required for each pullback based on soil conditions,
largest diameter of the pipe system component, capacity of the bentonite
mud pump, and the speed of pullback as recommended by the bentonite
drilling fluid manufacturer. Contain the bentonite slurry at the exit or
entry side of the directional bore in pits or holding tanks. The slurry may
be recycled at this time for reuse in the hole opening operation, or
hauled off to an approved dumpsite for proper disposal.
Fuse or join all pipe sections together according to manufacturer's
specifications as applicable. The pipe must be free of any chips,
scratches, or scrapes. All piping shall be installed with a continuous,
insulated TW, THW, THWN, or HMWPE insulated copper, 8 gauge or
thicker wire for pipeline location purposes by means of an electronic line
tracer:
− The wires must be installed along the entire length of the pipe.
− The insulation color shall match the color of the pipe being installed.
− Sections of wire shall be spliced together using approved splice caps
and waterproof seals. Twisting the wires together is not acceptable.
(3)
Handling Pipe
Take care during transportation of the pipe such that it will not be cut,
kinked or otherwise damaged.
Use ropes, fabrics or rubber protected slings and straps when handling
pipes. Do not use chains, cables or hooks inserted into the pipe ends.
Use two slings spread apart for lifting each length of pipe. Do not drop
pipe or fittings into rocky or unprepared ground.
City of Umatilla Standard Specifications
Water & Sewer Utilities
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April 2013
Store pipe on level ground, preferably turf or sand, free of sharp objects
that could damage the pipe. Limit the stacking of the pipes to a height
that will not cause excessive deformation of the bottom layers of pipes
under anticipated temperature conditions. Where necessary due to
ground conditions store the pipe on wooden sleepers, spaced suitably
and of such width as not to allow deformation of the pipe at the point of
contact with the sleeper or between supports.
Place a silt fence between all drilling operations and any drainage, wellfields, wetland, waterway or other area designated for such protection if
required by documents, state, federal, and local regulations. Put in place
any additional environmental protection necessary to contain any
hydraulic or drilling fluid spills, including berms, liners, turbidity
curtains, and other measures.
Record readings after advancement of each successive drill pipe (no
more than 10'), and plot on a scaled drawing of 1" - 2' vertical and 1" 20' horizontal. Make all recorded readings and plan and profile
information available at all times. At no time can the deflection radius of
the drill pipe exceed the deflection limits of the carrier pipe as specified
herein.
Submit a complete list of all drilling fluid additives and mixtures to be
used in the directional operation, along with their respective Material
Safety Data Sheets. Contain all drilling fluids and loose cuttings in pits
or holding tanks for recycling or disposal, no fluids should he allowed to
enter any unapproved areas or natural waterways. Dispose of all the
drilling mud and cuttings after job completion at an approved dumpsite.
Drill the pilot hole on the bore path with no deviations greater than 5%
of depth over the length of the bore unless previously agreed to by the
City. In the event that pilot does deviate from the bore path more than
5% of depth over the length of the bore, the pilot must be pulled back
and re-drilled from the location along bore path before the deviation. In
the event of a drilling fluid fracture, inadvertent returns, or returns loss
City of Umatilla Standard Specifications
Water & Sewer Utilities
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April 2013
during pilot hole drilling operations, stop drilling, wait at least 30
minutes, inject a quantity of drilling fluid with a viscosity exceeding 120
seconds as measured by a March funnel and wait another 30 minutes. If
mud fracture or returns loss continues, notify the City.
Upon completion of pilot hole phase of the operation, submit a complete
set of "as-built" records. Include in these records copies of the pilot bore
path plan and profile record drawing, as well as directional survey
reports as recorded during the drilling operation.
Upon approval of the pilot hole location, begin the hole opening or
enlarging phase. Increase the bore hole diameter to accommodate the
pullback operation of the required size of carrier pipe. The type of hole
opener or back reamer to be utilized in this phase is to be determined by
the types of subsurface soil conditions that have been encountered
during the pilot hole drilling operation. Select the proper reamer type
with the final hole opening being a maximum of 1.5 times the largest
outside diameter pipe system component to be installed in the bore hole.
Handle assembled pipe in such a manner that the pipe is not damaged by
dragging it over sharp and cutting objects. Position slings for handling at
pipe joints. Remove sections of the pipes with cuts and gouges or
excessive formation and replace.
(4)
Testing
Clean and flush all equipment and the surrounding site after completion.
Use only potable water for flushing and pressure testing.
Test directional drilling pipe after pullback. The average pressure should
be maintained at 150 psi for two hours. Arrange the test pump and water
supply to allow accurate measurements of the water required to maintain
the test pressure. Replace any material showing seepage or the slightest
leakage as directed by the City at no additional expense to the Contract.
City of Umatilla Standard Specifications
Water & Sewer Utilities
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April 2013
Observe and adhere to the pipe manufacturer's or City (whichever is
more stringent) recommendations on pipe stretch allowances, bending
radius, tensile strength, allowable test leakage allowance, and magnitude
and duration of test pressure.
Test pipeline end to end.
Connect all new service lines and test along with the newly installed
main.
Pressure testing the drilled pipe is not necessary if the pipe is intended to
be used as a casing for a finished product pipe.
(5)
Site Restoration
Following drilling operations de-mobilize equipment and restore the
work site to the original conditions or better. Backfill and compact all
excavations according to these specifications.
(6)
Record Keeping
Maintain a daily project log of drilling operations and a guidance system
log with a copy available to the City- at the completion of project.
Record the guidance system data during the actual crossing operation.
Furnish "as-built" plan and profile drawings based on these recordings
showing the actual location horizontally and vertically of the
installation, and all utility facilities found during the installation. Certify
the guidance data to the capability of the guidance System.
6.
PRESSURE PIPE RESTRAINT
a.
General
City of Umatilla Standard Specifications
Water & Sewer Utilities
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April 2013
Pressure pipe fittings and other items requiring restraint shall be braced with
thrust blocks or other restraining assemblies as specified in this Section. Thrust
blocks may only be used with specific approval of City Engineer and the Utility
Department.
For PVC pipe, 12" and smaller, where thrust blocking is allowed to prevent
movement of lines under pressure at bends, tees, caps, valves, hydrants etc.,
installation shall be by using thrust blocks as specified in Appendix A, paragraph
6.d.
All pressure pipe and fittings 16" and larger shall be restrained as specified in
Appendices A, paragraph 6.b. and A, paragraph 6.c. Use of thrust blocks for
pressure pipe and fittings 16" and larger shall not be allowed.
Ductile iron pressure pipe and fittings 12" and smaller may be restrained
following the criteria established in Appendix A, paragraph 6.c.
b.
Restrained Joint Construction
Sections of piping requiring restrained joints shall be constructed using pipe and
fittings with restrained "Locked-type" joints manufactured by the pipe and fitting
manufacturer and the joints shall be capable of holding against withdrawal for line
pressures 50% above the normal working pressure. Mechanical joint ductile iron
pipe retainer gland shall not be permitted. Any restrained joints that allow for
elongation upon pressurization will not be allowed in those locations where the
pipe comes out of the ground.
Restrained pipe joints that achieve restraint by incorporating cut out sections in
the wall of the pipe shall have a minimum wall thickness at the point of cut out
that corresponds with the minimum specified wall thickness for the rest of the
pipe.
The minimum number of restrained joints required for resisting forces at fittings
and changes in direction of pipe shall be determined from the length of restrained
City of Umatilla Standard Specifications
Water & Sewer Utilities
A - 44
April 2013
pipe on each side of fittings and changes in direction necessary to develop
adequate resisting friction with the soil.
The required lengths of restrained joint ductile iron pipe shall be determined by
the Engineer and shown in a tabular form as depicted on the "Restrained Pipe
Table" in the Standard Drawings. All calculations shall be based on the method
outlined in the publication entitled "Thrust Restraint Design for Ductile Iron
Pipe", latest edition, published by Ductile Iron Pipe Research Association,
Birmingham, AL 35244.
Wherever two (2) 45º bends are used in place of a 90º bend and the minimum
restrained joints required from one (1) 45º bend extend beyond the other 45º bend,
the two (2) 45º bends will be considered as though a 90º bend were located
midway between the two (2) 45º bends.
c.
Mechanical Restraining Devices
(1)
General
Manufacturers Mechanical Restraining Devices as specified herein may be
substituted for the restrained "Locked-Type" joints manufactured by the
ductile iron pipe and fitting manufacturer. The number of joints to be
restrained shall be based on the "Restrained Pipe Table" in the Standard
Drawings.
(2)
Joint Restraint Device
Mechanical joint restraint shall be incorporated in the design of the
follower gland and shall include a restraining mechanism which, when
actuated, imparts multiple wedging action against the pipe, increasing its
resistance as the pressure increases. Flexibility of the joint shall be
maintained after burial. Glands shall be manufactured of ductile iron
conforming to ASTM A 536. Restraining devices shall be of ductile iron
heat treated to a minimum hardness of 370 BHN. Dimensions of the gland
shall be such that it can be used with the standardized mechanical joint
City of Umatilla Standard Specifications
Water & Sewer Utilities
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April 2013
bell and tee-head bolts conforming to ANSI A21.11 and ANSI/AWWA
C153/A21-53. Twist-off nuts shall be used to insure proper actuating of
the restraining devices.
The mechanical joint restraint device shall have a working pressure of at
least 250psi with a minimum safety factor of 2:1.
d.
Thrust Block Construction
Restraining joints are preferable, however thrust blocks may be provided with
specific approval of the City as shown on the drawings. Where undisturbed
trench walls are not available for thrust blocking, the contractor shall furnish
additional concrete or install suitable pipe harnesses or ties designed and
manufactured specifically for this purpose. Additional concrete, harnesses, and/or
ties shall be approved by the City Engineer.
Fittings shall be protected by polyethylene film, minimum 8 mil thick, prior to
placing concrete thrust block.
Concrete for thrust blocking (where allowed) shall have a minimum compressive
strength of 2500psi. Concrete shall be placed against undisturbed material, and
shall not cover joints, bolts or nuts, or interfere with the removal of any joint.
Wooden side forms shall be provided for thrust blocks where trench conditions
require. Thrust blocks shall be properly set and adequately cured prior to
pressurizing the system.
7.
PRESSURE CONNECTION
a.
General
Installations of pressure connections 4" and larger shall be made in accordance
with this section.
City of Umatilla Standard Specifications
Water & Sewer Utilities
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April 2013
b.
Tapping Sleeves
(1)
General
Tapping sleeves shall be mechanical joint sleeves or fabricated steel
sleeves as specified below. All pressure connections to existing asbestos
cement pipe and all "size on size" taps shall utilize mechanical joint
sleeves.
(2)
Mechanical Joint Sleeves
Sleeves shall be cast of gray-iron or ductile-iron and have an outlet flange
with the dimensions of the Class 125 flanges shown in ANSI B16.1
properly recessed for tapping valve. Glands shall be gray-iron or ductile
iron. Gaskets shall be vulcanized natural or synthetic rubber. Bolts and
nuts shall comply with ANSI/AWWA C111/A21.11. Sleeves shall be
capable of withstanding a 200psi working pressure.
(3)
Steel Tapping Sleeves
Sleeves shall be fabricated of minimum 3/8" carbon steel meeting ASTM
A285 Grade C. Outlet flange shall meet AWWA C-207, Class "D" ANSI
150 lb. drilling and be properly recessed for the tapping valve. Bolts and
nuts shall be high strength, low alloy steel to AWWA C111 (ANSI
A21.11). Gasket shall by vulcanized natural or synthetic rubber. Sleeve
shall have manufacturer applied fusion bonded epoxy coating, minimum
12 mil thickness.
(4)
Tapping Valves
Tapping valves shall meet the requirements of Appendix C, paragraph 3.b.
except that units shall be flange by mechanical joint ends. Valves shall be
compatible with tapping sleeves as specified above and specifically
designed for pressure connection operations.
City of Umatilla Standard Specifications
Water & Sewer Utilities
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April 2013
c.
Notification and Connection to Existing Mains
All connections to existing mains shall be made by the contractor only after the
connection procedure and his work scheduling has been reviewed and approved
by the city. The contractor shall submit a written request to the city a minimum of
five (5) working days prior to scheduling said connections. In his request he shall
outline the following:
1.
Points of connection, fittings to be used, and method of flushing and
disinfection if applicable.
2.
Estimated construction time for said connections.
The city shall review the submittal within three (3) working days after receiving it
and inform the contractor regarding approval or denial of his request. If his
request is rejected by the city, the contractor shall resubmit his request modifying
it in a manner acceptable to the city.
All connections shall only be made on the agreed upon date and time. If the
contractor does not initiate and complete the connection work in the agreed upon
manner, he shall be required to reschedule the said connection by following the
procedure outlined above.
The contractor shall not operate any valves in the system.
d.
Installation
(1)
Excavation, Backfill, Compaction and Grading
The applicable provisions of Appendix A, paragraph 3. shall apply.
City of Umatilla Standard Specifications
Water & Sewer Utilities
A - 48
April 2013
(2)
Construction Details
Sufficient length of main shall be exposed to allow for installation of the
tapping sleeve and valve and the operation of the tapping machinery. The
main shall be supported on concrete pedestals or bedding rock at sufficient
intervals to properly carry its own weight, plus the weight of the tapping
sleeve valve and machinery. Any damage to the main due to improper or
insufficient supports shall be repaired at the Contractor's expense.
The inside of the tapping sleeve and valve, the outside of the main, and the
tapping machine shall be cleaned and swabbed or sprayed with 10% liquid
chlorine prior to beginning installation for water system pressure
connections.
After the tapping sleeve has been mounted on the main, the tapping valve
shall be bolted to the outlet flange, making a pressure tight connection.
Prior to beginning the tapping operation, the sleeve and valve shall be
pressure tested at 150psi to ensure that no leakage will occur.
For pressure connections through 12" diameter or less the minimum
diameter cut shall be 1/2" less than the nominal diameter of the pipe to be
attached. For 14" through 20" installations the minimum diameter shall be
1-1/2" less; for larger taps the allowable minimum diameter shall be 2" to
3" less than the nominal diameter of the pipe being attached. After the
tapping procedure is complete the contractor shall submit the coupon to
the city.
For pressure connections to wastewater force mains, the tapping valve shall be
placed horizontally. After the tapping procedure is complete a plug valve shall be
attached to the tapping valve. The tapping valve shall be left in the open position
prior to backfilling.
Adequate poured concrete thrust blocks or restrained joint fittings shall be
provided to prevent movement of the installation when test pressure is applied.
Provisions of Appendix A, paragraph 5. shall apply.
City of Umatilla Standard Specifications
Water & Sewer Utilities
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April 2013
8.
GREASE TRAPS
b.
Shape
Grease traps shall be rectangular in shape with inside length between two and
three times the inside width, or shall be of a shape approved by the Florida
Department of Health and Rehabilitative Services.
h.
Material of Construction
Grease traps shall be constructed of pre-cast concrete with base and walls poured
monolithically. All concrete used in the construction of grease traps shall have a
strength of not less than 3,000psi at 28 days. Tests to determine water tightness
will be required by the city, and shall be made by filling the tank with water to the
overflow point at the time of inspection. Metal, block, brick, fiberglass or
sectional tanks of any description shall not be permitted. The interior wall of the
grease traps shall be finished smooth and impervious. Voids, pits, or protrusions
on or in the inside walls of the grease trap are prohibited.
c.
Wall Thickness
Pre-cast concrete grease traps shall have a minimum wall and bottom thickness of
4". Tops shall have a minimum thickness of 4" when installed in non-traffic areas
and a minimum of 8" when installed in traffic areas. Pre-cast tanks shall be
sufficiently reinforced to resist cracking during handling or installation with a
minimum reinforcement of 6 x 6, ten-ten welded wire mesh or equivalent area.
Pre-cast grease tanks shall not be located where vehicular traffic or other
overburden loads are anticipated unless the design is approved by the City, and
the registered engineer certifies that the tank and soil conditions will support the
anticipated loads. Where support is provided without bearing on the tank, bearing
shall be on the soil independent from the grease tank and reinforced as specified
by the engineer.
d.
Accessibility
Tanks shall be so located and installed as to provide ready accessibility to the
tanks covers, and interior for ease in inspection, operation and maintenance of the
tank.
City of Umatilla Standard Specifications
Water & Sewer Utilities
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April 2013
e.
Clean Outs
Clean outs shall be provided and installed in conformance with the City's
specifications at both the inlet and outlet to the tank(s).
f.
Rings & Covers
Access to the tank(s) for cleaning and inspection shall be provided via a minimum
of two (2), 24" diameter ring and covers, located at each end (inlet and outlet) of
the tank. The cover shall have the words GREASE TRAP cast into it.
g.
Minimum Pipe Size
Minimum recommended inlet and outlet pipe size is 4".
h.
Minimum Slope
Minimum slope for all tank inlet and outlet piping is 1/8" per foot.
i.
Openings
All openings shall be sealed with a waterproof, non-shrinking grout, brushed
smooth inside and outside.
j.
Manhole Insert
Tanks located in areas of questionable drainage are required to have a waterproof
type frame and cover, with a manhole insert.
k.
Inspection
Pre-cast structures shall be inspected by the city prior to being set into the ground.
Any visible reinforcement wire, steel, or honeycombing shall be cause for
rejection.
City of Umatilla Standard Specifications
Water & Sewer Utilities
A - 51
April 2013
APPENDIX B
GRAVITY SEWERS, FORCE MAINS, AND PUMP STATIONS
1.
PIPE MATERIAL FOR GRAVITY SEWERS
a.
General
b.
Pipe Materials
(1)
PVC Gravity Sewer Pipe
(2)
DIP Gravity Sewer Pipe
(3)
Pipe Markings
c.
Joint Materials
(1)
PVC Pipe
(2)
Ductile Iron Pipe
(3)
Joints for Dissimilar Pipe
d.
Fittings
e.
Inspection and Testing
(1)
General
(2)
Miscellaneous Inspection and Testing Requirements
2.
GRAVITY SEWER PIPE LAYING, JOINTING, AND MISCELLANEOUS
CONSTRUCTION DETAILS
a.
Survey Line and Grade
b.
Pipe Preparation and Handling
c.
Sewer Pipe Laying
d.
Trench Preparation and Pipe Bedding
(1)
Trench Excavation, Dewatering, Bedding Material, Backfill, Compaction,
Fill and Grading
(2)
Placement of Pipe Bedding Material
(3)
Depth of Bedding Material
e.
Gravity Pipe and Water Main Separation
f.
Plugs and Connections
g.
Pipe Jointing
3.
MANHOLES
a.
General
b.
Pre-Cast Concrete Sections
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix B
January 2013
c.
d.
e.
f.
g.
h.
4.
(1)
General
(2)
Miscellaneous Requirements
(3)
Inspection
High Density Polyethylene (HDPE) Manholes
(1)
General
(2)
Miscellaneous Requirements
(3)
Inspection
Fiberglass Manholes
(1)
General
(2)
Miscellaneous Requirements
(3)
Inspection
Castings
Construction Details
(1)
Bedding
(2)
Cast In Place Bases
(3)
Pre-Cast Manholes
(4)
Excavation and Backfilling
(5)
Placing Castings
(6)
Channels
(7)
Pipe Connectors
(8)
Drop Manhole Connections
Cleaning
Inspection for Acceptance
SERVICE LATERALS
a.
General
b.
Materials
c.
Construction Details
(1)
General
(2)
Excavation and Backfill
(3)
Pipe Laying and Jointing
(4)
Line and Grade
d.
Termination of Service Laterals
e.
Inspection
f.
Restoration, Finishing and Cleanup
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix B
January 2013
g.
Location
5.
TESTING AND INSPECTION FOR ACCEPTANCE OF GRAVITY SEWERS
a.
General
b.
Testing For Leakage
(1)
Type of Test
(2)
Selection of Test Sections
(3)
Preparation and Coordination For Testing
(4)
Leakage Test
c.
Inspection For Alignment, Deflection and Integrity
6.
WASTEWATER FORCE MAINS
a.
General
b.
Pipe Inspection and Test
c.
PVC Pipe
(1)
PVC Pipe
(2)
Joints
(3)
Fittings
d.
Ductile Iron Pipe and Fittings
(1)
Ductile Iron Pipe
(2)
Fittings
(3)
Joints
(4)
Coatings and Linings
(5)
Polyethylene Encasement
e.
Pipe Handling
f.
Air and Vacuum Release Valves
(1)
General
(2)
Wastewater Air/Vacuum Valve
(3)
Wastewater Air Release Valve
g.
Notification and Connection to Existing Mains
h.
Plug Valves
(1)
General
(2)
Valve Construction
(3)
Valve Testing
(4)
Actuators
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix B
January 2013
i.
j.
k.
l.
m.
n.
7.
Valve Boxes
Separation of Force Mains, Water Mains and Reclaimed Water Mains
Force Main Construction
Hydrostatic Tests
Final Cleaning
Location and Identification
WASTEWATER PUMP STATIONS
a.
General
b.
Wet Well and Valve Vault
c.
Access Frames and Covers
d.
Pumps and Controls
e.
Submersible Wastewater Pumps
(1)
General
(2)
Pump Construction Details
(a)
Shaft
(b)
Impeller
(c)
Mechanical Seal
(d)
Guides
(3)
Motors
(a)
General Requirements
(b)
Heat and Moisture Sensors
(c)
Cables
f.
Pump Station Electrical Power and Control System
(1)
General
(2)
Panel Construction
(3)
Power Supply and Main Disconnect
(4)
Circuit Breakers
(5)
Motor Circuit Protectors
(6)
Motor Starter and Selector Switches
(7)
Pump Alternator
(8)
Lights and Alarms
(a)
Indicator Lights
(b)
High Level Alarm
(9)
Emergency Generator
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix B
January 2013
(10)
g.
h.
Additional Requirements
(a)
Wiring
(b)
Terminal Points
(c)
Engraved Nameplates
(d)
Surge Protector
(e)
Elapsed Time Meters.
(f)
Convenience Receptacle
(g)
Control Terminal Blocks
(h)
Control Power Transformers
(I )
Control Relay
(j )
Electrical Schematic
(k)
Phase Monitor
(11) Testing, Service and Warranty
(a)
Testing
(b)
Service
(c)
Warranty
Piping, Valves and Accessories
(1)
Piping
(2)
Plug Valves
(3)
Check Valves
(4)
Pressure Gauges
Standby Power Generator System
(1)
General
(2)
Generator Set
(a)
General
(b)
Requirements
(c)
Tests
(d)
Ratings
(e)
Engine
(f)
Generator
(g)
Engine Generator Control Panel
Control Equipment:
Metering Equipment:
Fault Indicators:
Function Switch:
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix B
January 2013
I
j.
k.
l..
m.
n.
o.
p.
q.
(h)
Battery Charger
(i)
Battery
(j)
Base and Mounting
(k)
Utility Connections
(l)
Cooling System
(m)
Fuel System
(n)
Exhaust System
(o)
Weatherproof Enclosure
(p)
Automatic Transfer Switch
(q)
Warranty
Flow Monitoring System
(1)
General
(2)
Acoustic Sensors and Mounting Requirements
(a)
For External Sensors (two inch Diameter Meters and Larger).
(b)
For “Hot Shot” Sensors (12 inch Diameter and Larger).
(c)
For In Stream Wetted Sensors ( 24 inch Diameter and Larger).
(d)
For Fabricated Spool Design.
(3)
Transmitter Requirements.
(4)
Electronic Recording Receiver
(5)
Performance Specifications.
(6)
Materials
(7)
Flow Meter Maintenance.
(8)
Warranty and Service
(a)
Warranty
(b)
Service.
Electrical Grounding System
(1)
General
(2)
Material and Installation
Inspection and Testing
Required Submittals
Shop Painting
Handling
Warranty
Tools and Spare Parts
Chain Link Fence
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix B
January 2013
(1)
(2)
(3)
r
g
General
Materials
Installation
(a)
Post Setting
(b)
Gates
(c)
Placing Fence
Wet Well Entrance
Wet Well Grounds
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix B
January 2013
APPENDIX B
GRAVITY SEWERS, FORCE MAINS, AND PUMP STATIONS
1.
PIPE MATERIAL FOR GRAVITY SEWERS
a.
General
Pipe used in gravity sewer construction shall be polyvinyl chloride (PVC) or
ductile iron pipe (DIP). Where reference is made to an ASTM, ANSI or
AASHTO designation, it shall be the latest revision.
The contractor shall be responsible for all materials furnished and storage of
same, until the date of substantial completion. The contractor shall replace at his
own expense all materials found to be defective or damaged in handling or
storage. The contractor shall, if requested by the City, furnish certificates,
affidavits of compliance, test reports, or samples for check analysis for any of the
materials specified herein. All pipe delivered to project site for installation is
subject to random testing for compliance with the designated specifications.
b.
Pipe Materials
(1)
PVC Gravity Sewer Pipe
PVC Gravity Sewer Pipe (4" - 15") (8’ or less depth), ASTM D3034,
Standard Dimension Ratio (SDR) 35. Uniform minimum "pipe stiffness"
at 5% deflection shall be 46 psi. The joints shall be integral bell
elastomeric gasket joints manufactured in accordance with ASTM D3212
and ASTM F477. Applicable UNI-Bell Plastic Pipe Association standard
is UNI-B-4.
PVC Gravity Sewer Pipe (4" - 15") (8’ or greater depth), ASTM D3034,
Standard Dimension Ratio (SDR) 28. Uniform minimum "pipe stiffness"
at 5% deflection shall be 46 psi. The joints shall be integral bell
elastomeric gasket joints manufactured in accordance with ASTM D3212
City of Umatilla Standard Specifications
Water & Sewer Utilities
B-1
January 2013
and ASTM F477. Applicable UNI-Bell Plastic Pipe Association standard
is UNI-B-4.
PVC Gravity Sewer Pipe (18" - 27"), ASTM F679, SDR 35. Uniform
minimum "pipe stiffness" at 5% deflection shall be 46 psi. The joints shall
be integral bell elastomeric gasket joints manufactured in accordance with
ASTM D3212 and ASTM F477. Applicable UNI-Bell Plastic Pipe
Association standard is UNI-B-7.
All PVC pipe shall bear the NSF-DW seal. The minimum standard length
of pipe shall be 13'.
7.
DIP Gravity Sewer Pipe
DIP shall only be used with written permission from city engineer and the
city utility department
Ductile iron pipe shall conform to ANSI/AWWA A21.51/Cl5l, class
thickness designed per ANSI/AWWA A21.50/Cl5O, with mechanical or
push on joints. All ductile iron pipe and fittings shall have an interior
protective lining of coal tar epoxy with a minimum dry thickness of 30
mils, applied by the pipe manufacturer. The polyethylene lining material
shall comply with ASTM D-1248. Additionally, the pipe shall be
polyethylene encased (8 mil) where required by the City in accordance
with ANSI/AWWA A21.51/C105. The minimum standard length of pipe
shall be 18'.
(3)
Pipe Markings
All pipe shall have a homing mark on the spigot provided by the
manufacturer. On field cut pipe, contractor shall provide homing mark on
the spigot in accordance with manufacturers recommendation. Reinforced
concrete pipe shall have markings indicating the minor axis of the
elliptical reinforcement.
c.
Joint Materials
City of Umatilla Standard Specifications
Water & Sewer Utilities
B-2
January 2013
(1)
PVC Pipe
PVC sewer pipe joints shall be flexible elastomeric seals per ASTM D
3212.
(2)
Ductile Iron Pipe
Ductile iron pipe and fitting joints shall be "push-on" or mechanical joints
conforming to ANSI/AWWA A21.11/C110.
(3)
Joints for Dissimilar Pipe
Joints between pipes of different materials shall be made with a flexible
mechanical compression coupling with No. 304 stainless steel bands.
d.
Fittings
Unless otherwise specified, wye branches shall be provided in the gravity sewer
main for service lateral connections. Wyes shall be 6" inside diameter, unless
otherwise approved by the City. All fittings shall be of the same material as the
pipe.
Plugs for stub outs shall be of the same material as the pipe, and gasket with the
same gasket material as the pipe joint, or be of material approved by the City.
The plug shall be secured to withstand test pressures specified in Appendix B,
paragraph 5.of these specifications.
e.
Inspection and Testing
(1)
General
City of Umatilla Standard Specifications
Water & Sewer Utilities
B-3
January 2013
Each length of pipe shall bear the name or trademark of the manufacturer,
the location of the manufacturing plant, and the class or strength
classification of the pipe. The markings shall be plainly visible on the
pipe barrel. Pipe which is not marked clearly is subject to rejection. All
rejected pipe shall be promptly removed from the project site by the
contractor.
(2)
Miscellaneous Inspection and Testing Requirements
All pipe and accessories to be installed under this Contract shall be
inspected and tested at the place of manufacture by the manufacturer as
required by the Standard Specifications to which the material is
manufactured.
Each length of pipe shall be subject to inspection and approval at the
factory, point of delivery, and site of work. If requested by the City, a
sample of pipe to be tested shall be selected at random by the City or the
testing laboratory hired by the City.
When the specimens tested conform to applicable standards, all pipe
represented by such specimens shall be considered acceptable based on the
test parameters measured. Copies of test reports shall be available before
the pipe is installed in the project.
In the event that any of the test specimens fail to meet the applicable
standards, all pipe represented by such tests shall be subjected to rejection.
The contractor may furnish two additional test specimens from the same
shipment or delivery, for each specimen that failed and the pipe will be
considered acceptable if all of these additional specimens meet the
requirements of the applicable standards. All such retesting shall be at the
Contractor's expense.
City of Umatilla Standard Specifications
Water & Sewer Utilities
B-4
January 2013
Pipe which has been rejected by the City shall be removed from the site of
the work by the contractor and replaced with pipe which meets these
specifications.
2.
GRAVITY SEWER PIPE
CONSTRUCTION DETAILS
a.
LAYING,
JOINTING,
AND
MISCELLANEOUS
Survey Line and Grade
The contractor shall set Temporary Bench Marks (TBM'S) at a maximum 500'
interval. The contractor shall constantly check line and grade of the pipe by laser
beam method. In the event line and grade do not meet specified limits described
hereinafter, the work shall be immediately stopped, the City notified, and the
cause remedied before proceeding with the work.
b.
Pipe Preparation and Handling
All pipe and fittings shall be inspected prior to lowering into trench to insure no
cracked, broken, or otherwise defective materials are being used. The contractor
shall clean ends of pipe thoroughly and remove foreign matter and dirt from
inside of pipe and keep clean during and after laying.
Proper implements, tools, and facilities shall be used for the safe and proper
protection of the work. Pipe shall be lowered into the trench in such a manner as
to avoid any physical damage to the pipe. Pipe shall not be dropped or dumped
into trenches under any circumstances.
c.
Sewer Pipe Laying
City of Umatilla Standard Specifications
Water & Sewer Utilities
B-5
January 2013
Laying of sewer pipe shall be accomplished to line and grade in the trench only
after it has been dewatered and the trench has been prepared in accordance with
specifications outlined herein. Refer to Appendix B.2.d. for additional bedding
requirements. Mud, silt, gravel and other foreign material shall be kept out of the
pipe and off the jointing surface.
All pipe laid shall be retained in position so as to maintain alignment and joint
closure until sufficient backfill has been completed to adequately hold the pipe in
place. All pipe shall be laid to conform to the line and grade shown on the
drawings.
Variance from established line and grade, at any point along the length of the
pipe, shall not be greater than 1/32 inch per inch of pipe diameter and not to
exceed 1/2 inch, provided that any such variation does not result in a level or
reverse sloping invert.
The sewer pipe, unless otherwise approved by the City, shall be laid up grade
from point of connection on the existing sewer or from a designated starting point.
The sewer pipe shall be installed with the bell end forward or upgrade. When
pipe laying is not in progress the open end of the pipe shall be kept tightly closed
with an approved temporary plug.
All PVC pipe shall be installed in accordance with the pipe manufacturer's written
recommendations as approved by the City. Laying of Ductile Iron Pipe shall
conform to the specifications outlined in Appendix C, paragraph 2.d.(7).
d.
Trench Preparation and Pipe Bedding
(1)
Trench Excavation, Dewatering, Bedding Material, Backfill, Compaction,
Fill and Grading
Applicable provisions of Appendix A, paragraph .3. shall apply. Also
refer to Standard Drawings.
(2)
Placement of Pipe Bedding Material
City of Umatilla Standard Specifications
Water & Sewer Utilities
B-6
January 2013
Contractor shall hand-grade bedding to proper grade ahead of pipe laying
operation. Bedding shall provide a firm, unyielding support along the
entire pipe length.
If without direction from the City, the trench has been excavated below
the required depth for pipe bedding material placement, contractor shall
fill the excess depth with pipe bedding material to the proper grade.
Contractor shall excavate bell holes at each joint to permit proper
assembly and inspection of the entire joint.
(3)
Depth of Bedding Material
Contractor shall provide pipe bedding material in accordance with the
Standard Drawings.
e.
Gravity Pipe and Water Main Separation
Gravity sewers that are laid in the vicinity of pipe lines designated to carry
potable water shall meet the conditions set forth in Appendix C, paragraph 2.c.
f.
Plugs and Connections
Plugs for pipe branches, stubs or other open ends which are not to be immediately
connected shall be made of an approved material and shall be secured in place
with a joint comparable to the main line joint.
g.
Pipe Jointing
All pipe shall be installed to the homing mark on the spigot. The City shall be
given an opportunity to check all joints in this manner before backfilling.
City of Umatilla Standard Specifications
Water & Sewer Utilities
B-7
January 2013
Type of joint to be used will conform to the requirements of Appendix B,
paragraph 1.c. All pipe and jointing for gravity sewers shall be subject to the tests
specified in Appendix B, paragraph 5.
3.
MANHOLES
a.
General
Manholes shall be leak-tight and constructed of pre-cast concrete units. High
density polyethylene or fiberglass manholes may be allowed with the approval of
the City Engineer.
b.
Pre-Cast Concrete Sections
(1)
General
Pre-cast manholes shall conform to specifications for Pre-cast Reinforced
Concrete Manhole Sections, ASTM Designation C478, except as
otherwise specified below.
(2)
Miscellaneous Requirements
The minimum wall thickness shall be 5". Pre-cast manholes shall be
constructed with a pre-cast monolithic base structure as shown on the
Standard Drawings. The minimum base thickness shall be 8".
Concrete for manholes shall be Type II, 4,000 psi at 28 days. Barrel, top
and base sections shall have tongue and groove joints. All jointing
material shall be cold adhesive preformed plastic gaskets, conforming with
FDOT Article 942-2.
City of Umatilla Standard Specifications
Water & Sewer Utilities
B-8
January 2013
The date of manufacture and the name or trademark of the manufacturer
shall be clearly marked on each pre-cast section.
Sections shall be cured by an approved method for at least 28 days prior to
painting and shall not be shipped until at least 2 days after having been
painted.
Pre-cast concrete top slabs shall be used where cover over the top of the
pipe is less than 4'. Lift rings or non-penetrating lift holes shall be
provided for handling pre-cast manhole sections. Non-penetrating lift
holes shall be filled with non-shrink grout after installation of the manhole
sections.
Concrete surfaces shall have form oil, curing compounds, dust, dirt and
other interfering materials removed by brush or sand blasting and shall be
fully cured prior to the application of any coatings.
Interior surfaces of manholes shall have a protective epoxy coal tar
coating with a minimum dry mil thickness of 16 mils. Exterior surfaces
shall have a protective epoxy coal tar coating with a minimum dry mil
thickness of 9 mils. Coatings shall be applied in two (2) applications by
the manhole manufacturer in strict accordance with the paint
manufacturer's recommendations.
(3)
Inspection
The quality of all materials, the process of manufacture, and the finished
sections shall be subject to inspection and approval by the City. Such
inspection may be made at the place of manufacture, or at the site after
delivery, or at both places, and the sections shall be subject to rejection at
any time on account of failure to meet any of the specification
requirements; even though sample sections may have been accepted as
satisfactory at the place of manufacture. Sections rejected after delivery to
the job shall be marked for identification and shall be removed from the
City of Umatilla Standard Specifications
Water & Sewer Utilities
B-9
January 2013
job at once. All sections which have been damaged after delivery will be
rejected and, if already installed, removed and replaced, entirely at the
contractor's expense.
At the time of inspection, the sections will be carefully examined for
compliance with the specified ASTM designation, and with the approved
manufacturer's drawings. All sections shall be inspected for general
appearance, dimension, "scratch-strength" blisters, cracks, roughness,
soundness, etc. The surface shall be dense and close-textured.
c.
High Density Polyethylene (HDPE) Manholes
(1)
General
HDPE manholes shall conform to the requirements of Type III, Class C,
category 5, Grade P34, high density, high molecular weight polyethylene
pipe material, as defined in ASTM D-1248, Standard Specification for
Polyethylene Plastics Molding and Extrusion Materials.
(2)
Miscellaneous Requirements
The manhole shall be manufactured by the fabrication of High Density
Polyethylene. Walls and stub-out shall be a minimum of Class160 as
defined in ASTM F-894.
Manhole sections shall be manufactured with bell and spigot ends.
Joining will be accomplished by rubber gasket in accordance with the
manufacturer's recommendations.
Rubber gaskets shall meet the physical requirements specified in the nonpressure requirements of ASTM Specification F-477.
Lubricant used for assembly shall have no detrimental effect on the gasket
or on the manhole section.
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 10
January 2013
The manhole sections and fittings shall be homogenous throughout and
free from visible cracks, holes, foreign inclusions or other injurious
defects. The minimum Ring Stiffness Constant for manholes is 160.
The date of manufacture and the name or trademark of the manufacturer
shall be clearly marked on each section.
(3)
Inspection
The quality of all material, the process of manufacture and the finished
sections shall be subject to inspection and approval by the City in
accordance with the requirements of Appendix B, paragraph 3.b.(3).
d.
Fiberglass Manholes
(1)
General
Fiberglass manholes shall conform to the requirements of ASTM
Specification D3753 for glass fiber-reinforced polyester manholes, and the
requirements of AASHO H-20 Axial Loads.
(2)
Miscellaneous Requirements
The manhole shall be constructed of glass fiber-reinforced Isopthalic
polyester resin containing chemically enhanced sand. The manholes shall
conform to the above design criteria as well as the following: ASTM C581, ASTM D-2412, ASTM D-695, and ASTM D-2584.
The standard wall thickness shall be 0.50" nominal. The nominal diameter
of the manhole shall be 48". The height shall be selected in accordance
with project drawings or the design engineer's specifications.
The interior surface of the manhole shall be smooth.
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 11
January 2013
The date of manufacture and the name or trademark of the manufacturer
shall be clearly marked on each manhole section.
Manholes shall be installed in accordance with the manufacturer's
instructions.
(3)
Inspection
The quality of all material, the process of manufacture and finished
manhole sections shall be subject to inspection and approval by the City in
accordance with the requirements of Appendix B, paragraph 3.b.(3).
e.
Castings
Gray iron castings for manhole frames, covers, adjustment rings and other items
shall conform to the ASTM Designation A 48, Class 30. Castings shall be true to
pattern in form and dimensions and free of pouring faults and other defects which
would impair their strength, or otherwise make them unfit for the service
intended. The seating surfaces between frames and covers shall be machined to
fit true. No plugging or filling will be allowed. Lifting or "pick" holes shall be
provided, but shall not penetrate the cover. Casting patterns shall conform to
those shown or indicated on the Standard Drawings. All manhole frames and
covers shall be traffic bearing to meet AASHTO H-20 loadings. Frames shall be
suitable for the future addition of a cast iron ring for upward adjustment of top
elevation. In certain locations bolt down covers and gasketed covers shall be
located as shown on the drawings (ie: flood prone areas).
f.
Construction Details
(1)
Bedding
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 12
January 2013
Base sections shall be placed on bedding rock conforming to the
requirements in Appendix A, paragraph 3.h.(2). The bedding rock shall be
firmly tamped and made smooth and level to assure uniform contact and
support of the pre-cast element. Refer to Appendix A, paragraph 3.i(2)
for density requirements. Refer to the Standard Drawings for additional
bedding details.
(2)
Cast In Place Bases
Cast in place bases shall be utilized only when specifically approved by
the City. Unless otherwise specified, cast-in-place bases shall be at least
8" in thickness and shall extend at least 6" radially outside of the outside
dimension of the manholes section. Reinforcement and connection to the
riser sections shall be designed by the Developer's Engineer and submitted
to the City for approval.
(3)
Pre-Cast Manholes
A pre-cast base section shall be carefully placed on the prepared bedding
so as to be fully and uniformly supported in true alignment and making
sure that all entering pipes can be inserted on proper grade.
Pre-cast manhole sections shall be handled by lift rings or non-penetrating
lift holes. Such holes shall be filled with non-shrink grout after installation
of the manhole.
The first pre-cast section shall be placed and carefully adjusted to true
grade and alignment. All inlet pipes shall be properly installed so as to
form an integral watertight unit. The sections shall be uniformly
supported by the base structure, and shall not bear directly on any of the
pipes.
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 13
January 2013
Pre-cast sections shall be placed and aligned to provide vertical alignment
with a 1/4" maximum tolerance per 5' of depth. The completed manhole
shall be rigid, true to dimensions, and watertight.
(4)
Excavation and Backfilling
Requirements of Appendix A, paragraph 3. shall apply.
(5)
Placing Castings
Casting shall be fully bedded in mortar with adjustment brick courses
placed between the frame and manhole. Bricks shall be a minimum two
(2) and maximum four (4) courses. Mortar shall conform to ASTM
C-270, type M, and the bricks shall be clay and conform to ASTM C-216,
grade SW, size 3-1/2" (w) x 8" (l) x 2-1/4" (h).
Top of manhole castings located in pavement, shouldered areas, and
sidewalks shall be set flush with grade. Top of manhole castings located
outside these areas shall be placed 2" above grade.
(6)
Channels
Manhole flow channels shall be as shown in the Standard Drawings, with
smooth and carefully shaped bottoms, built up sides and benching
constructed using cement and brick with no voids. Channels shall
conform to the dimension of the adjacent pipe and provide for evenly
changes in size, grade and alignment. Cement shall be Portland Cement
Type II only.
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 14
January 2013
(7)
Pipe Connectors
Special care shall be taken to see that the openings through which pipes
enter the structure are provided with watertight connections. For ductile
iron and PVC pipe, connections shall conform with ASTM C 923,
"Standard Specifications for Resilient Connectors between Reinforced
Concrete Manhole Structures and Pipes."
(8)
Drop Manhole Connections
Drop manhole connections shall conform in all respects to details shown
on Details of the Standard Drawings.
g.
Cleaning
All newly constructed manholes shall be cleaned of any accumulation of silt,
debris, or foreign matter of any kind, and shall be free from such accumulations at
the time of final inspection.
h.
Inspection for Acceptance
No visible leakage in the manhole or at pipe connections will be permitted.
Manholes shall be hydraulically tested using the method specified in ASTM
C969. All manholes shall be inspected by the City prior to acceptance. All
manholes failing to meet the specifications set forth above shall be reconstructed
or replaced by the contractor to comply with these specifications. Pressure
grouting of manholes for repair shall not be accepted.
4.
SERVICE LATERALS
a.
General
A service lateral is a branch gravity sewer constructed from the main gravity
sewer to the right-of-way line or to a point established by the City. A sewer
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 15
January 2013
cleanout shall be installed at the property line for each service lateral and a two by
two foot,4 inch thick cement pad placed around the top of lateral.
The general requirements for construction of gravity sewers in Appendices B,
paragraph 1. and B, paragraph 2. of these Specifications shall apply for service
laterals unless they are inconsistent with the provisions of this section.
Service laterals and fittings shall be a minimum of 6" in diameter.
b.
Materials
Pipe, fittings & joints shall be PVC or DI pipe and shall conform to the
requirement for gravity sewer construction in Appendix B, paragraph 1. of these
specifications.
Service laterals shall be connected to the wye, provided in the gravity sewer
where such is available, utilizing approved fittings or adapters.
On existing mains where no wye is provided or available, connection shall be
made by either a machine-made tap and suitable saddle, or a cast-in-place
manhole as referenced in Section 3, paragraph 2.C(4)(e).
c.
Construction Details
(1)
General
Service lateral connections shall conform to these specifications and
Standard Drawings.
All necessary approvals for service sewer
construction shall be obtained prior to beginning the work.
(2)
Excavation and Backfill
Excavation and backfilling for service sewers shall conform to the
requirements of Appendices A, paragraph 3. and B, paragraph 2.,
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 16
January 2013
excepting that no backfill in excess of that required to hold the pipe in true
alignment shall be placed prior to inspection.
(3)
Pipe Laying and Jointing
Pipe laying and jointing, except as hereinafter provided, shall in general
conform to the requirements of Appendix B, paragraph 2. During the pipe
laying and jointing, the service lateral shall be kept free of any water, dirt
or objectionable matter.
(4)
Line and Grade
Pipe shall be laid with a minimum slope of 1' per 100'. The contractor
shall establish such alignment and grade control as is necessary to
properly install the service sewer. Pipe shall be laid in a straight line at a
uniform grade between fittings.
d.
Termination of Service Laterals
Service laterals shall terminate at the right-of-way line in accordance with the
Standard Drawings. Water-tight factory made plug(s) shall be installed at the end
of each service lateral.
e.
Inspection
Service sewers shall meet the inspection requirements specified in Appendix B,
paragraph 1.e.
f.
Restoration, Finishing and Cleanup
The contractor shall restore all paved surfaces, curbing, sidewalks or other
surfaces to their original condition in such manner as to meet the requirements
established in Appendix B of these specifications. All surplus material and
temporary structures, as well as all excess excavation shall be removed and the
entire site shall be left in a neat and clean condition.
City of Umatilla Standard Specifications
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B - 17
January 2013
g.
Location
The exact location of the termination point of each installed service lateral shall
be marked by etching or cutting an "S" in the concrete curb. Where no curb
exists, locations shall be adequately marked by a method approved by the City.
Brass or aluminum markers may also be used.
5.
TESTING AND INSPECTION FOR ACCEPTANCE OF GRAVITY SEWERS
a.
General
All gravity sewers shall be tested for alignment, deflection and integrity prior to
acceptance. In addition, a leakage test may be required for gravity sewers, solely
at the discretion of the City. The leakage testing shall be performed by the
contractor who shall be responsible for furnishing all necessary labor and
equipment to conduct such testing. Alignment, deflection and integrity testing
shall be performed utilizing television inspection or other methods solely at the
discretion of the City.
b.
Testing For Leakage
(1)
Type of Test
If required by the City, gravity sewers shall be required to pass a leakage
test before acceptance. Leakage tests shall be by the low-pressure air test
as described below.
(2)
Selection of Test Sections
Each test section shall not exceed 400' in length and shall be tested
between adjacent manholes.
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 18
January 2013
(3)
Preparation and Coordination For Testing
The contractor shall flush all sewers with water sufficient in volume to
obtain free flow through each line. Flushing water and debris shall not
enter any pump station wet well. Water will be pumped from the sewer
system during flushing to an acceptable discharge location. A visual
inspection shall be made and all obstructions removed.
The contractor shall notify the City 48 hours prior to performing any
leakage testing.
The results of all leakage tests shall be presented by the contractor to the
City in neat, legible writing. These written results shall be formatted and
adequately labeled so that they are easily understandable.
The contractor shall install sufficient monitoring wells in the
representative areas of the gravity system, acceptable to the City, to
determine the groundwater elevations. Monitoring wells shall be installed
a minimum 24 hours prior to testing.
(4)
Leakage Test
Leakage testing shall be conducted in accordance with the procedure for
(Recommended Practice For Low Pressure Air Testing of Installed Sewer
Pipe) as established by the Uni-Bell PVC Pipe Association and ASTM
F1417. Passing this test shall be presumed to establish leakage test limits
of 50 gallons per day per inch diameter per mile of sewer.
c.
Inspection For Alignment, Deflection and Integrity
Internal video inspection or other testing methods for the gravity sewer shall be
performed to check for alignment and deflection. The television inspection may
also be used to check for cracked, broken or otherwise defective pipe, and overall
pipe integrity.
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 19
January 2013
Prior to inspection, the contractor shall flush all sewers with water sufficient in
volume to obtain free flow through each line. Flushing water and debris shall not
enter any pump station wet well. Water will be pumped from the sewer system
during flushing to an acceptable discharge location. A visual inspection shall be
made and all obstructions removed.
The first inspection will be within 30 days after Substantial Completion of the
installation of the gravity sewer pipe, provided the road base is in place and the
manhole rings and covers are to grade. The requirement of road base being in
place shall be waived if the top of the sewer is 12' below the finished grade. In
such cases, the video inspection shall be performed once the trench has been
compacted up to the road base.
If the video inspection reveals cracked, broken, or defective pipe, or pipe
misalignment resulting in vertical sags in excess of 1-1/2" and in the case of PVC
pipe a ring deflection in excess of 5%, the contractor shall be required to repair or
replace the pipeline. A mandrel deflection test shall be required on all gravity
sewer piping..
Successful passage of the leakage test, a mandrel deflection test, and video or
visual inspection is required before acceptance of any gravity sewer by the City.
Prior to repair or replacement of failed sewer pipe, the method of repair or
replacement shall be submitted to the City for approval. Pressure grouting of pipe
or manholes shall not be considered as an acceptable method of repair.
6.
WASTEWATER FORCE MAINS
a.
General
These specifications cover the pipe, fittings, and accessory items used for
wastewater force main systems.
Pipe used in wastewater force main systems shall be either PVC or DIP. HDPE
may be used subject to City approval.
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 20
January 2013
The contractor shall be responsible for all materials furnished and storage of
same, until the date of project completion. The contractor shall replace at his own
expense all materials found to be defective or damaged in handling or storage.
The contractor shall, if requested by the City, furnish certificates, affidavits of
compliance, test reports, or samples for check analysis for any of the materials
specified herein. All pipe delivered to project site for installation is subject to
random testing for compliance with the designated specifications.
b.
Pipe Inspection and Test
Requirements specified in Appendix B, paragraph 1.e. shall apply.
c.
PVC Pipe
(1)
PVC Pipe
All PVC pipe of nominal diameter 4" through 12" shall be manufactured
in accordance with AWWA standard C900. The PVC pipe shall have a
minimum working pressure rating of 100 psi and shall have a DR of 25.
Pipe shall be the same O.D. as ductile iron pipe.
(2)
Joints
PVC pipe shall have integral bell push on type joints conforming to
ASTM D3139.
(3)
Fittings
Fittings used with PVC pipe shall conform to Appendix B.6.d.
City of Umatilla Standard Specifications
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January 2013
d.
Ductile Iron Pipe and Fittings
7.
Ductile Iron Pipe
Ductile Iron Pipe - Shall only be used with written permission from city
engineer and the city utility department
All ductile iron pipe of nominal diameter 4" through 20" shall be Class
350 and for pipes larger than 20" shall be Class 250 and shall conform to
ANSI/AWWA A21.51/Cl5l.
(2)
Fittings
All fittings shall be mechanical joint ductile iron or gray iron conforming
to ANSI/AWWA A21.10/C110, 250 psi minimum pressure rating, or
ductile iron compact fittings in accordance with ANSI/AWWA
A21-53/Cl53.
(3)
Joints
Joints for ductile iron pipe and fittings shall be push-on or mechanical
joints conforming to ANSI/AWWA A21.11/C111, unless otherwise called
for on the DRAWINGS. Where called for on the Drawings, restrained or
flanged joints shall be provided. Flanged joints shall conform to ANSI
Standard B16.1-125 LB. Restrained joints shall conform to Appendices
A, paragraph 6.c.
(4)
Coatings and Linings
Where ductile iron pipe and fittings are to be below ground or installed in
a casing pipe the coating shall be a minimum 1.0 mil thick in accordance
with ANSI/AWWA A21.51/Cl5l. Where ductile iron pipe and fittings are
to be installed above ground, pipe, fittings and valves shall be thoroughly
cleaned and given one field coat (minimum 1.5 mils dry thickness) of rust
inhibitor primer. Intermediate and finished field coats of Alkyd shall also
be applied by the contractor (minimum 1.5 mils dry thickness each coat).
City of Umatilla Standard Specifications
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B - 22
January 2013
Primer and field coats shall be compatible and shall be applied in
accordance with the manufacturers recommendations. Final field coat
color shall be grey for raw wastewater and brown for treated wastewater.
All ductile iron pipe and fittings shall have an interior protective lining of
coal tar epoxy or polyethylene with a minimum dry thickness of 30 mils
applied by the pipe manufacturer. Polyethylene lining material shall
comply with ASTM D-1248 and shall be fused to the interior of the pipe
by heat forming a tightly bonded lining.
(5)
Polyethylene Encasement
The pipe shall be polyethylene encased (8 mil) where shown on the
drawings or required by the City in accordance with ANSI/AWWA
A21.51/C105.
e.
Pipe Handling
Requirements specified in Appendix C, paragraph 2.b. shall apply.
f.
Air and Vacuum Release Valves
(1)
General
Wastewater force mains shall be equipped with either air or air/vacuum
release valves located as shown on the drawings. Valves shall be located
in an enclosure as detailed on the Standard Drawings.
The valves shall be as described below.
(2)
Wastewater Air/Vacuum Valve
The valve body shall be of cast iron ASTM A126-B; the floats, float guide
and stem shall be of stainless steel Type 304. The resilient seat shall be of
Buna N. The valve shall be suitable for 150 psi working pressure. Valve
City of Umatilla Standard Specifications
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January 2013
shall have standard 2" NPT inlets and outlet ports unless otherwise shown
on the Drawings. Provisions shall be made for back-flushing the valve
with clean water.
(3)
Wastewater Air Release Valve
The valve body and cover shall be cast iron construction, ASTM A126-B,
and all internal working parts shall be of stainless steel Type 304. The
venting orifice shall be 3/8" in diameter and the seating material shall be
of Viton.
The inlet opening shall be standard 2” NPT screwed connection, unless
otherwise shown on the Drawings. The valve shall include a flush out
feature for periodic cleaning of the internal mechanism. The overall
height of the valve body shall not exceed 21", unless otherwise shown on
the Drawings.
g.
Notification and Connection to Existing Mains
Pressure connection to existing wastewater force mains shall comply with the
requirements of Appendix A, paragraph 7.
h.
Plug Valves
(1)
General
Only plug valves as specified below shall be used on wastewater force
main systems. All plug valves shall be installed so that the direction of
flow through the valve is in accordance with the manufacturer's
recommendations. Valves shall be eccentric plug valve type.
(2)
Valve Construction
Valves shall be of the non-lubricated eccentric type with resilient faced
plugs and shall be furnished with end connections as shown on the
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January 2013
drawings. Flanged valves shall be faced and drilled to the ANSI 125/150
lb. standard. Mechanical joint ends shall meet AWWA C111, Class B.
Valve bodies shall be of ASTM A126, Class B Semi-steel, 31,000 psi
tensil strength minimum in compliance with AWWA C507 and C504. All
exposed nuts, bolts, springs, washers, etc. shall be zinc or cadmium plated.
Resilient plug facings shall be of Hycar or Neoprene.
Port areas for valves 4" through 20" shall be 80% nominal pipe diameter.
Valves 24" and larger shall have a minimum port area of 70% of nominal
pipe diameter. All exposed nuts, bolts, springs, washers, etc., shall be zinc
or cadmium plated. Resilient plug facings shall be of Hycar or Neoprene.
Valves shall be furnished with permanently lubricated stainless steel or
oil-impregnated bronze upper and lower plug stem bushings. These
bearings shall comply with AWWA C507 and C504.
Seats in 4" and larger valves shall have a welded-in overlay of a high
nickel content on all surfaces contacting the plug face which comply with
AWWA C507 and C504.
Valve shaft seals shall be adjustable and comply with AWWA C507.
(3)
Valve Testing
Plug valves shall be tested in accordance with AWWA C504. Each valve
shall meet the performance, leakage, and hydrostatic tests described in
AWWA C504. The leakage test shall be applied to the face of the plug
tending to unseat the valve. The manufacturer shall furnish certified
copies of reports covering proof of design testing as described in AWWA
C504.
City of Umatilla Standard Specifications
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January 2013
(4)
Actuators
Manual valves shall have lever or gear actuators and tee wrenches,
extension stems, floor stands, etc. as indicated on the drawings. All valves
6" and larger shall be equipped with gear actuators. All gearing shall be
enclosed in a semi-steel housing and be suitable for running in a lubricant
with seals provided on all shafts to prevent entry of dirt and water into the
actuator. All actuator shafts shall be supported on permanently lubricated
bronze bearings. Actuators shall clearly indicate valve position and an
adjustable stop shall be provided to set closing torque. All exposed nuts,
bolts, and washers shall be zinc or cadmium plated. Valve packing
adjustment shall be accessible without disassembly of the actuator.
i.
Valve Boxes
Requirements specified in Appendix C, paragraph 3.e. shall apply, except that
covers shall have "sewer" cast into the top.
j.
Separation of Force Mains, Water Mains and Reclaimed Water Mains
Requirements specified in Appendix C, paragraph 2.c. shall apply.
k.
Force Main Construction
Requirements specified in Appendix C, paragraph 3. shall apply.
l.
Hydrostatic Tests
Requirements specified in Appendix C, paragraph 2.e. shall apply except that all
pipe sections to be tested shall be subjected to a hydrostatic pressure of 100 psi.
m.
Final Cleaning
Prior to final inspection and acceptance of the force main by the City, contractor
shall flush and clean all parts of the system. Flushing and cleaning shall remove
City of Umatilla Standard Specifications
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all accumulated construction debris, rocks, gravel, sand, silt, and other foreign
material from the sewer system at or near the downstream end.
Upon the City's final inspection of the pressure pipe systems, if any foreign matter
is still present in the system, contractor shall clean the sections and portions of the
lines as required.
n.
Location and Identification
All non-metallic force mains shall be installed with a continuous, insulated 14
gauge copper wire installed directly on top of the pipe for location purposes.
Detectable tape shall be placed 1' above the top of the pipe. See Standard
Drawings. In addition, all PVC force mains shall be either a solid green. All
lettering shall appear legibly on the pipe and shall run the entire length of the
pipe. Lettering shall read as is acceptable for the intended use.
All ductile iron force mains shall be marked with a continuous stripe located
within the top 90º of the pipe. Said stripe shall be a minimum 2" in width and
shall be green in color. Backfill shall not be placed for 30 minutes following
paint application.
7.
WASTEWATER PUMP STATIONS
a.
General
This section includes the specifications for equipment, materials, site work, fences
and appurtenances for the installation of wastewater pump stations.
b.
Wet Well and Valve Vault
The wet wells shall be lined or coated as approved by the City. Wet well and
valve vault shall be constructed as shown on the Standard Drawings and in
conformance with the specifications outlined in Appendix B, paragraph 3.
City of Umatilla Standard Specifications
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January 2013
c.
Access Frames and Covers
Both the wet well and the valve vault shall be furnished with an access frame and
cover. Equipment furnished shall include the necessary aluminum access frames,
complete with hinged and slide bar equipped covers, stainless steel upper guide
holder and level sensor cable holder. The frames shall be securely mounted above
the pumps. Doors shall be of aluminum checker plate. The access cover and
frame with stainless steel hardware shall be sized as shown on the drawings.
d.
Pumps and Controls
Pumps and miscellaneous accessories shall be as specified in Appendix B,
paragraph 7.e. Controls and miscellaneous accessories shall be as specified in
Appendix B, paragraph 7.f.
e.
Submersible Wastewater Pumps
(1)
General
The equipment covered by these specifications is intended to be standard
pumping equipment of proven ability as manufactured by a reputable firm
having at least five (5) years experience in the production of such
equipment. The equipment furnished shall be designed, constructed, and
installed in accordance with the best practices and methods, and shall
operate satisfactorily when installed as shown on the drawings.
All parts shall be so designed and proportioned as to have liberal strength,
and stiffness and to be especially adapted for the work to be done. Ample
space shall be provided for inspection, repairs, and adjustment. The stator
casing and oil casing shall be of gray iron construction, with all parts
coming into contact with sewage protected by a PVC epoxy primer with a
chloric rubber paint finish. All necessary foundation bolts, plates, nuts,
and washers shall be furnished by the equipment manufacturer, and shall
be of Type 304 stainless steel. Brass or stainless steel nameplates giving
the name of the manufacturer, voltage, phase, rated horsepower, speed,
City of Umatilla Standard Specifications
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January 2013
and any other pertinent data shall be attached to each pump.
nameplate rating of the motors shall not be exceeded.
The
The pumps shall be capable of handling raw unscreened domestic
wastewater and minimum 3" diameter solid spheres. Pump operation shall
be controlled automatically by means of a liquid level sensors in the wet
well with a supplemental float type backup control. Alternate or approved
equal are subject to City review and approval. Pumps shall be mounted in
the wet well as shown on the Drawings.
(2)
Pump Construction Details
(a)
Shaft
The pump shaft shall be of Series 300 or 400 stainless steel or
carbon steel. When a carbon steel shaft is provided, the
manufacturer shall demonstrate that any part of the shaft which
will normally come in contact with the wastewater has proven to
be corrosion resistant in this application. The shaft and bearings
shall be adequately designed to meet the maximum torque required
for any start-up or operating condition and to minimize vibration
and shaft deflection. As a minimum, the pump shaft shall rotate on
two (2) permanently lubricated bearings. The upper bearing shall
be a single row ball bearing. The lower bearing shall be a two (2)
row angular contact ball bearing, if required to minimize vibration
and provide maximum bearing life.
(b)
Impeller
The impeller shall be constructed of gray cast iron, ASTM A-48,
class 30. All external bolts and nuts shall be of Type 304 stainless
steel. Each pump shall be provided with a replaceable metallic
wear ring system to maintain pump efficiency. As a minimum one
(1) stationary wear ring provided in the pump volute or one (1)
City of Umatilla Standard Specifications
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January 2013
rotating wear ring provided on the pump impeller shall be required.
A two-part system is acceptable.
(c)
Mechanical Seal
Each pump shall be provided with a tandem double mechanical
seal running in an oil reservoir, composed of two (2) separate
lapped face seals, each consisting of one (1) stationary and one (1)
rotating tungsten carbide ring with each pair held in contact by a
separate spring, so that the outside pressure assists spring
compression in preventing the seal faces from opening. The
compression spring shall be protected against exposure to the
pumped liquid. Silicone carbide may be used in place of tungsten
carbide for the lower seal. The pumped liquid shall be sealed from
the oil reservoir by one (1) face seal and the oil reservoir from the
air-filled motor chamber by the other. The seals shall require
neither maintenance nor adjustment, and shall be easily replaced.
Conventional double mechanical seals with a single spring
between the rotating faces, requiring constant differential pressure
to effect sealing and subject to openings and penetration by
pumping forces shall not be considered equal to tandem seal
specified and required.
(d)
Guides
A sliding guide bracket shall be an integral part of the pump casing
and shall have a machined connecting flange to connect with the
cast iron discharge connection, which shall be bolted to the floor of
the wet well with stainless steel anchor bolts and so designed as to
receive the pump discharge flange without the need of any bolts or
nuts. Sealing of the pumps to the discharge connection shall be
accomplished by a simple linear downward motion of the pump
with the entire weight of the pumping unit guided by no less than
two (2) Type 316 seamless tubular stainless steel guides which will
press it tightly against the discharge connection. No portion of the
City of Umatilla Standard Specifications
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January 2013
pump shall bear directly on the floor of the wet well and no rotary
motion of the pump shall be required for sealing. Sealing at the
discharge connection by means of a diaphragm or similar method
of sealing will not be accepted as an equal to a metal to metal
contact of the pump discharge and mating discharge connection
specified and required.
Approved pump manufacturers, if
necessary to meet the above specification, shall provide a sliding
guide bracket adapter. The design shall be such that the pumps
shall be automatically connected to the discharge piping when
lowered into place on the discharge connection. The pumps shall
be easily removable for inspection or service, requiring no bolts,
nuts or fastenings to be removed for this purpose, and no need for
personnel to enter the wet well. Each pump shall be fitted with a
Type 304 stainless steel, 3/4" lifting chain of adequate strength. A
1/4" Type 304, stainless steel cable, air craft rating, shall be
provided between the cable holder and the lifting chain.
(3)
Motors
(a)
General Requirements
All motors shall be built in accordance with latest NEMA, IEEE,
ANSI and AFBMA Standards where applicable. Pump motors
shall be housed in an air-filled, water-tight casing and shall have
Class F insulated windings which shall be moisture resistant. The
motor shall be provided with over temperature sensors set at 125º
Centigrade (C) and shall be NEMA Design B, rated 155º C
maximum. Pump motors shall have cooling characteristics suitable
to permit continuous operation, in a totally, partially or
non-submerged condition. The pump shall be capable of running
continuously in a non-submerged condition under full load without
damage, for extended periods. The motor shall be capable of a
minimum of 10 starts per hour. If required by the City, before
final acceptance, a field running test demonstrating this ability,
with 24 hours of continuous operation under the above conditions,
City of Umatilla Standard Specifications
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January 2013
shall be performed for all pumps being supplied. Motors 25
horsepower and below shall be rated 230/460 volt, 3 phase.
Motors greater than 25 horsepower shall be 460 volt, 3 phase. All
motors shall be designed with a 1.15 service factor and shall not be
less than 5 horsepower unless approved by the City. Pumps shall
be capable of meeting all pump curve conditions without
exceeding the motors rated horsepower.
(b)
Heat and Moisture Sensors
Each motor shall incorporate a minimum of one (1) ambient
temperature compensated overheat sensing device and one (1)
moisture sensing device. These protective devices shall be wired
into the pump controls in such a way that if excessive temperature
or moisture is detected the pump will shut down. These devices
shall be self-resetting.
In lieu of moisture and temperature sensors, each pump motor shall
have its motor winding insulation resistance monitored
automatically by an automatic megger solid state electronics
module.
Each automatic megger must have an individual
disconnect terminal plug, manual shut off switch, three lights to
indicate 10 M ohm, 5 M ohm, and 1 M ohm, resistance values, two
(2) output circuits for external alarms, and two (2) switches for
manual testing. The power source shall be 110 VAC fused at 0. 24
AMP. The test voltage shall be 500-700 volts d.c. The automatic
megger shall monitor the motor resistance only when the motor is
off and shall activate an alarm system when the motor resistance
drops to 1 M ohm.
(c)
Cables
Cables shall be designed specifically for submersible pump
applications and shall be properly sealed. A type CGB water-tight
connector with a neoprene gland shall be furnished with each
City of Umatilla Standard Specifications
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January 2013
pump to seal the cable entry at the control panel. The pump cable
entry seal design shall preclude specific torque requirements to
insure a water-tight and submersible seal. The cable entry shall be
comprised of a single cylindrical elastomer grommet, flanked by
washers, all having a close tolerance fit against the cable outside
diameter and the entry inside diameter and compressed by the
entry body containing a strain relief function, separate from the
function of sealing the cable. The assembly shall bear against a
shoulder in the pump top. The cable entry junction chamber and
motor shall be separated by a stator lead sealing gland or terminal
board, which shall isolate the motor interior from foreign material
gaining access through the pump top. Secondary sealing systems
utilizing epoxy- potting compounds may be used. When this type
of sealing system is used the manufacturers shall supply a cable
cap as part of the spare parts for each pump. All cables shall be
continuous, without splices from the motor to the control panel,
unless otherwise approved by the City.
The junction chamber, containing the terminal board, shall be
perfectly leak proof.
f.
Pump Station Electrical Power and Control System
(1)
General
This section specifies the electrical power and control system
requirements for wastewater pump stations. These requirements apply to
duplex pump panels. Similar requirements shall apply when more than
two (2) pumps are involved except for the quantity of control equipment
and panel size shall be increased accordingly. The manufacturer of the
control panel shall provide data to indicate that the manufacturer has a
minimum of three (3) years experience in the building of pump control
panels.
City of Umatilla Standard Specifications
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January 2013
A pump station control panel shall be provided for each wastewater pump
station. The control panel shall respond to liquid level switches to
automatically start and stop pumps as well as sound an alarm upon high or
low wet well levels. The control panel shall operate two (2) electrical
submersible pumps at the power characteristics stipulated. The control
function shall provide for the operation of the lead pump under normal
conditions. If the incoming flow exceeds the pumping capacity of the lead
pump, the lag pump shall automatically start to handle this increased flow.
As the flow decreases, pumps shall be cut off at elevation as shown on the
drawings. Pumps shall alternate positions as lead pump at the end of each
cycle. A failure of the alternator shall not disable the pumping system.
The alternator shall include a safe, convenient method of manual
alternation and also have provisions to prevent automatic alternation
without disturbing any wiring. Should the "pump off" regulator fail, the
system shall keep the station in operation and provide a visual indication
of the regulator failure.
The control panel shall consist of main circuit breakers, a circuit breaker
and magnetic starter for each pump motor, and 15 ampere, 120-volt circuit
breakers as required. All pump control operations shall be accomplished
by a float type liquid level control system with all control components
mounted in one common enclosure. Control switches shall provide means
to operate each pump manually or automatically. When operated in the
automatic mode, the control assembly shall provide means to manually
select or automatically alternate the position of the "lead" and "lag" pumps
after each pumping cycle. A liquid level control system shall continuously
monitor wet well liquid level and control operation of the low-level cutoff
for the pumps and shall operate off a 24-volt circuit.
(2)
Panel Construction
The duplex pump panel shall be housed in a NEMA 3R, Type 304, 14
Gauge stainless steel enclosure with 30% extra mounting space for
additional equipment. Enclosure shall have provisions for padlocking the
City of Umatilla Standard Specifications
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January 2013
door and a dead front inner door unit for mounting controls. All exterior
hardware and hinges shall be stainless steel.
There shall be permanently affixed to the interior side of the exterior
enclosure door both a nameplate and a 10" x 12" pocket for log sheet
storage. The nameplate shall contain the following information, voltage,
phase, rated horsepower, speed, date manufactured and pump and control
panel manufacturer's name, address and telephone number, pump data,
including impeller data, operating point and head, KW input, and amps at
the operating point and at least two other points on the pump curve.
The control panel enclosure shall be Underwriters Laboratories (UL)
50,Type 3R listed.
(3)
Power Supply and Main Disconnect
Power supply to the control panel shall be either 240 volt, 3 phase, 4 wire
or 480 volt, 3 phase, 4 wire. Minimum service shall be 100 AMP. Singlephase power shall not be accepted.
Non-fusible safety service main disconnects shall be installed at all
stations. In all 240 volt systems, disconnects should be installed between
the meter and the panel and on all 480 volt systems, disconnect should be
installed ahead of the meter. LED power available indicators shall be
supplied on all legs.
7.
Circuit Breakers
All circuit breakers shall be heavy duty molded case breakers. The
handle on the circuit breakers shall be operational through the inner door.
All breakers shall be Square D or equal.
(5)
Motor Circuit Protectors
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January 2013
Each pump motor shall be protected by a 3-pole motor circuit protector.
The Motor Circuit Protector shall be operated by a toggle-type handle and
shall have a quick-make, quick-break over center switching mechanism
that is mechanically trip-free from the handle so that the contacts cannot
be held closed against a short circuit and abnormal currents which cause
the Motor Circuit Protector to trip. Tripping shall be clearly indicated by
the handle automatically assuming a position midway between the normal
ON and OFF positions. All latch surfaces shall be ground and polished.
All poles shall be so constructed that they open, close, and trip
simultaneously. Motor Circuit Protector must be completely enclosed in a
high-strength glass polyester molded case. Ampere ratings shall be clearly
visible. Contacts shall be of non-welding silver alloy. Arc extinction
must be accomplished by means of arc chutes. A manual push-to-trip
button shall be provided for manual exercising of the trip mechanism.
Each pole of these Motor Circuit Protector's shall provide instantaneous
short circuit protection by means of an adjustable magnetic-only element.
(6)
Motor Starter and Selector Switches
The panel shall contain two (2) motor starters. The motor starter shall be
across the line magnetic starter with individual overload protection on
each power leg with reset installed through the inner door unit. Local
Power Company Regulations shall govern.
Selector switches shall be installed on the face of the inner door unit.
Selector switch shall be a heavy duty oil tight "Hand-Off-Auto" three (3)
position switch to control the operation mode of each pump motor starter.
(7)
Pump Alternator
An eight (8) pin plug-in solid state alternator (see approved manufacturers'
list in Appendix F) shall be provided to change the pump starting sequence
on each pumping cycle. A three (3) position alternator test switch shall be
provided to control the alternation operation. Switch positions to include
the "Auto" to provide normal automatic sequence, "Off" position to
City of Umatilla Standard Specifications
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January 2013
disable alternator, and "test" position with a spring return to allow the
alternating of the pump sequence to check alternator operation.
(8)
Lights and Alarms
(a)
Indicator Lights
There shall be installed on the face of the inner door unit, heavy
duty oil tight indicator lights as shown on the Standard Drawings.
(b)
High Level Alarm
A vapor proof red light and horn shall be mounted on top of the
panel for high level alarm. Also, there shall be an alarm silence
push button on the inner door and a silence relay which will silence
the horn and automatically reset when these signals are restored to
normal. The push button shall be heavy duty oil tight. The red
globe shall be the screw-on type.
(9)
Emergency Generator
The city shall require permanent standby generator power at all lift
stations. The generator shall be sized to the full capacity of any up grades
that can be made to the lift station.
(10)
Additional Requirements
(a)
Wiring
All power wires shall be THW or THWN 75º C insulated stranded
copper conductors and shall be appropriately sized for the given
load application. All control circuit wire shall be type THW; Size
14, stranded type. All wiring within the enclosure shall be neatly
routed by the use of slotted type wiring duct with snap on type
covers. Wiring on the rear of the inner door shall be neatly
City of Umatilla Standard Specifications
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January 2013
bundled with nylon ties and include sufficient loop across the
hinges to prevent wire damage, with each end of conductor marked
(I.D.), Color: Red, 24 volt; white, neutral; black, 120 volts
(b)
Terminal Points
Terminal points of all terminal strips shall be permanently
identified. All terminal numbers and identifying nomenclature
shall correspond to and be shown on electrical diagrams. All
wiring shall be permanently shown on electrical schematic
diagrams.
(c)
Engraved Nameplates
All circuit breakers, control switches, indicator pilot lights and
other control devices shall be identified with permanently affixed
legend plates and lamicoid-type engraved nameplates where
applicable.
(d)
Surge Protector
A surge protector shall be included and wired to protect motors
and control equipment from lightning induced line surges. All
surge protectors shall be U.L. approved and installed per respective
power company requirements and manufacturers' specifications.
Surge protectors shall be attached to the main disconnects.
(e)
City of Umatilla Standard Specifications
Water & Sewer Utilities
Elapsed Time Meters.
B - 38
January 2013
Elapsed time meters shall be 115-volt not-reset type and shall
totalize pump running time in hours and tenths of hours to 99999.9
hours.
(f)
Convenience Receptacle
On the face of the inner door unit, there shall be installed a 15
AMP 120 volt, duplex convenience receptacle. It shall be provided
with it's own single pole, 15 AMP circuit breaker for protection.
Ground fault interrupt type shall be required.
(g)
Control Terminal Blocks
Control terminal blocks shall be of the clamp screw type, rated for
600 volts. Amperage rating shall accommodate the control circuit
amperage. An additional 30 space terminal strip shall be installed
in the cabinet for future use, with RTU equipment.
(h)
Control Power Transformers
There shall be a control power transformer with a minimum size of
500VA to provide 120VAC power for: coils for starters, 15A
duplex receptacle, indicator pilot lights, alarm horn, alarm light,
pump alternator, elapsed time meters etc. The secondary side shall
have one (1) leg fused and the other grounded. This control power
transformer is required only on 480 volt control panels.
The signal required by the float switches and relays shall be
24VAC. This shall be provided by a 24VAC control power
transformer properly sized with a fused secondary.
(i)
City of Umatilla Standard Specifications
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Control Relay
B - 39
January 2013
The level control relays shall operate from 24VAC. They shall be
enclosed, plug-in (8) pin type with octal-style screw terminal
sockets.
(j)
Electrical Schematic
There shall be permanently affixed to the interior side of the
exterior enclosure door an electrical schematic diagram and a copy
supplied to City personnel at start-up. The schematic diagram
shall include the rated amperage and voltage for all components.
(k)
Phase Monitor
For all 240 volt stations an eleven (11) pin plug-in type phase
monitor shall be provided for protection of electrical components
due to phase loss. Adequate dummy pin protection shall be
provided to prevent accidental interchanging of the eleven (11) pin
phase monitor with the eleven (11) pin alternator. All 480 volt
stations shall have surface mount type phase monitors.
(11)
Testing, Service and Warranty
(a)
Testing
After fabrication in the control panel manufacturer's plant, an
operational test shall be performed to check out the entire panel
before delivery. Three phase source voltage for which the panel is
intended , shall be used for the testing.
(b)
Service
The control panel manufacturer shall maintain a customer service
organization that is available for service.
City of Umatilla Standard Specifications
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January 2013
(c)
Warranty
The manufacturer shall furnish a five (5) year warranty against
defects in materials and workmanship covering parts and labor on
all items supplied under this section.
g.
Piping, Valves and Accessories
(1)
Piping
Influent piping to the wet well shall meet the requirements of Appendices
B, paragraph 1.and B, paragraph 6.except that the influent pipe to the wet
well shall be a minimum 18” section of Ductile Iron Pipe. All pipe inside
the wet well and the valve vault shall be as shown on the Standard
Drawings.
(2)
Plug Valves
Plug valves shall meet the requirements of Appendix B, paragraph 6.h.
(3)
Check Valves
Check valves for ductile iron pipelines shall be swing type and shall meet
the material requirements of AWWA C500. The valves shall be iron
body, bronze mounted, single disc, 150 Psi working water pressure, nonshock, and hydrostatically tested at 300 psi. Ends shall be 125 pound
ANSI B16.1 flanges.
When there is no flow through the line the disc shall hang lightly against
its seat in practically a vertical position. When open, the disc shall swing
clear of the waterway.
Check valves shall have bronze seat and body rings, extended bronze
hinge pins and stainless steel nuts on the bolts of bolted covers.
City of Umatilla Standard Specifications
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January 2013
Valves shall be so constructed that disc and body seat may easily be
removed and replaced without removing the valve from the line. Valves
shall be fitted with an extended hinge arm with outside lever and weight.
If pump shut off head exceeds 77 feet, then an air cushioned assembly
shall be installed.
(4)
Pressure Gauges
Pressure gauges shall be installed on each discharge pipe as indicated on
the Standard Drawings. Each pressure gauge shall be direct mounted,
stainless steel case, stainless steel sensing element, liquid filled, with a
4-1/2" diameter dial and furnished with a clear glass crystal window, 1/4"
shut-off (isolation) valve. All gauges shall be weatherproofed. The face
dial shall be white finished aluminum with jet-black graduations and
figures. The face dial shall indicate the units of pressure measured in psi,
with a 0-60 psi range.
Pressure gauges shall not be installed until after the substantial completion
date unless otherwise requested by the City.
h.
Standby Power Generator System
(1)
General
A standby power generator system shall be installed at all pump stations as
required by Section 3.2.E.5. Emergency Operations, for electrical power
during the loss of normal power.
(2)
Generator Set
(a)
General
The generator set shall consist of a diesel or alternate fuel engine
directly coupled to an electric generator, together with the
necessary controls and accessories to provide continuous electric
City of Umatilla Standard Specifications
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January 2013
power to the lift station for the minimum duration of 72 hours
failure of the normal power supply.
A complete engine generator system shall be furnished and
installed with fuel transfer pump, fuel day tank, battery, battery
charger, muffler, radiator, control panel, remotely mounted
automatic transfer switch (part of the control panel), and all other
accessories required for an operational system. All materials and
parts of the generator set shall be new and unused. Each
component shall be of current manufacture from a firm regularly
engaged in the production of such equipment. The set shall be of a
standard model in regular production at the manufacturer's place of
business. Units and components offered under the Specifications
shall be covered by the manufacturer's standard warranty on new
machines.
(b)
Requirements
The emergency generator set and accessories shall be of a type that
complies with the latest edition of the National Electrical Code and
all applicable state and local building codes.
The material and workmanship used in the manufacture of this
equipment shall be of the highest quality consistent with the
current standards for like equipment, and the equipment shall be
manufactured in such a manner so as to conform to the latest
applicable IEEE, ANSI, ISA, NEMA, and EEIA Standards.
The equipment supplier shall be liable for any latent defects due to
faulty materials or workmanship in the equipment which may
appear within one (1) year from the date of equipment start-up.
(c)
City of Umatilla Standard Specifications
Water & Sewer Utilities
Tests
B - 43
January 2013
Equipment shall be completely assembled and tested at the factory
prior to shipment. Certified copies of the data obtained during
these tests shall be submitted to the City.
Final tests shall be conducted at the site, after installation has been
completed, in the presence of the City's representative. The
emergency generator manufacturer shall furnish a service
representative to operate the engine during the tests, to check all
details of the installation and to instruct the City's representatives
in proper equipment operation.
Field tests shall include operating the diesel generating set for eight
(8) hours, carrying normal lift station loads. The contractor shall
refill the main fuel tank at the completion of the tests.
(d)
Ratings
The rating of the generator shall be as shown on the drawings.
These ratings must be substantiated by the manufacturer's standard
published curves. Special ratings shall not be acceptable. The
diesel generating set shall be capable of supplying the specified
usable KW for the specified duration, including the power required
for both pump start-up and run. With time delay so both pumps
will not start at same time, without exceeding its safe operating
temperature.
(e)
Engine
The engine shall be water cooled, four stroke cycle, compression
ignition diesel. It shall meet specifications when operating on No.
2 domestic burner oil. The engine shall be equipped with fuel,
lube oil and intake air filters; lube oil coolers, fuel transfer pump,
fuel priming pump, and gear-driven water pump.
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 44
January 2013
The engine and generator shall be torsionally compatible to
prevent damage to either engine or generator.
An engine instrument panel shall be installed on the generator set
in an approved location. The panel shall include oil and fuel
pressure and water temperature gauges. A mechanically driven
engine hour meter shall also be provided.
The engine governor shall be of the isochronous electronic type.
Frequency regulation shall not exceed plus/minus 0.25% under
steady state conditions. The engine shall start and assume its rated
load within 10 seconds, including transfer time.
(f)
Generator
The generator shall be a three-phase, 60 hertz, single bearing,
synchronous type, built to NEMA Standards. Epoxy impregnated
Class F insulation shall be used on the stator and the rotor.
The excitation system shall employ a generator-mounted volts per
hertz type regulator. Voltage regulation shall be plus/minus 2%
from no load to full load. Readily accessible voltage drop, voltage
level and voltage gain controls shall be provided. Voltage level
adjustment shall be a minimum of plus/minus 5%.
(g)
Engine Generator Control Panel
A generator mounted NEMA 3R Type 304, vibration isolated, 14
gauge stainless steel control panel shall be provided. Panel shall
contain, but not be limited to, the following equipment:
Control Equipment:
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 45
January 2013
Control equipment shall consist of all necessary exciter control
equipment, generator voltage regulators, voltage adjusting rheostat,
and speed control equipment and automatic starting controls, as
required to satisfactorily control the engine/generator set. In
addition an automatic safety shut down shall be provided for low
oil pressure and/or high temperature conditions in the engine. An
emergency shut down lever switch shall be provided on the air
intake.
Metering Equipment:
Metering equipment shall include 3-1/2" meters (dial or digital type
frequency meter, 2% accuracy voltmeter, and ammeter and
ammeter-voltmeter phase selector switch). The control panel shall
also include the engine water temperature, lube oil pressure and
hour meter.
Fault Indicators:
Individual press-to-test fault indicator lights for low oil pressure,
high water temperature, low water level, over-speed, over crank,
and for fuel tank high and low level shall be provided.
Function Switch:
A four position function switch marked "Auto," "Manual,"
"Off/Reset," and "Stop" shall be provided.
(h)
Battery Charger
The battery charger shall be so designed that it shall not be
damaged and shall not trip its circuit protective device during
engine cranking or it shall be automatically disconnected from
battery during cranking period. The charger shall be mounted in
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 46
January 2013
the emergency generator control panel. The charger shall have a 7
day/24 hour timer control.
(i)
Battery
The battery shall be lead-acid type with sufficient capacity to
provide 90 seconds total cranking time without recharging. The
battery shall be adequately rated for the specific generator set. The
battery shall be encased in hard rubber or plastic and shall be
furnished with proper cables and connectors, together with rack
and standard maintenance accessories. The battery shall be
provided with a 48 month warranty for the replacement of the
battery if found to be defective.
(j)
Base and Mounting
A suitable number of spring-type vibration isolators with a noise
isolation pad shall be provided to support the set and its liquids.
(k)
Utility Connections
All connections to the generator set shall be flexible.
(l)
Cooling System
The generator set shall be equipped with an engine mounted
radiator sized to maintain safe operation at 110 degree F maximum
ambient at the pump station altitude. A blower type fan shall be
used directing the air flow from the engine through the radiator.
The entire cooling system shall be filled with 50% glycol-water
solution.
(m)
City of Umatilla Standard Specifications
Water & Sewer Utilities
Fuel System
B - 47
January 2013
An above ground, main fuel oil storage tank with float switch and
fuel level indication or approved equivalent shall be furnished and
installed. The emergency system shall include low fuel level
contacts for remote alarm. If necessary to guard against loss of
prime to pump, a check valve shall be mounted on pump intake.
The emergency system shall include a float switch, fuel level
gauge and standard control panel.
A fuel containment system shall be provided to prevent the
accidental release of fuel to the environment. The containment
area shall be of sufficient size to contain 110% the volume of the
largest fuel tank. A minimum 2" drain and valve shall be provided
for drainage of the containment area. An approved epoxy coating
shall be applied to any concrete area.
Fuel oil piping, including mounting of any required fuel tanks,
shall be furnished and installed by the contractor.
(n)
Exhaust System
The generator set supplier shall provide a critical-type silencer,
with flexible exhaust fittings, properly sized and installed,
according to the manufacturer's recommendation. The silencer
shall be mounted so that its weight is not supported by the engine.
Exhaust pipe size shall be sufficient to ensure that measured
exhaust back pressure does not exceed the maximum limitations
specified by the generator set manufacturer. The exhaust system
shall include a flexible, seamless, stainless steel connection
between the engine exhaust outlet and the rest of the exhaust
system. The exhaust system shall be a part of generator enclosure.
(o)
City of Umatilla Standard Specifications
Water & Sewer Utilities
Weatherproof Enclosure
B - 48
January 2013
For generator installation in the outdoors, the weatherproof
enclosure and all other items shall be designed and built by the
engine manufacturer as an integral part of the entire generator set
and shall be designed to perform without overheating in the
ambient temperature specified. The city may require noise
reduction enclosures
Enclosure shall be constructed of 14 or 16 gauge sheet metal
suitably reinforced to be vibration free in the operating mode.
Four hinged doors shall be provided to allow complete access
without their removal.
Each door shall have at least two satch-bearing points.
Side and rear panels shall be completely and simply removable for
major service access.
Roof shall be peaked to allow drainage of rain water.
Baked enamel finish with primer and finish coat shall be painted
before assembly. All fasteners shall be rust resistant.
Unit shall have sufficient guards to prevent entrance by small
animals. Padlocks shall be provided.
Batteries shall be designed to fit inside enclosure and alongside the
engine. Batteries under the generator are not acceptable.
Unit shall have coolant and oil drains outside the unit to facilitate
maintenance. Each drain line shall have a high quality valve
located near the fluid source.
Fuel filter shall be inside the base perimeter and located so spilled
fuel cannot fall on hot parts of engine or generator. A cleanable
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 49
January 2013
primary fuel strainer shall be used to collect water and sediment
between tank and main engine fuel filter.
Crankcase fumes disposal shall terminate in front of the radiator to
prevent oil from collecting on the radiator core and reducing
cooling capacity.
(p)
Automatic Transfer Switch
The automatic transfer switch shall be part of the control panel
described in Appendix B.7.f.
The transfer switch shall be provided with the following features:
Complete protection, close differential voltage sensing relays
monitoring all three phases (pick-up set for 95% of nominal
voltage, drop-out set for 85% nominal voltage).
Voltage sensing relay on emergency source (pick-up set for 95% of
nominal frequency).
Time delay on engine starting--adjustable from 1 second to 300
seconds (factory set at 3 seconds.) Time delay normal to
emergency transfer--adjustable from zero second to 300 seconds
(factory set at 1 second). The contractor shall request time delay
settings in accordance with the priority rating or their respective
loads.
Time delay emergency to normal transfer--adjustable 30 seconds to
30 minutes (factory set at 5 minutes), and time delay bypass switch
shall be provided on door of the switch cabinet.
Unload running time delay for emergency engine generator cooling
down-adjustable from 0 to 5 minutes (factory set at 5 minutes)
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 50
January 2013
unless the engine generator control panel includes the cool down
timer.
Automatic exercise control so as to exercise the generator (under
full load) at a day, time and length of exercise as needed.
(q)
Warranty
Products shall be guaranteed to be free from defects in material
and workmanship under normal use and service for a period of one
(1) year after start-up.
I
Flow Monitoring System
(1)
General
When indicated on the drawings or as required by Section 3.2.E.4, a flow
monitoring system capable of indicating, recording, and totalizing
wastewater flows shall be provided. The system shall include magnetic
flow meter / transmitter, electronic recording receiver, and miscellaneous
related accessories as specified herein. It shall be the Contractor's
responsibility to provide and install such equipment resulting in a
completely operational flow monitoring system.
(2)
Acoustic Sensors and Mounting Requirements
Two flow sensors shall be permanently mounted to the pipe to ensure
accurate and stable measurements of flow. The sensors shall be positioned
in accordance with the manufacturer’s specifications and factory approved
methods. Mounting templates and /or fixtures for sensor attachments shall
be provided by manufacturer. The mounting hardware and transducers
shall have sufficient integrity to maintain accurate sensor placement
withstanding normal pipe vibration and shall be capable of operating over
a temperature range of (-) 30 to 150 degrees F. In addition, the sensor shall
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 51
January 2013
be so designed as to operate under submerged conditions indefinitely. The
acoustic sensors shall alternately transmit and receive acoustic energy
pulses propagated along the centerline of the fluid. Only transmit – time
method of operation will be accepted.
(a)
For External Sensors (two inch Diameter Meters and Larger).
The integrity of the pipe shall be maintained during installation and
operation. Cutting into the pipe to install the sensors or holders
shall not be allowed. Stainless steel mounting bands shall be placed
around the pipe circumference to secure the sensor brackets. The
mounting bands shall have sufficient strength to maintain accurate
sensor position. Positioning of the sensor mounting brackets shall
be in accordance with manufacturer’s specifications. The acoustic
sensors shall be securely held in the sensor brackets and shall
transmit acoustic energy through the pipe wall for measurement of
flow. The sensors shall be designed as to be operated directly
buried in accordance with the manufacturer’s recommendations or
underwater.
(b)
For “Hot Shot” Sensors (12 inch Diameter and Larger).
Two acoustic sensors of the “hot shot” style shall be mounted on
the piping at the position shown on the drawings. Valve assemblies
shall be supplied to allow the insertion or withdrawal of the sensors
without dewatering the conduit.
(c)
For In Stream Wetted Sensors ( 24 inch Diameter and Larger).
The sensor design and mounting hardware shall be such as to allow
mounting against the inside of the pipe wall. Installation shall be in
accordance with the manufacturer’s specifications.
(d)
City of Umatilla Standard Specifications
Water & Sewer Utilities
For Fabricated Spool Design.
B - 52
January 2013
The meter body shall be constructed from material, conforming to
AWWA Class 150#, carbon steel for plain end connections. The
design shall incorporate externally mounted sensors that are field
replaceable factory mounted on the meter body. The design will be
in accordance with ASME pressure vessel code.
(3)
Transmitter Requirements.
The transmitter shall contain all the circuitry necessary to produce a (4-20
MA DC ) signal linear with the flow rate. The transmitter shall be capable
of measuring and totalizing forward and reverse flow. It shall be
microprocessor controlled. The microprocessor shall be of a single chip
design. The transmitter shall be housed in foam molded polycarbonate
enclosure suitable for wall or panel mounting rated NEMA 4X. The
display on the enclosure will be a 24 character, 2- line alpha numeric LCD
clearly indicating instantaneous flow rate and totalized flow information.
The transmitter shall utilize menu-driven sequencing of the internal
functions from the front panel switches without the need or use of external
equipment. The functions shall include: rate indication, totalization, online meter status, self-test, meter identification and tag number, 4-20 MA
span adjustment, flow damping, 4-20 MA zero adjustment, meter re-scale
and meter recalibration. Meter output shall be isolated 4-20 MA signal
linearly proportional to the flow rate operating into a maximum of 1,000
ohms. The power requirements for the meter shall be a maximum of five
watts operating on 117 VAC 50 /60 HZ. It shall be capable of operating on
12 VDC continuous or battery back up. The temperature range of the
transmitter shall be 32-140 degrees F. For installations at wastewater
treatment plant, the installation shall also include a remote chart recorder
to be located in the operations building.
(4)
Electronic Recording Receiver
The electronic recording receiver shall be of the solid state, null-balance,
servo operated potentiometer type.
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 53
January 2013
The instrument shall contain a differential amplifier, a TORQ-ER driving
motor to position the pin, and a Flux Bridge contact-less solid state
position feedback device for balancing. The instrument shall be capable of
receiving one process variable input. Inputs shall be provided with
electrical isolation. The instrument shall accept an input signal of 4 to 20
ADC. Electrical zero and span adjustments shall be provided. Power
requirements shall be 120 VAC + 10%, 60 Hz. A power supply shall be
provided for two-wire transmitters. Accuracy shall be + 0.5% of span,
with repeatability of + 0.2% of span.
The Receiver shall be provided with an indicating 5 inch segmental scale.
The electronic recording receiver shall be housed in a cast aluminum case
suitable for panel mounting. The case shall have a door with gasket and
glass window. A 12 inch circular chart shall be provided, with 7 day/rev.
and chart rotation. An eight (8) digit electronic totalizing counter shall also
be provided.
(5)
Performance Specifications.
The meter shall measure, indicate, totalize and record the flow within the
following parameters:
Accuracy: 1% +/ - of actual flow above 1 foot per second
Linearity of the units: 0. 5% + / Repeatability: to within 0. 25 % + / Sensitivity: 0.005 feet per second
(6)
Materials
Sensors: PVC
Strap-on Hardware: 304 stainless steel
Hot-Shot Valve Hardware: brass
Sensor Cable: Triax Beldon 9222
Sensor Cable Length: 1,000 feet maximum
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 54
January 2013
(7)
Flow Meter Maintenance.
The flow meter manufacturer shall incorporate trouble shooting guides
with the instruction manuals. In addition the meter shall be designed to
provide a continuous on line indication of meter status via the LCD
display. The front panel shall have a menu with user operated self test
program which can be activated to check signal strength, transmission
status as well as electronic circuitry to assure reliable operation of the
motor.
(8)
Warranty and Service
(a)
Warranty
Products shall be guaranteed to be free from defects in material
and workmanship under normal use and service for a period of one
(1) year after start-up.
(b)
Service.
Service shall be available for instrument repair of the products.
Manufacturer’s service personal shall be based in Florida to insure
a reasonable response time of not more than two working days.
j.
Electrical Grounding System
(1)
General
A grounding system shall be installed as per National Electrical Code,
Local Codes and Ordinances. The drawings shall clearly show the
Electrical Grounding System. An underground perimeter cable grounding
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 55
January 2013
system shall be installed with connections to at least the following
equipment:
1.
2.
3.
4.
5.
6.
7.
(2)
Wet Well Cover
Valve Vault Cover
Control Panels
Generator
Utility Company Transformer
Main Disconnect Switch
Fence
Material and Installation
The drawings shall show details of material and installation to construct a
completely functional and operational Electrical Grounding System.
k.
Inspection and Testing
A factory representative knowledgeable in pump operation and maintenance shall
inspect and supervise a test run at the pumping station covered by this Manual. A
minimum of one (1) working day shall be provided for the inspections.
Additional time made necessary by faulty or incomplete work or equipment
malfunctions shall be provided as necessary to meet the requirements in this
Manual at no additional cost to the City. Upon satisfactory completion of the test
run, the factory representative shall issue the required manufacturer's certificate.
The test run shall demonstrate that all items of this Manual have been met by the
equipment as installed and shall include, but not be limited to, the following tests:
1.
That all units have been properly installed.
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 56
January 2013
l..
2.
That the units operate without overheating or overloading any parts and
without objectional vibration.
3.
That there are no mechanical defects in any of the parts.
4.
That the pumps can deliver the specified pressure and quantity.
5.
That the pumps are capable of pumping the specified material.
6.
That the pump controls perform satisfactorily.
Required Submittals
Submittals shall be provided to the City in triplicate and include the following:
•
Shop and erection drawings showing all important details of construction,
dimensions and anchor bolt locations.
•
Descriptive literature, bulletins, and/or catalogs of the equipment.
•
Data on the characteristics and performance of each pump. Data shall
include guaranteed performance curves, based on actual shop tests of
similar units, which show that they meet the specified requirements for
head, capacity, efficiency, NPSHR, submergence and horsepower. Curves
shall be submitted on 8- 1/2" by 11" sheets, at as large a scale as is
practical. Curves shall be plotted from no flow at shut off head to
maximum manufacturer recommended pump capacity. Catalog sheets
showing a family of curves will not be acceptable.
•
Complete layouts, wiring diagrams, elementary or control schematics,
including coordination with other electrical control devices operating in
conjunction with the pump control system. Suitable outline drawings shall
be furnished for approval before proceeding with manufacture of any
equipment. Standard preprinted sheets or drawings simply marked to
indicate applicability will not be acceptable.
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 57
January 2013
•
A drawing showing the layout of the pump control panel shall be
furnished. The layout shall indicate all devices mounted on the door and
in the panel shall be completely identified.
•
The weight of each pump.
•
Complete motor data shall be submitted including:
-
m.
Name plate identification
No-load current
Full load current
Full load efficiency
Locked rotor current
High potential test data
Bearing Inspection Report
Shop Painting
Before exposure to weather and prior to shop painting, all surfaces shall be
thoroughly cleaned, dry and free from all mill-scale, rust, grease, dirt and other
foreign matter. All pumps and motors shall be shop coated with a corrosion
resistant paint proven to withstand an environment of raw wastewater. All
nameplates shall be properly protected during painting.
Gears, bearing surfaces, and other similar surfaces obviously not to be painted
shall be given a heavy shop coat of grease or other suitable rust-resistant coating.
This coating shall be maintained as necessary to prevent corrosion during periods
of storage and erection and shall be satisfactory to the City up to the time of the
final acceptance test.
n.
Handling
All parts and equipment shall be properly protected so that no damage or
deterioration will occur during a prolonged delay from the time of shipment until
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 58
January 2013
installation is completed and the units and equipment are ready for operation.
Finished surfaces of all exposed pump openings shall be protected by wooden
planks, strongly built and securely bolted thereto. Finished iron or steel surfaces
not painted shall be properly protected to prevent rust and corrosion.
o.
Warranty
The pump manufacturer shall warrant the units being supplied to the City against
defects in workmanship and material for a period of five (5) years or 10,000
hours.
p.
Tools and Spare Parts
One (1) set of all special tools required for normal operation and maintenance
shall be provided. All such tools shall be furnished in a suitable steel tool chest
complete with lock and duplicate keys.
The manufacturer shall have in stock the following spare parts for each size pump
supplied:
1.
2.
3.
4.
One (1)
One (1)
One (1)
One (1)
5.
6.
7.
8.
9.
One (1)
One (1)
One (1)
One (1)
One (1)
upper bearing.
lower bearing.
set of upper and lower shaft seals.
set of "O-Rings" or gaskets required for replacement of
bearings and seals.
set impeller wear ring, and impeller bolt and key
shaft sleeve (if applicable).
cable cap (if applicable).
motor cable and cable entry washer/grommet.
set of inspection plug washers.
The pump supplier shall have a guaranteed parts stock program in the State of
Florida.
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 59
January 2013
q.
Chain Link Fence
(1)
General
The contractor shall furnish and erect the chain link fence and gate in
accordance with these specifications and in conformity with the lines,
grades, notes and typical sections shown on the drawings and Details of
the Standard Drawings.
(2)
Materials
The fence, posts, fastenings, fittings and other accessories for chain link
fence shall meet the requirements of AASHTO M 181 with the following
changes:
1.
The weight of coating of wire fabric shall be 1.2 ounces of zinc per
square foot (Class B).
2.
The galvanizing of steel materials shall be hot-dipped galvanized.
3.
The weight of coating on posts and braces shall be 1.8 ounces of
zinc per square foot, both inside and outside to meet the
requirements of AASHTO M 111.
The base metal of the fence shall be a good commercial quality 9 Gage
Steel wire. The fabric shall be of uniform quality, and shall be 6' high
with a 2" mesh size.
All posts and rails shall be in accordance with the following schedule:
End, corner and pull posts 2-3/8"
O.D., Schedule 40.
Line posts and gate frames 2" O.D.,
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 60
January 2013
Schedule 40.
Gate Posts - 3" O.D., Schedule 40.
Post braces and top rail - 1-5/8" O.D.,
Schedule 20.
Tension wire shall be 0.177" coiled spring wire tensioned along the
bottom of the fabric and shall be coated similarly to the wire fence.
Miscellaneous fittings and hardware shall be zinc coated commercial
quality or better steel or zinc coated cast or malleable iron as appropriate
for the article.
Post caps, designed to provide a drive fit over the top of the tubular post to
exclude moisture, shall be provided.
(3)
Installation
(a)
Post Setting
All posts shall be set 3' deep in concrete footings, 18" diameter for
line posts, gate and corner posts.
After the post has been set, aligned and plumbed, the hole shall be
filled with 2500 p.s.i. concrete. The concrete shall be thoroughly
worked into the hole so as to leave no voids. The exposed surface
of the concrete shall be crowned to shed water.
End, corner, pull and gate posts shall be braced to the nearest post
with horizontal brace used as a compression member and a
galvanized 3/8" steel truss rod and truss tightener used as a tension
member. Corner posts and corner bracing shall be constructed at
all changes of fence alignment of 30º or more. All chain link fence
shall be constructed with a top rail and bottom tension wire.
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 61
January 2013
(b)
Gates
Swing gates shall be two (2), 6' wide double hung gates as
indicated on the Details of the Standard Drawings and hinged to
swing through 180º from closed to open and shall be complete with
latches, locking device, stops keeper, hinges, fabric and braces.
Gates shall be the same height as the fence and the gate fence shall
be of the gage and quality as the fence.
Gate leaves less than 8' wide shall have truss rods or intermediate
braces and gate leaves 8' or more in width shall have intermediate
braces and diagonal truss rods or shall have tubular members as
necessary to provide rigid construction, free from sag or twist.
(c)
Placing Fence
The fence shall not be placed until the posts have been
permanently positioned and concrete foundations have attained
adequate strength. The fence shall be placed by securing one end
and applying sufficient tension to remove all slack before making
permanent attachments at intermediate points. The fence shall be
fastened to all corner, end and pull posts by substantial and
approved means. Tension for stretching the fence shall be applied
by mechanical fence stretchers.
r
Wet Well Entrance
The wet well entrance shall be paved from the street to the double gates.
Pavement shall be at least ten feet wide.
g
Wet Well Grounds
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 62
January 2013
The grounds inside the fence shall be rock. Before the fence is installed three
inches of ground around all pads and panel box stands shall be removed, weed
control fiber put down and brought back to ground level with rock.
City of Umatilla Standard Specifications
Water & Sewer Utilities
B - 63
January 2013
APPENDIX
C
WATER DISTRIBUTION
1.
Pipe material for water mains and service connections.
a.
b.
c.
d.
e.
2,
General
Pipe Inspection and Testing.
PVC Pipe
(1)
PVC PIPE
(2)
Joints.
(3)
Fittings.
Ductile Iron Pipe and Fittings
(1)
Ductile Iron Pipe
(2)
Fittings.
(3)
Joints.
(4)
Coatings and Linings.
(5)
Polyethylene Encasement.
Service Pipe, Stops, Fittings, and Service Saddles
Service Pipe.
(1)
(2)
Stops
(3)
Fittings.
(4)
Service Saddles
Pipe installation for water mains.
a.
General
b.
Pipe Handling.
c.
Separation of Water Mains, Sewers and Reclaimed Water
(1)
(2)
(3)
(4).
d.
General
Horizontal Separation
Vertical Separation
Crossing of Water Mains and Sewers.
Trench Preparation and Pipe Bedding
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
Trench Preparation and Pipe Bedding.
Pipe Preparation and Handling.
Trench Dewatering and Drainage Control.
Survey Line and Grade.
Pipe Laying in Trench. 6
Laying PVC Pipe.
Laying Ductile Iron Pipe.
Laying of Pipes on Curves
Pipe Restraining and Thrust Block.
Bedding and Backfill for Pipes.
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix C
January 2013
e.
f.
g.
h.
i.
3.
Hydrostatic Tests
(1)
General.
(2)
Testing Criteria.
(3)
Procedure for Pressure Test.
(4)
Procedure for Leakage Test.
Disinfection of Water Mains
(1)
General.
(2)
Flushing.
(3)
Disinfection Criteria.
(4)
Form of Applied Chlorine.
(5)
Point of Application.
(6)
Operation of City Valves.
(7)
Retention Period.
(8)
Chlorinating Valves and Hydrants.
(9)
Final Flushing and Testing.
(10) Repetition of Flushing and Testing.
Notification and Connection to Existing Mains.
Water Service Piping and Connection.
Location and Identification.
Valves, Hydrants And Accessories For Water Mains
a.
General
b.
Resilient Seat Gate Valves
(1)
General.
(2)
Material.
(3)
Miscellaneous Requirements.
c.
Butterfly Valves
(1)
General.
(2)
Material.
(3)
Face to Face Dimension.
(4)
Valve Shaft.
(5)
Valve Operator.
d.
Valve Installation.
e.
Valve Boxes.
f.
Air Release Valves.
g.
Fire Hydrants.
(1)
Material.
(2)
Painting.
(3)
Construction Details.
(4)
Location.
h.
Water Meters.
i
Backflow Preventer
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix C
January 2013
APPENDIX
C
WATER DISTRIBUTION
1.
Pipe material for water mains and service connections.
a.
General
These specifications cover the pipe, fittings, and accessory items used for
water distribution systems. Pipe used in water distribution systems shall be
either standard PVC, fusible PVC, or DIP. The contractor shall be responsible
for all materials furnished and storage of same, until the date of substantial
completion. The contractor shall replace at his own expense all materials found
to be defective or damaged in handling or storage. The contractor shall, if
requested by the City, furnish certificates, affidavits of compliance, test reports,
or samples for check analysis for any of the materials specified herein. All pipe
delivered to project site for installation is subject to random testing for
compliance with the designated specifications.
b.
Pipe Inspection and Testing.
Requirements specified in Appendix B, paragraph 1 e. shall apply
.
c.
PVC Pipe
(1)
Standard PVC PIPE
PVC Pipe of nominal diameter, four inches through 12 inches, shall be
manufactured in accordance with AWWA Standard C900, latest edition.
All PVC pipe shall be DR of 18. Pipe shall be the same O.D. as ductile
iron pipe. Pipe of 14 inch diameter and larger shall be manufactured in
accordance with AWWA Standard C905, latest edition, and shall have a
DR of 18. PVC pipe shall be blue in color. All PVC pipe under pavement
must be sleeved, refer to Appendix A.4 b. for sleeve materials.
(2)
Joints.
PVC pipe shall have integral bell push on type joints conforming
ASTM D3139
City of Umatilla Standard Specifications
Water & Sewer Utilities
C-1
January 2013
to
.
(3)
Fittings.
Fittings used with PVC pipe shall conform to Appendix B, paragraph
d.
Ductile Iron Pipe and Fittings
(1) Ductile Iron Pipe.
D I P shall only be used with written permission of city engineer and
utility Department
All ductile iron pipe of nominal diameter four inches through 20 inches
shall be Class 350 and for pipe sizes larger than 20 inches shall be Class
250 and shall conform to ANSI/AWWA A21.51/Cl5l
.
(2)
Fittings.
Any fittings required shall be mechanical joint ductile iron or gray iron
conforming to ANSI/AWWA A21.10/C110, 250 Psi minimum pressure
rating, or ductile iron compact fittings in accordance with ANSI/AWWA
A21.53/C153
.
(3)
Joints.
Joints for ductile iron pipe and fittings shall be push- on or mechanical
joints conforming to ANSI/AWWA A21.11/C111. Where called for on the
drawings, restrained or flanged joints shall be provided. Flanged joints
shall conform to ANSI Standard B 16.1-125 LB. Restrained joints shall
conform to Appendix A, paragraph 6. b. and paragraph 6.c.
(4) Coatings and Linings.
Where ductile iron pipe and fittings are to be below ground or installed in
a casing pipe the coating shall be a minimum 1.0 mil thick in accordance
with ANSI/AWWA A21.51/C151. Where ductile iron pipe and fittings are
to be installed above ground, pipe, fittings and valves shall be thoroughly
cleaned and given one field coat (minimum 1.5 mils dry thickness) of rust
inhibitor primer. Intermediate and finished field coats of Alkyd shall also
be applied by the contractor (minimum 1.5 mils dry thickness each coat).
Primer and field coats shall be compatible and shall be applied in
accordance with the manufacturers recommendations. Final field coat
shall be green for raw water and blue for finished water. All ductile iron
pipe and fittings shall have an interior protective lining of cement-mortar
City of Umatilla Standard Specifications
Water & Sewer Utilities
C-2
January 2013
with a seal coat of asphalt material in accordance with ANSI/AWWA
A21.4/C104.
(5)
Polyethylene Encasement.
The pipe shall be polyethylene encased (8 mil) where shown on the
drawings or required by the City in accordance with ANSI/AWWA
A21.51/C105.
e.
Service Pipe, Stops, Fittings, and Service Saddles
(1) Service Pipe.
All service lines shall be one inch, one and one-half inch or two inch
polyethylene tubing conforming to specifications in AWWA C800 and
AWWA C901
.
(2) Stops.
Corporation stops shall be one inch, one and one-half inch or two inch
brass, equipped with connections compatible with the polyethylene tubing
and threaded in accordance with specifications in AWWA C800 and
AWWA C901. Curb stops shall be sized to match the meter size and
conform to the specifications in AWWA C800 and AWWA C901
.
(3) Fittings.
Fittings shall be brass, cast and machined in accordance with
specifications in AWWA C800 and AWWA C901, with compatible
polyethylene tubing connections
.
(4)
Service Saddles
A service saddle shall be used for all service line taps. Service saddles
shall be double strap, anchored by a minimum four bolt pattern on a
ductile iron saddle body. Service saddles for PVC pipe shall have the
double strap sized exactly to the pipe outside diameter. Sealing gaskets
shall be BUNA-N rubber and straps shall be corrosion resistant alloy
steel. The City may require a stainless steel strap and fusion epoxy or
nylon coated ductile iron body with stainless steel hardware in areas
designated as corrosive.
City of Umatilla Standard Specifications
Water & Sewer Utilities
C-3
January 2013
2,
Pipe installation for water mains.
a.
General
Pipe shall be installed in accordance with the manufacturer’s specifications and
instructions for the type of pipe used and applicable AWWA standards, such as
C900 and C903, unless otherwise stated in these specifications.
b. Pipe Handling.
All types of pipe shall be handled in such manner as will prevent damage to the
pipe or coating. Accidental damage to pipe or coating shall be repaired to the
satisfaction of the City or be removed from the job. When not being handled, the
pipe shall be supported on timber cradles or on properly prepared ground, graded
to eliminate all rock points and to provide uniform support along the full length.
When being transported, the pipe shall be supported at all times in a manner
which will not permit distortion or damage to the lining or coating. Any unit of
pipe that, in the opinion of the City, is damaged beyond repair by the contractor
shall be removed from the site of the work and replaced with another unit. Joint
gaskets shall be stored in clean, dark, dry location until immediately before use.
Dirt or other foreign material shall be prevented from entering the pipe or pipe
joint during handling or laying operations and any pipe or fitting that has been
installed with dirt or foreign material in it shall be removed, cleaned and relaid. At
times when pipe laying is not in progress, the open ends of the pipe shall be
closed by a water-tight plug or by other means approved by the City to ensure
absolute cleanliness inside the pipe
.
c.
Separation of Water Mains, Sewers and Reclaimed Water
(1) General
Water mains that are laid in the vicinity of pipe lines designated to carry raw
wastewater or reclaimed water (wastewater effluent) shall meet the
horizontal and vertical separations specified below.
(2) Horizontal Separation
Normal conditions: water mains shall be located at least 10’ horizontally
from pipes carrying raw wastewater, and 3’ horizontally from pipes carrying
reclaimed water, whenever possible. The distance shall be measured from
inside edge of pipe to inside edge of pipe.
Unusual conditions: When local conditions prevent a horizontal separation
of ten feet, a water main may be laid closer to a pipe carrying raw
wastewater provided that the bottom of the water main is at least 18 inches
above the top of the sewer pipe and the water main is laid in a separate
City of Umatilla Standard Specifications
Water & Sewer Utilities
C-4
January 2013
trench or on an undisturbed earth shelf. All Florida Department of
Environmental Protection (FDEP) regulations regarding separation between
water and sewer mains shall apply and in the case of a discrepancy between
the City and FDEP requirements, the stricter shall prevail. However, in no
circumstance shall a reclaimed water pipe be installed closer than three feet
from a water main.
(3)
Vertical Separation
Normal conditions: water mains shall be laid to provide a separation of at
least 18 inches between the bottom of the water main and the top of the
sewer or reclaimed water pipe.
Unusual conditions: When construction conditions prevent a vertical
separation of 18 inches as described herein above, the sewer or reclaimed
water pipe shall be constructed of ductile iron pipe with mechanical joints.
(4). Crossing of Water Mains and Sewers.
Water mains shall be above the sewer or reclaimed water pipe whenever
they cross. A vertical separation of at least 18 inches shall be maintained
between the top of the sewer or reclaimed water pipe, and the bottom of the
water main. Adequate structural support for both the water main and sewers
shall be provided to prevent excessive deflection of joints and settling.
Sewer or reclaimed water mains shall be constructed of PVC or ductile iron
pipe with mechanical joints and the length of PVC or ductile iron pipe shall
be minimum 18 feet and centered at the point of crossing so that the joints
will be equidistant and as far as possible from the water main.
d. Trench Preparation and Pipe Bedding
(1)
Trench Preparation and Pipe Bedding.
Provisions of Appendix A, paragraph 3.h. shall apply. Also refer to
Standard Drawings.
(2) Pipe Preparation and Handling.
All pipe and fittings shall be inspected prior to lowering into trench to
insure no cracked, broken, or otherwise defective materials are being used.
Contractor shall clean ends of pipe thoroughly and remove foreign matter
and dirt from inside of pipe and keep clean during and after laying.
Contractor shall use proper implements, tools, and facilities for the safe and
proper protection of the work. Contractor shall lower pipe into the trench in
City of Umatilla Standard Specifications
Water & Sewer Utilities
C-5
January 2013
such a manner as to avoid any physical damage to the pipe and shall remove
all damaged pipe from the job site. Care shall be taken to not drop or dump
pipe into trenches under any circumstances.
(3)
Trench Dewatering and Drainage Control.
Specifications from Appendix A-3.f shall apply. Contractor shall prevent
water from entering the trench during excavation and pipe laying operations
to the extent required to properly grade the bottom of the trench and allow
for proper compaction of the backfill. Pipe shall not be laid in water.
(4) Survey Line and Grade.
Pipe shall be laid to the lines and grades shown on the plans. The contractor
shall provide line and grade stakes at a 100’ maximum spacing and at all
line or grade change locations. Contractor shall provide Temporary Bench
Marks at maximum 1,000’ intervals in compliance with state statutes. The
minimum pipe depth shall be 3’ feet below the finished grade surface or 3’
below the elevation of the edge of pavement of the road surface whichever
is greater.
(5)
Pipe Laying in Trench.
Contractor shall prevent foreign material from entering the pipe while it is
being placed in the trench. Contractor shall remove all foreign material from
the pipe or joint ring before the next pipe is placed. If the pipe laying crew
cannot put the pipe into the trench and in place without getting earth into the
pipe, the City may require that snugly-fitted, tightly-woven canvas bags be
placed over each end before lowering the pipe. The bags shall be left in
place until the connection is to be made to the adjacent pipe. During laying
operations, contractor shall keep debris, tools, clothing, or other materials
out of the pipe.
(6)
Laying PVC Pipe.
All PVC pipe shall be installed in accordance with standards set forth in the
UNI-BELL “ Handbook of PVC pipe design and construction” unless such
standards conflict with this Code in which case this Code shall apply.
City of Umatilla Standard Specifications
Water & Sewer Utilities
C-6
January 2013
(7)
Laying Ductile Iron Pipe.
All ductile iron pipe shall be installed in accordance with AWWA C600
unless such standards conflict with this Code in which case this Code shall
apply. Contractor shall cut pipe only as necessary to comply with alignment
shown on the plans. Flame cutting of pipe shall not be allowed. Contractor
shall provide special tools and devices, such as special jacks, chokers, and
similar items required for proper installation. Lubricant for the pipe gaskets
shall be furnished by the pipe manufacturer, and no substitutes shall be
permitted under any circumstances. The pipe shall be polyethylene encased
(8 mil) where shown on the drawings in accordance with ANSI/AWWA
A21.51/C105
(8)
Laying of Pipes on Curves
Long radius curves, either horizontal or vertical, may be laid with standard
pipe by deflections at the joints. Maximum deflections at pipe joints and
laying radius for the various pipe lengths shall be as recommended by the
pipe manufacturer.
(9)
Pipe Restraining and Thrust Block.
Requirements specified in Appendix A, paragraph 6.b., 6.c., and 6.d. shall
apply.
(10) Bedding and Backfill for Pipes.
Requirements specified in Appendix A, paragraph 3.h. shall apply.
e.
Hydrostatic Tests
(1)
General.
Hydrostatic tests shall consist of pressure test and leakage test. Hydrostatic
tests shall be conducted on all newly laid pressure pipes, joints and valves
including all service lines to the curb stops. Air testing of pressure pipes will
not be permitted under any circumstance. Tests may be made on sections not
exceeding 2,000’, when this procedure is acceptable to the City. Contractor
shall furnish all necessary equipment and material, make all taps, and
furnish all closure pieces in the pipe as required. Equipment to be furnished
by the contractor shall include graduated containers, pressure gauges,
hydraulic force pumps, and suitable hoses and piping. The City will monitor
and approve a satisfactory test. The contractor may conduct hydrostatic
tests after the trench has been partially backfilled with the joints left exposed
for inspection for his informational purposes only. The hydrostatic tests for
City of Umatilla Standard Specifications
Water & Sewer Utilities
C-7
January 2013
acceptance shall only be conducted after the trenches have been completely
backfilled and compacted as specified. Where any section of pipe is
provided with concrete thrust blocking, pressure test will not be made until
at least five days have elapsed after the thrust blocking is installed. If highearly cement is used for the concrete thrust blocking, the time may be
reduced to 24 hours if the City concurs that the concrete has cured and
reached adequate strength.
(2)
Testing Criteria.
All pipe sections to be pressure tested shall be subjected to a hydrostatic
pressure of 150 psi. The duration of each pressure test shall be for a period
of 2 hours. If during the test, the integrity of the tested line is in question, the
City may require a 6 hour pressure test. The basic provisions of AWWA
C600 for Ductile Iron Pipe or C605 for PVC Pipe shall be applicable.
(3)
Procedure for Pressure Test.
Each section of pipe to be tested, as determined by the City, shall be slowly
filled with water and the specified test pressure shall be applied by means of
a pump connected to the pipe in a satisfactory manner. Before applying the
specified test pressure, all air shall be expelled from the pipe. To accomplish
this, taps shall be made, and appropriate valves installed to ensure bleeding
of all air from the main. If defective pipes, fittings, valves, or hydrants are
discovered in consequence of this pressure test, all such items shall be
removed and replaced by the contractor with sound material and the test
shall be repeated until satisfactory results are obtained. Provisions of
AWWA C600 or C605, where applicable, shall apply
.
(4)
Procedure for Leakage Test.
After completion of the pressure test, a leakage test shall be conducted to
determine the quantity of water lost by leakage under the specified test
pressure. Applicable provisions of AWWA C600 for Ductile Iron Pipe and
C605 for PVC Pipe shall apply. Allowable leakage in gallons per hour for
pipeline shall not be greater than that determined by the formula:
L = SD(P) ½
148,000
Note:
L = Allowable leakage in gallons per hour.
S = Length of pipe tested, in feet.
D = Nominal diameter of the pipe in inches.
City of Umatilla Standard Specifications
Water & Sewer Utilities
C-8
January 2013
P = Average test pressure during leakage test in pounds per square
inch gauge.
Leakage is defined as the quantity of water to be supplied in the newly laid
pipe or any valved section under test, which is necessary to maintain the
specified leakage test pressure after the pipe has been filled with water and
the air expelled. Should any test of pipe laid disclose leakage greater than
that allowed, contractor shall locate and replace or repair the defective
joints, pipe or valve until the leakage from subsequent testing is within the
specified allowance.
f.
Disinfection of Water Mains
(1) General.
Before being placed in service, all new water mains shall be chlorinated in
accordance with the specifications below and the procedures outlined in
AWWA C651 “Standard Procedure for Disinfecting Water Mains”
(2) Flushing.
Sections of pipe to be disinfected shall first be flushed (full diameter) to
remove any solids or contaminated material that may have become lodged in
the pipe. If no hydrant is installed at the end of the main, then a blow-off
valve shall be provided large enough to develop a velo of at least 2.5 feet
per second in the main. All taps required for chlorination or flushing
purpose, or for temporary or permanent release of air shall be provided for
by the contractor as a part of the construction of water mains. After the
disinfection, all such taps shall be sealed to the satisfaction of the City
.
(3)
Disinfection Criteria.
Before being placed into service, all new mains and repaired portions of, or
extensions to existing mains shall be chlorinated so that the initial chlorine
residual is not less than 50 mg/l and that a chlorine residual of not less than
25 mg/l remains in the water after standing 24 hours in the pipe.
(4)
Form of Applied Chlorine.
Chlorine may be applied as a liquid chlorine (gas-water mixture as specified
in AWWA B300. Contractor shall assume responsibility for safe handling
of chlorine and shall meet requirements of OSHA and other regulatory
agencies for safe handling of chlorine.
City of Umatilla Standard Specifications
Water & Sewer Utilities
C-9
January 2013
(5)
Point of Application.
The preferred point of application of the chlorinating agent is at the
beginning of the pipeline extension or any valved section of it, and through
a corporation stop inserted in the pipe. The water injector for delivering the
chlorine-bearing water into the pipe should be supplied from a tap made on
the pressure side of the gate valve controlling the flow into the pipeline
extension. Alternate points of applications may be used when approved or
directed by the City
.
(6)
Operation of City Valves.
Valves shall be manipulated by the City personnel so that the strong
chlorine solution in the line being treated will not flow back into the line
supplying the water.
(7)
Retention Period.
Treated water shall be retained in the pipe at least 24 hours. After this
period, the chlorine residual at pipe extremities and at other representative
points shall be at least 25 mg/l.
(8)
Chlorinating Valves and Hydrants.
In the process of chlorinating newly laid pipe, all valves or other
appurtenances shall be operated while the pipe line is filled with the
chlorinating agent and under normal operating pressure.
(9)
Final Flushing and Testing.
Following chlorination, all treated water shall be thoroughly flushed from
the newly laid pipe at its extremity until the replacement water throughout
its lengths shows upon test, a free chlorine residual not in excess of that
normally carried in the system. After flushing, water samples collected on 2
successive days from the treated piping system, as directed by the City, shall
show acceptable, bacteriological results. All bacteriological testing shall be
performed by the Contractor. However, in order to expedite testing, the
Developer may request testing by a private laboratory. All such
bacteriological analysis must be performed by a laboratory certified by the
State of Florida. Proper chain of custody procedures must be followed.
Copies of testing results and all related correspondence with the FDEP shall
be submitted to the City.
City of Umatilla Standard Specifications
Water & Sewer Utilities
C - 10
January 2013
(10) Repetition of Flushing and Testing.
Should the initial treatment result in an unsatisfactory bacterial test, the
original chlorination procedure shall be repeated by the contractor until
satisfactory results are obtained.
g.
Notification and Connection to Existing Mains.
Requirements specified in Appendix A, paragraph 7. shall apply.
h.
Water Service Piping and Connection.
Water service piping and connection shall be installed as indicated in the Standard
Drawings. The location of all service lines shall be as shown on the drawings and
shall be either single or dual service. On curbed streets the exact location for each
installed service shall be marked by etching or cutting a “W” in the concrete curb.
Where no curb exists, locations shall be adequately marked by a method approved
by the City. Brass or aluminum markers may also be used.
i.
Location and Identification.
.
All non-metallic water mains shall be installed with a continuous, insulated 14
gauge copper wire installed directly on top of the pipe for location purposes.
Detectable tape shall be placed 1’ above the top of the pipe. See Standard
Drawings. In addition, all PVC water mains shall be either a solid blue color or
white with blue lettering. All lettering shall appear legibly on pipe and shall run
the entire length of the pipe. Lettering shall read as is acceptable for the intended
use. As an alternate to the above requirements metallic tape shall be installed 12”
above the pipe. All ductile iron water mains shall be marked with a continuous
stripe located within the top 90° of the pipe. Said stripe shall be a minimum 2” in
width and shall be blue in color. Backfill shall not be placed for 30 minutes
following paint application.
3.
Valves, hydrants and accessories for water mains.
a.
General.
All valves and appurtenances shall be products of well established firms who are
fully experienced and qualified in the manufacture of the particular equipment to
be furnished. The equipment shall be designed, constructed and installed in
City of Umatilla Standard Specifications
Water & Sewer Utilities
C - 11
January 2013
accordance with the best practices and methods and shall comply with these
specifications as applicable.
b.
Resilient Seat Gate Valves
(1) General.
All gate valves 12” and smaller shall be resilient seat gate valves. Such
valves shall be resilient seated, manufactured to meet or exceed the
requirements of AWWA C509, latest revision, and in accordance with the
following specifications. Valves shall have an unobstructed waterway equal
to or greater than the full nominal diameter of the valve.
(2)
Material.
The valve body, bonnet, and bonnet cover shall be cast iron ASTM A126,
Class B. All ferrous surface inside and outside shall have a fusion-bonded
epoxy coating. A 2” wrench nut shall be provided for operating the valve.
All valves are to be tested in strict accordance with AWWA C509
(3)
Miscellaneous Requirements.
The valves shall be non-rising stem with the stem made of cast, forged, or
rolled bronze as specified in AWWA C509. Two stem seals shall be
provided and shall be of the O-ring type. The stem nut must be independent
of the gate. The resilient sealing mechanism shall provide zero leakage at
the water working pressure when installed with the line flow in either
direction.
c.
Butterfly Valves
(1) General.
All shut-off valves 16” and larger shall be Butterfly valves. Butterfly valves
and operators shall conform to the AWWA Standard Specifications for
Rubber Seated Butterfly Valves, Designation C504, except as hereinafter
specified. Valves, except as specified hereinafter, shall be Class 150A or B.
(2)
Material.
The valve body shall be constructed of close grain cast iron per ASTM
A126, Class B or equivalent material. All retaining segments and adjusting
devices shall be of corrosion resistant material. Valve seats shall be a
natural rubber or synthetic rubber compound. Valve seats 30” and larger
shall be field adjustable and replaceable without dismounting operator disc
City of Umatilla Standard Specifications
Water & Sewer Utilities
C - 12
January 2013
or shaft and without removing the valve from the line. All retaining
segments and adjusting devices shall be of corrosion resistant material.
Valves 24” and smaller shall have bonded or mechanically restrained seats
as outlined in AWWA C504.
(3)
Face to Face Dimension.
The face-to-face dimensions of valves shall be in accordance with above
mentioned AWWA Specification for short-body valve.
(4)
Valve Shaft.
The valve shaft shall be turned, ground, and polished, constructed of 18-8
stainless steel and designed for both torsional and shearing stresses when the
valve is operated under its greatest dynamic or seating torque. Shaft shall be
of either a one piece unit extending full size through the valve disc and
valve bearing or it may be of a stub shaft design
(5)
Valve Operator.
In general, the butterfly valve operators shall conform to the requirements of
AWWA Standard Specifications for Rubber Seated Butterfly Valves,
Designation C504, in so far as applicable.
d.
Valve Installation.
All valves shall be inspected upon delivery in the field to insure proper working
order before installation. They shall be set and jointed to the pipe in the manner as
set forth in the AWWA Standards for the type of connection ends furnished. All
valves and appurtenances shall be installed true to alignment and rigidly
supported. Any damage to the above items shall be repaired to the satisfaction of
the City before they are installed. Valves shall be installed in a vertical position
and be provided with a standard valve box so arranged that no shock will be
transmitted to the valve. The box shall be vertically centered over the operating
nut, and the cast iron box cover shall be set flush with the road bed or finished
surface. After installation, all valves shall be subjected to the field test for piping
as outlined in Appendix A 2. E. of these specifications. Should any defects in
materials or workmanship appear during these tests, the contractor shall correct
such defects to the satisfaction of the City. Flanged joints shall be made with hot
dipped galvanized bolts, nuts and washers. Mechanical joints shall be made with
mild corrosion resistant alloy steel bolts and nuts. All exposed bolts shall be
painted the same color as the pipe. All buried bolts and nuts shall be heavily
coated with two coats of bituminous paint.
e.
Valve Boxes.
City of Umatilla Standard Specifications
Water & Sewer Utilities
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January 2013
All buried valves shall have cast-iron three piece valve boxes. Valve boxes shall
be provided with suitable heavy bonnets and shall extend to such elevation at or
slightly above the finished grade surface as directed by the City. The barrel shall
be two-piece, sliding type, having 5-1/4” shaft. The upper section shall have a
flange at the bottom having sufficient bearing area to prevent settling and shall be
complete with cast iron covers. Covers shall have “Water” cast into the top for all
water mains. The actuating nuts for deeper valves shall be extended to come up to
4’ depth below finished grade. Care shall be taken while constructing valve boxes
to ensure that valve stems are vertical and the cast iron box has been placed over
the stem with base bearing on compacted fill and top flush with final grade. Boxes
shall have sufficient bracing to maintain alignment during backfilling. Contractor
shall remove any sand or undesirable fill from valve box prior to final inspection.
Each valve box shall have a 2’ x 2’ concrete pad 4” thick. Etched in the pad will
be arrows to indicate the direction of flow the valve will control and the size of
the valve.
f.
Air Release Valves.
The air release valves for use in water mains shall be installed as shown on the
Standard Drawings. The valves shall have a cast iron body, cover and baffle,
stainless steel float, bronze water diffuser, Buna-N or Viton seat and stainless
steel trim. Valves shall be provided with a vacuum check to prevent air from
reentering the line. The fittings shall be threaded.
g.
Fire Hydrants.
(1)
Material.
Fire hydrants shall have 5-1/4” valve opening and shall comply with
AWWA Standard C502 for fire hydrants for water works service, unless in
conflict with this Code in which case this Code shall apply. Each hydrant
Shall have 6” mechanical joints ends with harnessing lugs (dog ears) and
shall open by turning to the left
(counter clockwise).Fire hydrants shall
be of ample length for 42” depth of bury. It shall be provided with two 21/2” hose nozzles and one 4-1/2” pumper nozzle, all having National
Standard hose threads. Nozzles shall have caps attached by chains.
Operating nuts shall be AWWA Standard (pentagonal, measuring 1-1/2”
point to flat). Fire hydrants shall be equipped with “O-Ring” packing.
(2)
Painting.
All iron parts of the hydrant both inside and outside shall be painted, in
accordance with AWWA C502. All inside surfaces and the outside surfaces
below the ground line shall be coated with asphalt varnish in accordance
with AWWA C550. They shall be covered with two coats, the first having
dried thoroughly before the second is applied. The outside of the hydrant
City of Umatilla Standard Specifications
Water & Sewer Utilities
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January 2013
above the finished ground line shall be thoroughly cleaned and there after
painted with one coat of paint of a durable composition, and one additional
coat of red paint.
(3) Construction Details.
Hydrants shall be plumb and shall be set so that the lowest hose connection
is at least 18” above the surrounding finished grade. All hydrants shall be
inspected in the field upon delivery to the job to insure proper operation
before installation. The resetting of existing hydrants and moving and
reconnecting of existing hydrants shall be handled in a manner similar to a
new installation. (Fire flows shall be done on each hydrant and a copy of the
results submitted to the City). Hydrant shall be constructed in accordance
with the Standard Drawings.
(4)
Location.
Fire hydrants shall be located in the general location as shown on the
drawings. Final field location of all hydrants shall be as approved by the
City. All hydrants shall be located no less than 5’ and no more than 10’ from
the edge of pavement of the adjacent roadway and no less than 5’ from any
physical feature which may obstruct access or view of any hydrant unless
otherwise approved by the City
.
h.
Water Meters.
All water meters 4” and less shall be the positive displacement type with brass
bodies. Water meters greater than 4” shall be either the compound or turbine type.
Turbine types will be used for irrigation only. All meters shall register in gallons
per minute (gpm) with leak indicator, shall have oil filled hermetically sealed dial
and shall be programmed to read in thousands. All meters shall be compatible
with all Neptune meter reading equipment and billing software.
i
Backflow Preventer.
All potable water lines shall have a backflow preventer. The type shall be
determined by the city.
City of Umatilla Standard Specifications
Water & Sewer Utilities
C - 15
January 2013
APPENDIX D
RECLAIMED WATER TRANSMISSION/DISTRIBUTION
1.
PIPE MATERIAL FOR RECLAIMED WATER MAINS
a.
b.
c.
d.
e.
2.
General
Pipe Inspection and Testing
PVC Pipe
(1)
PVC Pipe
(2)
Joints
(3)
Fittings
Ductile Iron Pipe and Fittings
(1)
Ductile Iron Pipe
(2)
Fittings
(3)
Joints
(4)
Coatings and Linings
(5)
Polyethylene Encasement
Service Pipe, Stops, Fittings and Service Saddles
(1)
Service Pipe
(2)
Stops
(3)
Fittings
(4)
Service Saddles
PIPE INSTALLATION FOR RECLAIMED WATER MAINS
a.
General
b.
Pipe Handling
c.
Separation of Reclaimed Water Mains, Sewers and Water Mains
d.
Trench Preparation and Pipe Bedding
e.
Hydrostatic Tests
f.
Disinfection Reclaimed Water Mains
g.
Notification and Connection to Existing Reclaimed Water Main
h.
Reclaimed Water Service Piping and Connection
i.
Location and Identification
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix D
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March 2013
3.
VALVES, HYDRANTS AND ACCESSORIES FOR RECLAIMED WATER MAINS
a.
General
b.
Resilient Seat Gate Valves
c.
Butterfly Valves
d.
Valve Installation
e.
Valve Boxes
f.
Air Release Valves
g.
Fire Hydrants
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix D
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March 2013
APPENDIX D
RECLAIMED WATER TRANSMISSION/DISTRIBUTION
1.
PIPE MATERIAL FOR RECLAIMED WATER MAINS
a.
General
These specifications cover the pipe, fittings, and accessory items used for
reclaimed water transmission and distribution systems.
Pipe used in reclaimed water transmission and distribution systems shall either be
PVC or DIP.
The contractor shall be responsible for all materials furnished and storage of same,
until the date of substantial completion. The contractor shall replace at his own
expense all materials found to be defective or damaged in handling or storage.
The contractor shall, if requested by the City, furnish certificates, affidavits of
compliance, test reports, or samples for check analysis for any of the materials
specified herein. All pipe delivered to the project site for installation is subject to
random testing for compliance with the designated specifications.
b.
Pipe Inspection and Testing
The reclaimed water pipe shall be inspected and tested as required in Appendix B,
Section 1.e.
c.
PVC Pipe
(1)
PVC Pipe
All PVC pipe of nominal diameter 4" through 12" shall be manufactured
in accordance with AWWA standard C900, latest edition, and shall have a
DR of 18. Pipe of 14" diameter and larger shall be manufactured in
City of Umatilla Standard Specifications
Water & Sewer Utilities
D-1
March 2013
accordance with AWWA C905, latest edition, and shall have a DR of 18.
Pipe shall have the same O.D as DIP. Pipe shall be lavender color.
(2)
Joints
PVC pipe shall have integral bell push on type joints conforming to ASTM
D3139.
(3)
Fittings
Fittings used with PVC pipe shall conform to Appendix C, Section 1.d.
d.
Ductile Iron Pipe and Fittings
(1)
Ductile Iron Pipe
DIP shall only be used with written permission from the city engineer and
the city utility department.
All DIP of nominal diameter 4" through 20" shall be Class 350 and for
pipe larger than 20" shall be Class 250 and shall conform to
ANSI/AWWA A21.51/C151.
(2)
Fittings
Any fittings required shall be mechanical joint ductile iron or gray iron
conforming to ANSI/AWWA A21.10/C110, 250 psi minimum working
pressure rating, or ductile iron compact fittings in accordance with
ANSI/AWWA A21.53/C153.
(3)
Joints
Joints for DIP and fittings shall be push-on or mechanical joints
conforming to ANSI/AWWA A21.11/C111. Where called for on the
drawings, restrained or flanged joints shall be provided. Flanged joints
City of Umatilla Standard Specifications
Water & Sewer Utilities
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March 2013
shall conform to ANSI Standard B16.1-125 lb. Restrained joints shall
conform to Appendx A, Sections 6.b. and 6.c.
(4)
Coatings and Linings
Where DIP and fittings are to be below ground or installed in a casing pipe
the coating shall be a minimum of 1.0 mil thick in accordance with
ANSI/AWWA A21.51/C151. Where DIP and fittings are to be installed
above ground, pipe, fittings and valves shall be thoroughly cleaned and
given one (1) coat (minimum 1.5 mil dry thickness) of rust inhibitor
primer. Immediate and finished field coats of Alkyd shall also be applied
by the contractor (minimum 1.5 mils dry thickness each coat). Primer and
field coats shall be compatible and shall be applied in accordance with the
manufacturers recommendations. Final field coat shall be lavender.
All DIP and fittings shall have an interior protective lining of cement mortar with a seal coat of asphaltic material in accordance with
ANSI/AWWA A21.4/C104.
(5)
Polyethylene Encasement
The DIP shall be polyethylene encased (8 mil) where shown on the
drawings or required by the City in accordance with ANSI/AWWA
A21.51/C105.
e.
Service Pipe, Stops, Fittings and Service Saddles
(1)
Service Pipe
Service pipe shall be 1", 1-1/2" or 2" polyethylene tubing conforming to
specifications in AWWA C800 and AWWA C901. Larger size service
pipe, 3" and above shall be PVC pipe conforming to paragraph c.(1)
above. All service pipe shall be lavender in color.
City of Umatilla Standard Specifications
Water & Sewer Utilities
D-3
March 2013
(2)
Stops
Corporation stops shall be 1", 1-1/2" or 2" brass, equipped with
connections compatible with the polyethylene tubing and threaded in
accordance with specifications in AWWA C800 and AWWA C901. Curb
stops shall be sized to match the meter size and conform to the
specifications in AWWA C800 and AWWA C901.
(3)
Fittings
Fittings shall be brass, cast and machined in accordance with
specifications in AWWA C800 and AWWA C901, with compatible
polyethylene connections.
(4)
Service Saddles
A service saddle shall be used for all service line taps. Service saddles
shall be double strap, anchored by a minimum four (4) bolt pattern on a
ductile iron saddle body. Service saddles for PVC pipe shall have the
double strap sized exactly to the pipe outside diameter. Sealing gaskets
shall be BUNA-N rubber and straps shall be corrosion resistant alloy steel.
The City may require stainless steel straps and fusion epoxy or nylon
coated ductile iron body with stainless steel hardware in areas designated
as corrosive.
2.
PIPE INSTALLATION FOR RECLAIMED WATER MAINS
a.
General
Pipe shall be installed in accordance with the manufacturer's specifications and
instructions for the type of pipe used and applicable AWWA standards, such as
AWWA C600 and C605, unless otherwise stated in these specifications.
City of Umatilla Standard Specifications
Water & Sewer Utilities
D-4
March 2013
b.
Pipe Handling
All pipe, fittings and appurtenances shall be handled in such a manner as will
prevent damage as specified in Appendix C, Section 2.b.
c.
Separation of Reclaimed Water Mains, Sewers and Water Mains
When reclaimed water mains are laid in the vicinity of pipe lines designated to
carry potable water or raw wastewater they shall meet horizontal and vertical
separation distance requirements specified in Appendix C, Section 2.c.
d.
Trench Preparation and Pipe Bedding
The trench preparation and bedding for the reclaimed water main shall meet the
requirements specified in Appendix C, Section 2.d.
e.
Hydrostatic Tests
Hydrostatic testing of the reclaimed water mains shall comply with the
requirements specified in Appendix C, Section 2.e.
f.
Disinfection Reclaimed Water Mains
Before being placed into service, all new reclaimed water mains shall be
chlorinated in accordance with Appendix C, Section 2.f.
However,
bacteriological tests as specified in Appendix C, Section 2.f.(9) will not be
required.
g.
Notification and Connection to Existing Reclaimed Water Main
Connections to the existing reclaimed water main shall comply with the
requirements specified in Appendix A, Section 7.
City of Umatilla Standard Specifications
Water & Sewer Utilities
D-5
March 2013
h.
Reclaimed Water Service Piping and Connection
Reclaimed water service piping and connection shall be installed as indicated in
the Standard Drawings for a water service connection. The location of all serve
lines shall be as shown on the drawings and shall be either single or dual service.
On curbed streets the exact location for each installed service shall be marked by
etching or cutting a "RW" in the concrete curb. Where no curb exists, locations
shall be adequately marked by a method approved by the City.
i.
Location and Identification
All non-metallic reclaimed water mains shall be installed with a continuous,
insulated 14 gauge copper wire installed directly on top of the pipe for location
purposes. Detectable tape shall be placed 1' above the top of the pipe. See
Standard Drawings. In addition, all PVC reclaimed water mains shall be a solid
lavender color. All lettering shall appear legibly on pipe and shall run the entire
length of the pipe. Lettering shall read as is acceptable for the intended use.
All DIP reclaimed water mains shall be marked with a continuous stripe located
within the top 90º of the pipe. Said stripe shall be a minimum 2" in width and
shall be lavender in color. Backfill shall not be placed for 30 minutes following
paint application.
3.
VALVES, HYDRANTS AND ACCESSORIES FOR RECLAIMED WATER MAINS
a.
General
All valves and appurtenances shall be products of well established firms who are
fully experienced and qualified in the manufacture of the particular equipment to
be furnished. The equipment shall be designed, constructed and installed with the
best practices and methods and shall comply with these specifications as
applicable.
City of Umatilla Standard Specifications
Water & Sewer Utilities
D-6
March 2013
b.
Resilient Seat Gate Valves
The resilient seat gate valves shall meet the requirements of AWWA C509 and
the Appendix C, Section 3.b. of these Specifications.
c.
Butterfly Valves
All shut-off valves 16" and larger shall be butterfly valves and shall conform to
the AWWA C504 and Appendix C, Section 3.c. of these Specifications.
d.
Valve Installation
All valves shall be inspected and installed in accordance with the AWWA
Standards for the type of valve and connection and shall comply with the
requirements specified in Appendix C, Section 3.d.
e.
Valve Boxes
All buried valves shall have cast-iron three (3) piece valve boxes and shall comply
with the requirements specified in Appendix C, Section 3.e., except that covers
shall have "Reclaimed Water" cast into the top.
f.
Air Release Valves
The air release valves for use in the reclaimed water mains shall be installed as
shown on the Standard Drawings and shall comply with the requirements
specified in Appendix C, Section 3.f.
g.
Fire Hydrants
Fire hydrants installed on the reclaimed water mains shall meet the requirements
specified in Appendix C.3.g., except that the final exterior coat shall be lavender.
City of Umatilla Standard Specifications
Water & Sewer Utilities
D-7
March 2013
APPENDIX E
INTERIM PACKAGE AND SUBREGIONAL WASTEWATER TREATMENT
FACILITIES DESIGN CRITERIA
1.
ENGINEERING
a.
Scope and Intent
b.
Purpose
(1)
Variation
(2)
The Quantity Of The Influent Flow
(3)
Effluent Standards
(4)
Technical Design
(5)
Inherent Problems
(6)
Design And Operation Data
c.
Facility Designations
(1)
Size
(2)
Facility Description
d.
Submittals
e.
Engineer's Report
(1)
Contents of the Engineer's Report
(2)
Field Data
(3)
Laboratory Analyses
(4)
Existing Establishments
(5)
Soil Investigations
(6)
Inflow/Infiltration
(7)
100 Year Flood
(8)
Land Application of Effluent
(9)
Solids Handling
(10) Contributing Area
(11) Site Selection
(12) Treatment Process
(13) Existing WWTF
(14) Future Expansion
f.
Engineering Drawings
(1)
Topography
(2)
Structures
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix D
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March 2013
g.
h.
i.
j.
2.
(3)
Schematic
(4)
Piping
(5)
Hydraulic Profile
(6)
Test Borings
(7)
Proposed Facilities
(8)
Expansions
(9)
Miscellaneous
Specifications
Cost Estimates
Revisions to Approved Drawings
Operation During Construction
GENERAL
a.
Site Selection
b.
Design
c.
WWTF Details
(1)
General
(2)
Construction Materials
(3)
Structural Materials
d.
e.
f.
g.
h.
i.
j.
k.
(4)
Operating Equipment
(5)
Grading, Landscaping and Irrigation Minimum Requirements
Essential Facilities
Effluent Disposal
Safety
Plant Performance
Energy Requirements
Chemicals, Chemical Storage and Handling
(1)
General
(2)
Chemical Storage
(3)
Chemical Handling
(4)
Chemical Safety
Preventive Maintenance Program
Operation and Maintenance Manual
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix D
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March 2013
l.
m.
n.
Spare Parts
System / Facility Reliability
(1)
Pretreatment
(2)
Pumps
(3)
Aeration Facilities
(4)
Secondary Clarifiers
(5)
Effluent Filtration
(6)
Disinfection
(7)
Miscellaneous Components
Facility Expansion
3.
INFLUENT PUMPING STATION
a.
General
b.
Design Parameters
(1)
General
(2)
Pump Capacity
(3)
Piping Systems
(4)
Future Expansion
c.
Facilities and Equipment
4.
PRELIMINARY TREATMENT
a.
General
b.
Bar Screening Facilities
(1)
Facilities and Equipment
(2)
Manually Cleaned Bar Screens
(3)
Mechanically Cleaned Bar Screens
(4)
Grit Removal Facilities
c.
Flow Equalization
d.
Odor Control
5.
SECONDARY TREATMENT
a.
Activated Sludge
(1)
Processes to be Considered
(2)
Process Design Parameters
(3)
Aeration Facilities and Equipment
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix D
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March 2013
b.
c.
d.
e.
(4)
Aeration Basins
(5)
Return Activated Sludge
Oxidation Ditch
(1)
Design Parameters
(2)
Facilities and Equipment
Carrousel Process
(1)
Process Design Parameters
(2)
Facilities and Equipment
Secondary Clarification
(1)
Process Design Parameters
(2)
Equipment and Facilities
Waste Activated Sludge Facilities
6.
ADVANCED WASTE TREATMENT
a.
General
b.
Phosphorus Removal
(1)
Aerobic Digestion
(2)
Lime Stabilization
(3)
Anaerobic Digestion
(4)
Other Sludge Stabilization Processes
c.
Sludge Dewatering
(1)
Air Drying Beds
(2)
Centrifugation
(3)
Belt Filter Press
d.
Sludge Disposal
9.
WASTEWATER EFFLUENT DISPOSAL
a.
General
b.
Submittals
1.
Location
2.
Topography
3.
Geology
4.
Soils
5.
Groundwater Hydrology
c.
Treatment Guidelines - Land Application
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix D
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March 2013
d.
e.
f.
10.
(1)
Spray Irrigation - Restricted and Public Access
(2)
Rapid-Rate
(3)
Overland Flow
(4)
Other Effluent Disposal Systems
Operations and Maintenance - Land Application
Groundwater Monitoring - Land Application
Groundwater Injection
INSTRUMENTATION AND POWER
a.
Instrumentation
b.
Power Reliability
1.
Class I Reliability
2.
Class II Reliability
3.
Class III Reliability
c.
Power Source
d.
Power Distribution
e.
Breakers and Fuses
1.
Switch Gear
2.
Wires
3.
Outdoor Motors
4.
Explosion Proof Motors
5.
Conduit Routing
6.
Three Phase Motors
f.
Equipment Testing
City of Umatilla Standard Specifications
Water & Sewer Utilities
Appendix D
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March 2013
APPENDIX E
INTERIM PACKAGE AND SUBREGIONAL WASTEWATER TREATMENT
FACILITIES DESIGN CRITERIA
1.
ENGINEERING
a.
Scope and Intent
The scope of this Design Criteria for Interim Package and Subregional
Wastewater Treatment Facilities (WWTF) for City of Umatilla, Florida include
guidelines for engineering, general aspects for design, influent pumping stations,
preliminary, secondary and advanced treatment facilities, disinfection, sludge
treatment and management, treated effluent disposal, and instrumentation and
power systems. This design criteria is not a facility specification or a facility
design; rather this section provides criteria guidelines for future design activities
in the City. At this juncture, some technical areas may not have been considered
or may have been considered not favorable for the present "state of the art" in
wastewater treatment. The intent of this section is to state the present guidelines
of design criteria for interim package and subregional WWTFs which are intended
to be owned or operated by the City or to be connected to the City system.
Moreover, this section is not intended to preclude innovative designs, alternate
designs or other process trains which the City's design engineer may consider
more appropriate. Rather, this design criteria permits the City staff to recognize
deviations from the criteria and discuss justifications for the deviations with a
sound design basis for comparison.
b.
Purpose
The purpose of this section is to provide guidance for the selection of wastewater
treatment processes equipment and materials which will produce a final effluent
which will meet the requirements established by the Florida Department of
Environmental Protection (FDEP). Some of the problems associated with the
design and operations of an adequate WWTF are:
City of Umatilla Standard Specifications
Water & Sewer Utilities
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March 2013
(1)
Variation: The wide variation which occurs in the composition of the
municipal wastewater. While generated mainly in residential and
commercial areas, municipal wastewater may contain some storm water
discharge, infiltration, and minor amount of miscellaneous industrial
wastes. The wide range of organic and inorganic compounds contained in
these flows impose serious problems in the selection of the treatment
process and on the effective operation of the plant.
(2)
Quantity: The quantity of the influent flow varies widely. Significant
changes in the flow rate may occur over a relatively short period of time.
These surges impose serious problems for both the system’s hydraulic
balance and treatment processes.
(3)
Effluent Standards: High effluent standards promulgated by the State
and/or Federal agencies having jurisdiction in the area frequently require a
quality of treatment which necessitates the use of a sophisticated, involved
and expensive process.
(4)
Technical Design: Appropriate technical design data is frequently
unavailable or inadequate, impairing confidence in and the reliability of
the performance of a specific system or subsystem.
(5)
Inherent Problems: The inherent problems associated with odor, noise,
traffic, and plant operation demand that aesthetic considerations be a
prime factor in site selection, design, construction and plant operation.
(6)
Design & Operational Data: Design and operation data available from
recent research in many areas of wastewater treatment have not been
correlated to the point of acceptable engineering practice.
City of Umatilla Standard Specifications
Water & Sewer Utilities
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March 2013
c.
Facility Designations
(1)
Size
The facility guidelines are stipulated with respect to flow capacity
throughout this manual. These flow designations are intended to be
guidelines for design. Such flow capacities assume that the average 5-day
carbonacious biochemical oxygen demand (BOD5) and total suspended
solids (TSS) loadings are as presented in Section E.2. As the BOD5 and
TSS loadings are defined for a specific facility, then an adjustment of the
applicable wastewater flow capacity guidelines may be appropriate.
The minimum initial phase of a subregional WWTF shall be 0.1 million
gallons per day (MGD). The primary flow categories shall be as follows:
•
From 0.1 MGD to 0.5 MGD.
•
Greater than 0.5 MGD to 2.0 MGD.
•
Greater than 2.0 MGD.
Other flow distinctions are made in this section and are not to be precluded
by the above general category delineations. The maximum capacity
facility provided for herein is 10.0 MGD.
All WWTFs with an average daily flow of less than 0.10 MGD in capacity
will be considered package WWTFs. Interim package WWTFs must:
i.
Include provisions for interconnection (i.e., manifold force main,
gravity, etc.) to a sub-regional or City sub-regional facility. Such
provisions must be approved by the City, and be consistent with the
City's Comprehensive Land Use Plan and City Utility System Master
Plan for the area.
City of Umatilla Standard Specifications
Water & Sewer Utilities
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March 2013
(2)
ii.
Include the investigation and rationale why an interim package
WWTF is being proposed versus an interconnection.
iii.
Include an agreement to connect to a sub-regional system once such
system is available and decommission the interim package WWTF.
Facility Description
Throughout this section facility descriptions are presented with regard to
process, equipment and material. Moreover, annual capital, operation and
maintenance (O&M) costs for the WWTF shall be provided to the City for
budgeting purposes.
d.
Submittals
Reports, plans, and specifications for interim package and sub-regional WWTF's
in the City should conform with the design criteria and other provisions presented
herein, unless otherwise justified. All work shall be conducted under the
supervision of a professional engineer registered in the State of Florida. All work
shall be in conformance with the requirements and provisions of all state
regulations including but not limited to Chapter 62-4, 62-600, 62-610 and 62-640,
Florida Administrative Code (FAC), shall be of accepted engineering practice and
shall conform to the Land Development Regulations and the building and zoning
codes of the City.
All reports, plans and specifications shall be submitted at least 60-days prior to the
date set by the City. The documents submitted for formal approval shall include
the engineer's report, plans and specifications. It is suggested that preliminary
plans be submitted with the engineer's report for review prior to the preparation of
the final plans. No approval for construction can be issued until final, detailed
plans and specifications have been submitted to the City and judged satisfactory.
All submittals will be subject to an operation and maintenance review by the City.
All revisions shall be completed prior to approval.
e.
Engineer's Report
City of Umatilla Standard Specifications
Water & Sewer Utilities
E-4
March 2013
The purpose of this report is to present to the City in a clear, concise form a
description of the problem, alternative solutions examined, rejected and
recommended; their technical and financial feasibility; and their environmental
impact within the area of the proposed project. The report should be written for
easy public understanding, and serve as a convenient and permanent summary of
the principal information required by regulatory and funding agencies to support
the recommended project. Controlling assumptions made and factors used in the
functional design of the systems should be summarized for convenient and
permanent reference.
1.
Contents
The contents of the Engineer's report shall be in conformance with the
requirements and provisions of 62-600, FAC, and shall include, but not be
limited to the following:
(a)
A description of the project, including a statement of need.
(b)
Pertinent data regarding relevant existing permits, orders, etc.
issued by the approving authority.
(c)
Describe the geographic location of the project, with reference to
maps, exhibits. Provide specific locations of existing and proposed
transmission systems, lift stations, and WWTFs.
(d)
Describe the topography and include a contour map of the general
area with specific reference to the area involved in the project.
(e)
Provide an estimated population growth with time for the proposed
project.
(f)
Discuss potential or planned improvements which would impact
future water use or wastewater flow projections.
City of Umatilla Standard Specifications
Water & Sewer Utilities
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March 2013
(g)
2.
Address the possibility of increased or decreased wastewater
concentrations due to the use of gray water systems, industrial
wastes, etc.
Field Data
Where there are existing sewers, the volume and strength of wastewater
flows shall be determined. The design engineer shall confer with the City
to establish the scope of the necessary data. These data shall be obtained
from actual flow measurements, preferably during both dry and wet
weather periods. If a public water supply is already in use, give
approximate maximum, minimum and average daily consumptions and,
where appropriate, analysis of the water as it might affect the character of
the wastewater.
3.
Laboratory Analyses
Laboratory analyses should be made on samples collected with
consideration of quantity and quality variations in a 24-hour period. These
data should include composite samples for the maximum significant
period of sewage and industrial waste discharge and should cover a
sufficient period of time to be representative of actual conditions. The
design engineer shall confer with the City for details concerning the
collection and analysis of samples.
4.
Existing Establishments
(a)
City of Umatilla Standard Specifications
Water & Sewer Utilities
All establishments producing non-domestic wastes shall be listed,
and include the quantity, producing periods, and character of
industrial wastes insofar as they may affect the sewer system or
WWTF. The quantity and character of the wastes shall be based on
flow gauging and laboratory analysis of composite samples.
Additionally, the characteristics and volume of the industrial
wastes should be determined for the foreseeable future.
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March 2013
(b)
5.
The expected amounts of septic tank and grease trap cleanings
discharged into the system, and their seasonal variations should be
provided, if applicable.
Soil Investigations
The extent of soil investigations shall be provided, including but not
limited to, geologic regimes and unusual conditions likely to be
encountered. Soil borings shall indicate depth, nature of soil encountered,
existing and anticipated high groundwater levels, etc.
6.
Inflow/Infiltration
The quantity of infiltration/inflow (I/I) shall be measured in the existing
sewer systems and a comparison made to determine if the I/I can be most
economically eliminated by reconstruction or repair of the sewer system,
or treated at the proposed interim package or subregional WWTF.
7.
100 Year Flood
If any part or parts of the project will be subject to upland flooding of a
100-year or less frequency, the extent and effects of such flooding shall be
discussed. The precautions against flooding that shall be incorporated in
the design, with respect to flooding of the sewer collection system, lift
stations, and WWTF shall be discussed.
8.
Land Application of Effluent
The report shall incorporate the technical feasibility of public access and
non-public access land treatment and disposal systems. For all projects the
report shall comply with the most recent FDEP requirements on evaluation
of land application. The report should present a summary survey of
alternative land treatment and disposal sites considered, and state the
reasons for rejecting the least favorable ones. The most favorable sites
shall be studied in depth and a thorough exposition of technical feasibility
City of Umatilla Standard Specifications
Water & Sewer Utilities
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March 2013
shall be presented. Additionally, the report shall present a detailed
discussion of the site requirements, soil conditions, etc. of the most
favorable sites for land treatment and disposal.
9.
Solids Handling
A complete solids handling system shall be described, per unit process,
with respect to the total pounds of solids, percent solids, and volume.
Some preliminary determinations shall be made for the organic and
inorganic content of the sludge. The report shall assess the technical
feasibility and cost, as well as, the long-term reliability of the sludge
treatment system.
10.
Contributing Area
The extent of the existing and proposed contributory area to the proposed interim
package or subregional WWTF with reference to a map or exhibit shall be
provided. The areas of probable future expansions of the sewer system
contributory to the interim package or subregional WWTF shall be provided. The
location of the WWTF and effluent disposal sites shall be described.
11.
Site Selection
The various sites available for the interim package or subregional WWTF, and the
reasons for choosing the site recommended shall be discussed. The proximity of
residences or developed areas to the site shall be indicated, and discuss the
accessibility of the WWTF site. Include a sketch of the property to be used for the
WWTF on which shall be indicated the topography and the arrangement of
present and future treatment works.
12.
Treatment Process
The type of treatment processes evaluated and reasons for choosing the
recommended wastewater treatment alternative shall be discussed. Included in
this discussion shall be considerations for industrial flows, septage loading, ability
City of Umatilla Standard Specifications
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March 2013
to handle shock loads from failing industrial pretreatment facilities, ease of
operation, energy consumptions, capital and operating costs, level of operator's
skill and effort required, and expandability.
13.
Existing WWTF
If there is an existing WWTF, the limitations of the overall WWTF or of
individual units that require additions, modifications, or expansions shall be
discussed.
The basis of design shall include, but not be limited to the following:
(a)
The ultimate design period shall be 30-years, unless otherwise
justified. The phasing procedure of the facilities shall be described
in detail, as it relates to this WWTF.
(b)
The resident and nonresident sewered and unsewered population
and industrial wastes population equivalent where appropriate for
the design period shall be provided.
(c)
The strength of the BOD5 and TSS for domestic wastewater and
for industrial wastewater shall be described. Allowances should be
made for contributions from septic tank cleanout wastes. Other
wastewater constituents should be listed as appropriate (e.g.,
nitrogen, phosphorus, metals, organic chemicals, temperature,
chlorides, color, etc.).
(d)
The total per capita and total daily flows, including I/I allowances
shall be provided.
(e)
The minimum, average, maximum flow rates for both the 24-hour
period and the maximum hourly period for wet and dry weather
conditions shall be indicated. Additionally, the peak instantaneous
wet and dry weather flows should be provided.
City of Umatilla Standard Specifications
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March 2013
(f)
14.
The major units of the interim package or subregional WWTF with
capacities, size, equipment, and operation factors under varying
conditions and methods of operation, including emergencies and
major maintenance periods shall be described.
Future Expansions
The recommendations should be discussed in detail concerning the
proposed project and future expansion thereof, including:
f.
(a)
Alternate plans should be discussed where two (2) or more
solutions exist for a particular problem, each of which is feasible
and practical, and provide the reasons for selecting the one (1)
recommended.
(b)
The area and extent to which the plans provide sewerage facilities
for future development should be described. A description should
be provided together with information as to the probability of
future development, and how this area can be served.
(c)
The degree and type of wastewater treatment, reasons for adopting
the proposed method, the adequacy for present and future needs
should be discussed. A general layout and quantitative flow
diagram should be provided.
(d)
Preliminary project cost estimates should be provided for the
integral parts of the system and a detailed estimated annual cost of
maintenance and operation.
(e)
Where pretreatment of industrial wastes is necessary or where they
are of such a character that they should be excluded from the
sewers, pertinent information shall be provided.
Engineering Drawings
City of Umatilla Standard Specifications
Water & Sewer Utilities
E - 10
March 2013
All drawings for the interim package and subregional WWTFs shall bear an
appropriate title showing the name, scale in feet, a graphical scale, the north
arrow, date, and the name of the engineer and imprint of his registration seal. The
drawings shall be clear, legible, and drawn to scale which will permit all
necessary information to be plainly displayed. The size of the drawings should
not be larger that 24" by 36". Datum used and its relation to mean sea level datum
should be indicated. Locations and logs of test borings, when made, shall also be
shown on the drawings. Detail drawings shall consist of plan views, elevations,
sections and supplementary views which, together with the specifications and
general layouts, provide the working information for the contract and construction
of the project. Dimensions and relative elevations of structures, the location and
outline form of equipment, location and size of piping, water levels, and ground
elevations shall also be included.
A location plan shall also be submitted showing the subregional WWTF in
relation to other elements of the system. Sufficient topographic features shall be
included to indicate its location with relation to water bodies and to the proposed
effluent disposal system.
Layouts of the proposed interim package or subregional WWTF provided on the
drawings shall show the following:
1.
Topography
Topography of the site. Property corners of the site shall be tied to the
state plane coordinate system NAD 83 (1990 Adjustment).
2.
Structures
Size and location of the WWTF structures and buildings.
3.
Schematic
Schematic flow diagram showing the flow through various process units.
City of Umatilla Standard Specifications
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March 2013
4.
Piping
Piping, including any arrangements for by-passing individual units.
Materials handled and direction of flow through pipes shall be indicated.
Also, a complete schematic diagram of all sludge and chemical piping
systems.
5.
Hydraulic Profile
Hydraulic profiles showing the flow of wastewater, supernatant and sludge
for average, minimum and maximum conditions.
6.
Test Borings
Test borings and groundwater elevations.
7.
Proposed Facilities
Location, dimensions, and elevations of all existing and proposed
facilities.
8.
Expansions
All future plant expansions shall be shown on the drawings including all
major yard piping, unit locations and areas reserved for the expansion.
9.
Miscellaneous
Adequate descriptions of any features not otherwise covered by the
specifications.
g.
Specifications
City of Umatilla Standard Specifications
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E - 12
March 2013
Complete technical specifications for the construction of the interim package or
subregional WWTF, and all appurtenances, shall comply with the drawings. The
design engineer shall review all equipment selections with the City. The
specifications accompanying the construction drawings shall include, but are not
limited to, all construction information not provided on the drawings which is
necessary to inform the builder in detail of the design requirements as to the
quality of materials, workmanship and fabrication of the project.
The
specifications shall include:

The type, size, pertinent features, operating characteristics and features,
piping and manufacturer's rated capacity of all pumps, blowers, motors
and other mechanical equipment.

Allowable infiltration including allowable methods of measuring
infiltration.

The complete requirements for all electrical and mechanical apparatus,
wiring, and meters.

Laboratory fixtures and equipment.

Operating tools.

Construction materials, installation specifications, etc.

Miscellaneous appurtenances.

Chemicals when used.

Testing materials and equipment as necessary to meet design standards.

Operating tests for the completed works and component units.
The use of the Construction Specifications Institute (CSI) format is preferred.
City of Umatilla Standard Specifications
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March 2013
h.
Cost Estimates
Final design cost estimates shall be submitted to the City by the design engineer
15-days prior to advertisement of the project or negotiations with potential
contractors. A detailed capital cost estimate shall be submitted by the design
engineer with the design drawing submittal. This estimate shall detail the costs of
the project and break-out unit process/facility costs. Comparison with at least
three (3) similar projects constructed in the past 5-years shall be required.
Additionally, detailed O&M cost estimate shall be submitted by the design
engineer. This work task shall include estimates for the first 5-years of operations.
Moreover, an annual renewal and replacement (R & R) cost estimate shall be
submitted with the design projecting the design life of all major facilities and
equipment.
i.
Revisions to Approved Drawings
Any proposed or requested deviations from the approved drawings or
specifications shall be approved in writing by the City before such changes are
made. Drawings or specifications so revised should, therefore, be submitted well
in advance of any construction work which will be affected by such changes, to
permit sufficient time for review and approval. The "As-Built/Record Drawings"
clearly showing such alterations shall be submitted to the City within 90-days of
acceptance by the City.
j.
Operation During Construction
If required, specifications shall contain a program for keeping existing treatment
plant units in operation during construction of plant additions. Should it be
necessary to take plant units out of operation, a shutdown schedule agreed to by
the FDEP shall be adhered to and shall minimize pollution effects on the receiving
waters.
2.
GENERAL
City of Umatilla Standard Specifications
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E - 14
March 2013
a.
Site Selection
The engineer shall confer with the City before proceeding with the design of the
detailed drawings. Subregional WWTF design should take into consideration the
estimated population and flows from start-up through the design life span at least
30-years after start-up. Complete consideration of facility phasing shall be
provided. An interim package WWTF shall include an expected schedule for
interconnection with a City subregional WWTF.
The site selection for the WWTF is left to the discretion of the City, the design
engineer, and the FDEP. However, new facilities unprotected from the 100-year
flood will not be approved for construction. The effluent disposal system shall be
determined by the City, the design engineer, and the FDEP. Sufficient land shall
be acquired for all projected future plant expansions.
The following items shall be considered when selecting a WWTF site:
(1)
Proximity to residential area.
(2)
Direction of prevailing winds.
(3)
Accessibility by all-weather roads.
(4)
Area available for expansion.
(5)
City zoning requirements
(6)
Local soil characteristics, geology, hydrogeology, and topography
available to minimize pumping.
(7)
Access to effluent disposal system.
(8)
Capacity and treatment requirements for effluent disposal system through
the design life of the WWTF.
City of Umatilla Standard Specifications
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March 2013
b.
(9)
Compatibility of treatment processes with the present and planned future
land use, including noise, potential odors, air quality, and anticipated
sludge processing and disposal techniques.
(10)
Facility phasing and expansion program.
(11)
Availability of land for future effluent disposal.
Design
The accepted methods of treatment are provided in Subsections E.4, 5, 6, 7, and 8.
Careful consideration should be given to the type of treatment prior to making a
final decision. Important factors which should influence the type of treatment are:
(1)
Flow, character, and effluent disposal system.
(2)
Location and topography of the site.
(3)
Present and future effluent limits.
(4)
The effect of industrial wastes likely to be encountered.
(5)
Ultimate method of sludge disposal.
(6)
Operating costs.
(7)
Probable type of supervision and operation which the WWTF will have.
Additionally, the WWTF design should achieve the longest possible useful life,
incorporate flexibility and convenience of operation, require minimum energy
expenditures, minimum maintenance effort, and minimum capital and operating
costs.
Where significant amounts of industrial wastes are involved, the quantity and
character of the wastes should be determined by analysis and provision made in
City of Umatilla Standard Specifications
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March 2013
the design for the raw waste or waste after pretreatment. The engineer shall
provide, to the extent feasible, the flexibility to handle shock loads resulting from
pretreatment failure.
The treatment units shall be designed on the basis of hydraulic loading, BOD5 and
TSS in accordance with the requirements outlined in Subsections E.4, 5, 6, and 7.
The design flow for the WWTFs servicing of new sewer systems should be
determined in a manner consistent with:
(a)
Planned future improvements to the potable water system which may
increase or decrease flows.
(b)
Future use of water conservation devices.
(c)
The trend of increasing or decreasing water usage within the geographic
area.
An allowance shall be made for industrial and commercial /institutional flows,
and I/I. The design flow shall allow for future growth of domestic, industrial and
commercial flows and shall take into consideration increasing I/I as sewers
deteriorate with age.
Design flow for WWTFs servicing existing sewers should be based on actual flow
measurements, initial reductions of I/I achieved by rehabilitation, and shall
otherwise consider all the factors provided above.
Where such information cannot be obtained, new systems shall be designed on the
basis of average daily flow of the wastewater as indicated in Table E-1.
Unless satisfactory justification can be given for using different values for
strength of wastes, plans for the WWTF to serve a new sewer system will be
examined on the basis of an average daily concentration of 220 milligrams per
liter (mg/l) for both BOD5 and TSS, exclusive of industrial wastes or unusual
commercial wastes. Consideration should be given to 2-times the average to
City of Umatilla Standard Specifications
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March 2013
treatment units caused by influent pumping, industrial flows and/or diurnal
variations and its impact on unit process performance.
TABLE E-1
WASTEWATER TREATMENT FACILITY
WASTEWATER FLOW DESIGN BASIS
Description
1.
Flow
Residential
a.
Single Family
300 GPD
b.
Multi-Family and Duplex (1 and 2 bedrooms)
250 GPD
c.
Multi-Family and Duplex (3 and 4 bedrooms)
300 GPD
d.
Mobile Homes
300 GPD
2.
Peak flow rates should be determined in accordance with actual field data or under
the ratio method presented in Figure E-1.
3.
Data from similar projects, in the case of new systems.
4.
Wet weather flows.
5.
Recirculation.
6.
Pumping rates.
7.
Consideration should be given to the hydraulic surge loading to treatment units
caused by influent pumping, industrial flow or diurnal variations. The design should
minimize effects by flow equalization, or other means.
8.
Consideration should be given to the seasonal hydraulic loading to treatment units.
City of Umatilla Standard Specifications
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E - 18
March 2013
Piping and channels shall be designed to carry the maximum future flows. The
incoming sewer shall be designed for free discharge. Bottom corners of channels
should be filleted and pockets and corners where solids can accumulate shall be
eliminated. Suitable gates should be placed in channels to seal off unused
sections which may accumulate solids. The use of shear gates or stop gates is
permitted where they may be used in place of gate valves or sluice gates.
Channels which may not be in use for considerable periods shall be provided with
valved drains.
The size and number of WWTF units should be selected to provide flexibility to
meet varying flows and facilitate emergency treatment with some units when a
unit is out of service for maintenance or other reasons. Component parts of the
plant should be arranged for greatest operation convenience, flexibility and
economy, and in such a manner as to facilitate addition of future treatment units.
c.
WWTF Details
(1)
General
The specifications should be written such that the installation and initial
operation of the major items of mechanical equipment will be supervised
by a representative of the manufacturer.
Except where duplicate units are available, properly located and arranged
bypass structures should be provided so that each major unit of the WWTF
can be removed from service independently. Under certain circumstances,
bypasses may be required even though duplicate units are provided. The
design should provide for maximum treatment and convenient operation
with any given unit out of operation. Particular attention should be given
to solids retention, sludge handling and disinfection during such periods.
Additionally, means should be provided to dewater each process unit
preferably by a gravity drain. Consideration should also be given to
protection of tanks from flotation.
City of Umatilla Standard Specifications
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March 2013
(2)
Construction Materials
Consideration should be given to the selection of materials which are to be
used in wastewater treatment works because of the possible presence of
hydrogen sulfide (H2S) and other corrosive gases, greases, oils and similar
constituents frequently present in wastewater. This is particularly
important in the selection of metals and paints. Dissimilar metals should
be avoided to minimize galvanic action.
An approved coating system with an approved thickness shall be applied
to all treatment unit surfaces. In concrete facilities, as a minimum, the top
3' below the water level are an exception to this requirement. Secondary
clarifiers and filtration units are excluded from this requirement.
(3)
Structural Materials
The major types of properly designed structural materials are summarized
below:
(a)
Influent pumping station and flow equalization facilities:
Concrete.
(b)
Grit removal facilities: Concrete.
(c)
Process treatment trains: The structural material selected for each
treatment unit shall be reviewed by the City prior to final design.
(d)
Effluent storage: The structural material selected for effluent
storage shall be reviewed by the City prior to final design.
All walls shall be designed to contain the maximum hydrostatic pressure
which could be experienced due to operational practices.
The use of paints containing lead or mercury shall not be used. In order to
facilitate identification of piping, particularly in the large plants, it is
City of Umatilla Standard Specifications
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E - 20
March 2013
suggested that the different pipes have contrasting colors, and the contents
and direction of flow indicated. The recommended color scheme and
labels for the purposes of standardization are presented in Table E-2.
(4)
Operating Equipment
The specifications shall include a set of tools, accessories for adequate
maintenance and spare parts for the WWTF. Readily accessible storage
space and work bench facilities shall be provided, and consideration given
to provision of a garage for large equipment storage, maintenance and
repair.
TABLE E-2
RECOMMENDED COLOR CODING OF
PROCESS PIPING
Piping Description
Recommended Color
Raw sewage
Dark gray
Return and waste sludge
Dark brown
Potable water
Light blue
Raw water
Olive green
Non-potable water
Bright orange
Reclaimed water
Purple
Gas or fuel oil
Red
Compressed air
Dark green
Chlorine gas
Yellow
Chlorine solution
Yellow with 2" red bands spaced 24" apart
Other coding
As directed by the City Utilities Department
(5)
Grading, Landscaping and Irrigation Minimum Requirements
Upon completion of the WWTF, the ground should be graded and seeded.
Sod shall be provided 10-feet around each structure, building or walkway.
An irrigation system utilizing reuse water shall be installed. Paved or
gravel walkways should be provided for access to all treatment units.
City of Umatilla Standard Specifications
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March 2013
Where possible, steep slopes should be avoided to prevent erosion.
Surface water shall not be permitted to drain into any unit. In small or
interim package WWTFs receiving part-time operation, consideration
should be given to minimizing the need for landscape/grounds
maintenance. Provisions should be made for landscaping, particularly
when a WWTF must be located close to residential areas; however, the
operator's view of the units should not be obstructed. The City's Land
Development Regulations regarding grading, landscaping and irrigation
requirements shall be adhered to.
d.
Essential Facilities
An adequate supply of potable water under pressure shall be provided for general
cleaning around the WWTF, operator use, fire protection and laboratory
requirements. No piping or other connections shall exist in any part of the
WWTF which, under any conditions, might cause the contamination of the
potable water supply. Potable water from a municipal or separate supply may be
used directly at points above grade and installed in accordance with the "Southern
Standard Plumbing Code" specifications and backflow prevention for the
following hot and cold supplies:
(1)
Water closet and shower.
(2)
Drinking fountain.
(3)
Laboratory sink, if protected against back siphonage.
(4)
Outside hydrants, if protected against back siphonage.
(5)
Slop sink, if protected against back siphonage.
Hot water for any of the above units shall not be taken directly from a boiler used
for supplying hot water to a treatment unit. Hot water to the above units shall be
supplied by a hot water heater separated from the boiler.
City of Umatilla Standard Specifications
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March 2013
Where potable water is to be used for any purpose in the WWTF other than those
listed above, a reduced pressure type backflow prevention device shall separate
the potable water supply from all sources of possible toxic or non-toxic
contamination caused by back siphonage or back pressure. Where it is not
possible to provide potable water from a public water supply, a separate well may
be provided. Location and construction of the well should comply with the
requirements of the State and City's Land Development Regulations. Where a
separate non-potable water supply is to be provided, a backflow prevention device
will not be necessary but all sill cocks and hose bibs shall be posted with a
permanent sign indicating that the water is not safe for drinking.
The sanitary facilities at the WWTF shall consist of a toilet, shower, lavatory and
locker for the convenient use of the projected number of operators for WWTFs
with design capacities over 0.5 MGD. Slop sinks for general cleaning shall be
provided. A minimum of 150 square feet shall be allocated for the sanitary
facilities. Additional areas shall be provided as deemed appropriate by the City.
All WWTFs with a design capacity over 2.0 MGD shall include a laboratory for
making the necessary analytical determinations and operating control tests. The
laboratory shall have sufficient size, bench space, equipment and supplies to
perform all self-monitoring analytical work required by the permits, and to
perform the process control tests necessary for good management of each
treatment process included in the design. Fume hoods should be used where
odors or hazardous vapors are present during testing. The laboratory size and
arrangement must be sufficiently flexible and adaptable to accomplish all required
assignments. The layout should consider future needs for expansion in the event
that more analytical work is required.
The laboratory should be located on ground level, easily accessible to all sampling
points, with environmental control as an important consideration. It shall be
located away from vibrating equipment which may have adverse effects on the
performance of laboratory equipment. A minimum of 300 square feet of floor
space shall be allocated for the laboratory. If more than two (2) persons will be
working in the laboratory at any given time, an additional 100 square feet shall be
provided for each additional person. Bench-top working surface should occupy a
City of Umatilla Standard Specifications
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E - 23
March 2013
minimum of 35% of the total floor space. The minimum ceiling height shall be
8'- 6". If possible, this height should be increased to provide for the installation of
wall-mounted water stills, distillation racks, and other equipment with extended
height requirements. The laboratory should be equipped with the necessary
equipment to test and analyze at a minimum for BOD5, TSS, pH, total solids,
settleable solids, dissolved oxygen (DO), chorine residual and sludge index.
All WWTFs shall have suitable facilities for measuring, recording and totaling the
flow of the wastewater at the influent to the facility. The principal flow
equipment should generally be installed at the pretreatment structure.
Additionally, metering should be provided on the effluent from the WWTF, the
return and waste sludge pumps, sludge loading pumps for ultimate disposal and
other locations as deemed appropriate.
Flow splitting facilities shall be provide in all WWTFs with a design capacity of
over 0.5 MGD. Flow splitting devices shall be easily adjustable by the operator.
Generally, they should be preceded by relatively long, straight channels of
uniform cross-section and provide for only a 2-way division. Flow splitting
devices should be visible and accessible for the operator to verify the quantity or
flow issuing from each leg of the split.
Stairways shall be installed wherever possible in lieu of ladders. Spiral or
winding stairs are permitted only for secondary access where dual means of egress
are provided. Stairways shall have slopes between 50º and 30º from horizontal to
facilitate carrying samples, tools, etc. Each tread and riser shall be of uniform
dimension in each flight. Minimum tread riser shall not be less than 8". The sum
of the tread run and riser shall not be less than 17" nor more than 18". A flight of
stairs shall consist of not more than a 12 foot continuous rise without a platform.
All WWTFs with a design capacity of greater than 0.5 MGD shall include an
office/control area for keeping necessary records and monitoring/recording
necessary plant functions. This area shall be located away from vibrating
machinery or equipment which may have an adverse effect on recording
equipment. A minimum of 250 square feet of floor space shall be allocated for
City of Umatilla Standard Specifications
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E - 24
March 2013
the office/control area, with minimum ceiling heights of 8'-6". Additional space
shall be provided as deemed appropriate.
All WWTFs with design capacities greater than 2.0 MGD shall include a covered
and enclosed maintenance/storage area for on-site maintenance functions. This
maintenance/storage area shall have a minimum of 300 square feet and a
minimum ceiling height of 11'. Additional space shall be provided as deemed
appropriate.
All WWTFs shall include a covered and enclosed chemical storage area. The
location and size shall be determined by the design engineer.
e.
Effluent Disposal
The effluent disposal for the WWTP shall be accomplished by methods
acceptable to both the City and FDEP as indicated in Subsection E.9. All
WWTFs shall be designed to consistently produce the quality of effluent required
in the applicable WWTF operations permit. The design basis shall include all
industrial wastes which will enter the sanitary sewerage system. The engineering
report shall state the average and peak flows, and strengths of all industrial wastes
and shall discuss the aspect of hazardous and/or toxic materials that may enter the
system. All WWTF bypass structures/systems shall be indicated on the drawings,
and the need for such facilities shall be described in the engineering report. The
piping within all WWTFs shall be arranged so that when one (1) unit is out of
service for repairs, the operation of the WWTF will continue and emergency
treatment can be accomplished.
City of Umatilla Standard Specifications
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March 2013
f.
Safety
Adequate provisions shall be made to effectively protect the operator and visitors
from hazards. The following shall be provided to fulfill the particular need of
each WWTF:

Enclosure of the WWTF site with a fence designed to discourage the
entrance of unauthorized persons and animals.

Installation of handrails and guards where necessary and per the United
States Department of Labor, Occupational Safety and Health
Administration (OSHA) standards. Vertical ladders over 6' shall have
cages. Kickplates shall be required in liquid tankage areas.

Provisions for first aid equipment and MSA Foille Burn Kit.

Posting of "No Smoking" signs in hazardous areas.

Provisions of protective clothing and equipment such as gas masks, selfcontained air packs, goggles, gloves, safety belts, oxygen deficiency, H2S
and combustible gas indicators, and suitable fire extinguishers.

Portable blowers, and portable "mud hog" type pump and sufficient hose.

Portable non-flammable lighting equipment.

Appropriately placed warning signs for slippery areas, non-potable water
fixtures, low head clearance areas, open service manhole, hazardous
chemical storage areas, flammable fuel storage areas, etc.

The design of the WWTF shall incorporate all necessary facilities to assure
safe working conditions including all appropriate requirements of OSHA.
The electrical design shall conform to local and State building codes.
Nonsparking electrical equipment shall be utilized where flammable gas may
City of Umatilla Standard Specifications
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March 2013
exist. The equipment shall bear the seal of the Underwriters Laboratory, Inc. (UL)
and comply with the National Electrical Code (NEC). Adequate lighting must be
provided in the buildings, as well as, on the grounds, especially around treatment
units to be serviced by personnel on duty during hours of darkness.
With regard to process/equipment the following should be provided or considered:

Where frequent movement of equipment and material is required,
consideration should be given to the use of ramps with non-skid treads, to
supplement stairs, wherever feasible.

Provisions of "Panic" hardware on all doors leading from hazardous areas.
Ensure that the hardware selected for all other doors will permit opening
from the inside.

Monorail and lifting hoist systems located in potentially explosive gas
areas shall be electrically explosion-proof and have one (1) sparkproof
hook and cable chain (i.e., brass hook and stainless steel cable/chain), and
two (2) brass monorail track wheels.

Air flow switches and associated common alarms in Heating, Ventilation
and Air Conditioning (HVAC) ductwork in hazardous process areas shall
be provided to ensure positive air flow for the safety of operational
personnel.

Local isolation switches shall be provided on all process equipment.

Safety guards on all exposed moving parts of machinery.

Evaluate the effects on noise produced by equipment and limit such noise
to 85 dBA within 3' of the equipment. Never locate roof leader piping
over motor control centers (MCC) or other electrical equipment.

All areas designated hazardous, must be truly isolated and made explosion
proof, including all motors on process equipment, ventilation systems, and
City of Umatilla Standard Specifications
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March 2013
overhead doors, as well as, all lighting fixtures. Check details on all wall,
floor, sky lighting and ceiling penetrations for sealing.
g.

Provide H2S and combustible monitoring and alarm systems, in areas
subjected to direct exposure to raw wastewater. The system should
include a warning light over the entrance doors, to indicate no entry
without special equipment.

For areas where insects could be a nuisance (e.g., pretreatment structure,
sludge storage, etc.) electric insect killer units should be considered.
Plant Performance
All WWTFs shall provide the required level of performance for the method of
effluent disposal utilized. Adequate performance shall be provided for all design
flow and quality conditions.
h.
Energy Requirements
The most cost effective and energy efficient system is desired. The design
engineer shall illustrate the energy aspects of the facility design. Where payback
is achieved within 5-years, power factor correction shall be provided. The energy
requirements of the proposed facility shall be estimated by the design engineer
from initial start-up through attainment of design capability of the WWTF. These
estimates shall be submitted to the City for review.
i.
Chemicals, Chemical Storage and Handling
(1)
General
The following items shall be provided in all chemical storage and feed
systems installed at the WWTF:
(a)
City of Umatilla Standard Specifications
Water & Sewer Utilities
Acid resistant stainless steel floor drains in chemical areas
subjected to vehicular traffic.
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March 2013
(2)
(b)
Isolation valve adjacent to all tank level transmitters to permit their
removal for maintenance and calibration.
(c)
Chemical delivery truck doorways shall be a minimum of 13'-6"
high to permit trailer truck entrance.
(d)
Baffles in chemical mixing tanks to prevent vortexing and ensure
proper operation of the mixer.
(e)
Review the need for a permanent water supply at all chemical
facilities.
(f)
Unions at all chemical pumps, tanks and diffusers.
(g)
Adequate piping supports and thrust anchorages for all chemical
lines.
(h)
Chemical lines shall be designed to be flush-cleaned or replaced
without draining the process or chemical tanks.
(i)
Pipe outlets from pressure relief valves on chemical feed lines to
drain to floor drainage systems, if resistant to chemicals, or, if
possible, back into the chemical tanks.
Chemical Storage
All chemical storage tanks shall be located within containment curbing to
control spillage. Containment curbing shall be designed to contain at least
one (1) tank rupture until it can be safely transferred to alternate storage or
released to the wastewater at controlled rates which will not damage
facilities or inhibit the treatment processes. Additionally, ramps on
curbing for chemical deliveries should be provided where possible. The
chemical storage tanks must have a sufficiently large screen and weather
protected vent pipe, vented to a safe area, to eliminate problems with rapid
City of Umatilla Standard Specifications
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filling from a delivery truck. For facilities using large quantities of liquid
polymer, bulk storage facilities should be considered as opposed to drums.
If drums are used, provide sufficient drum racks storage area. All storage
tanks shall be provided with a level-indicating device, minimum 12"
diameter access hole, and easily accessible drain valve. The use of
translucent panels for level detection will not be permitted. Similarly, if
external sight glasses are utilized, valves and clean-out drains for
maintenance shall be provided. Sulfuric acid storage tank suction piping
drain lines shall be installed at a level above the tank bottom to avoid
clogging from sediment accumulation. Adequately size inlet and outlet
pipes on chemical storage tanks, especially those containing concentrated
polymers with high viscositys. The inlet pipes shall be compatible with
delivery truck discharge facilities. Lime storage silos must be provided
with a vibrator, to facilitate easy removal of the lime and to be compatible
with the type of lime stored. The lime storage silo and feed hopper sides
shall be sloped a minimum of 60º to the horizontal. Bag feeders for lime
systems, with dust exhaust units can be utilized if the facility is not greater
than 1.0 MGD.
(3)
Chemical Handling
A diaphragm pump shall be used for pumping ferric chloride (FeCl3),
sodium hypochlorite (NaCl), alum, and dilute polymers. A progressive
cavity pump shall be used for concentrated polymers. For pipelines
carrying alum, hot water flushing facilities shall be provided, to keep these
lines from clogging because of crystallization.
Dry polymer and/or lime systems should have provisions for handling and
emptying bagged lime or polymer to the storage and mixing tanks.
For lime slurry systems, a strainer shall be installed on the suction limes of
the slurry pumps to remove grit. Where practical, gravity flow efficiency
can be improved on slaker systems employing dilution chambers by
increasing the size of the grit outlet insert. A diaphragm, plunger, or
abrasion resistant rubber-lined centrifugal pump which has been specially
City of Umatilla Standard Specifications
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March 2013
designed for lime slurry service shall be used. Additionally, an adequate
supply of flushing water to the suction and discharge pipes of the lime
pumps shall be provided.
Bulk chemical delivery connections shall be located over a bermed area of
the service road, to allow for clean-up of normal spillage's during delivery.
Provide a hose bib in this area together with a drain pipe into the nearest
suitable disposal point. Additionally, good access shall be provided for
deliveries of bagged hydrated lime, liquid chemical drums, etc.
(4)
Chemical Safety
The materials utilized for the storage, piping, valves, pumping, metering,
splash guards, etc., shall be specially selected, considering the physical and
chemical characteristics of each chemical utilized at the WWTF. Eyewash fountains and safety showers utilizing potable water shall be
provided in the laboratory and on each floor or work location involving
hazardous or corrosive chemical storage, mixing, pumping, metering, or
transportation unloading. These facilities are to be as close as practical to
possible chemical exposure sites and are to be fully useful during all
weather conditions. The eye-wash fountains shall be supplied with water
of moderate temperature (50º to 90º Fahrenheit), separate from the hot
water supply, and suitable to provide 15 to 30 minutes of continuous
irrigation of the eyes. The emergency showers shall be capable of
discharging 30 to 50 gallons per minute (gpm) of water at a moderate
temperature and pressures of 20 to 50 pounds per square inch (psi). The
eye-wash fountains and showers shall be no more than 25' from points of
hazardous chemical exposure.
All pumps and feeders for hazardous or corrosive chemicals shall have
splash guards which will effectively prevent the spray of chemicals into
space occupied by personnel. The splash guards are in addition to the
guards to prevent injury from moving or rotating parts.
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All piping containing or transporting hazardous or corrosive chemicals
shall be identified with labels every 10' with at least two (2) labels in each
hood, closet, or pipe chase. Color-coding may also be used, but is not an
adequate substitute for labeling. All connections (Flanged or other type),
except those adjacent to storage or feeder areas, shall have guards which
will direct any leakage away from space occupied by personnel. Pipes
containing hazardous or corrosive chemicals should not be located above
shoulder level except where continuous drip collection trays, double
walled pipe, and coupling guards will eliminate chemical spray or dripping
onto personnel.
The following items of protective clothing or equipment shall be available
and utilized for all operations or procedures where their use will minimize
injury hazard to personnel:
(a)
Respirators, air supply type recommended for protection against
chlorine.
(b)
Chemical worker's goggles or other suitable goggles (safety glasses
are not sufficient).
(c)
Face masks or shields for use over goggles.
(d)
Rubber gloves, aprons with leg straps, and boots.
(e)
Safety harness and line.
Facilities shall be provided with automatic shutdown of pumps and
sounding of alarms when failure occurs in a pressurized chemical
discharge line. Additionally, warning signs requiring the use of goggles
shall be located near chemical unloading stations, pumps, and other points
of frequent hazard.
Dust control equipment shall be provided to protect personnel from dust
injurious to the lungs or skin and to prevent chemical dust from settling on
City of Umatilla Standard Specifications
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walkways. The latter is to minimize slick floors which result when a
chemical covered floor becomes wet.
j.
Preventive Maintenance Program
The contractor shall supply a manual containing each manufacturer's preventive
maintenance suggestions. These items shall be integrated into a bound booklet
comprising the preventive maintenance program.
k.
Operation and Maintenance Manual
Prior to completing the construction of a new package or subregional WWTF or
facility expansion and effluent disposal system, an O&M manual covering the
recommended operating procedures for the entire facility shall be furnished to the
City. The O&M manual shall include the following contents:
(1)
Description of unit processes and component parts. Functional, normal
operating characteristics and limiting conditions. Performance curves,
engineering data and tests. Complete nomenclature and commercial
number of replaceable parts.
(2)
Operating procedures. Start-up, break-in, routine and normal operating
instructions. Regulation, control, sequences required, stopping, shut-down
and emergency instructions. Summer, winter and special operating
instructions.
(3)
Maintenance procedures. Guide to "troubleshooting". Disassembly, repair
and reassembly, alignment, adjusting and checking.
(4)
Servicing and lubrication.
(5)
Manufacturer's printed operating and maintenance instructions.
(6)
Description of sequence of operation by control manufacturer.
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l.
(7)
Original manufacturer's parts list, illustrations, assembly drawings and
diagrams required for maintenance. Predicted life of parts subject to wear.
Items recommended to be stocked as spare parts.
(8)
As-installed control diagrams by controls manufacturer.
(9)
As-installed color coded piping and wiring diagrams.
(10)
Charts of valve tag numbers, with location and function of each valve.
(11)
Circuit directories and panel boards for electrical service, controls and
communication.
(12)
List of original manufacturer's spare parts, manufacturer's current prices
and recommended quantities to be maintained in storage.
(13)
Other data as required under pertinent specifications.
Spare Parts
Sufficient spare parts shall be provided by the contractor at start-up of the WWTF
for a projected 3-year operating period as stipulated by the design engineer.
m.
System/Facility Reliability
The design of the package and subregional WWTF shall include provisions for
system back-up and reliability, as required by FDEP for the size of the WWTF
and type of effluent disposal, as presented in the United States Environmental
Protection Agency (USEPA) Manual MCD-05, Design Criteria for Mechanical
and Fluid System and Component Reliability. The design of the following
requirements for system back-up and reliability shall be considered during the
design phases of the WWTF.
(1)
Pretreatment
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All pretreatment structures will be designed with dual channels each sized
to handle the anticipated peak hour flow rate. Mechanically cleaned bar
screens shall be installed on all facilities 1.5 MGD and larger. A second
bar screen shall be provided. It is permissible that this back up bar screen
be designed for manual cleaning only. WWTFs with only two (2) bar
screens shall have at least one (1) bar screen designed to permit manual
cleaning.
For grit removal facilities only hydraulically induced or mechanically
induced vortex type units will be acceptable. The grit removal units shall
be designed to treat the maximum day flow. No secondary treatment unit
will be required for grit removal. The grit removal units shall consist of
isolation gates that can be closed in case of maintenance.
(2)
Pumps
Standby pumps shall be provided for each set of pumps which perform the
same function. The capacity of the pumps shall be such that with any one
(1) pump out of service, the remaining pump(s) will have capacity to
handle the peak flow requirements. It is permissible for one (1) pump to
serve as backup to more than one (1) set of pumps.
(3)
Aeration Facilities
A backup aeration basin shall not be required; however, at least two (2)
compartments of equal volume basins shall be provided within the basin.
There shall be a sufficient number of blowers or mechanical aerators to
enable the design oxygen transfer to be maintained with the largest unit
out of service. It is permissible for the backup unit to be out of service.
Additionally, it is permissible for the backup unit to be an uninstalled unit,
provided that the installed unit can be easily removed and replaced. At
least two (2) units shall be installed. The air diffusion system for each
aeration basin shall be designed such that the largest section of diffusers
can be isolated without impairing the oxygen transfer capability of the
system.
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(4)
Secondary Clarifiers
There shall be a sufficient number of units of a size, such that with the
largest unit out of service, the remaining unit(s) shall have a design
capacity equal to 75-percent of the total design to that unit operation. The
secondary clarifier shall be designed around the maximum daily flow
conditions.
(5)
Effluent Filtration
There shall be a sufficient number of filters of a size, such that with the
largest unit out of service, the remaining unit(s) shall have a design
capacity equal to 75-percent of the total design to that unit operation. The
filtration facilities shall be designed around the maximum daily flow
conditions. The filters shall be designed for operating at an average
hydraulic loading rate of 2 gpm/square foot or a peak loading rate not
exceeding 5 gpm/square foot.
(6)
Disinfection
There shall be a sufficient number of units of a size, such that with the
largest unit out of service, the remaining unit(s) shall be capable of treating
50-percent of the design basis flow to that unit operation. Additionally,
there shall be complete backup disinfection facilities in the event one (1)
unit should be out of service.
(7)
Miscellaneous Components
At least two (2) chemical feed systems (e.g., pumps, mixing basins, etc.)
or a back-up means for adding and mixing chemicals, separate from the
basin, shall be provided. If only one (1) system is provided, at least a
second uninstalled unit or bypass around the basin shall be provided.
n.
Facility Expansion
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The size and number of treatment units should be selected to provide the
flexibility to meet varying flows and facilitate emergency treatments with some
units when a unit is out of service for maintenance or other reason. Component
parts of the plant should be arranged for greatest operating convenience,
flexibility, and economy and in such a manner as to facilitate possible future
treatment units. The City shall review the preliminary engineering provisions for
facility expansions and comment on conceptual design prior to proceeding with
final design as specified in Subsection E.1.
Additionally, the land area acquired for the WWTF shall be of sufficient size to
accommodate all projected treatment plant expansions, not necessarily including
land for effluent disposal.
3.
INFLUENT PUMPING STATION
a.
General
The design engineer shall comply with the criteria listed herein and Appendix A.
Unless justification is given by the design engineer, all WWTFs with capacities
greater than 0.5 MGD shall be provided with an influent pumping station,
including equalization storage. WWTFs with capacities less than 0.5 MGD and
not requiring an influent pumping station shall be provided with equalization
storage. Pumping stations shall be preferably of the submersible type. The wet
well-dry well type may be considered when justified by the design engineer. Such
stations shall preferably minimize the head differential between the station and the
treatment units in order to minimize the energy requirements.
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b.
Design Parameters
(1)
General
The design flows shall be the total ultimate development flow from all
tributary areas. The tributary area shall include existing development,
planned developments, and projected future developments. The maximum
influent flow shall be the product of the average daily flow and the
selected peak factors computed as set forth in Subsection E.1. However,
due to the sensitivity of various process units to excessive surges in
hydraulic flows, the pump station shall be designed for a maximum
capacity of 2.0 times the average estimated flows. The flow differential
between the maximum peak hourly flow and the maximum design
capacity of the pump station shall flow into equalization storage.
No single method for sizing wet wells applies to all design situations.
Proper wet well sizing considers three (3) critical factors:
(a)
Pump cycle time.
(b)
Detention time.
(c)
Turbulence at the pump intake.
Pump cycle time refers to the elapsed time between successive motor
starts. It has been determined that excessive motor wear and shortened
service lives result from cycle times less than the manufacturer's
recommendation. Therefore minimum cycle times shall range from about
10-minutes up to 30-minutes. The design engineer shall consult with the
motor manufacturer for minimum cycle time recommendations or special
motor designs. The minimum cycle time recommendations of the motor
manufacturer shall be obtained in all cases. In the absence of other
information, summarized in Table E-3 are the minimum cycle times for
full voltage starting that can be used.
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The minimum wet well volume required to control cycle times shall be
sized according to the following equation:
V = t(Qp)/4N
where: V
Qp
N
t
= the minimum wet well volume in gallons.
= Capacity of one (1) pump in gpm.
= Number of pumps in the lift station.
= Minimum pump cycle time in minutes.
For constant speed pumps, the minimum cycle time results if the influent
flow equals 50% of the rated pump capacity. In multiple pump
installations, alternating the lead pump after each pumping cycle
effectively doubles the cycle time and reduces the wet well volume
accordingly. Consideration will also be given to strategic "on" and "off"
settings to optimize the wet well volumes. Wet wells for variable speed
pumping systems can be significantly smaller than for comparably sized
constant speed stations. However, the cycle time for variable speed pump
stations will still be the limiting factor if the influent flow is 50% of the
pumping capacity at the minimum pump speed. If multiple variable speed
installations are used, the wet well capacity required is the sum of the wet
well capacities required for the individual pumps.
Wet wells shall also provide sufficient space for installed equipment and
required suction pipe submergence and spacing. When determining the
pump operating levels in the wet well, the design engineer will need to
consider the net positive suction head (NSPH) requirements of the pumps.
Wet well designs should allow adequate submergence and clearance
between the pump intakes to prevent eddy currents, air binding, vortexes
and other design considerations that could otherwise reduce pump
efficiency or capacity. In general, the normal operating water level shall
provide a positive suction head for the pumps. Operational, maximum, or
high water levels shall not exceed the invert elevation of the lower influent
pipe, with the high water alarm no higher than the 0.8 point of said pipe.
City of Umatilla Standard Specifications
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TABLE E-3
WASTEWATER MASTER LIFT STATION
MINIMUM CYCLE TIMES
Motor Size
Minimum Cycle Time
15 Hp and smaller
10-minutes
20 Hp through 50 Hp
15-minutes
60 Hp and larger
30-minutes
A minimum size hopper bottom shall be provided, with the wet well floor
sloping to said bottom at a slope of not less than one to one (1:1).
Sufficient volume shall be provided in the wet well or in an auxiliary basin
to store flows in excess of the pump station peak design flow. The volume
shall be calculated based upon a 2 hour sustained flow rate. If an auxiliary
basin is used for equalization storage, it shall be aerated with diffused air
and provisions shall be made for gravity drainage to the wet well. Odor
control shall be provided, if necessary.
The size of wet well-dry well systems will depend on the number and type
of pumps selected and piping arrangement. A minimum of 3' from each of
the outboard pumps to the nearest side wall and a minimum of 4' between
each pump discharge casing shall be required. Additionally, sufficient
space between the pumps shall be provided to remove the pumps from
their base with ample remaining clearance between the suction and
discharge piping in the room for on-site repairs, inspection, or removal
from the pit to the surface for repairs. The installation of monorails, lifting
eyes in ceiling, and A-frames for the attachment of portable hoists, cranes,
and other devices should be considered. Additionally, all doorways and
openings in the dry well shall have sufficient width and headroom for
installation and removal of equipment.
Other wet well design considerations include:
City of Umatilla Standard Specifications
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March 2013
(2)
(a)
Arranging the influent pipe inlet in the wet well so that any
splashing or eddy current is directed away from the pump intakes
to prevent air entrainment and pump air locks.
(b)
Dividing the wet well into two (2) sections that are properly
interconnected to ease repairs, cleaning, and expansion if the pump
station must operate continuously or future flows will substantially
exceed existing flows.
(c)
Providing for a well lighted wet well with vapor-proof and
explosion proof fixtures.
(d)
Odor control.
Pump Capacity
The selected pumping system shall have a minimum capability of pumping
at the design peak flow rate with the largest pumping unit out of service
(firm pumping capacity). The peak flow rate from the pumping system
shall not be greater than 2-times the average daily flow. In order to
dampen any surge effect of the pumping system on the WWTF, the
pumping station shall be provided with either three (3) or more constant
speed pumps or an automatic control variable speed system.
Head capacity curves shall be prepared for the proposed pumping system
and shall include system curves and pump head capacity curves (modified
for piping system losses) illustrating the performance of the pumps
operating alone and in combination with one another at the anticipated wet
well water levels. Hydraulic computations shall be based upon the HazenWilliams formula at a friction factor, "C-Factor", equal to 110. In
addition, system curves shall be calculated at a "C-Factor" equal to 140 in
order to protect against runout conditions. Finally, the pumping system
should be analyzed to determine the validity for providing 2-speed motors
or variable speed devices.
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(3)
Piping Systems
Piping material, sizes and arrangements are very important. Suction and
discharge piping, valves and fittings should be adequately supported by the
pump flanges. Pipe sizes should be selected on the basis of sustaining a
reasonable head loss with substantially reducing the velocity.
Suction piping for wet well-dry well stations should not include any
elevated sections where air or gas could accumulate. Each pump shall
have a separate suction pipe with a turn down bell and shutoff plug valve
prior to the pump. Additionally the suction piping shall be as short and
straight as possible to minimize suction lift requirements. If reducers are
required, the eccentric type shall be installed so that the top of the suction
pipe profile is level. Suction piping shall be sized to produce a velocity of
not greater than 4.0 feet per second (fps). Additionally, suction pipe lines
shall have a valved hose connection so that the pipeline can be
backflushed periodically with water.
The velocity in the discharge piping shall not exceed 6.0 fps. A check
valve, followed by a plug valve shall be provided on the discharge side of
each pump.
The design velocity in the force main piping shall be a minimum of 2.0 fps
with the smallest pump operating, unless facilities are provided for
periodic flushing or when a flushing velocity of 5.0 fps or more will occur
one (1) or more times per day. If the force main is to be sized for future
flows, and current flows will not achieve flushing velocities, the use of
multiple force mains should be considered. The force main and piping of
the discharge side of the pump will need to be pressure rated to withstand
the maximum hydraulic head on the system, including abnormal pressures
that may be produced by hydraulic transients, such as water hammer and
surge pressures.
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March 2013
(4)
Future Expansion
When designing a pump station, the engineer shall allow for required
future capacities. One (1) option that can be utilized includes modifying
the original pump by installing a new impeller with a larger diameter.
This option may also require installing larger motors, starters, controls, or
electrical systems. A second option is by installing an additional pump if
the structure and the piping are designed initially to accept additional units
that are identical to the existing pumps that are installed in the pump
station. A third option consists of replacing the pumps and motors with
larger units. However, it should be noted that this option must also
account for the existing pipe sizes, electrical capacity and other elements.
c.
Facilities and Equipment
The site of the pump station shall not be subject to flooding, and shall be
accessible to maintenance personnel and equipment during all types of weather.
In addition, the site shall be provided with pavement and walkways, and shall be
on or as close as practical to the WWTF site.
Where buildings and/or structures are constructed, the relevant provisions of
Appendix A shall apply with special design considerations for the following
where applicable:
(1)
Combined pumping station structures shall provide complete separation
between wet and dry wells, including their superstructures. Separation by
common-wall construction is acceptable, provided that interconnecting
pipes, ducts, etc. are designed to preclude unwarranted or detrimental
passage of fluids or gases.
(2)
Pumping station structures shall be of adequate size to allow easy access to
all operating equipment for service and maintenance.
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(3)
Structural openings shall be provided to facilitate equipment removal,
including pumps and motors, stand-by generators, bar screens and other
large items.
(4)
Well designed stairways shall be provided for all dry well access and to
the service landings for wet wells when regular inspection or maintenance
is required therein. Removal ladders may be provided in small stations
where it is impractical to install stairways. Manhole steps or fixed ladders
are not acceptable in wet wells.
(5)
All floor and stairway surfaces shall be sloped to an adequate point of
drainage. The pump room floor shall be provided with a small channel
against the divider wall for pump seal drainage.
(6)
All access openings, stair wells or other abrupt drops in traffic areas shall
be covered by protected gratings, checkerplates, handrails, or other
applicable methods. Stairways into wet well areas shall be constructed of
non-corrosive materials.
(7)
Structural provisions shall be made for future pumping station expansion.
(8)
Should hoisting equipment be required for initial or future installation,
adequate ceiling height and structural consideration shall be provided.
(9)
Wet wells and dry wells shall be separated by at least a water and gas-tight
wall with separate entrances provided to each. Equipment requiring
regular or routine maintenance and inspection shall not be located in the
wet well, unless the maintenance can be accomplished without entering
the wet well.
The raw sewage pumps shall be of the non-clog type design and be capable of
passing 2-1/2" diameter solids and the suction and discharge shall be a minimum
of 3" diameter and shall be either submersible or vertical dry well mounted. The
maximum rotational speed of any pump shall not exceed 1,800 revolutions per
minute (rpm). The dry well mounted pumps shall have an inspection and cleanCity of Umatilla Standard Specifications
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out plates on the body of the pump or a hand hole in the suction elbow to provide
for clearing stoppages. All pumps shall be equipped with stainless steel wearing
rings and mechanical seals for dry well mounted pumps. Protected potable water
or chlorinated plant effluent shall be used for sealing. Grease seals will not be
allowed. Seal water drainage shall be piped to the drainage receptacle or sump.
Safety guards shall be provided on all exposed rotating shafts and couplings.
Vertical shafting and couplings must have safety guards up to 7' above the floor.
All dry well mounted pumps shall be provided with pet cocks on the top of the
volute at the discharge to facilitate removal of air from the pump and placement of
pressure gauges. The submersible pumps installation shall be equipped with
stainless steel guides for raising and lowering the pumps. Additionally,
submersible pumps shall be capable of running for extended periods without
damage under full load in a totally dry condition.
All interior piping and fittings shall be ductile iron with interior bituminous
coating and ANSI 125 pound (lb) standard flange. At least one (1) grooved
coupling on the suction and on the discharge piping shall be provided to expedite
removal and replacement for equipment. The wall penetration below the water
table or below the wet well operating level shall be by wall pipes with 2" water
stops. Wall sleeves with rubber link-seal arrangements shall be used in lieu of
wall pipes. Caulking below water elevations shall not be acceptable. Where the
pipes extend through the exterior walls, a flexible connection (mechanical joint or
push-on-type joint) shall be provided at the exterior wall face. The face of the bell
shall not be more than 2' from the outside face of the wall. Additionally,
restrained joints shall be provided on all discharge lines as necessary.
Shut off valves on the suction and discharge piping shall be non-lubricated plug
valves. The plug valves located more than 6' off the floor shall be provided with
chain wheel operators. Additionally, check valves shall be installed in the
horizontal piping only.
The pump control systems shall be of the encapsulated float type and shall be
located in areas unaffected by flow currents in the wet well. Provisions shall be
made to prevent grease and other floating materials and rags in the wet well from
interfering with the operation of the controls. Additionally, provisions shall be
City of Umatilla Standard Specifications
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made to automatically alternate the pumps. Alarm systems shall be provided on
all pumping stations. The alarm shall be activated for high or low water levels in
the wet well, loss of power, high water level in pump room sump (wet well-dry
well system), loss of alarm transmission line and failure of pump to start. The
alarm system shall be provided with an independent battery power source with
continuous charge. Finally, each pump shall be provided with an elapsed time
meter.
For all wet wells and pump rooms below grade, continuous ventilation is required
with a minimum of six (6) air changes per hour. In rooms where motors are
located, ventilation must be provided to also dissipate the heat from the electric
motors. Intake ducts in below grade rooms shall extend to within 2' of the floor
level. Separate ventilation systems shall be provided for the wet well and dry
well. Wet wells for submersible installations, without free access, shall be
ventilated with not less than one (1) 4" diameter open vent pipe.
Two (2) separate submersible non-clog sump pumps shall be provided for the
removal of leakage or other water from the dry well floor. Each sump pump shall
be provided with a double check valve system, a shut off valve, and a minimum of
2" diameter discharge piping and shall be capable of passing a 1-1/2" solid.
Additionally, an alarm shall be provided for high water level in the sump. The
sump pumps piping discharge should be as high as possible in the wet well and
above the design high water level.
The pump motors shall meet the requirements for the NEC for Class I, Division 2
locations. Motors mounted on the pump in the dry well areas shall be totally
enclosed fan-cooled squirrel-cage induction with Class F insulation limited to a
Class B temperature rise. The motors that are mounted above grade in the motor
control areas shall be open-dripproof squirrel-cage induction with Class F
insulation limited to a Class B temperature rise. Motors mounted outside and
exposed to the environment shall be weather protected type II squirrel-cage
induction motors with epoxy encapsulated windings or approved equal. All
electrical equipment (e.g., lights, cables, conduits, switch boxes, control circuits,
etc.) located in the raw sewage wet well or enclosed spaces where hazardous
City of Umatilla Standard Specifications
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gasses may be present, shall comply with the NEC requirements for Class I,
Group D, Division I locations.
The submersible motors shall be housed in an air-filled watertight casing and shall
have Class F insulated windings which shall be moisture resistant. The motors
shall be NEMA Design B rated to 155 degrees Fahrenheit (ºF) maximum. The
pump motors shall have cooling characteristics suitable to permit continuous
operation, in a totally, partially, or non-submerged condition.
All motors shall be non-overloading at all points on the pump characteristic curve
and shall be provided with a 1.15 service factor. Two (2) or more RTD's
imbedded at various depths in the motor winding shall be provided to shut-off
power and initiate an alarm for motor over-heating conditions.
Consideration shall be given in large installations to providing variable speed
drive equipment of either the eddy-current coupling type or the liquid rheostat
type. The eddy-current couplings, if supplied, should not be mounted in dry well
areas, but connected by extended shafting from the motor control area to the pump
in the dry well. Slip loss shall not exceed 3% of the full motor load. The woundmotor for the liquid rheostat variable speed system mounted in dry well areas shall
be suitable for mounting in Class I, Division 2 locations with the slip rings in an
explosion proof enclosure. The slip loss at full load shall not exceed 6-percent of
the motor's synchronous speed.
Odor control shall be provided as appropriate.
4.
PRELIMINARY TREATMENT
a.
General
Screening equipment shall be provided at all WWTFs. The screens shall be
preferably provided at the pretreatment structure, prior to discharging to either the
grit removal facilities or to the aeration basins. Comminutors will not be
considered an alternative to screening. Coarse screens shall be considered as units
with openings that are 3/8" and larger, whereas, fine screens shall have openings
City of Umatilla Standard Specifications
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1/4" and less. The purpose of the screening units is to remove solids and trash
that could otherwise damage or interfere with the downstream operations of the
wastewater treatment equipment and processes. Manually cleaned bar screens
shall be required for all WWTFs with a design capacity of less than 1.5 MGD, and
mechanically cleaned bar screens shall be installed in all WWTFs with design
capacities 1.5 MGD and greater.
Grit removal facilities may be omitted from WWTFs that have an initial capacity
or 0.25 MGD or less. In larger facilities the initial grit removal facility shall be
designed for the initial design flow or 50% the ultimate plant design capacity,
whichever is greater. Grit removal shall be installed immediately after screening
and prior to discharging to the aeration basins. The method of grit removal shall
be a vortex type system, either hydraulically or mechanically induced system. The
use of horizontal non-aerated grit chambers, aerated grit chambers, or detritus
tanks will not be an accepted method.
Odor control facilities shall be provided as appropriate. However, at a minimum,
provisions for odor control shall be provided in the initial design, so that if
required, the necessary odor control facilities can be simply added to the system.
b.
Bar Screening Facilities
Either manually or mechanically cleaned bar screens shall be provided at the
WWTF to remove the larger objects which may damage mechanical equipment
installed, form obstructions in the pipes or channels, or interfere with the normal
operation of the WWTF. The bar screens may be divided into two (2) categories
according to size as noted above. Design parameters used in the design of a bar
screen shall include the following:

Bar spacing, material of construction and dimensions.

Channel depth, width and approach velocity.

Discharge height to accommodate screenings conveying units.
City of Umatilla Standard Specifications
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
Angle of screen.

Headloss through the unit.

For mechanically cleaned bar screens, provisions for a redundant screen or
bypass manually cleaned unit should be considered.

For mechanically cleaned bar screens, the motor size and enclosure,
service factor etc. should be considered.

Odor control.
Location of the bar screen is an important aspect of the overall effectiveness of the
unit. When locating the screen, the design engineer needs to consider the effects
of the backwater caused by the headloss through the screen. Additionally, an
overflow weir shall be provided to a bypass channel to prevent upstream
surcharging if the screen becomes "blinded". If the screen is enclosed in a
structure, ventilation shall be required to reduce the accumulation of moisture and
odors.
The velocity distribution in the approach channel has an important influence on
the operation of the bar screen. A straight channel is required ahead of the screen
to ensure that a good approach velocity is attained across the screen.
Additionally, the design engineer must ensure that the wastewater's approach
velocity to the screen does not fall below a self-cleaning value or rise enough to
dislodge screenings. The minimum approach velocity to the screen shall be
1.0 fps and the maximum approach velocity shall be 4 fps.
The method of cleaning the screens, manual or mechanical, relates to the method
of removing and transporting screenings from the screens to a disposal site. For
manually cleaned bar screens, the screenings shall be deposited onto a drainage
plate to allow the drainage from the screenings to discharge into the influent
channel prior to depositing the screenings to a dumpster or some other method of
disposal. For mechanically cleaned units, the screenings can either be discharged
directly to a dumpster or to a conveyor system with ultimate disposal to a
City of Umatilla Standard Specifications
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dumpster. Prior to being discharged onto the conveyor system or directly to the
dumpster, the screenings shall be dewatered using a compactor system. The basis
of design for the screening facilities are summarized in Table E-4.
(1)
Facilities and Equipment
All screening facilities shall be provided with at least dual channels each
sized to carry the anticipated peak flows. Gates shall be provided to
isolate the flow from any channel to facilitate dewatering and cleaning.
The approach channels shall be designed to prevent the deposition of
solids and provided with velocity control devices to limit the maximum
approach velocities to the unit. All grating and handrails shall be
aluminum. All bar screens shall be installed prior to the grit chambers.
(2)
Manually Cleaned Bar Screens
Manually cleaned bar screens shall typically have openings ranging from
3/8" to 1.5" with the bars set at 30º to 45º angles from the vertical to
facilitate cleaning. The bars shall be constructed of either aluminum or
316 Type stainless steel and shall consist of bars that are 3/8" thick by 21/2" wide. The bar screen shall be readily removed from the channel. The
screen shall be provided with an accessible perforated platform where the
screenings that are manually removed from the screen can be deposited
where they can drain before removal for disposal.
(3)
Mechanically Cleaned Bar Screens
Mechanically cleaned bar screens shall have clear openings that are less
than 1/4", with the unit set at 0 to 30º from the vertical. Acceptable types
of mechanically cleaned bar screens consist of reciprocating rake and
continuous screens. The materials of construction shall be 316 Type
stainless steel, and if acceptable the element of the screen itself may be
plastic. The screen unit shall be readily accessible for maintenance and
shall be capable of being removed from the influent channel. The bypass
channel as a minimum shall be equipped with a manually cleaned bar
City of Umatilla Standard Specifications
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March 2013
screen. The controls shall operate the screen based on a time interval with
auxiliary controls which will start the mechanism in operation at a preset
high water level. Additionally, a screen failure alarm shall be included in
the design. Manual overrides shall be provided. If a conveyor system is
used then the controls for the screening system shall be interlocked into
the auxiliary equipment of the screen, such as spray wash, conveyors,
compactors or other equipment associated with the operation of the screen.
The electrical fixtures and controls housed in the screening areas where
hazardous gases may accumulate shall meet the requirements of the NEC
for Class 1, Group D, Division 1 locations.
TABLE E-4
TYPICAL DESIGN CRITERIA FOR
BAR SCREENS
Item
Range
Manual screen
Used in facilities with design capacities less
Openings
0.375" to 1.5"
Approach Velocity
1.0 to 2.0 fps
Bar depth
1" to 3"
Slope from vertical
30º to 45º
Allowable headloss
6"
Mechanically cleaned bar screen
Openings
Comments
than 1.5 MGD or in bypass channels
Used in facilities with design capacities
greater
0.25" to 0.5"
than 1.5 MGD
2.0 to 4.0 fps
Maximum approach velocity based on
headloss through the screen
Minimum Velocity
1.0 to 2.0 fps
Minimum velocity required to prevent grit
accumulation
Slope from vertical
0º to 30º
Allowable headloss
6"
Approach Velocity
(maximum)
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(4)
Grit Removal Facilities
The removal of grit, sand, and other inert debris from the waste flow is
considered a protective process and does not materially reduce the
pollutant load. This inert material causes wear on the pumps and other
mechanical downstream equipment. Additionally, this material settles in
tanks, clogs pipes and channels and reduces the effective treatment volume
of the individual treatment units, thereby, increasing the O & M costs.
While the quantity and characteristics of the grit and its potential impact
on downstream processes are important considerations in selecting a grit
removal process, other factors should be considered. These factors
include:

Headloss requirements.

Space requirements.

Grit removal efficiency.

Organic content.

Economics.
A number of grit removal processes may be utilized, however, only
mechanically or hydraulically induced vortex type units will be
considered. The grit removal system shall be capable of removing at least
95% of the grit that is 150 micron (µ) and larger, having a specific gravity
of 2.65.
The vortex grit removal system relies on a mechanically or hydraulically
induced vortex to capture grit solids in the center hopper of a circular tank.
For the mechanically induced unit a rotating turbine maintains a constant
flow velocity, and its adjustable pitch blades promote separation of the
organics from the grit. The action of the turbine shall produce a toroidalCity of Umatilla Standard Specifications
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flow path for the grit particles. Generally the headloss through this type of
unit is 1/4". These units are generally effective in removing grit that is 150
micron (µ) and larger. The mechanically induced vortex unit shall be
constructed of concrete. Carbon or galvanized steel, fiberglass or other
materials will not be acceptable.
In the second type of unit, a hydraulic or "free" vortex is generated by the
flow entering tangentially at the top of the unit. The effluent exits the
center of the top of the unit from a rotating cylinder or "eye" of the fluid.
Gravitational forces within this cylinder minimize the release of particles
with densities greater than water. Grit settles by gravity to the bottom of
the unit, while organics, including those separated from the grit particles
exit principally with the effluent. Headloss through this type of unit is a
function of the size of the particle removed, and can in some cases exceed
48". However, these units will remove particles less than 64" in diameter.
The free vortex tankage shall be constructed of at least 304 Type stainless
steel. Carbon or galvanized steel, fiberglass or other materials will not be
acceptable.
Ideally, the flow to the unit shall be straight, smooth, and streamlined.
Generally, the influent channel length is 7-times the width of the influent
channel, or 15', whichever is greater. However, the length and overall
dimensions of the influent channel to the grit removal unit shall be in
accordance with the manufacturer's recommendation. The approach
velocity in the influent channel shall range from 2.0 to 3.0 fps. The ideal
range shall be 40% and 80% of the peak flow experienced. The minimum
acceptable approach velocity is 0.5 fps, since lower velocities will not
carry grit into the unit.
Sizing of the units shall be based on manufacturer's recommendations.
Typical detention times for these units at peak design flows range between
20 and 30-seconds. Deviations from the recommended dimensions
without the manufacturer's prior approval, may be considered by the City
if it is in the best interest of the WWTF.
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Grit shall be removed from the unit utilizing either an air lift or other type
pump or gravity. Air lift and pumping methods for removal of the grit
shall be considered for the mechanically induced vortex grit removal units,
whereas, gravity is most commonly used for the free vortex unit. If
gravity is utilized a flushing system to pump water at a high pressure to
loosen the grit prior to the solenoid valve opening for discharge of grit
from the unit is required.
Vortex or recessed impeller type pumps, and air lifts shall be utilized to
pump the grit slurry to the grit washing unit. The pump casing and
impeller shall be constructed of abrasive resistant ni-hard material. The
piping shall be a minimum of 4" in diameter and the configuration utilized
shall minimize the horizontal and vertical bends to reduce plugging.
Cleanouts shall be provided at bends to readily clear any blockages. The
minimum velocity through the pipes shall be maintained at 2.0 fps.
Additionally, check valves shall be placed in the horizontal section of the
grit discharge line. Pump controls shall be provided which will allow for
manual initiation of operation, timed interval operation, and continuous
operation.
After the grit is removed from the unit, it shall be washed to remove
putrescible organic material that may be present in the grit. To wash the
grit, a cyclone type unit shall be used prior to classifying. The cyclone
separator shall have a minimum of 4" diameter inlet and discharge selected
to meet the requirements of the expected grit load. The separator shall be
provided with replaceable rubber liner, adjustable apex and pressure
gauge. The constant feed rate to the units generally shall operate within a
range of 200 to 500 gpm, depending upon the size of the unit, and shall be
based upon the manufacturer's recommendations. The discharge from the
cyclone shall than discharge into a grit classifier. The grit classifier shall
consist of either an inclined screw or cleated belt system. For a target
particle size the design engineer shall select a minimum pool area and
overflow weir length to ensure the proper removal of the grit.
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c.
Flow Equalization
Accommodating wide variations in flow rates and organic mass loadings is one of
the major challenges faced in the design of WWTFs. Because of the naturally
occurring variations in the generation of wastewater and the related effects of I/I,
all municipal WWTFs must process unsteady wastewater flows. Efficiency,
reliability, and control of the unit process operations within the WWTF can be
adversely affected by the cyclic nature of waste generation. Equalization of the
influent flow can dampen the diurnal variations and the variations caused by I/I to
achieve a relatively constant loading of downstream treatment processes.
Two (2) types of equalization on influent flows may be used:

Hydraulic Flow equalization.

Waste strength equalization.
The primary objective of hydraulic flow equalization is simply to dampen the
diurnal flow variation and thus achieve a constant or nearly constant rate of flow
through the downstream processes. Waste strength equalization, commonly using
industrial applications dampens the variability of the strength of the waste by
blending the wastewater in the equalization basin. For this purpose the volume of
wastewater in the equalization basin normally remains constant.
Equalization may be used to minimize the effects of loading variations and can be
used to reduce the required size of downstream facilities. However, the design
engineer shall perform an economic and operational analysis to determine the
feasibility of utilizing equalization basins versus the required size of the
downstream treatment units.
If feasible, the equalization basins shall be located immediately following the
pretreatment structure. The equalization basins shall be designed as either in-line
or off-line systems. For the in-line system all of the wastewater passes through
the equalization basin. Whereas, for the off-line system only the portion of the
flow that exceeds the average daily demand is diverted to the basin.
City of Umatilla Standard Specifications
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The equalization basins shall be constructed of concrete, and if necessary, covered
for odor control purposes. Steel tanks shall not be acceptable. Either diffused air
or floating mechanical aerators can be used to adequately mix and aerate the
wastewater. The design of the mixing equipment shall provide for blending of the
contents of the tank and preventing the deposition of solids in the basin. Whereas,
aeration will be necessary to prevent the wastewater from becoming septic.
Mixing requirements will be based on a wastewater with a TSS concentration of
200 mg/l, and shall range from 0.02 to 0.04 horsepower (HP) per 1,000 gallons of
storage. To maintain aerobic conditions, the air should be supplied at a rate of
1.25 to 2.0 cubic feet (cf) per 1,000 gallons of storage. Mechanical aerators can
be used as one method of providing both mixing and aeration and shall have
oxygen transfer capabilities varying from 1.0 to 1.5 pounds of oxygen per
Hp/hour. The minimum operating depth of the equalization basin shall be 5 feet.
Low level shut-off controls shall be required to protect the mixing and aeration
units. Baffling should be provided to prevent short circuiting and ensure proper
mixing. Additionally, if diffused aeration systems are used, then coarse or
intermediate bubble diffusers shall be used. Other operational appurtenances that
should be considered by the design engineer include:

Facilities for flushing any solids and grease that may tend to accumulate
on the basin walls.

An emergency overflow in case of pump failure.

A high-water takeoff for the removal of floating material and foam.

Water sprays to prevent the accumulation of foam on the sides of the
basin, if foam is a problem.
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d.
Odor Control
Wastewaters entering the WWTF may contain odorous compounds that can
escape from open channels and tanks in the preliminary treatment systems,
particularly at points of turbulence. Prevention and control of odors shall be
required to prevent complaints from nearby residents, to provide a reasonable
working environment for WWTF operators, and to reduce the corrosive effects of
the gases on the equipment. The malodorous gases emanated from municipal
wastewater may contain numerous components, including H2S, indoles, skatoles,
amines, ammonia (NH3), carbon dioxide (CO2), methane (CH4), and others. The
acceptable methods for odor control shall include:

Prevention, which entails minimizing the formation of anaerobic
conditions, largely through good housekeeping.

Chemical treatment in the wastewater ahead of the pretreatment structure
can help minimize the formation and release of odorous substances. Some
of the common chemicals used to control odors include chlorine and
chlorine compounds, hydrogen peroxide, metal salts, and caustics or
alkalis.

Preaeration to replenish the DO in the influent wastewater, thereby
reducing the septicity and odor. However, preaeration will strip the H2S
and volatile organics from the wastewater and, hence may require a cover
and air scrubbing system.

Air scrubbing of gas streams collected from covered treatment processes
can provide effective and economical odor control. Odor scrubbers
remove odorous compounds from the air stream by many methods,
including activated carbon, biological towers, dissolution in liquids
containing oxidants using packed towers or aerosol contact vessels, and
ozonation.
All WWTFs shall be designed with the provisions to add an odor control system
should conditions warrant after start-up of the facilities.
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5.
SECONDARY TREATMENT
a.
Activated Sludge
An activated sludge process cultivates large populations of the soil bacteria and
other microorganisms commonly found in the aquatic environment. The
microorganisms utilize the soluble organic material found in wastewater as a
source of food and energy. The soluble material is thus converted to a form which
can be readily separated from the liquid phase by sedimentation. The growth of
the desired microbial populations are encouraged by maintaining aerobic
conditions and by controlling pH and temperature.
The growth of
microorganisms and their settleability can be enhanced by selecting a proper ratio
between the available food (F) and the quantity of available microorganisms (Mv).
Although a reduction in the F/Mv ratio will result in a reduction in the quantity of
waste activated sludge, the power costs required to enhance this auto-oxidation
process will increase.
Mechanical aerators or diffused air systems are used to mix the biological solids
in the wastewater and to provide a source of air from which the oxygen required
for the biological process can be obtained. The wastewater and biological solids
mixture, mixed-liquor-suspended-solids (MLSS), are transferred from the aeration
basins to the secondary clarifiers to separate the treated effluent and remove the
heavier, biological solids by sedimentation. The treated effluent is then
chlorinated prior to discharge. A major portion of the settled biological solids are
returned to the aeration basins for continued removal of organic waste material.
The remaining solids are wasted to the solids treatment stream.
Activated sludge plants have been shown to be very effective in the nitrification of
ammonia to nitrate under proper loading conditions and with an adequate source
of oxygen. The oxygen required to nitrify one pound of ammonia is more than
four (4) times the oxygen required to oxidize 1-pound of organic matter (BOD5).
Thus the required aerator or blower capacity and the resultant power consumption
for a nitrifying activated sludge plant are sharply increased.
City of Umatilla Standard Specifications
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(1)
Processes to be Considered
The following activated sludge processes shall be considered:
(a)
Conventional activated sludge with plug flow and tapered aeration.
This modification consists of a primary settling tank, two (2) or
more long, narrow aeration tanks, secondary clarifiers, and a sludge
recycle system consisting of a pumping unit and a sludge recycle
line.
The effluent from the primary tank is mixed with the settled
activated sludge from the secondary settling basin and discharged
into the aeration tank. Air is supplied to the tank for aeration either
using mechanical aerators and/or diffused aeration. The oxygen
demand decreases as the waste moves along the tank in a plug flow
fashion, and more air is needed at the inlet end. Thus the air flow
is tapered with about 40% being supplied to the inlet quarter and
about 10% to the outlet quarter. The detention time in the aeration
tank may vary from 4 to 10 hours with 6 being average. During
this period, the microorganisms in the returned activated sludge
adsorb or absorb the organic material in the waste stream
converting it from a colloidal and dissolved form to a settleable
material. The waste flow is allowed to settle and the biological cell
mass is removed. A portion of this cell mass is returned to the
inlet end of the aeration tank and the process repeated. In order to
maintain a balance between the food supply in the waste stream
and the cell mass in the return sludge, it is necessary to waste some
of the activated sludge.
(b)
City of Umatilla Standard Specifications
Water & Sewer Utilities
Step-feed activated sludge system. In this modification of the
conventional activated sludge system, the effluent from the
pretreatment structure is discharged into the aeration tank at
several points rather than at the tank inlet.
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This equalizes the food-to-microorganisms ratio thereby lowering
the peak oxygen demand which occurs at the tank inlet in the
conventional system and spreads it more uniformly over the tank
length. Thus, higher BOD5 loadings are possible per unit of
aeration tank volume.
(c)
Contact stabilization. It has been found that removal of BOD in
the activated sludge process occurs in two (2) stages. The first is
the adsorptive and absorptive stage where the colloidal material is
adsorbed and the dissolved material is absorbed into the cell itself.
The second phase is the utilization of the organic material by the
cell mass and its conversion into energy, new cell mass, and waste
products. The first phase is generally accomplished in less than an
hour whereas the second phase requires 4 to 8-hours. The settling
characteristics of the waste at the end of the first phase is excellent
and by separating the two phases and aerating the smaller volume
of the recycled sludge for the longer period of time the plant
capacity may be increased substantially.
This method of treatment is particularly adaptable to those
situations where a high percentage of the organic waste load is in
colloidal form. In such cases, the primary settling basin may be
omitted.
However, because the residence time in the contact tank is
relatively short, some of the dissolved organics may not be
absorbed thus this method is not as efficient as can be achieved by
the conventional method.
Therefore, this method is not
recommended, nor will it be acceptable to the City.
(d)
City of Umatilla Standard Specifications
Water & Sewer Utilities
Complete mix process. In this modification of the activated sludge
process, the recycled sludge and the waste stream are mixed
together and fed into the aeration tank at several points. Using
some means of aeration, the waste stream and the tank volume are
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March 2013
mixed almost instantaneously. This evens out the oxygen
demand and supply throughout the tank.
(e)
Extended aeration. The extended aeration system is an attempt to
totally oxidize the organic fraction in the waste by extending the
aeration time from the 4 to 10 hours common in the conventional
system to 20 to 36 hours and increasing the concentration of
(MLSS) in the aeration tank. This additional residence time and
MLSS concentration allows almost complete oxidation of the
organic material and therefore minimizes the volume of waste
sludge.
Because of the required increase in tank volume extended aeration
is required for relatively small installations. With capacities of less
than 0.10 MGD, the extended aeration process is required. The
units are particularly adaptable to situations where the flow into the
plant is intermittent as would be expected from small installations.
Due to the long detention time provided and the high MLSS
concentration, the raw waste may be discharged directly into the
aeration tank from the pretreatment facility. When good operating
conditions exist, excellent reduction in BOD5 can by achieved.
When the operating conditions are poor or when high hydraulic
loadings are received, the quality of the effluent will degenerate
dramatically. This is true because of a washout of the settling
activated sludge from the settling basin by the surge in flow.
(2)
(f)
Oxidation Ditch (See Section E.5.b)
(g)
Carrousel Process (See Section E.5.c)
Process Design Parameters
The size of the aeration tank for any modification of the activated sludge
process shall be determined by rational calculations based upon the F/Mv,
City of Umatilla Standard Specifications
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MLSS level and sludge retention times (SRT). In addition, the following
items will be considered:
(a)
Degree of treatment required.
(b)
Wastewater temperature.
(c)
pH.
(d)
Dissolved solids.
(e)
Organic load variations.
The basis for sizing of the aeration basins relates to the sludge production
rate as determined by the influent BOD5 load. The sludge production
determines the size of the aeration basin when the values for the mixed
liquor volatile suspended solids and the SRT are established.
The basic relationship normally used for calculating sludge production is:
Sv = aF - bMv
where:
Sv
=
Total volatile solids produced
deliberately
or in the final effluent) in lbs/day.
Mv
=
Total mass of volatile solids in the aeration system (usually
only the solids in the aeration basin are considered) in lbs.
F
=
lbs. of BOD5; removed in the activated sludge process in
lbs/days.
City of Umatilla Standard Specifications
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and
wasted
(either
March 2013
a
=
The cell yield coefficient in terms of lbs of volatile
suspended solids, produced per lb. of BOD5, removed. For
unsettled domestic wastewater, this value will be taken as
1.10. For settled domestic wastewater this value will be
taken as 0.70.
b
=
Endogenous respiration coefficient. For unsettled domestic
wastewater this value will be taken as 0.08. For settled
domestic wastewater this value will be taken as 0.075.
The entire analyses shall be based upon volatile solids since any inert
solids, either entering or precipitated by chemical addition, are not
involved in the biological process. Their amounts must, of course, be
added to Sv in order to determine the total amount of sludge to be wasted,
but they need not be considered with the relationship for calculating sludge
age.
By transposing the above equation, a more useful form results:
Sv/Mv = a(F/Mv ) - b
The value of Sv/Mv is the reciprocal of the SRT. Therefore,
1/SRT = a(F/Mv)) - b
The overall design parameters for a WWTF required to remove only
carbonaceous BOD5 are as shown in Table E-5.
For the removal of carbonaceous plus nitrogenous BOD, the use of the
sludge age parameter shall be required. As has been demonstrated the.
growth rate of nitrifying organisms is much slower than those organisms
needed to metabolize the carbonaceous matter and is very dependent upon
temperature. The theoretical relationship, as developed by Downing, for
nitrification in domestic wastewater is:
City of Umatilla Standard Specifications
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1/SRT = (0.18) (1.128)T-15
This means that in any activated sludge system requiring nitrification at a
given design temperature, the sludge age, (SRT) must be greater than the
value obtained from the above equation. If the operation sludge age is less
than the value obtained, the slow-growing nitrifiers will be washed out of
the system.
In designing aeration basins for nitrification the value of the SRT shall be
determined using a wastewater temperature of 18 degrees Celsius (°C).
This results in a minimum SRT of approximately 4 days. Furthermore,
because of the unpredictable variations and the possibility of some
inhibition of the growth rate of nitrifying organisms, a safety factor of 2.0
for sludge age based an the average BOD load shall be used providing that
at the maximum day BOD load the SRT is not less than the minimum of 4
days.
The value of the MLSS must be projected on the basis of what can
normally be carried for any particular activated sludge system and method
of aeration. With diffused air systems, the range of MLSS for normally
loaded plants is 2,000 to 3,500 mg/l, with higher values being for
treatment of unsettled domestic wastewater. For mechanical surface
aerators the MLSS ranges up to 4,500 mg/l. Because the solids become
somewhat densified in plants operating in or very close to the endogenous
phase (F/Mv, less than 0.15) MLSS values of up to 5,000 mg/l can be
used.
The F/Mv is based upon MLVSS which is 75% to 80% of the MLSS for
settled domestic wastewater, and 65% to 70% for unsettled wastewater.
The oxygen input requirement for the removal of carbonaceous BOD5
shall be determined by the following equation:
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Or = cF + dMv
where:
Or
=
lbs/day of oxygen required.
c
=
0.55 lb 02/lb BOD5 Applied.
d
=
0.15 lb 02/lb MLVSS.
In those plants where nitrification is needed, an additional requirement of
4.6 lb. O2/lb. total kjeldahl nitrogen (TKN) applied shall be used. A DO
concentration of 2.0 mg/l or higher shall be maintained in the aeration
tanks. The oxygen requirements shall be based upon the maximum day
BOD5 and TKN applied.
(3)
Aeration Facilities and Equipment
The method for transferring oxygen to the mixed liquor shall be by either a
diffused aeration system or by low speed mechanical aerators. Pure
oxygen systems will not be considered for use in the City due to their
complexity and labor intensive requirements.
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TABLE E-5
TYPICAL ACTIVATED SLUDGE DESIGN PARAMETERS
Process
Modification
Sludge
Retention
Time
(days)
F/M
lbs
BOD5/MLVSS/
day
Aeration
Loading
lbs BOD5/1,000
cf of tank
volume
MLSS
(mg/l)
Detention
Time
(hours)
Conventional
5 to 15
0.2 to 0.4
20 to 40
1,500 to
3,000
4 to 8
Complete Mix
5 to 15
0.2 to 0.4
40 to 60
3,000 to
3 to 5
3,500
Step Aeration
5 to 15
0.2 to 0.4
40 to 60
2,000 to
3,500
3 to 5
Contact
Stabilization
(not
recommended)
5 to 15
0.2 to 0.6
30 to 75
1,000 to
4,0001
4,000 to
10,0002
0.5 to 1.51
Extended
Aeration
20 to 30
0.05 to 0.15
10 to 15
2,000 to
5,000
24
Notes: 1.
2.
Contact unit.
Stabilization unit.
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Air requirements for a diffused air system shall be determined by
incorporating such factors as:

Tank depth, not less than 12.0'.

Alpha factor of waste; 0.4 for fine bubble diffusers; 0.7 for coarse
bubble diffusers.

Beta factor of 0.95.

Certification of aeration device transfer efficiency.

Minimum aeration tank DO concentration at 2.0 mg/l.

Minimum wastewater temperature of 18° C.

Minimum mixing intensity required of 0.75 to 1.0 HP per 1000 cf.
of volume.
To the air requirements shall be added air required for channels, pumps,
aerobic digesters, or other plant air use demands. Diffuser efficiencies
shall be as recommended by the manufacturer but shall in all cases exceed
10% for coarse bubbler diffusers and 25% for fine bubble diffusers in
clean water tests at a power density in excess of 1.0 HP per 1000 cf.
Documentation from the manufacturer shall be provided for all proposed
diffuser efficiencies. The installed diffuser system shall be tested in clean
water and corrected to standard conditions to determine conformance with
the stated efficiencies. Dissolved oxygen probes shall be used and
determination of DO content by the Winkler method shall not be allowed.
The specified capacity of blowers should take into account that the air
intake temperature may reach 40° C and the pressure may be less than
normal. The specified capacity of the motor drive should also take into
account that the intake air may be 0° C (32° F) and may require oversizing
of the motor or a means of reducing the rate of air delivery to prevent
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overheating or damage to the motor. The blowers shall be provided in
multiple units to meet the maximum air demand with the single largest
unit out of service. Centrifugal blowers shall be equipped with intake and
exhaust silencer's and shall be equipped with inlet control butterfly valves.
The design shall also provide for varying the volume of air delivered in
proportion to the load demand of the WWTF.
Aeration equipment shall be easily adjustable in increments and shall
maintain solids suspension within these limits. The spacing of diffusers
should be in accordance with the oxygen requirements through the length
of the channel or tank, and should be designed to facilitate adjustment of
their air flow rate without major revisions to air header piping. All
WWTFs employing less than four (4) independent aeration tanks shall be
designed to incorporate removal diffusers that can be serviced and/or
replaced without dewatering the tank. Air piping for fine bubble diffusers
shall be stainless steel to prevent accumulation of scale and eventual
clogging of the diffuser. Individual assembly of units of diffusers shall be
equipped with control valves, preferably with indicator markings for
throttling or for complete shutoff. Diffusers in any single assembly shall
have substantially uniform pressure loss. Air filters shall be provided in
numbers, arrangements, and capacities to furnish at all times an air supply
sufficiently free from dust to prevent damage to blowers and clogging of
the diffuser system used.
For low speed mechanical aerators, the equipment shall be standard
mechanical surface aeration equipment capable of transferring the required
atmospheric oxygen into the mixed liquor. The aerators shall maintain the
activated sludge solids in suspension throughout the aeration tank while
maintaining a minimum of 2.0 mg/l DO in the mixed liquor at all times.
Adjustable outlet weirs for controlling the aeration tank's liquid level and
thereby controlling the amount of atmospheric oxygen transferred shall be
provided. Alpha factor for mechanical aeration shall be taken as 0.90.
The aerator blades shall be sized based on the following conditions:
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The coefficient, Pc, as calculated below, at maximum design speed and
power input,not being less than 0.0045.
Pc = P/(N3)(D5)
where:
P=
motor electrical input HP at maximum speed of aerator.
N=
maximum rotational
revolutions/second.
D=
Diameter of the aerator impeller in feet.
speed
of
aerator
impeller
in
At maximum design speed of the aerator, the tip or peripheral speed of the
impeller shall not exceed 20 fps. Transfer efficiencies of mechanical
surface aerators shall not be less than 2.75 lbs. O2 per electrical input HP
under standard conditions. Proposed transfer rates shall be based upon the
manufacturers recommendation where consideration is given to the
geometric shape, area and volume of the basin. Transfer efficiency tests
shall be conducted on the installed system to determine conformance with
the specifications.
The aerator drives shall be either of the lower extended bearing type or of
the independent bearing support construction with a speed reducer. The
minimum AGMA Service Factor shall be 2.3 for speed reducers and for
gear motors. Gear reducers shall be provided with bearings having a
minimum rating life expectancy (B-10) of 100,000 hours, except those
bearings attached directly to the output shaft which shall have a rating-life
expectancy (B-10) of 300,000 hours.
Gear reducers shall have a reliable lubrication system incorporating a
pressure, flow or temperature switch device to stop the motor in the event
of insufficient lubrication. Motors shall be TEFC type suitable for outdoor
operation having NEMA Class F insulation and B temperature rise. The
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motor shall have encapsulated or vacuum pressure impregnated windings
capable of passing a mist/spray and direct wash down test.
(4)
Aeration Basins
All aeration basins shall be of reinforced concrete design either above or
below grade as dictated by site constraints. In addition, all aeration basins
shall be provided with:

A minimum of 1.5' freeboard.

Sufficient units of a size to enable proper operation of the WWTF
in its initial years.

Visible return sludge discharges for each tank, particularly when
the sludge flow to each tank is not metered.

Floor slopes and gravity drain piping to facilitate periodic flushing
of solids from the tank bottom.

Strategically located yard hydrants for easier clean-up operations.

Adequately sized influent and effluent channels to prevent
deposition of MLSS.

Foam control water sprays for channels.

Bitumastic coating in channel areas and in the tank interior to 3'
below the nominal water surface elevation.

All grating, entrance hatches and handrailing shall be aluminum or
fiberglass.
The aeration basins using diffused air system shall also be provided with
the following:
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(a)
Gravity drains where air header galleries are used.
(b)
An adequate froth or foam control water spray system.
(c)
Swing arm diffusers with air measuring and shut-off features.
(d)
Main butterfly valve controls at each basin to enable the air flow to
each basin to be independently controlled depending on flow
pattern and demand.
The aeration basins using low speed mechanical aerators shall be
provided, in addition to that listed above, with the following:
(5)
(a)
Stilling baffles in front of outlet weirs to ensure even flow
distribution and prevent surging.
(b)
Means of removal of the aerator's motor and/or gear units.
(c)
Access manholes in aerator platform.
(d)
Aeration platforms shall be a minimum of 5' above the water
surface.
(e)
Provisions for aerosol and splash control.
Return Activated Sludge
The basic relationship for the quantity of return sludge is developed from
the mass balance around the clarifier and is as follows:
(Q + Qr)Ca = QrCr + QCe + QwCr
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where:
Q = plant influent flow rate.
Qr = sludge recycle flow rate.
Qw = sludge wasting rate.
Ca = required MLSS concentration in the aeration tank.
Ce = plant effluent concentration.
Cr = sludge recycle concentration.
For the purposes of calculating the return sludge rate the two (2) terms
QCe and QwCr are relatively small in comparison to the other terms and
are normally taken as zero. Thus the following form of the equation
results:
Qr = (Q)(Ca)/(Cr - Ca)
The return sludge concentration (Cr) for those plants removing only
carbonaceous BOD5 may be taken at a maximum value of 8,000 mg/l. For
those WWTFs which are nitrifying the effluent or operating in the
endogenous phase, the value of Cr shall take a maximum of 6,000 mg/l.
The rate of sludge return expressed as a percentage of the average plant
design flow should generally be variable between the limits set forth in
Table E-6.
The maximum return sludge capacity shall be obtained with the largest
pump out of service. A positive head shall be provided on pump suctions.
Pumps should have at least 3" suction and discharge openings. When
possible, each group of aeration tanks and clarifiers shall have separate
return and waste sludge removal capabilities. Additionally, the capability
to return and waste sludge concurrently shall be provided. Automatic
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proportioning of return sludge flow to influent flow should be provided at
larger facilities.
The pumps shall be equipped with mechanical seals (grease stuffing boxes
will not be considered). The seal water may be either clean potable water
after it has passed through a reduced pressure backflow preventer or
strained plant effluent. Seal water pressure must be 10 psi greater than
maximum pump discharge pressure. Automatic solenoid shut off valves,
manual isolation valves, and rotometer shall be required for seal water
installations. Pumps shall be equipped with replaceable stainless steel
wearing rings.
Suction and discharge piping should be at least 4" in diameter and should
be designed to maintain a velocity of not less than 2-fps when return
sludge facilities are operating at normal return sludge rates. Suitable
devices for observing sampling, and controlling return activated sludge
flow from each settling tank shall be provided. It is recommended that
return sludge piping be terminated above the aeration tank liquid level to
allow for observation and sampling.
TABLE E-6
RETURN ACTIVATED SLUDGE RATES
AS A PERCENTAGE TO AVERAGE WWTF FLOW
Type of Process
Minimum Percentage
Maximum Percentage
Processes without nitrification
15
100
Processes with nitrification
50
125
Extended Aeration
50
150
b.
Oxidation Ditch
The oxidation ditch is essentially an extended aeration modification of the activated
sludge process. The system consists of a "racetrack" shape basin and a large brush
type rotor. The rotor is placed across the ditch to provide the air required and to move
the liquid around the basin.
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(1)
Design Parameters
All design parameters shall be equivalent to the extended aeration process
design parameters as given in Subsection E.5.a.
(2)
Facilities and Equipment
There shall be at least two (2) ditches of equal volume. Each rotor shall be
sized so that its oxygen capacity is equal to the total oxygen demand of the
plant. The rotor shall provide at least a 1 fps velocity to the mixed liquor.
Provisions shall be made to easily vary the liquid level in the ditch to
control immersion depth on the rotor. The rotor bearing should have
grease fittings that are readily accessible to maintenance personnel.
Bearing shall have a minimum B-10 life rating of 300,000 hours. The gear
reduction limit shall have a minimum service factor at 2.5. Gear housing
and outboard bearings shall be shielded from rotor splash. The oxidation
ditch may be trapezoidal and lined with reinforced concrete or as approved
by the City.
c.
Carrousel Process
The carrousel process is a patented modification to the activated sludge process. It
utilizes a plug flow regime with the mixed liquor continually circulating in a
"racetrack" shaped basin. The mechanical surface aerator is used in this process
to supply the energy required to maintain a sufficient velocity in the channel and
to supply the oxygen required for the biological process. The zone of aeration is a
relatively small volume where the mixed liquor is intensely mixed with the
influent flow and the oxygen transferred from the atmosphere.
(1)
Process Design Parameters
The design of a carrousel process shall conform to the requirements as set
forth in Section E.5.a.
(2)
Facilities and Equipment
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The facilities and equipment shall conform to the requirements as set forth
in Section E.5.a.
d.
Secondary Clarification
Inlets shall be designed to dissipate the inlet velocity, to distribute the flow
equally and to prevent short circuiting. Scum baffles shall be provided ahead of
all effluent weirs. Outlet weirs shall be adjustable for leveling. Multiple units are
required. In plants where two (2) units are furnished, each unit shall be sized for
75% of the total design capacity.
All secondary clarifiers shall be designed to provide easy access for maintenance
and protection to the operator. Such features shall include stairways, walkways,
and handrails.
Sludge removal shall be as dictated by the particular process utilized.
(1)
Process Design Parameters
Since the rate of recirculation of return sludge from the secondary settling
tanks to the aeration or reaeration tanks is quite high in activated sludge
processes, the detention time, surface settling rate and weir overflow rate
should be adjusted for the various processes to minimize the problems
with sludge loadings, density currents, inlet hydraulic turbulence, and
occasional poor sludge settleability. The design parameters shown in
Table E-7 should be observed in the design of secondary settling tanks for
the various activated sludge processes. Consideration must be given to the
flow duration.
The minimum sidewater depth for secondary clarifiers shall be a function
of tank diameter as shown Table E-8.
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TABLE E-7
DESIGN PARAMETERS FOR SECONDARY CLARIFIERS
Hydraulic Loading Rates
(gpd/sf)
Solids Loading Rates
(lbs./day/sf)
Type of Treatment
Average
Peak
Average
Peak
Extended aeration and nitrification
processes
200 to 400
600 to 800
10 to 20
30 to 35
All other activated sludge processes
400 to 600
1,000 to 1,200
8 to 30
40 to 45
TABLE E-8
SECONDARY CLARIFICATION
RECOMMENDED SIDEWATER DEPTHS
Diameter
Minimum Sidewater Depth
up to 70'
12'
71' to 100'
13'
101' to 140'
14'
Greater than 140'
15'
The bottom slope for clarifiers following an activated sludge process, which are preceded by
primary clarification, shall not be less than 0.5' in 12'. The bottom slope
for units following fixed film reactors and activated processes, not
preceded by primary clarification shall not be less than 1' in 12'.
(2)
Equipment and Facilities
Clarifiers following the activated sludge processes, that are less than 100'
in diameter shall be the scraper/rake sludge collection mechanism type
which continually moves the settled solid toward a centrally located
hopper. Whereas clarifiers greater than 100' in diameter should be of the
rapid sludge return type incorporating a suction type removal system with
suction nozzle attached to the moving sludge collection arms. For
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clarifiers that incorporate suction type removal systems, the sludge is
continuously withdrawn from the clarifier bottom by a hydrostatic
differential head between the water surface level in the clarifier and the
discharge elevation in the sludge well of the suction pipe. The discharge
of the suction pipe shall be equipped so that the discharge elevation can be
raised or lowered to adjust the return sludge flow.
The sludge collection equipment shall not have chains, bearings, or
operating mechanisms below the liquid surface. The maximum allowable
stresses on structural steel members when the full stall torque is applied
shall not exceed those permitted by the latest AISC Specifications. The
entire drive assembly shall be designed on the basis of maximum
continuous working output torque and shall be designed for a stalled
torque of twice the maximum continuous working output torque.
Overload device assemblies of either the worm shaft thrust actuated type
or the ampere measuring type shall be provided. The overload alarm
device shall show a value indicating impending overload and further shut
the unit down if this value is exceeded.
e.
Waste Activated Sludge Facilities
Waste sludge facility design is highly dependent on the sludge handling system to
which the sludge will be discharged. Wasting will be accomplished either
continuously or in a very definite time span based on the downstream sludge
handling units and the plant's operating schedule. Continuous wasting should be
the goal of larger facilities, and in this case the wasting system should be designed
to function in the range of 0.5% to 5.0% of the average wastewater flow expected
(initial and design). In systems where continuous wasting cannot take place,
waste sludge control facilities should have a maximum capacity of not less than
25% of the average rate of wastewater flow and function satisfactorily at rates of
0.5% of average wastewater flow.
The abrasive nature of sludges, especially those containing grit, must be
considered in the selection of pump type and materials of construction. The pump
capacity shall be adequate to cover the full range of solids concentrations and
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sludge reproduction. Variable speed or other rate control systems are desirable.
Maximum operating pressure should be calculated to account for the high friction
factor when pumping sludges. Duplicate pumping units shall be provided where
failure of one unit would seriously hamper plant operation. Interconnection of
pump suction and discharge manifolds is recommended, so that one pump
discharge can be used to backflush other suction piping. A minimum positive
head of 24" shall be provided at the suction side of centrifugal type pumps and is
desirable for all types of sludge pumps. Plunger pumps, screw feed pumps,
recessed impeller-type centrifugal pumps, progressive cavity pumps, or other
types of pumps with demonstrated solids handling capability shall be provided for
handling raw sludge.
Plunger pump backup for centrifugal pumps is
recommended.
Sludge withdrawal piping should have a minimum diameter of 8" for gravity
withdrawal and 6" for pump suction and discharge lines. Where withdrawal is
by gravity, available head shall be adequate to provide a velocity of at least 3 fps.
Gravity piping should be laid on a uniform grade and alignment. The slope of
gravity discharge lines should not be less than 3%. Provisions should be made for
cleaning, draining, and flushing sludge piping. Flanges, tees and crosses, and
cleanouts to allow rodding of suction lines are desirable. Provisions for back
flushing with positive displacement pump discharge is desirable. Provisions for
cleaning by hot water, steam injection, or chemical degreasing should be
considered in long lines containing raw sludge or scum.
Flow meters should be provided on all essential lines. Provisions should be made
for metering equipment isolation, cleaning, and calibrating. Variable timer
equipment should be provided for sludge pumps used in intermittent withdrawal
service. Unless sludge sampling facilities are otherwise provided, quick-closing
sampling valves shall be installed at the sludge pump. The size of the valve and
piping shall be at least 1-1/2".
Aerated sludge holding tanks should be sized on the basis of 2 cf per capita.
Chemical conditioning facilities that would allow chemical addition prior to
discharge to sludge conditioning should be installed. The holding tanks should be
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provided with devices such as telescoping valves and multiple suction lines to
allow supernatant to be returned to the main flow pattern of the plant.
6.
ADVANCED WASTE TREATMENT
a.
General
Advanced waste treatment includes those physical, chemical or biological
processes or any combination thereof designed specifically to reduce the
concentration of any pollutant not adequately reduced by conventional
preliminary, primary, and secondary wastewater treatment processes. These
pollutants may include BOD5, TSS, nitrogen, phosphorus, toxic materials,
dissolved salts, and any other material considered to be detrimental to the
environment. The advance treatment needs may be addressed as an integral part
of the new WWTF flowsheet or an add-on to the existing secondary treatment
train.
This Subsection will deal specifically with selected processes which may have
application in the area. These include:
-
Phosphorus removal
Suspended solids removal by filtration
Nitrogen removal
Activated carbon adsorption of trace organics
Each unit process added to a conventional secondary WWTF process flowsheet to
achieve enhanced degrees of treatment has certain design objects and capabilities
that, in light of the treated effluent limits, provide the basis for process selection.
In general, as a minimum, the following factors should be considered:




Effluent goals.
Process capabilities and compatibility with the overall treatment
flowsheet.
Operational factors.
Process control.
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




Sidestreams and recycle flows.
Solids production and air emissions.
Energy requirements.
Economics.
Other factors (e.g., space requirements, worker health and safety, etc.).
Many advanced waste treatment processes are still in the experimental stage and
design criteria based on years of proven results are unavailable. Therefore, it may
be necessary that pilot plant studies be conducted to establish design criteria for
the specific installation.
b.
Phosphorus Removal
Phosphorus can be removed from wastewater biologically or by chemical
precipitation using lime, alum, or ferric chloride. Conventional secondary
biological treatment systems take up phosphorus from solution for biomass
synthesis during BOD oxidation. Since phosphorus is required in intracellular
energy transfer, it becomes an essential cell component. For this reason,
phosphorus is taken up in an amount related to the stoichiometric requirement for
biosynthesis. Generally, for biological phosphorus removal the most common
method of phosphorus removal is the addition of an anaerobic basin prior to the
aeration basin. Generally, the anaerobic and aerobic stages are each divided into a
number of equally sized, completely mixed compartments, and the RAS is
returned to the first compartment of the anaerobic zone. The process can be
adapted for nitrification by allowing the necessary detention time in the aerobic
zone. This process is commonly called the A/O™ process. Other processes for
biological phosphorus removal include the use of sequential batch reactors
(SBR's), and the PhoStrip™ and the OWASA™ process both of which are
sidestream type treatment processes. Typical design parameters for the A/O™,
SBR and the PhoStrip™ processes are presented in Table E-9. The OWASA™
process is a relatively new process and firm design data is not available at this
time.
For chemical precipitation of the phosphorus, the chemicals, as a slurry, are mixed
with the waste usually ahead of the primary settling tank. Precipitation takes
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place in the tank where the compounds settle out and are removed together with
the normal organic sludges. Modifications of the process allow the chemicals to
be added either to the aeration tank or following the secondary settling tank. In
the latter case, a second settling tank is necessary. Approximately 90% to 95% of
the phosphorus compounds can be removed by chemical precipitation. However,
the chemical costs add substantially to the operating costs and significantly
increase sludge volume to be disposed of.
TABLE E-9
TYPICAL DESIGN PARAMETERS FOR BIOLOGICAL
PHOSPHORUS REMOVAL PROCESSES
Process
Design Parameter
Units
A/O
PhoStrip
SBR
lbs. BOD/lbs. MLVSSday
0.2 to 0.7
0.1 to 0.5
0.15 to 0.5
Solids Retention Time
days
2 to 25
10 to 30
N/A
MLSS
mg/l
2,000 to
4,000
600 to
5,000
2,000 to
3,000
F/M Ratio
Hydraulic Retention Time_hours__
Anaerobic Zone__0.5 to 1.5
Aerobic Zone__1 to 3
Return Activated Sludge_% of influent_25 to 40
Internal Recycle_% of influent_N/A
UUDesign Parameter_Units_A2/O_5-Stage
UCT_VIP
F/M Ratio_lbs. BOD/lbs. MLVSS-day_0.15 to 0.25_0.1 to 0.2
Solids retention time_days_4 to 27_10 to 40
MLSS_mg/l_3,000 to 5,000_2,000 to 4,000
Hydraulic retention time
UU2.0
1.5
4.0
3.0
6.0
4.5
8.0
7.5
10.0
14.0
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When designing a sludge stabilization process the design engineer shall consider
the sludge quantity to be treated, the integration of the stabilization process with
the other treatment units. and the objectives of the stabilization process. The
objectives of the stabilization process will be affected by the existing state and
federal regulations.
While there are many methods to stabilize the sludge generated from a WWTF,
only a few are truly applicable to the City's present needs, based on the size of the
regional WWTFs. Therefore, the City will primarily consider lime stabilization,
aerobic digestion and anaerobic digestion, and also will consider other viable
processes on a case by case basis (e.g., auto thermal digestion, composting, etc.).
(1)
Aerobic Digestion
The purpose of aerobic digestion is to reduce the volume of organic
factions, to improve the dewatering characteristics and to destroy and/or
reduce the putrescible portion in the sludge. This can be accomplished by
subjecting the sludge to long-term times under aeration. Generally this is
accomplished in two (2) or more tanks with air supplied by either diffused
air or by mechanical aeration.
This process is usually used to treat WAS. In some cases the process has
been used to treat a mixture of waste activated sludge or trickling filter
sludge.
The aerobic sludge digestion process reduces the volatile solids to a level
that is approximately equal to that of anaerobic digestion. However, this
process produces a lower BOD5 concentration in the supernatant that is
returned to the head of the WWTF for treatment. Additionally this process
produces a superior end product that can be disposed of easily and has
excellent sludge dewatering characteristics. Moreover, the aerobically
digested sludge has higher fertilizer values than other sludge stabilization
processes. The design parameters for aerobic digestion facilities are
provided in Table E-13.
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Consideration should be given to either following a thickening process
with an aerobic digestion process to increase the SRT in the aerobic
digester and thereby reducing the overall digester volume. Additionally,
multiple tanks should be considered so that the aerobic digestion facilities
can either be operated in a batch mode or in series. Moreover, multiple
tanks allow continuous wasting, draining one (1) tank for repairs or
maintenance, and alternate treatment modes of operation.
Aeration equipment shall conform to that outlined in Section E.5.a.
"Activated Sludge." Methods for aeration and mixing include mechanical
aerators, diffused aeration or combined systems. Air rates to the aerobic
digester should range from 20 to 40 cfm/1,000 cf to ensure adequate
mixing. Whereas, air flow rates necessary to meet oxygen transfer
requirements depend on digester loading. If mechanical surface aerators
are used, pontoon-mounted devices of either low- or high-speed design
should be considered. Additionally, mechanical submerged turbine
aerators combined with diffused air systems can be utilized for mixing and
aeration.
The tank should have a bottom slope ranging from 1' in 12' to 3' in 12' or
greater. Additionally, provisions shall be provided to drain the tank. Side
water depths are similar to those used in activated sludge systems and will
depend on factors such a available space limitations, type of oxygenation
and mixing system, and other considerations. Generally, aerobic digester
side water depths range from 10' to 25' and a freeboard of at least 4' should
be provided to allow for foaming.
Specific piping requirements for aerobic digesters shall include provisions
for feeding sludge, decanting the supernatant, withdrawing the digested
sludge and supplying air for aeration. Additionally, if multiple tanks are
used then provisions should be provided for flexibility in feeding and
withdrawing the sludge. It is recommended that a minimum of two (2)
supernatant withdrawal lines located a different elevations in the basin
shall be incorporated into the tank design. Additionally, an emergency
overflow should be provided if the potential for overfilling exists.
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Sludge removal from the aerobic digester shall be by means of a
progressive cavity pump. Other types of pumps will not be acceptable.
Supernatant from the process shall be returned to either the primary
(pretreatment) or secondary (aeration) treatment process. The respective
treatment process shall be capable of handling the additional hydraulic
flow resulting from the return of supernatant.
The operational control of the aerobic digester shall be manual. However,
operating variables that currently lend themselves to automatic control are
DO and tank level. Therefore, the DO signal can be used to maintain an
optimum DO level and provide energy conservation. However, DO
changes in an aerobic digester are generally minimal and maintenance of
the DO equipment may be time consuming. Therefore, it is recommended
that a tank level signal, indicating high levels be the only monitoring
control required.
TABLE E-13
DESIGN PARAMTERS FOR AEROBIC DIGESTERS
Parameter
Value
Hydraulic Detention Time at 20 C
Waste activated sludge only
15 to 40 days
Activated sludge from WWTF without primary clarifiers
18 to 40 days
Solids loading
0.3 to 1.0 lbs. VSS/cf/day
Oxygen requirements
lbs. O2/lb. cell tissue destroyed
2.3 lbs. O2
Energy requirements for mixing
Mechanical aerators
1.0 to 1.5 HP/1,000 cf
Air mixing
20 to 40 cfm/1,000 cf
Dissolved oxygen level in liquid
1 to 2 mg/l
Volatile solids reduction
40% to 50%
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(2)
Lime Stabilization
In the lime stabilization process, lime is added to untreated sludge in
sufficient quantities to raise the pH to 12 or higher. The high pH creates
an environment that is not conducive to the survival of microorganisms.
Consequently, the sludge will not purify, create odors, or pose a health
hazard, so long as the pH is maintained at this level.
Process design of the lime stabilization process is based on selecting a
suitable chemical dose to achieve and maintain an elevated pH for a
sufficient time to accomplish microbial inactivation. The pH must remain
high, in excess of 12.0 for 2 hours and 11.5 for 22 hours, at which time the
sludge can be disposed of at an approved site. However, it should be
noted that the required chemical dose depends on an variety of factors,
including:
-
Chemical characteristics of the lime.
-
Chemical characteristics of the sludge, including both the organic
and inorganic constituents.
-
Physical characteristics of the sludge, including moisture content
and viscosity.
-
Adequacy and speed of mixing the sludge and the lime.
The effectiveness of the lime stabilization process is a function of the pH
and the contact time, the pH of the sludge and the lime mixture must be
maintained at an adequate level for a specific time period to reduce
pathogens and achieve other stabilization objectives.
The lime stabilization process consists of two (2) main components:
-
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Lime handling, inclusive of receiving, storing, transferring, and
delivering lime to a lime and sludge blending tank.
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-
Mixing of the lime and sludge.
The required design features of lime-handling facilities depend on the type
of lime to be used. Quicklime (CaO) and hydrated lime (Ca(OH)2) are the
two (2) most commonly used types of lime used in lime stabilization of
domestic sludges and are available in varying quality. However, lime is
available in bags or bulk as well as in a premixed slurry. Additionally,
quicklime is converted to hydrated lime through a slaking process on-site,
or hydrated lime can be slaked by the supplier and delivered to the facility.
Bagged lime is generally delivered to the site loose on pallets. Delivery of
bulk lime is shipped by truck or rail and is unloaded using a pneumatic or
mechanical conveyance systems. Storage requirements are an important
aspect to the overall design of the system. Generally, hydrated lime can be
stored for approximately 1-year, whereas, quicklime has a 3 to 6-month
storage period. Bagged-lime should be stored in a covered area to prevent
the rain from wetting the bags, and should not be stored near combustible
materials. Steel silos are used for the bulk storage of dry lime. The silo
must be watertight and airtight. A height to diameter ratio for the silo of
approximately 2.5 to 4 is suggested. Additionally, a steep coned (60º or
greater) bottom is necessary for the discharge of the lime. Vibrators,
commonly used for pulverized quicklime, shall be installed on the hopper
and operated during discharge of the lime.
The dry lime, when delivered in bulk, must be transferred from the storage
silos to the point of mixing with the sludge or to the point at which water
is added to form a slurry. Dry chemical feeders are typically located on the
bottom of the silo hopper, and are either volumetric or gravimetric types.
The volumetric type supplies a constant proportional delivery of lime by
volume and will not recognize a change in material density. As a result,
this type of feeder will need to be calibrated for the type of lime being
used. However, a gravimetric type feeder supplies a constant weight of
lime over a given time, and compensates for changes in form, type, size,
and density.
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Dry lime may be made into a wet suspension or slurry before being mixed
with the sludge. In small systems, bagged hydrated lime may be mixed
with water in a batch tank. In larger systems, a volumetric feeder or
gravimetric feeder supplies the lime to a dilution tank. The dilution tank
shall be mixed with a mechanical mixer. The batch or dilution slurry tank
can be constructed of either steel or fiberglass.
The lime slurry is generally the most troublesome step in the limehandling operation. The slurry feed equipment should be located as close
as possible to the lime and sludge mixing tank to minimize plugging
problems. Additionally, the lime slurry may be pumped or flow by gravity
to the lime and sludge mixing basins. Due to the characteristics of the
lime slurry, heavy duty rubber hoses, quick-disconnect fittings, and an acid
cleaning system should all be considered in the design. However, if the
acid cleaning system is used then the piping, valves and appurtenances
must be constructed of suitable material.
The lime sludge mixing/holding tank shall be constructed of concrete and
shall consist of a minimum of three (3) basins. The geometric
configuration of the tank can either be circular or square. However, in
either case, baffling of the tank may be necessary to enhance the mixing
characteristics of the lime sludge mixture. Mixing of the tank contents
shall be accomplished using mechanical mixers and shall be based on the
bulk velocity and impeller.
Since lime is a caustic material that can cause burns. Safety considerations
should include having operations and maintenance personnel wear
protective clothing and be trained to use proper handling procedures.
Additionally, eyewash stations and safety showers will need to be
installed.
(3)
Anaerobic Digestion
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Anaerobic digestion is a process which biologically converts volatile
solids to methane, carbon dioxide, and water in a mixed, heated, oxygendeficient digester. The gas formed during the process is typically 40% to
75% methane and can be burned to heat the digester and, in some cases, to
provide supplemental energy for auxiliary treatment plant functions. A
two (2) stage system is often used in which digestion takes place in the
first (heated, mixed) stage. In this stage high molecular weight organic
compounds are converted to organic acids by acid forming bacteria. In the
second stage is the conversion of the organic acids to methane and carbon
dioxide by the acid-splitting methane-forming bacteria takes place.
The methane bacteria are strict anaerobes and are extremely sensitive to
the presence of minute quantities of oxygen and other changes in their
environment. This sensitivity exhibited by the methane forming bacteria
coupled with the rugged nature of the acid-forming bacteria create a
situation which can be easily upset, thus care and understanding of the
biological process is essential for effective operation.
Supernatant quality from the digesters is high in pollutants, which
contributes a significant load when recycled through the wastewater
treatment plant. Thickening sludge before anaerobic digestion is usually
advantageous, especially when working with thin activated sludge.
Thickening minimizes the digester volume required, as well as the heating
and mixing energy requirements and shall be considered during the design
process.
Multiple units shall be required. In a two (2) stage system each stage shall
be designed and equipped to act as the primary digester. The system shall
be designed such that the units well operate both in series and in parallel.
In calculating the volume of the digester for determining unit loading
rates, the cone volume should not be considered as part of the volume,
because of the possibility of limited biological activity and solids
destruction occurring in this region.
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The heat exchange capacity of the anaerobic sludge digestion process
should be based on an influent sludge temperature of 60° F, ambient air
temperature of 45° F, and the digester temperature of 95° F. A minimum
sidewater depth of 20' is required. The criteria for efficient operation of an
anaerobic digester is given in Table E-14.
Tank covers shall be floating steel type, including gas storage type units,
equipped with a guide rail system to prevent tipping, lower-landing ridges,
and cover restraints. Multiple recirculation withdrawal and return points,
to enhance flexible operation and effective mixing, should be provided,
unless mixing facilities are incorporated within the digester. The returns,
in order to assist in scum breakup, should discharge as near as possible to
the liquid level and the center of the tank. Discharge to the digester should
be through the sludge heater and recirculation return piping, or directly to
the tank if internal mixing facilities are provided. Sludge withdrawal to
disposal should be from the bottom of the tank. The disposal pipe should
be interconnected with the recirculation piping, if such piping is provided,
to increase versatility in mixing the tank contents.
The diameter of the supernatant piping should not be less than 6". Piping
should be arranged so that withdrawal can be made from three (3) or more
levels in the digester, if necessary. A positive unvalued vented overflow
shall be provided. If a supernatant selector is provided, provisions shall be
made for at least one (1) other draw-off level located in the supernatant
zone of the tank, in addition to the unvalved emergency supernatant drawoff pipe. High pressure backwash facilities shall be provided in the sludge
pipe lines. Additionally, provisions should be made for sampling at each
supernatant draw-off level. Sampling pipes should be at least 1-1/2" in
diameter, and should terminate at a suitably-sized sampling sink or basin.
All portions of the gas system, including the space above the tank liquor,
storage facilities, and piping shall be so designed that under all normal
operating conditions, including sludge withdrawal, the gas will be
maintained under positive pressure. All enclosed areas where any gas
leakage might occur shall be adequately ventilated. All necessary safety
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facilities shall be included where gas is produced. Pressure and vacuum
relief valves and flame traps, together with automatic safety shut off
valves, shall be provided.
Heating capacity sufficient to consistently maintain the design sludge
temperature to within 1º shall be provided. Where digester tank gas is
used for sludge heating, an auxiliary fuel supply is required. Piping shall
be designed to provide for preheating of feed sludge before introduction to
the digesters. Provisions shall be made in the lay-out of the piping and
valving to facilitate cleaning of these lines. Heat exchanger sludge piping
should be sized for heat transfer requirements.
All gas utilization equipment shall be provided with flame traps.
Consideration should be given to using digester gas to fuel direct electric
power generation. Additionally, waste gas burners equipped with an
automatic ignition shall be provided.
All electrical fixtures and controls in enclosed areas where hazardous
gases may accumulate shall comply with the NEC for Class I, Division 1,
Group D locations.
Digester floors shall slope at least 2' in 12'. The digester contents shall
operate under a complete mix mode.
(4)
Other Sludge Stabilization Processes
Other methods of sludge stabilization include composting, pasteurization,
heat treatment, incineration, wet air oxidation, and thermal drying. These
processes are considered to be not cost effective at this time. As additional
data are reviewed, the applicability of these processes will be reconsidered.
c.
Sludge Dewatering
After the wastewater sludge has been properly treated, it can be dewatered and the
moisture content reduced to the point where the sludge can be handled as a semi-
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solid instead of a liquid. The methods to be considered for dewatering sludge
include air drying on sand beds, centrifugation, and belt filter presses.
TABLE E-14
GENERAL DESIGN CRITERIA FOR
ANAEROBIC DIGESTION
Item
Values
Temperature
95° F
pH
Optimum
7.0 to 7.1
General limits
6.7 to 7.4
Gas production
cf/lbs.VSS added
6 to 8 cf
cf/lbs.VSS destroyed
16 to 18 cf
Gas composition
Methane
65% to 69%
Carbon dioxide
31% to 35%
Hydrogen sulfide
trace
Volatile acids concentration as acetic acid
Normal operation
200 to 800 mg/l
Maximum
approximately 2,000 mg/l
Alkalinity concentration as CaCO3
Normal operation
2,000 to 3,000 mg/l
Normal hydraulic retention time
(1)
20 to 25 days
Air Drying Beds
The oldest method of drying digested wastewater sludges is the open sand
bed. Beds of sand 8" to 12" thick are surrounded by a low retaining wall
and flooded to a depth of 10" to 12" with well digested sludge. During
this process a portion of the liquid or filtrate, in the sludge percolates
through the sand layer and is collected in an underdrain system and
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returned to the WWTF flow. The remainder of the filtrate is lost by
evaporation. After the sludge reaches the desired moisture content, it is
removed manually from the bed surface. Under favorable weather
conditions a moisture content of 60-percent may be achieved in 10 to 20days.
The economical use of open sand drying beds is generally limited to small
and medium size municipal facilities. The large land area required and the
high operation cost associated with the removal of the sludge and the
replacement of sand generally precludes the use of this process where the
population served exceeds 20,000. Sludge bed loadings are computed
either on a per capita basis or in a unit loading of pound of dry solids per
square foot per year.
The lower course of media should be properly graded gravel and should be
approximately 12" in depth at the underdrains, extending at least 6" above
the top of the underdrains. The minimum depth of this course at any point
in the bed should be 6". It is desirable that this lower course be placed in
two or more layers. The top layer of preferably 3" should consist of gravel
1/8" to 1/4" in size. The top course layer should consist of 6" to 9" of
clean coarse sand, the finished sand surface should be level .
Underdrains should be vitrified clay bell and spigot pipe at least 4" in
diameter laid with open joints, farm distribution tile appropriately spaced
and covered, or perforated clay pipe. Underdrains should be spaced not
more than 12' apart on centers. Walls should be water-tight and extend at
least 15" above and 6" below the sand surface.
At least two (2) beds should be provided and arranged to facilitate sludge
removal. Concrete truck tracks are preferable for all sludge beds. It is
usually advantageous that the design be such that no drying area is more
than 10' from a prepared truck access. The sludge pipe to the beds should
terminate at least 15" above the sand surface, and preferably be so
arranged that it will drain. Concrete splash plates at least 4' by 4' should
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be provided at sludge discharge points. Drainage from the drying beds
should be returned to the raw or settled sewage.
(2)
Centrifugation
Centrifuges may be used to dewater sludge or to thicken slurries for further
processing. The solids are separated from the liquid under the influence of
a centrifugal force 100 to 600 times that of gravity. Solid particles are
deposited against the spinning bowl and the overflow is a relatively clear
liquid. Two (2) types of centrifuges which are common in the wastewater
industry are the basket type and the solid bowl type.
The basket centrifuges are generally used for partial dewatering of sludges
from small plants and are not designed for continuous operation. The
sludge feed must be interrupted to release the accumulated cake. The
cycle of operation may vary from 10 to 30 minutes with the removal of the
cake requiring 1 to 2 minutes of the total.
In the solid-bowl machine the sludge is fed into the unit at a constant rate,
and the centrifugal force of the rotating bowl separates liquid and solid
fraction forming a dense cake containing 75% to 80% moisture. The
sludge cake is continuously removed from the unit by a screw feeder and
discharged into a hopper outside the unit. The cake can then be hauled
away for disposal.
The major advantage of the solid bowl centrifuge is the flexibility of
operation. The feed rate, solids content and prior chemical conditioning
can be varied to meet specific requirements. However, clarification of the
solid bowl type of centrifuge is better in the basket type and thus
reasonable results can often be obtained without prior chemical
conditioning.
Advantages of the centrifuge as a means of dewatering is the small area
required for its installation with respect to that required by the vacuum
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filter and its lower initial costs. However, the higher operating costs
partially negate this factor.
The hydraulic and solids loading rates and the conditioning requirements
of the centrifuges system shall be based on operational results from similar
treatment facilities. The results which may be anticipated from a solidbowl centrifuge should be a cake solids of approximately 5% to 20%
solids with solids capture of 90%.
It is not possible to design a centrifuge for a specific application, rather the
design most often is based upon pilot test data. In the absence of pilot
data, past performance at similar installations is used. Data shall be
submitted to the City to substantiate the proposed design loading rates.
(3)
Belt Filter Press
Belt filter press systems attempt to overcome the sludge pick-up problem
occasionally experienced with rotary vacuum filters. A combination of
sludge conditioning, gravity dewatering and pressure dewatering is utilized
with this dewatering process to increase the solids content of either
digested or undigested sludge.
The influent mixture of solids and polymer (or other chemical) is placed
onto a moving porous belt. Dewatering occurs as the sludge moves
through a series of rollers which squeeze the sludge to the belt or squeeze
the sludge between two (2) belts much like an old washing machine
wringer. The cake is discharged from the belt by a scraper mechanism.
Many physical differences exist between various types of belt filter
presses. For example, the type of filtration belt used for each unit varies in
size, porosity and material. The design engineer should note the specific
requirements of the equipment. Filtrate from the belt filtration unit is
usually returned to the secondary treatment process and normally causes
no problem to process operation.
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Hydraulic and solids loading rates and conditioning requirements shall be
based on operational results on similar projects. This process is
considered to be not cost effective at this time. As additional data are
reviewed, the applicability of this process will be reconsidered.
d.
Sludge Disposal
There are many methods of acceptable sludge disposal. The four (4) most
common methods are liquid injection, composting, landfilling, and removal by a
sludge hauler for reuse. The sludge disposal method used shall be subject to
approval of the City.
9.
WASTEWATER EFFLUENT DISPOSAL
a.
General
After treatment, the wastewater is either reused or disposed of in the environment.
In the natural environment, physical, chemical, and biological processes occur
when water, soil, plants, microorganisms, and the atmosphere interact. The
method of effluent disposal and associated treatment requirements may
significantly impact the facilities necessary at an interim package or subregional
WWTF. The general method of effluent disposal shall be by a public access or
non-public access land application system (e.g., spray irrigation, reclaimed water
reuse, overland flow or rapid infiltration basins) or a wetland system.
Wastewater effluent disposal facilities designed for subregional treatment plants
shall conform to FDEP Chapter 62-610, FAC, the "Land Application of Domestic
Wastewater Effluent in Florida" manual and accepted engineering practice.
b.
Submittals
Due to the many complex hydrogeological factors that must be evaluated in the
design of public and non-public access land application disposal systems, case by
case review of each proposed system will be conducted in accordance with the
requirements and provisions of Chapters 62-4, 62-600 and 62-610, FAC,
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information regarding project design and performance shall be provided to the
City by the engineer. General engineering report requirements are specified in
Section 62-600, FAC. Certain information, described below and in the FDEP
report, "Land Application of Domestic Wastewater Effluent in Florida," shall also
be included.
(1)
(2)
(3)
Location: The location of the proposed effluent disposal system,
illustrated on a 7.5 or 15 minute series USGS topographic map showing
the following:
(a)
Proposed wetted area of the wastewater discharge.
(b)
Buffer zones.
(c)
Surrounding land uses.
(d)
Watercourses and water wells.
(e)
Storage lagoons.
Topography. A detailed map indicating:
(a)
Original and proposed slope, with a contour interval of 2'.
(b)
Limits of all flood plains and inland wetlands.
(c)
Natural site drainage zones.
Geology
(a)
Depth to limerock.
(b)
Limerock type.
(c)
Geologic discontinuities - faults, fractures, sinkholes.
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(d)
(4)
(5)
(6)
Jointing and permeability of rock.
Soils
(a)
Depth, type, and texture of soil all from field confirmation of
USDA Soil Conservation Service (SCS) information for a
minimum depth of 20'.
(b)
Permeability of soil mantle based on field testing.
(c)
Chemical soil properties such as pH, nutrient levels, and cation
exchange capacity may be required for some systems.
Groundwater Hydrology
(a)
Groundwater depth confirmed by field investigations for each
season.
(b)
Location of perched water tables.
(c)
Groundwater contours.
(d)
Direction of groundwater movement and flow.
(e)
Groundwater points of discharge.
(f)
Existing analyses of site groundwater quality and drinking water
wells in the vicinity, including but not limited to coliform bacteria,
pH, nitrates, total nitrogen, chloride sulfates, and total hardness.
(g)
A description of the depth and type of all water supply wells in
proximity to the land treatment - disposal site.
Climate
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c.
(a)
Monthly precipitation versus application rate.
(b)
Monthly temperature versus application rate.
(c)
Monthly wind velocities and direction.
(d)
Monthly estimate of water lost through evaporation as applicable.
Treatment Guidelines - Land Application
(1)
Spray Irrigation - Restricted and Public Access
Slow-rate land application usually involves treatment and disposal of
domestic wastewater effluent through spray irrigation of crops or other
vegetation. The waste treatment requirements for restricted and nonrestricted public access spray irrigation systems are as follows:
(a)
For irrigation to sod farms, forests, fodder crops, pasture land, or
similar areas where it is intended that public access shall be
restricted, preapplication waste treatment shall result in an effluent
meeting, at a minimum, secondary treatment and basic disinfection
levels prior to the land application.
(b)
For all slow-rate systems involving irrigation of golf courses,
cemeteries, public parks, landscaped areas, residential areas and
other areas intended to be accessible to the public, waste treatment
more stringent than secondary shall result in an effluent containing
the following, prior to land application:
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(i)
A BOD5 concentration not greater than
treatment criteria.
(ii)
A TSS concentration of not greater than 5 mg/l.
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(c)
(2)
(iii)
No detectable fecal coliforms (high-level disinfection
criteria).
(iv)
Methods for ensuring protection from virus shall be
approved by the FDEP and City.
The effluent limitations shall be met after disinfection and before
discharge to holding ponds or effluent disposal systems.
Additional treatment may be required as a result of the alternate
discharge, subsurface drainage, and the hydraulic application rate.
Rapid-Rate
Rapid-rate land application generally involves treatment and disposal of
domestic wastewater effluent by spreading in a system of percolation
ponds, "Rapid Infiltration Basins" (RIB's) or cells. The percolation area
shall be divided into two (2) or more cells to allow for alternate loading
and resting. Because of the somewhat limited ability of these systems to
renovate effluent, the engineer shall, in his report, address, in detail, the
potential groundwater quality violations.
The waste treatment
requirements for rapid rate systems shall be:
At a minimum, preapplication waste treatment shall result in an effluent
meeting secondary treatment and basic disinfection levels prior to
spreading into the ponds. The nitrate-nitrogen (NO3-N) content of the
effluent prior to spreading into the pond system shall not exceed 12 mg/l
unless reasonable assurance is provided in the engineering report that
NO3-N as measured in any hydraulically down-gradient monitoring well
will not exceed 10 mg/l or background level in the receiving groundwater,
whichever is less stringent. Design NO3-N content of the effluent prior to
disposal shall be established by the design engineer subject to City and
FDEP approval. Additional treatment may be required as a result of the
pond location, subsurface drainage, and the hydraulic application rate.
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(3)
Overland Flow
This method of land application involves treatment of domestic
wastewater in order to meet effluent limitations for discharge to surface
waters. Wastewater is applied by sprinkling or flooding upper reaches of
terraced, sloped, vegetated surfaces, such as sod farms, forests, fodder
crops, pasture lands, and similar areas. A runoff conveyance system shall
be provided at the ends of the sloped surfaces. The waste treatment
requirements for this type of system are as follows:
Approval of projects involving preapplication treatment below secondary
treatment and basic disinfection levels may be provided based upon the
review of the physical site conditions. Proposed preapplication treatment
levels shall provide reasonable assurance that long-term performance of
the land treatment system shall, at a minimum, result in an effluent
meeting the secondary treatment and basic disinfection levels prior to
release of effluent to the environment via final surface water discharge
from land treatment sites. The pollutant content of the final effluent may
be more stringently limited via effluent limitations required in Chapter 62610, FAC, as required to satisfy water quality requirements.
Preapplication treatment processes shall produce an effluent prior to
discharge to holding not more than 40 to 60 mg/l BOD5, or TSS, and
meeting the low level disinfection criteria of 2,400 fecal coliforms per 100
ml. Additional treatment may also be required as a result of the alternate
discharge, hydraulic application rate, and the provided surface runoff
control facilities.
(4)
Other Effluent Disposal Systems
Other treatment requirements for land application systems not described
herein will be reviewed by the City on a case-by-case basis.
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d.
Operations and Maintenance - Land Application
All operations and maintenance specifications shall conform to requirements set
forth in Chapter 62-610, FAC and the FDEP report entitled "Land Application of
Domestic Wastewater Effluent in Florida," Chapter 6, "Operational and
Maintenance Requirements." The Design Engineer's Report shall have a separate
section discussing the proposed operations and maintenance program for the
facility. The design engineer shall review this program with the City and shall
modify the program in accordance with this review.
e.
Groundwater Monitoring - Land Application
All facilities and associated appurtenances shall be provided as stated in Chapter
62-610, FAC and the FDEP report entitled "Land Application of Domestic
Wastewater Effluent in Florida".
f.
Groundwater Injection
The feasibility of shallow well injection of treated domestic wastewater has been
studied. Presently, regulatory concerns regarding groundwater contamination may
result in very stringent water quality requirements which may render this
technique not viable. Until this technique has been further studied, specific water
quality requirements delineated, and the present FDEP positions changed, shallow
well injection will not be acceptable in City.
10.
INSTRUMENTATION AND POWER
a.
Instrumentation
The control system for the package or subregional WWTF may be analog. The
process variable will be sensed and a current signal (4 to 20 mA) will be produced
in proportion to the process variable. The current signal will be transmitted to a
local or remote indicator, recorder or controller. If the measured variable is
controlled, then a controller will receive the input, compare it to the desired
setpoint and then output a current signal proportional to the deviation from the
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setpoint. The output signal may control the position of a valve, the speed of the
motor or other process equipment applications. The analog control system will
involve all monitoring and control from a central panel with satellite panels for
specific unit processes.
All WWTFs shall be provided with a flow indicator-recorder-totalizer which shall
pace the chlorine feed system. All WWTFs with design capacities of less than 0.5
MGD shall have a 30 day chart. For WWTFs with a design capacity equal to and
greater than 0.5 MGD, they shall be equipped with either a 7-day (week) recorder
or a 24-hour (day) recorder as approved by the City.
Manual overrides of control systems shall be provided where applicable.
Automatic control systems whose failure could result in a controlled diversion or
a violation of the effluent limitations shall be provided with a manual override.
These automatic controls shall have annunciators to indicate malfunctions which
require use of the manual override. The means for detecting the malfunction shall
be independent of the automatic control system, such that no single failure will
result in disabling both the automatic controls and the alarm annunciators.
Instrumentation failure which could result in a controlled diversion or a violation
of the effluent limitations shall be provided with an installed backup sensor and
readout. The backup equipment may be of a different type and located at a
different point, provided that the same function is performed. No single failure
shall result in disabling all instrumentation systems installed at the WWTF.
Alarm annunciators shall be provided to monitor the condition of equipment
whose failure could result in a controlled diversion or a violation of the effluent
limitations.
Alarm annunciators shall also be provided to monitor conditions which could
result in damage to vital equipment or hazards to personnel. The alarms shall
sound in areas normally occupied and also in areas near the equipment. For
WWTFs that are not continuously manned, they shall have the alarm signals
transmitted to a point stipulated by the City which is continuously manned, (i.e.,
fire station, Sheriff's station, etc) via an auto-dialer. The alarm annunciators shall
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be such that each announced condition is uniquely identified. Test circuits shall
be provided to enable the alarm annunciators to be tested and verified to be in
working order.
Vital instrumentation and control equipment shall be designed to permit
alignment and calibration without requiring a controlled diversion or a violation
of the effluent limitations.
The provisions for telemetry to remote pumping stations and other City facilities
shall be in accordance with the instrumentation master plan (Data Acquisition
System Study), when completed and approved by the City to ensure system compatibility. Instrumentation systems at the interim package or subregional WWTFs
shall be compatible. Instrumentation plans and type of equipment shall be
approved by the City prior to ordering the materials. Additionally, the
instrumentation system shall be provided with lightening protection.
b.
Power
As a minimum, two (2) separate and independent sources of electric power shall
be provided to the interim package or subregional WWTF from a single substation
and a site based emergency generator. If available from the electric utility, at least
one (1) of the facility's power sources shall be a preferred source (i.e., a utility
power source which is one of the last to lose power from the utility grid due to
loss of power generating capacity). The City shall determine the reliability class
to be utilized; this determination shall be governed by flow and effluent discharge
sensitivity of the facility. The capacity of the backup power source for each class
of treatment facilities shall be:
(1)
Class I Reliability: Sufficient to operate all vital components, during peak
wastewater flow conditions together with critical lighting and ventilation.
(2)
Class II Reliability: Same as Reliability Class I, except that vital
components used to support the secondary processes (i.e., mechanical
aerators or aeration basin air compressors) need not be included as long as
treatment equivalent to sedimentation and disinfection is provided.
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(3)
c.
Class III Reliability: Sufficient to operate the screening or communication
facilities, the main wastewater pumps, the primary sedimentation basins,
and the disinfection facility during peak wastewater flow condition,
together with critical lighting and ventilation.
Power Source
Each utility source of power to the plant shall be transformed to usable voltage
with a separate transformer. The transformers shall be protected from common
mode failure by physical separation or other means.
d.
Power Distribution
The internal power distribution system shall be designed such that no single fault
or loss of a power source will result in disruption (extended, not momentary) of
electric service to more than one (1) motor control (MCC) center associated with
the reliability of Class I, II, or III vital components requiring backup power. Vital
components of the same type and serving the same function shall be divided as
equally as possible between at least two (2) MCC's. Additionally, all non-vital
components shall be divided in a similar manner, where practical.
Where power feeder or branch circuit can be transferred from one (1) power
source to another, a mechanical or electrical safety device shall be provided to
assure that the two (2) power sources cannot be cross-connected, if
unsynchronized. Automatic transfer shall be provided in those cases when the
time delay required to manually transfer power could result in a failure to meet
effluent limitations, a failure to process peak influent flow, or cause damage to
equipment. Where automatic pump control is used, the control panel power
source and pump power source shall be similarly transferred. The actuation of an
automatic transfer switch shall be alarmed and annunciated.
e.
Breakers and Fuses
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March 2013
Breaker settings or fuse ratings shall be coordinated to effect sequential tripping
such that the breaker or fuse nearest the fault will clear the fault prior to activation
of other breakers or fuses to the degree applicable. Failures resulting from
plausible causes, such as fire or flooding, shall be minimized by equipment design
and location. The following requirements apply:
1.
Switch Gear: Electric switchgear and MCC's shall be protected from
flooding, sprays, or moisture from liquid processing equipment and from
breaks in liquid handling piping. Where practical, the electric equipment
shall be located in a separate room from the liquid processing equipment.
Liquid handling piping shall not be permitted to run through this room.
2.
Wires: Wires in underground conduits or in conduits that can be flooded
shall have moisture resistant insulation as identified in the NEC.
3.
Outdoor Motors: All outdoor motors shall be adequately protected from
the weather. Waterproof, totally enclosed or weather-protected, open
motor enclosures with epoxy encapsulated windings or approved equal
shall be used for exposed outdoor motors. Motors located indoors and
near liquid handling piping or equipment shall be, at least, splash-proof
design.
4.
Explosion Proof Motors: Explosion proof motors, conduit systems,
switches and other electrical equipment shall be used in areas where
flammable liquid, gas, or dust is likely to be present.
5.
Conduit Routing: To avoid a common mode failure, conductors to
components which perform the same function in parallel shall not be
routed in the same conduit or cable tray. Conduits housing such cable
shall not be routed in the same underground conduit bank unless the
conduits are protected from common mode failure (such as by encasing the
conduit bank in a protective layer of concrete).
6.
Three Phase Motors: Three (3) phase motors and their starters shall be
protected from electric overload and short circuits on all three (3) phases.
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Large motors shall have a low voltage protection device which on the
reduction or failure of voltage will cause and maintain the interruption of
power to that motor.
f.
Equipment Testing
Provisions shall be included in the design of equipment requiring periodic testing,
to enable the tests to be accomplished while maintaining electric power to all vital
components. This requires being able to conduct tests, such as actuating and
resetting automatic transfer switches, and starting and loading emergency
generating equipment. The electric distribution system and equipment shall be
designed to permit inspection and maintenance of individual items without
causing a controlled diversion or causing violation of the effluent limitations.
Considerations shall be given to reduce voltage starting where required and/or
economically justified. Power factor correction equipment shall be provided
where required and/or economically justified.
The means for starting a works based emergency power generator shall be
completely independent of the normal electric power source. Air starting systems
shall have an accumulator tank(s) with a volume sufficient to furnish air for
starting the generator engine a minimum of three (3) times without recharging.
Batteries used for starting shall have a sufficient charge to permit starting the
generator engine a minimum of three (3) times without recharging. The starting
system shall be appropriately alarmed and instrumented to indicate loss of
readiness (e.g., loss of charge on batteries, loss of pressure in air accumulators,
etc.).
Control provisions shall be made for automatic and manual start-up and cut-in.
The controls shall be such that upon automatic start-up under emergency
conditions, shut-down can only be accomplished manually except for conditions
which would damage the generator or engine. Provisions shall be made to permit
the auxiliary power generator to peak-shave, if economically justified.
City of Umatilla Standard Specifications
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March 2013
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