Wastewater reuse in the Urban Environment: selection of

Wastewater reuse in the Urban Environment:
selection of technologies
February 2006
This study was prepared by Ecological Engineering at the request of Landcom.
Landcom does not warrant the accuracy of the study. The representations, statements and
advice in the study are made in good faith, and on the basis that Landcom and Ecological
Engineering, and their respective agents and employees, accept no responsibility or liability
(whether by reason of negligence or otherwise) to any person for any damage or loss
whatsoever which has occurred or may occur in relation to a person taking or not taking (as
the case may be) action in respect of any representation, statement, or advice made or
referred to in the study.
The study may not be published, reproduced or copied in part or in whole without the
express written consent of Landcom.
Document Control Sheet
Report title:
Wastewater reuse in the Urban Environment: selection of
technologies
Suggested Reference:
Landcom’s WSUD strategy (2003)
Version:
Final
Author(s):
Dr Peter Holt, Emma James
Approved by:
Dr Tony Wong
Signed:
Date:
February 2006
File Location:
I:\04_05\2108
Distribution:
Armineh Mardirossian
ii
Table of Contents
EXECUTIVE SUMMARY..........................................................................................................1
1
2
Reused Water and ‘Fit-for-Purpose’ Applications .............................................................5
1.1
Water end use........................................................................................................................... 5
1.2
Alternative water sources.......................................................................................................... 5
1.3
Demand management for water reuse ..................................................................................... 6
Selection of Appropriate Water Treatment Technologies .................................................8
STEP 1. Identify site characteristics and interaction with the built environment ....................11
Interactions with the built environment .............................................................................................. 11
STEP 2. Water balance and demand profile ..........................................................................13
Demand profile – satisfying peak requirements ................................................................................ 15
STEP 3. Water reuse scenarios - options analysis ................................................................17
STEP 4. Human health and social considerations .................................................................20
Social acceptance ............................................................................................................................. 20
Ownership models............................................................................................................................. 21
STEP 5. Interactions with the natural environment ................................................................23
Impact on aquatic environment ......................................................................................................... 23
Impact on the land suitability ............................................................................................................. 24
Greenhouse gas emissions ............................................................................................................... 24
Production of biosolids ...................................................................................................................... 24
STEP 6. Life cycle costing......................................................................................................26
STEP 7. Evaluation of water reuse options............................................................................27
3
The water reuse technologies .........................................................................................29
3.1
General descriptions ............................................................................................................... 30
3.2
Types of technologies ............................................................................................................. 31
3.3
Biological processes ............................................................................................................... 32
3.3.1
Activated sludge .............................................................................................................. 32
3.3.2
Fixed growth .................................................................................................................... 33
3.3.3
Natural systems – subsurface flow wetland .................................................................... 33
3.3.4
Recirculating media filter ................................................................................................. 33
3.4
Sand and media filtration ........................................................................................................ 34
3.5
Membrane filtration ................................................................................................................. 34
3.5.1
4
Reverse osmosis ............................................................................................................. 35
3.6
Membrane bioreactor .............................................................................................................. 35
3.7
Disinfection.............................................................................................................................. 36
Summary of water treatment technologies......................................................................37
4.1
Chemical ................................................................................................................................. 39
4.1.1
WaterFresh – Struvite Crystalliser ................................................................................... 39
iii
4.2
4.2.1
COPA Water – ReAqua HBNR........................................................................................ 40
4.2.2
RootZone – Greywater Vertical Treatment Unit .............................................................. 41
4.2.3
Biolytix with ultrafiltration ................................................................................................. 42
4.2.4
Waterpac – NatureFlow Systems .................................................................................... 43
4.2.5
Novasys – BIOSYS.......................................................................................................... 44
4.2.6
RootZone – All wastewater Horizontal Subsurface Wetland........................................... 45
4.2.7
KEWT – GBG Project Management ................................................................................ 46
4.3
Hybrid systems........................................................................................................................ 47
4.3.1
Clearwater Aquacell......................................................................................................... 47
4.3.2
TCI Port Marine – ROCHEM Bio-Filt ............................................................................... 48
4.3.3
Ludowici Zenon................................................................................................................ 49
4.3.4
Veolia ............................................................................................................................... 50
4.3.5
Aquatec-Maxcon: Kutoba ................................................................................................ 51
4.3.6
Memcor MBR, Memjet Xpress......................................................................................... 52
4.3.7
Nubian.............................................................................................................................. 53
4.3.8
Packaged Environmental Solutions (ISWETS)................................................................ 54
4.3.9
COPA Water – ReAqua MBR .......................................................................................... 55
4.4
Physical................................................................................................................................... 56
4.4.1
Perpetual Water – Perpetual Water - Home™ Grey Water Purification System............. 56
4.4.2
COPA Water – ReAqua CAS........................................................................................... 57
4.4.3
Baleen Filters ................................................................................................................... 58
4.4.4
Memcor AXIM and AXIA CMF-S ..................................................................................... 59
4.4.5
NuSource Water .............................................................................................................. 60
4.5
5
Biological................................................................................................................................. 40
Alternative sewer technologies ............................................................................................... 61
4.5.1
Innoflow - Interceptor Tank , Orenco Sewer and AdvanTex Treatment Pods................. 61
4.5.2
Mono-Pumps - small diameter sewer .............................................................................. 62
4.5.3
FLOVAC – Vacuum sewer system .................................................................................. 63
References......................................................................................................................64
Appendix A – Water quality treatment....................................................................................65
A1. Guidance for residential development ........................................................................................ 67
A2. Guidance for multi-unit dwellings ................................................................................................ 68
A3. Guidance for onsite systems....................................................................................................... 68
A4. Guidance for environmental systems.......................................................................................... 68
A5. Guidance for approval................................................................................................................. 69
Appendix B – Contact list of all treatment technologies .........................................................70
Appendix C - Additional technologies and systems ...............................................................72
iv
EXECUTIVE SUMMARY
Why reuse water?
Sustainable water management is an important goal and a key element of sustainable urban
development. Government authorities and the land development industry are increasingly seeking to
use alternative sources, such as water reuse, to conserve drinking water supplies and minimise
wastewater.
Water reuse must be considered in the context of the specific development and management of the
entire water cycle. A Water Sensitive Urban Design (WSUD) strategy is the starting point for
developments’ water management planning. Within such a strategy, reusing water may be deemed
appropriate for a particular site after considering all other water streams and their interactions.
Water reuse describes the treatment of wastewater to a standard where it can be used within our
community. Throughout the document the term “reused water” is used to describe recycled water,
greywater reuse (wastewater from the household excluding toilet water), sewer mining or reclaimed
effluent. References to particular water streams will be made where required. Reused water is used
on a ‘fit-for-purpose’ basis – that is, of an appropriate quality for the intended use (see Page 5).
Sustainable and integrated water cycle management
The conventional urban water cycle consists of a large-scale centralised water supply and disposal
system. Water is collected from catchments, treated and piped to customers. After use, wastewater
flows through a second set of pipes (sewers) to sewage treatment plants. The treated water is then
discharged to creeks, rivers, bays or oceans.
Sustainable development aims to minimise water use and dependence on natural resources and
maximise reuse within the built environment (see Figure 1). In Figure 1, the dotted red line separates
the natural and built environments. The general approach is to minimise water and pollutants crossing
the boundary, and maximising water reuse within the boundary. This can be achieved by:
•
reducing drinking water demand (through demand management)
•
using available water sources for the most appropriate purposes (‘fit-for-purpose’)
•
identifying and maximising alternative water sources
•
minimising the impact of urban stormwater on the receiving aquatic ecosystem.
Wastewater reuse in the Urban Environment: selection of technologies
1
MINIMISE
Drinking
water
supply
Stormwater
System boundary
Natural environment
Reservoirs, dams, water
treatment plants
Built environment
REUSE
Stormwater
Rainwater harvesting
treatment
Greywater reuse
USE
Human
consumption
- kitchen
Sewer mining
Hot water
system
Greywater
treatment
Shower and
bathroom taps
Clothes
washing
Sewer
Garden
irrigation
mining
Toilet flushing
Blackwater to STP
Built environment
Natural environment
System boundary
Sewage
treatment
plant
(STP)
Reclaimed
water
Discharged to
aquatic
environment
MINIMISE
Stormwater discharged to
aquatic environment
PROTECT
Figure 1. Integrated water cycle systems approach for water reuse with typical urban
applications 1
Context and outline of this document
Landcom commissioned Ecological Engineering to identify and review available water reuse
technologies. This report evaluates 30 treatment technologies, ranging from natural processes to fully
automated systems that can be remotely controlled and monitored, and assesses the technologies’
suitability to different forms of urban development 2 . The project covers a range of operational scales,
from onsite treatment, clustered development to neighbourhood. Centralised systems are beyond the
scope of this project.
The selection of appropriate, sustainable and suitable water treatment technologies is dependent on
economic, environmental and social considerations, as well as the development scale, water balance,
1
Developed for the City of Melbourne’s WSUD guidelines
2
The primary mechanism of information collection was via media advertising (a combination of print and
electronic) calling for submissions. Advertisements were placed in the Sydney Morning Herald, The Australian
and Australian Water Association (AWA)’s electronic bulletin.
Wastewater reuse in the Urban Environment: selection of technologies
2
space available and surrounding infrastructure. In some cases, competing issues must be evaluated.
A framework has been designed to help land developers, local councils and others to provide a stepby-step guide to select the most appropriate water reuse technologies (see Page 8).
The technologies that are considered are brought together in a Table 7 on Page 38.
Wastewater reuse in the Urban Environment: selection of technologies
3
PART A
REUSED WATER AND ‘FIT-FOR-PURPOSE’
APPLICATIONS
Wastewater reuse in the Urban Environment: selection of technologies
4
1 Reused Water and ‘Fit-for-Purpose’ Applications
Many industry participants, including Landcom, want to increase water reuse in their developments as
part of a general shift towards sustainable land development and water management. But at the
moment, knowledge is limited about reused water and associated technologies.
To help the industry increase knowledge and understanding, this report examines water reuse and
identifies localised and decentralised technologies that are viable for urban developments.
Especially in this context, water reuse raises questions for safe, successful and sustainable
applications including what level of treatment is required to achieve a given application and what is
‘clean’ water? The answers depend on the water’s intended application.
This ‘fit-for-purpose’ concept, in which water of an appropriate quality is matched to its intended use, is
a key part of sustainable water management systems.
1.1
Water end use
As water is used and reused, the quality decreases as does its potential usefulness, and the treatment
required for reuse increases. For urban developments, reused water is suitable for:
a. toilet flushing
b. public open space irrigation
c.
private garden irrigation/outdoor use
d. cold washing machine tap
e. environmental flows
f.
ornamental water bodies integrated into the development.
Some of these uses and applications are subject to approval and guidance from regulatory authorities,
for example, local councils, NSW Health Department and the NSW Department of Environment.
Appendix A briefly explores the roles of these organisations.
1.2
Alternative water sources
Drinking water is currently the primary water source for most urban developments. Potential
alternative water sources include rainwater and stormwater runoff, greywater and blackwater. The fitfor-purpose approach identifies water sources that can be used depending on the required application
and water quality.
Wastewater reuse in the Urban Environment: selection of technologies
5
Table 1. Summary of water quality and treatment requirements for urban water streams
Water
Drinking
water
Rainwater
runoff
Stormwater
runoff
‘Light’
greywater
Source
Reticulated water
distribution
Primarily roof runoff
Catchment runoff
(includes impervious
surfaces such as
roads, pavements, etc)
Shower, bath,
bathroom basins
Greywater
Laundry (basin and
washing machine)
Blackwater
Kitchen and toilet,
industrial wastewater
1.3
Quality
High quality
Treatment required
Minimal – typically chlorination and filtration
Reasonable quality
Low level – typically sedimentation occurs
within a rainwater tank
Treatment to remove litter and reduce
sediment and nutrient loading.
Moderate quality
Cleanest wastewater
– low pathogens and
low organic content
Low quality – high
organic loading and
highly variable
Lowest quality – high
levels of pathogens
and organics
Moderate treatment to reduce pathogens
and organic content
High level due to high organic level and
highly variable quality
Advanced treatment and disinfection
Demand management for water reuse
Demand management is an important measure to reduce water consumption. Typically this applies to
drinking water but it also applies to reused water. Why do we need to conserve reused water? A
frequent misconception is that reused water is an inferior product that is cheaper and in plentiful
supply. In fact, reused water can be a high quality resource and should be considered as such.
To upgrade water quality, treatment is usually required. This process requires energy to remove
pollutants. The reused water may then need to be pumped to the end user. By minimising
consumption of reused water, energy is also minimised, ensuring a more efficient and sustainable
water supply system.
Typical demand management strategies include the installation of water-efficient taps and fittings (e.g.
6/3L dual flush toilets). These are cost-effective and sustainable ways of minimising resource
consumption.
Reused water is a
resource – water
efficient measures are
important
The selection of water
efficient species
gardens reduce water
demand
Reused water can be
used in the washing
machine
Wastewater reuse in the Urban Environment: selection of technologies
6
Mechanical systems such as membrane systems Source:
Memcor
PART B
SELECTION
OF
APPROPRIATE
TREATMENT TECHNOLOGIES
WATER
Natural systems are viable treatment technologies Source: Ecological Engineering
Wastewater reuse in the Urban Environment: selection of technologies
7
2 Selection of Appropriate Water Treatment Technologies
Conventional evaluation of treatment technologies compared technical viability and cost-effectiveness.
But a simple cost-benefit analysis does not adequately assess the breadth of issues for water reuse.
Site characteristics, an integrated water management perspective and ‘externalities’ such as
downstream infrastructure interactions and the impact on the natural environment must be taken into
account.
The identification of water reuse as an alternative water source will occur before the evaluation of
water treatment technologies. Typically a Water Sensitive Urban Design (WSUD) strategy is
formulated to identify structural (eg. water treatment, storage and distribution infrastructure) and nonstructural (eg. policies, pricing, demand management) solutions for the provision of urban water
services within the urban design. An integrated water cycle management strategy will then identify the
opportunities for water reuse following which an evaluation and selection of appropriate water
treatment technologies is undertaken.
The viability and suitability of technologies within an ecologically sustainable framework depend on
criteria including:
•
•
•
•
•
•
•
•
•
•
water end use and demand profile
water quality and quantity
available space for treatment and storage
infrastructure near the site e.g. trunk sewers, proximity to local centralised treatment facility
interaction with the environment e.g. greenhouse gas emissions, land capability, receiving
waterbodies
social considerations e.g. community receptiveness to alternative water sources
economic considerations
climatic conditions
operating and maintenance
ongoing ownership of the treatment system
A structured decision-making process, as outlined in Figure 2 below, can help assess and compare
the suitability of water reuse technologies for a specific site.
Wastewater reuse in the Urban Environment: selection of technologies
8
1. Identify site characteristics and
interactions with the built environment
Refer to page 11
2. Conduct a site water balance
Refer to page 13
3. Identify water reuse
treatment options
Refer to page 17
4. Social and human health
considerations
Refer to page 20
5. Evaluate the impact on
natural environment
Refer to page 23
6. Life cycle costing evaluation
Refer to page 26
7. Evaluation of water reuse options
Refer to page 27
Figure 2. Flow diagram for the evaluation of appropriate water reuse technologies
Step 1. Identify site characteristics and interaction with the built environment
a.
b.
c.
d.
identify development scale, type, location
evaluate current centralised capacity
evaluate potential upgrades to cater for development
investigate offsetting investment in infrastructure upgrades with reuse treatment
opportunities
Step 2. Conduct a water balance
a. align water uses with available water sources (including rainwater, stormwater,
drinking water) on a fit-for-purpose basis
b. assess water demands with an end-use analysis
c. calculate water balance
d. align demand profile with supply profile
Step 3. Identify water reuse options, for example
a. onsite
b. localised treatment
c. dual supply pipeline
Wastewater reuse in the Urban Environment: selection of technologies
9
Step 4. Social and human health considerations
a. adopt a risk-based approach to defining methods of delivery and corresponding water
quality requirements
b. define requirements for pre-commissioning monitoring and demonstration of
compliance to current health standards for reused water
c. identify community receptiveness to different applications of reused water
Step 5. Evaluation of the impact on the natural environment
a. receiving water quality impacts
b. greenhouse gas emissions
c. land suitability
Step 6. Life cycle costing and economic considerations
a. economies of scale
b. capital, operational, replacement and decommissioning costs
Step 7. Select an appropriate technology based on the above six steps, having completed an
analysis of economic, environmental and social considerations in the context of site
characteristics.
Wastewater reuse in the Urban Environment: selection of technologies
10
STEP 1. Identify site characteristics and interaction with the built
environment
To understand the drivers and appropriate end uses for the water, an understanding of the site, the
development and the environment is required.
Development characteristics and location influences viable options for water reuse. The factors
influencing water reuse viability include:
•
•
•
•
•
the size (equivalent tenancy, occupancy)
development density (subdivision, medium density, high rise)
development type (Greenfield, Brownfield, retrofit, infill for residential or commercial)
public open space requiring irrigation
integration with the surrounding environment.
Interactions with the built environment
The drivers for reusing water must have a demonstrable benefit to the natural and built environments.
The benefits to the natural environment are the reduction of wastewater discharge volumes and
contaminants including nutrients to creeks, rivers, bays and oceans.
Sustainable water management solutions must consider the most efficient use of our resources. This
includes our past investment in the built environment, particularly the centralised water services
infrastructure. The community and our cities have made significant investments in the infrastructure for
centralised systems of water supply, wastewater collection, treatment and disposal, and stormwater
management. Here the investment has been predominately in the transportation of water (i.e. the
pipes and pumping reticulation networks). These investments have provided safe, reliable and costeffective water services.
A sustainable approach recognises the value of decentralised and localised water treatment systems.
Local treatment enables water reuse to occur locally to provide appropriate water quality where
required. Combined with centralised management, localised water reuse solutions provide a safe and
reliable water alternative.
The opportunity for water reuse must consider the interaction with the built environment and past
investments. A sustainable approach aims to optimise the community’s past investments with future
requirements to deliver ecologically sustainable solutions. The ideal approach is to transfer investment
from water transportation to the treatment, creating a useful resource.
Currently, much existing infrastructure is aging or is under capacity. Alternative decentralised systems
can augment this older infrastructure to maximise the usefulness of the existing system while ensuring
a sustainable water cycle management strategy. Opportunities for Greenfield and Brownfield sites are
discussed in the following section.
Greenfield sites
Greenfield sites present a broad range of opportunities to include water reuse. The consideration of an
integrated water cycle management strategy early in the design phase ensures all viable options are
taken into account. Development scale will determine the opportunities for water reuse and
infrastructure will be designed accordingly.
Brownfield sites and infill developments
Water reuse within Brownfield sites or infill developments requires a consideration of the surrounding
infrastructure. Typically, the developments will be located next to existing developments. There will be
Wastewater reuse in the Urban Environment: selection of technologies
11
an opportunity to connect to services already provided near the site. The community has already
invested in this infrastructure, with developers expected and required to connect to centralised
systems. The current mechanisms for the recovery of these investments are through developer
service charges and ongoing usage charges.
New developments will increase population density. Each development site will increase the pressure
and capacity of the existing reticulation network – both water supply and wastewater disposal.
Sufficient capacity is required for conveyance of wastewater from the development site to the
centralised treatment facilities. Typically, the surrounding infrastructure will be upgraded to
accommodate this population growth. Upgrades range from a de-bottlenecking of the reticulation
network to an increase in capacity of the entire system (from headworks to disposal). The extent of the
upgrade is crucial for the consideration of water reuse.
Infrastructure upgrades that can be avoided or deferred provide an opportunity for investment in water
reuse in these infill developments. Reusing water reduces demand for drinking water and generation
of wastewater. Wastewater generation from the site is reduced by harvesting, treating and reusing it.
Summary
The development type and size determines the water demand and hence viable operational scale of
the water treatment technology.
Offsetting infrastructure upgrades provides a strong argument for reusing wastewater. The
community’s current large-scale investment is maintained and additional expenditure achieves a more
sustainable outcome.
Wastewater reuse in the Urban Environment: selection of technologies
12
STEP 2. Water balance and demand profile
The water balance provides a starting point to assess the viability of reusing water to complement
other available water sources i.e. drinking water, rainwater harvesting and conventional large scale
water management approaches. The availability of reused water is dependent on a combination of:
•
•
•
•
•
•
the site boundary
operation scale
potential water resource (e.g. sewer carrier)
treatment capacity (average and peak flows)
treatment reliability
onsite storage.
An end-use water approach is utilised for the water balance. An end-use model enables specific water
uses to be matched to appropriate water sources on a fit-for-purpose basis and calculates the water
demand for each use (refer Part A). Relating water demands to specific activities and end uses
provides a greater understanding of the demands on water services. The focus shifts from supplying a
finite amount of water to the provision of appropriate and sustainable urban water services (including
wastewater and stormwater management services). Within this framework, water reuse opportunities
are identified and quantified.
Quantifying water reuse indicates the average water reuse flow rate required and thus the operational
scale. Operational scale provides a first assessment in the selection of viable water reuse
technologies. Commercially available water treatment technologies have a defined operational scale
and these are grouped according to their operating scales as summarised in Table 2 and illustrated in
Figures 3 to 6.
Table 2. Summary of typical applications and corresponding viable operating scales of reused
water treatment technologies
Typical applications
Equivalent
population
Operating
range (kL/d)
Reference
Single household
1-25
0-5
Figure 3
Clustered development
50-500
10-100
Figure 4
Localised or high rise development
500-2500
100-500
Figure 5
Residential subdivision
>2500
>500
Figure 6
An equivalent population (EP) of 200 L/p/d is utilised for these calculations.
Wastewater reuse in the Urban Environment: selection of technologies
13
Ope ra ting R a nge (k L/d)
5
4
Hybrid
MBR
Biological Treatment Fixed Film Processes
3
Greywater
Diversion
Device
2
Hybrid
Fixed Film
& Filtration
Physical
Process
1
0
Ecodesign
Nubian
Perpetual
Water
Clearwater
Aquacell
Biolytix
Rootzone
Novasys
Biosys
Waterpac
Figure 3. Water reuse technologies for single households
100
Operating Range (kL/d)
Physical
Membrane
80
Chemical
Process
Hybrid Processes: Biological & Physical
Biological Treatment Processes
60
40
20
od
N
uS
em
ou
co
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F,
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oo
tz
No
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va
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sy
s
Bi
os
ys
CO
PA
( ID
EA
)
0
Figure 4. Water reuse treatment technologies for 10-100 kL/d (50-500 EP)
Wastewater reuse in the Urban Environment: selection of technologies
14
500
450
Operating Range (kL/d)
400
Physical
Membrane
350
Chemical
Process
300
250
Hybrid Processes: Biological & Physical
200
150
100
Biological Treatment Processes
50
h
W
at
er
Fr
es
AX
IM
CM
F,
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EW
s
s
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Bi
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y
on
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as
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No
v
Ro
ot
z
(ID
EA
)
0
Figure 5. Water reuse technologies for 100 - 500 kL/d (500-2500 EP)
7000
Operating Range (kL/d)
6000
5000
4000
3000
Biological
Treatment
Physical
Processes
Hybrid Processes:
MBR
2000
Chemical
Process
Physical
Membrane
1000
0
COPA (IDEA)
KEWT
Port Marine
Ludowici
Zenon
Zenon Zmod
Aquagenics
COPA
'ReAqua'
NuSource
Memcor WaterFresh
CMF, AXIM
Figure 6. Water reuse technologies for greater than 500 kL/d (>2500 EP)
Demand profile – satisfying peak requirements
The demand profile influences the technology selection. The sizing and selection of water treatment
technologies must cater for peak as well as average demands. For example, water supplied for toilet
flushing has a fairly constant demand throughout the year whereas irrigation requirements fluctuate
with seasonal requirements, peaking in the summer months. Satisfying peak demands requires a
Wastewater reuse in the Urban Environment: selection of technologies
15
technology that can respond rapidly to peak demands or provide adequate storage to buffer against
fluctuating water demands.
Physical treatment systems are particularly well suited to meeting fluctuating demands by being able
to respond quickly.
Biological systems require a greater lag time to respond to changing water demands, and often
require storage volumes to cater for daily and seasonal variations in demands. Storages such as
tanks, dams, ornamental waterbodies, etc provide a buffer. This enables reused water to be
processed at a constant rate despite variable water demand. The storage requirements can be high,
especially to meet seasonal variations in water demands. In some such cases, it may be more
sustainable to provide reused water for a baseload and have this supplemented by other water
sources during periods of high water demands.
Storage requirements must be considered in the evaluation, and sufficient land allocated during the
master-planning phase. Tanks can be incorporated into buildings, underground or within public open
spaces. Often, ornamental waterbodies are considered for onsite storage. The key factors in the
evaluation of waterbodies are:
•
•
•
nutrient loads from reused water
appropriate algal management strategies to prevent algal blooms
draw down of waterbodies impacting on aesthetics. (Typically the highest demand for water
occurs during summer periods when evapotranspiration rates are the greatest, exacerbating
the water body draw down.)
Summary
The site characteristics and water balance provide an initial understanding of how much water is
required and its end use. The water balance and demand profile quantifies the demand for reused
water.
Commercially available water treatment technologies have a defined operational scale. Initial sizing
and capacity requirements can be evaluated by matching the demand profile of the project with
technologies of suitable operational scale.
Wastewater reuse in the Urban Environment: selection of technologies
16
STEP 3. Water reuse scenarios - options analysis
A suite of water reuse scenarios can be developed for the site to quantify the impacts of different
water management decisions. Options to reduce demand for drinking water need to be considered
case-by-case, taking into account the development or redevelopment scale, layout, proximity to
centralised sewage treatment facilities and climate conditions. Each scenario describes the role of
water reuse and how it integrates into the water cycle management strategy. For example, within a
WSUD strategy, water reuse may have been identified as an option for a Greenfield development.
Three broad scenarios might be considered; the first option is a conventional approach with water
efficient fittings (no alternative water sources) (the base case), the second option considers the
inclusion of onsite reuse (greywater reuse) and the third option considers a localised water reuse
scheme for the proposed development. The last two options are investigated in more detail with water
reuse technologies identified to determine the most appropriate reuse scenario. A smaller number of
water reuse technologies appropriate to the operational scale and development type (as identified in
Steps 1. and 2.), will be considered in assessing these options.
In developing a WSUD strategy for a project the role of other urban water streams including drinking
water supply, stormwater, wastewater and dual supply would have been considered prior to arriving at
options involving water reuse. An iterative approach is often necessary in refining the WSUD strategy
and comparisons can be made to conventional approaches to help select appropriate water
management solutions and water reuse technologies. The water reuse technologies selected can then
be compared with alternative water reuse measures including:
•
•
•
rainwater harvesting
stormwater harvesting (including aquifer storage and recovery)
dual supply pipeline.
Indicative scenarios are considered for typical types of developments below.
Greenfield residential subdivision
Greenfield residential developments can cater for a wide range of water management options.
Centralised and localised stormwater harvesting and water reuse schemes are suitable. Localised and
neighbourhood water reuse schemes can also be incorporated. It is essential for all Greenfield sites to
incorporate sufficient land allocation to cater for the desired water services into the master-planning
process. WSUD strategies must be developed for all Greenfield sites to integrate urban design with
the water management.
Currently reusing treated sewage effluent is an efficient way of supplying alternative water on a large
scale. The proximity to and scale of the local sewage treatment plant determines the viability of dualpipe reticulation. Advances in water reuse technology and their commercialisation have reduced real
costs with this trend expected to continue. In the future, as technology advances, the accessibility to
reused water will not be limited by location to sewage treatment plants, rather it will be limited by
infrastructure. Therefore the installation of dual pipe reticulation in Greenfield sites caters for future
access to reused water and should be considered.
Residential urban development/redevelopment
The scale of the redevelopment will determine the suitability of water reuse options. Larger scale
redevelopments will enable localised water reuse schemes such as sewer mining to be incorporated
into the masterplan.
Initiatives in residential development on a smaller scale, either an infill development (knock down and
rebuild) or renovation of an existing building, create opportunities for rainwater harvesting and
greywater reuse on an individual lot scale.
Wastewater reuse in the Urban Environment: selection of technologies
17
Mixed use urban development
Building height, density, landscape area and use will determine the integrated WSUD strategy for
mixed use urban development. Typically an alternative water source on a localised scale is required
for toilet flushing and garden irrigation. The ratio of stormwater roof runoff to the number of residents
will determine the feasibility of rainwater harvesting while the feasibility for greywater reuse will
depend on the mix of residential and commercial uses. Residential developments generally generate
more greywater than can be reuse while commercial developments generally have a high reuse
demand with low greywater generating capacity. With a higher density environment, reclaimed water
from sewer mining may also be a feasible alternative water source.
High rise residential development
A high rise urban development is typical of future residential growth within cities. Residential water
demand is similar to a typical household apart from garden irrigation. Stormwater capture from the
roof is often limited due to the relative small surface area to water demand (i.e. number of people)
ratio. Thus a combination of demand management and reused water (greywater and/or water reuse
from sewer mining) for toilet use and laundry is the preferred approach.
Commercial development
The commercial sector includes offices, schools, business premises and event venues (e.g. sporting
stadiums). Typically in commercial buildings, water use is dominated by toilet flushing. Relatively little
demand exists for drinking water and garden irrigation. Greywater generation is expected to be small
as there is minimal showering in these buildings, so a combination of demand management and
reused water (involving sewer mining) for toilet flushing and landscape irrigation is the preferred
approach. Buildings with large catchments (e.g. roof areas) can harvest rainwater and use this water
for landscape irrigation.
Summary
An options analysis takes into account developments characteristics and sites to help identify viable
water treatment reuse technologies. Comparison between alternative water sources including
stormwater harvesting, connection to dual pipe supply, onsite water use, enables a comprehensive
overview of all options available to ensure the most sustainable solution is attained.
A summary of the development type and indicative reuse option is provide in Table 3 following.
Wastewater reuse in the Urban Environment: selection of technologies
18
Table 3. Summary of development type and indicative water reuse options
Development type
Water reuse options
Greenfield residential subdivision
A broad range of opportunities with site WSUD strategies
identifying water management solutions. Essential to incorporate
WSUD strategy into the master plan.
Installation of dual pipe reticulation infrastructure should be
considered.
Residential urban
development/redevelopment
Opportunities determined by redevelopment scale.
Large scale redevelopments – localised water reuse systems
such as sewer mining.
Small scale systems – rainwater harvesting, greywater reuse
and onsite wastewater reuse.
Mixed use urban development
Residential development can be integrated with commercial
precincts for water reuse.
Building density determines rainwater harvesting feasibility.
Scale determines water reuse options.
High rise residential development
Reused water – sewer mining.
Limited potential for stormwater harvesting.
Commercial development
Reused water – site and industry specific.
Wastewater reuse in the Urban Environment: selection of technologies
19
STEP 4. Human health and social considerations
Reused water is a safe and reliable alternative water source for our community. Reliable treatment is
essential to ensure health risks are minimised. Human risks from the use of reused water are primarily
associated with exposure to pathogenic microorganisms causing illness, in extreme cases leading to
illness and possibly death. Pathogenic organisms can be discharged into waterways by humans
(infected by a disease or a carrier) and are typically in high concentrations in wastewater. Adequate
treatment is required to reduce pathogens with a risk based approach defining the water quality
requirements for end uses. Generally a higher water quality is required as potential human exposure
increases.
Pathogens to be removed from reused water include cryptosporidium (left; source www.who.int) and
giardia (right; source www.med-chem.com)
Guidelines and targets have been specified by regulatory authorities on National and State levels for
water quality, receiving waterbody quality and a range of water reuse applications. Past approaches
have defined targets and limits for the quality of reused water with guidance provided by NSW Health
in Appendix A. This approach has been successful for large scale, centralised treatment systems.
More recently, National guidelines are being revised by Environment Protection and Heritage Council
and the Natural Resource Management Ministerial Council for water reuse options and their potential
risk to human health evaluated using a risk-based approach. This approach is advocated by
Environment Protection and Heritage Council and the Natural Resource Management Ministerial
Council to develop safe, reliable and responsible water reuse treatment technologies. Tools including
quantitative microbial risk assessment (QMRA) can be used to assess the risk to human health by
exposure to pathogens. Pathogenic organisms in waterways can be classified as viruses, bacteria and
parasites (protozoa and helminths). Indicative species are selected for each type of microorganism for
risk assessment, and selected pathogens characterised and quantitatively evaluated.
Social acceptance
The social acceptance of water reuse is an important consideration for urban development. Public
concerns predominately surround (Po et al., 2004):
•
•
•
•
•
•
•
•
perceived health risks
“yuck factor” or disgust of reusing water that once contained waste
specific applications of reused water
source of water to be reused
trust and knowledge
attitudes about the environment
environmental justice issues
cost of reused water
Wastewater reuse in the Urban Environment: selection of technologies
20
•
socio-demographic factors.
Public opinion has a strong influence on the success of water reuse projects. The “yuck” or disgust
factor associated with reused water can sway public perception. Negative public perception can lead
to the demise of water reuse projects. Education and awareness campaigns are essential for the
successful adoption of water reuse projects.
The idea of water reuse is becoming more widely accepted by the Australian community. The current
prolonged drought has increased community awareness of alternative water sources.
In general, people are comfortable with reused water when the end use is not directly ingested. There
is high community acceptance of reused water for most applications including toilet flushing and
outdoor use (garden irrigation and car washing). Community acceptance reduces as and when reused
water comes closer to human contact or ingestion, for example, for use in the laundry for clothes
washing (Po et al., 2004). At present, reused water is generally not accepted for drinking.
Institutional transparency and openness is essential for the successful adoption of water reuse.
Community trust of scientists and engineers to provide expert and reliable information is essential for
successful projects. Education also contributes to a greater understanding of water reuse. The
perceived risks and safety of recycled water can be addressed.
Ownership models
There are numerous models for ownership and management of a water reuse system. The preferred
model will be influenced by operational scale, location, maintenance and operation availability and
community structure. The four main models for localised water treatment systems are:
1. Local regulatory body for example either the Council or water authority
2. Body corporate owns and operates the system
3. Private company owns the systems and the service provision is leased (e.g. BOOT schemes),
or
4. Hybrid models.
Hybrid models encompass the sharing of responsibilities between different parties, for example the
body corporate owns the treatment system and the Council provides an ongoing maintenance support.
In Australia there are only a few models for operating decentralized water treatment systems
including:
•
Owned by a body corporate and maintained a local water authority.
o
•
Owned and operated by a independent body
o
•
the DeLux development (formerly Inkerman Oasis) in Victoria is owned by a body
corporate and maintained by South East Water
Sydney Olympic Park Authority (SOPA) – WRAMS system - Combined stormwater
and sewer mining system owned and operated by SOPA
Owned and operated by a local water authority
o
The Picnic Bay installation on Magnetic Island is maintained and owned by the
Townsville Water Authority.
Wastewater reuse in the Urban Environment: selection of technologies
21
Summary
All human health risks must be minimised by ensuring adequate pathogen removal. Guidelines and
targets have been specified by regulatory authorities on National and State levels for water reuse
applications. Draft national guidelines are available from the Environment Protection and Heritage
Council and the Natural Resource Management Ministerial Council for water reuse options and their
potential risk to human health evaluated using a risk-based approach.
Social considerations are critical for the successful adoption of water reuse schemes and must be
incorporated into the water reuse scheme.
Ownership models are tailored to the individual site and typically involve shared responsibility for the
treatment system.
Wastewater reuse in the Urban Environment: selection of technologies
22
STEP 5. Interactions with the natural environment
Reused water can have several associated environmental risks. These are site-specific and
dependent on the topography, geography and location associated with specific water treatment
technology and water end use. Key risks to the environment are:
•
•
•
•
impact on the aquatic environment
impact on the land primarily from irrigation
production of greenhouse gases
production of biosolids and other wastes.
Impact on aquatic environment
The overriding aims of water reuse are to protect the natural ecosystem of the receiving water body,
conserve drinking water and reduce wastewater discharge. This ensures a more sustainable use of
our water resources.
The reuse of water to increase environmental flows or for ornamental waterways requires case-bycase investigation. The quality of reused water can lead to adverse impacts on receiving waters. The
major concern is the potential increase in nutrient loading. Elevated nitrogen and phosphorus levels
can contribute to algal blooms and degradation of the receiving waterway. Adequate treatment is
required to achieve appropriate water quality. Guidance is provided by environmental guidelines
including:
• Australian and New Zealand Environment and Conservation Council (ANZECC) and
Agriculture and Resource Management Council of Australia and New Zealand (2000) National
Water Quality Management Strategy – Paper No. 4 – Australian and New Zealand Guidelines
for Fresh and Marine Water Quality
• Australian and New Zealand Environment and Conservation Council (ANZECC) and
Agriculture and Resource Management Council of Australia and New Zealand (2000) National
Water Quality Management Strategy – Paper No. 14 – Guidelines for Sewerage Systems –
Use of Reclaimed Water
• Department of Environment and Conservation (NSW) (2004) Environmental guidelines – use
of effluent by irrigation
Elevated nutrients can potentially cause algal blooms in receiving water bodies (left, source
www.dlwc.nsw.gov.au) especially cyanobacteria (blue-green alga right source www.ucmp.berkeley.edu)
Wastewater reuse in the Urban Environment: selection of technologies
23
Impact on the land suitability
Reused water in urban settings provides water for irrigation. Irrigation provides an appropriate use of
reused water and should not be viewed as a disposal mechanism. The suitability of reused water to
specific environmental conditions depends on soil conditions, site topography and geology. The risks
associated with applying reused water for land irrigation (both rural and urban) are:
•
•
•
elevated nutrient levels
elevated salinity levels
excessive sodicity.
Increased salinity from reused water irrigation has the potential to impede plant growth and degrade
soil conditions. Soil sodicity due to the high presence of sodium ions relative to magnesium and
calcium ions can also degrade the soil structure.
Increased nutrient levels will also be present in reused water. The urban environment with an adjusted
botanical landscape (from pre-development conditions) may benefit from the increased nutrient
loading. Proper management is required to ensure minimal nutrients excretion to the groundwater,
thereby protecting the groundwater quality.
A land capability assessment undertaken at the planning phase will be required to assess the
suitability of land for irrigation by reused water. This approach is detailed by the Department of
Environment and Conservation (NSW) in their Environmental Guidelines – Use of Effluent Irrigation
(2003).
Greenhouse gas emissions
The interaction between water use, water treatment, water transportation and energy determines
greenhouse gas emissions. A combination of factors determines greenhouse gas emissions including:
• the type of water treatment and its energy consumption
• organic loading in wastewater
• transportation – energy requirements for reticulation.
The potential generation of greenhouse gas emissions from treating water can be calculated. Each
technology will generate gas from biological processes or energy consumption. Greenhouse gas
emissions can be quantified according to the Australian Greenhouse Office method (Australian
Greenhouse Office, 2004) for each technology option. It is recommended that greenhouse gas
emissions be incorporated into the final evaluation process for water reuse technology selection.
Onsite abatement of greenhouse gas emissions may not always be possible. To mitigate greenhouse
gas emissions, options include offsite abatement or the purchase of CO2 trading credits.
Production of biosolids
Wastewater contains solids, known as biosolids or sludge, that requires disposal. The site boundary
and surrounding infrastructure determine the options for sludge disposal. The solids are wastes and
require disposal through the conventional sewer system or by dedicated sludge processing facilities.
Water reuse aims to extract water from the sewer. Sewer mining applications will dispose sludge and
other waste directly into the sewer for centralised treatment. Minimum flows in the sewer must be
maintained to ensure adequate flow and avoid odour issues.
Localised water treatment systems, away from centralised facilities, must be self-contained.
Consequently, sludge handling and processing will be required.
Wastewater reuse in the Urban Environment: selection of technologies
24
Summary
Selection of water reuse technologies must consider the broader environmental impact. The
interaction between the water reuse technology to the aquatic environment, land capability,
greenhouse gas emissions and solids management is a key part of the decision-making process.
A common application of reused water in urban settings is for open space/garden irrigation. Possible
risks associated with applying reused water for land irrigation include elevated nutrient levels, elevated
salinity levels and excessive sodicity and the suitability of reused water to specific environmental
conditions depends on soil conditions, site topography and geology.
Wastewater reuse in the Urban Environment: selection of technologies
25
STEP 6. Life cycle costing
Life cycle costing is important to assess relative merit of each water reuse technology option. Life
cycle costing enables the consideration of all costs including the capital expenditure, operating costs
and ongoing replacement costs to be considered. The overall cost to the community then provides a
better assessment of the total cost. In the past larger scale centralised options were more efficient and
present a more economical solution, yet the surrounding infrastructure costs increases. As the system
becomes larger and services a wider catchment, more pipes, associated pumps, transfer stations and
additional processes (e.g. chlorine boosting stations) will be required, contributing to a diseconomy of
scale.
Life cycle costing enables the entire costs over a scheme’s life time to be compared for treatment
technologies. It provides an important economic indicator for the selection of water reuse
technologies. The key components to a life cycle costing evaluation are:
•
•
•
•
•
capital expenditure
ongoing maintenance and labour costs
replacement costs and timing for significant expenditure
life span
decommissioning costs.
The life cycle cost is the sum of all discounted costs over the life cycle of the asset. The life cycle cost
is expressed in dollars relevant to the base date (typically now). A typical life cycle cost is over a 50year period. All costs are discounted to the base date using an appropriate discount rate. A ‘real
discount rate’ is used for discounting future costs that are expressed in real terms relative to a base
date.
For each water reuse technology, the indicative costs for a life cycle costing are supplied where
available. The key costs are supplied within the summary sheet for each technology. This provides the
base information for a life cycle cost analysis. As water reuse technologies and their
commercialisation are developing quickly, costs are expected to decrease. It is recommended that for
specific water reuse applications, the technology supplier be contacted to provide a more accurate
estimate within the site constraints.
Summary
A life cycle costing analysis is required for all water reuse options to enable the entire costs over a
scheme’s life time to be compared.
Wastewater reuse in the Urban Environment: selection of technologies
26
STEP 7. Evaluation of water reuse options
The final stage is the evaluation of the water reuse technology and selection of an appropriate
approach.
For simple projects, each criterion must be satisfied. For complex and larger scale projects, a
structured approach for the evaluation options is warranted. Each technology can be ranked with more
complex systems utilising a multi-criteria decision analysis. The application of the step-wise process
ensures key issues are addressed. It is important to recognise that sustainable solutions must be
tailored to an individual site and cater for specific environmental conditions. A simplistic ‘one size fits
all’ cannot cater for the breadth of solutions required to achieve integrated and sustainable water
management objectives.
Summary
Select the appropriate water reuse scenario for the development ensuring that minimum criteria are
satisfied. It is important to recognise that sustainable solutions must be tailored to an individual site
and cater for specific environmental conditions.
Wastewater reuse in the Urban Environment: selection of technologies
27
Source: Veolia Water – BIOSEP MBR
PART C
WATER TREATMENT TECHNOLOGIES
Flat sheet membranes Source: Aquatec-Maxcon
Wastewater reuse in the Urban Environment: selection of technologies
28
3 The water reuse technologies
Increasing demand on water resources and the prolonged drought have combined to drive the market
for water reuse. Numerous commercially viable water treatment technologies are available in Australia
and the market for decentralised and localised water treatment systems is developing.
Water treatment processes are typically a combination of biological, chemical and physical removal
processes. The main processes are:
Physical removal – treatment technologies rely on physical separation processes such as filtration,
sedimentation and flotation to remove pollutants.
Chemical removal – chemicals, typically coagulants and flocculants, are used to increase the
removal rate of pollutants.
Biological removal – biological processes are used to transform pollutants to more manageable
forms for separation.
Landcom called for a Register of Information for interested technology providers through the media 3 .
Thirty responses were received. The water reuse technologies are summarised and classified
according to their key pollutant removal mechanisms in Figure 7. A Hybrid category is included that
describes processes that are primarily a combination of biological and physical processes. The
Hydrosmart technology is classified as “Other” technology.
Note that the classifications below consider the key removal mechanism within the treatment process.
Typically the overall packed treatment system is a combination of processes.
3
The primary mechanism of information collection was via media advertising (a combination of print and
electronic) calling for submissions. Advertisements were placed in the Sydney Morning Herald, The Australian
and Australian Water Association (AWA)’s electronic bulletin.
Wastewater reuse in the Urban Environment: selection of technologies
29
TREATMENT PROCESS TYPES
CHEMICAL
BIOLOGICAL
HYBRID
PHYSICAL
Crystalliser
Suspended
MBR
Adsorption
- WaterFresh
- COPA (ReAqua
- Clearwater Aquacell
- Perpetual Water
HBNR)
- Port Marine
Screening
Fixed Film
- Ludowici Zenon
- COPA – ReAqua
- RootZone (grey)
- Veolia
CAS
- Biolytix
- Aquatec-Maxon: Kutoba
- Baleen
- WaterPac
- Memcor Memjet Xpress
Membrane
- Innoflow
-COPA – ReAqua MBR
- Memcor CMF
- Novasys
Fixed Film / Filtration
- Memcor AXIM
- Biolytix (+UF)
- NuSource Water
OTHER
Other
Hydrosmart
(resonant freq)
Natural
- PES (ISWETS)
- RootZone (wetland)
- Nubian
- KEWT
Figure 7. Broad classification of treatment technologies
Alternative sewer collection and treatment systems encompass small diameter sewer technologies
that minimise wastewater exfiltration are summarised in Figure 8.
ALTERNATIVE
SEWER SYSTEMS
Small Diameter Sewer Technology
- Innoflow (Orenco) : primary separation
- Mono-pumps : maceration pumps
- FLOVAC vacuum sewers
Figure 8. Alternative sewer systems for urban development
The focus here is on water treatment technologies. Additional technologies and systems were also
collated during the technology review and are presented in Appendix C.
A list of all respondents and their contact details are provided in Appendix B (Page 71). Appendix C
(Page 73) summarises the additional treatment technologies and systems not addressed in the report.
3.1
General descriptions
The conventional approach to water treatment processes is based on large-scale centralised water
treatment facilities. Historically, water treatment plants combined “unit operations” to remove selected
Wastewater reuse in the Urban Environment: selection of technologies
30
pollutants. The treatment level ranges from primary to advanced (refer to Table 4). This terminology is
also often used for description of smaller water treatment systems.
Table 4. Levels of wastewater treatment (adapted from Crites and Tchobanoglous, 1998)
Treatment level
Preliminary
Primary
Advanced primary
Secondary
Secondary
with
nutrient removal
Tertiary
Advanced
Description
Removal of wastewater constituents such as rags, sticks, floatables, grit
and grease that may cause maintenance or operational problems
Removal of a portion of the suspended solids and organic matter
Enhanced removal of suspended solids and organic matter – typically by
chemical addition or filtration
Removal of biodegradable organic matter (in solution or suspension) and
suspended solids. Disinfection is also typically included in the definition of
conventional secondary treatment
Removal of biodegradable organics, suspended solids and nutrients
(nitrogen, phosphorus or both)
Removal of residual suspended solids (after secondary treatment) by
granular medium filtration or microscreens. Disinfection is typically part of
tertiary treatment. Nutrient removal is also included in this definition
Removal of dissolved and suspended materials after normal biological
treatment
To obtain water quality suitable for non-potable urban use, tertiary treatment followed by disinfection
or advanced treatment is required.
3.2
Types of technologies
To further explore the broad groups of technologies available for water treatment, representative
technology types are described. These technologies listed below provide an overview of the most
common and applicable treatment systems available and include;
•
biological systems including:
o
suspended growth systems e.g. activated sludge systems and sequencing batch
(SBR)
o
fixed growth systems e.g. trickle filters, rotating biological contactors (RBC) and
recirculating media filters (fixed film bioreactor)
o
natural systems e.g. subsurface flow wetlands
•
sand and media filtration
•
membrane filtration (micro, ultra, nanofiltration and reverse osmosis)
•
membrane bioreactor.
To provide an indication of pollutants removed, an overview of main pollutant removal is presented in
Table 5, with more detailed information provided throughout this chapter.
Wastewater reuse in the Urban Environment: selection of technologies
31
Table 5. Overview of treatment technologies and their pollutant removal abilities 4
Suspended
solids (TSS)
Biodegradable organics
(BOD removal)
Nutrients:
nitrogen
Biological
processes
Yes
Yes
Yes
Limited
No
Limited
Natural systems
Yes
Yes
Yes
Yes
No
Good
Recirculating
media filter
Yes
Yes
Yes
Limited
No
Limited
Media filtration
Yes
Function of size
Limited
Limited
No
Limited
Membrane
filtration
Yes
Function of size
Function
of size
Function of size
Reverse
osmosis
only
Function of
size
Membrane
bioreactor
Yes
Yes
Function
of size
Function of size
No
Function of
size
Subsurface flow
wetland
Yes
Yes
Yes
Yes
No
Good
Disinfection
No
No
No
No
No
Yes
3.3
Nutrients:
5
phosphorus
Salts
Pathogens
6
Biological processes
Biological treatment accelerates natural biological processes and efficiently removes soluble and
some insoluble pollutants in water. Suspended growth systems refer to those where microorganisms
are freely suspended in water. They are primarily designed to oxidise organic and ammonium-nitrogen
(to nitrate nitrogen), decrease suspended solids concentrations and reduce pathogen concentrations.
3.3.1
Activated sludge
Activated sludge is a suspension of microorganisms in water. The microorganisms are activated by air
that provides oxygen and hence the activated sludge process is an aerobic suspended-growth
process. The process usually occurs in two distinct phases and vessels; aeration followed by the
settling. A relatively high proportion of microorganisms are maintained by recycling settled biomass
back into the treatment.
The activated sludge process is typically continuous-flow with aerobic suspended-growth. The process
maintains a high population of microorganisms (biomass). There are two main mechanisms that
remove organics:
1. Biomass oxidises and synthesises the soluble and colloidal organic matter into cell mass and
metabolic materials.
2. Suspended organics are flocculated with biomass and settle.
The suspended biological growth is typically the first stage in the membrane bioreactor process (refer
to Section 3.6).
4
Refer to Crites and Tchobanoglous (1998) Small and decentralised wastewater management systems, McGraw-Hill.
5
Phosphorus removal is dependent on the reactor configuration and the scale of treatment system.
6
Further pathogen removal, such as disinfection may be required to meet DEC (NSW EPA) requirements.
Wastewater reuse in the Urban Environment: selection of technologies
32
3.3.2
Fixed growth
Biological treatment systems are primarily used to remove dissolved and colloidal organic matter from
water. Biological treatment promotes natural processes to break down high nutrient and organic
loading waters. Fixed growth refers to systems where the microorganisms are attached to a surface
that is exposed to the water. Typical fixed film growth systems are trickling filters and rotating
biological contactors.
The rotating biological contactor (RBC) is a modified form of a trickling filter. It uses rotating discs to
support active biofilm growth. This biofilm metabolises and hence removes organic material from the
wastewater.
RBCs are available in ‘package treatment plants’ which allow for ease of installation and operations.
These plants contain a primary sedimentation tank, the biological chamber, a secondary clarifier and a
sludge storage zone. They come packaged in containers with their own electrical device and remote
telemetry systems.
The rotating shaft naturally aerates the biomass. Typically wastewater flows perpendicular to the discs
and flows under gravity and displacement. The RBC has several baffled chambers to ensure a wellmixed reactor. Rotation also causes biomass ‘sloughing’ (excess biomass sliding) from the discs.
Thus to remove the biomass and suspended solids sedimentation, clarification is usually required.
Rotating biological contactor treatment technologies suppliers include:
•
3.3.3
WaterPac system
Natural systems – subsurface flow wetland
Wetlands are a complex collection of water, soils, microbes, plants, organic debris, and invertebrates.
Subsurface wetlands are a proven technology to remove organic matter and suspended solids. In
subsurface flow wetlands, all the flow is through the soil substrata. The soil typically has a high
permeability and contains gravel and coarse sand. The bed is planted out with appropriate vegetation.
As the flow percolates through the wetland, biological oxygen demand (BOD) and total suspended
solids (TSS) are predominately reduced by biological decomposition.
Subsurface wetlands are typically applied in wastewater treatment systems where there is a relatively
consistent influent flow rate. In comparison, surface wetlands used to treat stormwater flows must be
able to cope with variations in flows as a result of rainfall patterns. Subsurface flow wetlands provide a
low cost, very low energy, natural treatment system.
Natural technologies suppliers include:
•
Rootzone
•
Ecological Engineering
3.3.4
Recirculating media filter
Recirculating textile filters (RTF) and recirculating sand filters (RSF) are biological treatment
processes removing organic material from the wastewater. Recirculating textile filters are similar to
trickling filters, however the media used for the growth of biofilms are textiles rather than plastics or
rocks. RTFs are available in small compact footprint package plants, suitable for decentralised
treatment.
The RTF and RSF consist of two major components. The first is the biological chamber and lowpressure distribution system. The wastewater flows between and through the non-woven lightweight
textile material in the RTF and through a bed of sand in the RSF.
Wastewater reuse in the Urban Environment: selection of technologies
33
The second major component is a recirculating tank and pump which pumps typically 80% of the
filtrate back to the chamber. The pump fills the chamber every 20 to 30 minutes. The remaining
effluent can be diverted to a storage tank or discharged.
Recirculating media treatment technologies suppliers include:
•
3.4
Innoflow system (centralised treatment system)
Sand and media filtration
Filtration is a tertiary treatment process that typically occurs after the secondary biological process.
Filtration may be required to remove residual suspended solids and organic matter for more effective
disinfection.
Filters have been used for water treatment for more than 100 years. Sand (or other media) filters
typically treat settled wastewater effluent. For onsite treatment, sand filters are usually lined excavated
structures filled with uniform media over an underdrain system. The wastewater is dosed on top of the
media and percolates through to the underdrain system. Design variations include recirculating sand
filters where the water is collected and recirculated through the filter (refer to Section 3.3.4).
Sand filters are essentially aerobic, fixed film bioreactors. Straining and sedimentation also occur,
removing solids. Chemical adsorption to media surfaces removes dissolved pollutants (e.g.
phosphorus).
Water is applied to the top of the filter and allowed to percolate through the media. With time the
headloss builds up and the filter media has to be cleaned by backwashing. The principal removal
mechanism is by straining where particles larger than the pore space are strained out and smaller
particles are trapped within the filter by chance. The hydraulic flow rate determines the dominant
pollutant removal mechanisms. Pollutants are removed by infiltration. Larger particles are retained
within the filter media by filtration. If organic they will decompose during low-dose periods.
Typically a biofilm forms on upper layers. This layer helps to adsorb colloidal pollutants and
encourages oxidation of the organic material. For effective microbial control, low flow is desired
through the sand filter. This ensures contact between the sand media’s biofilm and water. During low
flow, the interstitial spaces between the sand granules enable oxygen to diffuse to the biofilm and
encourage oxidation of organic material.
Depth filtration is a variation of a sand filter. Depth filtration uses a granular media, typically sand or a
diatomaceous earth, to filter effluent. Typically there are four layers of filter media. The particle size
decreases through the filter’s layers. The coarser top layer removes larger particles and finer material
is removed towards the lower layers, increasing the efficiency of the filter (compared with a
conventional sand filter).
Sand and media filtration technologies suppliers include:
•
3.5
Baleen Filters
Membrane filtration
Membrane (or cross flow membrane) filtration is a physical separation process to filter pollutants using
a semipermeable media. There are four classes: microfiltration has the largest pore size, decreasing
to ultrafiltration, nanofiltration and reverse osmosis. As water is passed through a membrane under
Wastewater reuse in the Urban Environment: selection of technologies
34
pressure, it ‘squeezes’ through the structure. The membrane selectively traps larger pollutants. The
feed stream is effectively split into two effluents: a purified stream and a waste stream.
Table 6. Membrane filtration key features summary
Filtration
Pore size
Operating
pressure
Typical target pollutant
Microfiltration
0.03 to 10
microns
100-400 kPa
Sand, silt, clays, Giardia lambia,
Cryptosporidium
Ultrafiltration
0.002 to 0.1
microns
200-700 kPa
Nanofiltration
About 0.001
microns
600-1000 kPa
As above plus some viruses (not an
absolute barrier)
Some humic substances
Virtually all cysts, bacteria, viruses and
humic materials
Reverse
osmosis
About 4 to 8 Å
300-6000 (or
13,000kPa –
13.8 bar) kPa
Nearly all inorganic contaminants
Radium, natural organic substances,
pesticides, cysts, bacteria and viruses
Salts (desalination)
Membrane filtration processes can remove particles, bacteria, other microorganisms, particulate
matter, natural organic matter and salt (desalination), with removal determined by the membrane’s
pore size. As the pore size decreases smaller pollutants can be removed and pressure requirements
increase. The smaller pore size requires greater pressure and greater energy requirements for
effective treatment. The pressure requirements, pore size and typical pollutant removal are
summarised in Table 6.
3.5.1
Reverse osmosis
Reverse osmosis (RO) is the finest membrane filtration process with the smallest pore size, estimated
to be 4 to 8 Angstroms (about the size of a molecule) and the highest pressure requirements. RO
removes most pollutants including pathogens, viruses and salts. It is typically used for sewer mining or
desalination. It can separate ions (dissolved salt) from water and produces very high quality water. A
very high pressure (determined by the osmotic pressure and ionic concentration) is required. This high
pressure results in high energy requirements. The small pore size can be more readily blocked (or
fouled) and requires regular maintenance. Fouling can be managed by upstream water treatment such
as sedimentation. Reverse osmosis units are particularly effective when used in a series configuration.
RO membranes are typically constructed from cellulose acetate and polyamide polymers. Chlorine
concentration has the potential to damage RO membranes. The cellulose acetate can tolerate chlorine
levels used for microbial control whereas any chlorine present will destroy the polyamide polymers.
Membrane treatment technologies suppliers include:
3.6
•
NuSource
•
Memcor
Membrane bioreactor
A membrane bioreactor (MBR) combines the process of a biological reactor and membrane filtration
(refer to Section 3.5). The treatment process has a small footprint and produces high quality effluent
with low TSS, BOD, and turbidity that meets almost all health criteria guidelines. MBRs are relatively
new processes with a demonstration plant installed at Werribee, west of Melbourne.
Wastewater reuse in the Urban Environment: selection of technologies
35
There are two basic configurations for a MBR: a submerged integrated bioreactor that immerses the
membrane within the activated sludge reactor and a bioreactor with an external membrane unit.
MBRs provide a proven and reliable treatment technology, having been used extensively in Japan for
greywater and blackwater reuse systems. MBRs replace the need for a separate filtration process.
Membranes are costly to replace. Control of membrane fouling is an important operational issue. If
fouling is not controlled, membranes will wear quicker, and there will be increased energy costs and
decreased effluent quality. MBRs also have higher capital cost and energy costs than other treatment
systems.
Membrane bioreactor technology suppliers include:
3.7
•
Clearwater Aquacell
•
Port Marine
•
Ludowici Zenon
•
Veolia Water Systems
•
Aquatec-Maxcon: Kutoba
•
Memcor Memjet Xpress
•
Nubian Systems
Disinfection
Disinfection destroys pathogenic microorganisms in water to ensure public health. Eradication of
waterborne pathogens is the most important public health concern for water treatment.
Disinfection ranges from boiling water to large-scale chemical treatment for water supplies. The three
most common disinfection methods are ultraviolet radiation, chlorination and ozonation.
Ultraviolet (UV) disinfection – uses UV light to deactivate microorganisms in water. The short UV
wavelength irradiates microorganisms. When the UV radiation penetrates the cell of an organism, it
destroys the cell’s genetic material and its ability to reproduce. UV disinfection has low capital and
operating costs, is easy to install and operate and is well suited to small-scale water treatment
processes.
Chlorination – chlorine, a strong oxidant, is the most common water disinfectant. Chlorine can be
added in gaseous form (Cl2), hypochlorous acid or as hypochlorous salt (typically Ca(OCl)2). Chlorine
addition requires chemical handling and storage. Byproducts of chlorination could be carcinogenic,
with particular concern and research to understand trihalomethanes (THMs).
Chlorine provides residual microbial control; that is, it continues to disinfect water after it has passed
through the treatment process. It is typically selected for drinking water supply systems. Optimal
chlorination dosage is dependent on the concentration and water pH and temperature. The pH exerts
a strong influence on the chlorination performance and should be regulated.
Ozonation – ozone is a more powerful oxidising agent than other disinfectants. Ozone is created by
an electrical discharge in a gas containing oxygen, i.e. 3O2 → 2O3
Ozone production depends on oxygen concentration and impurities such as dust and water vapour in
the gas. The breakdown of ozone to oxygen is rapid. It is impossible to maintain free ozone residuals
in water for any significant time.
Wastewater reuse in the Urban Environment: selection of technologies
36
4 Summary of water treatment technologies
This chapter provides a summary of water treatment technologies. The technologies are broadly described to reflect the type of technology as identified in Figures 7 and 8.
Table 7. Summary of water reuse technologies and their key elements (the figures quoted are those supplied by the manufacturer or distributor of each technology)
Water treatment
technology
Treatment technology
Other information
0.5 – 1.1 kL/d
(2-6 EP)
Biological filtration followed by
membrane filtration
Greywater treatment
0.5 – 0.7 kL/d
(2-6 EP)
Physical – sedimentation
followed by adsorption
Modular greywater system
0.5 – 100 kL/d
(2- 500 EP)
Membrane bioreactor
Modular system catering to wide range of
scales.
0.5 – 10 kL/d
(2-50 EP)
Natural - Humus filter situated
at each household
Decentralised treatment
12 – 100 kL/d
(60-500 EP)
Natural - Humus filter coupled
with a modular ultrafiltration
unit
Combines decentralised treatment with reuse
opportunities
1 - 150 kL/d
(5-1000 EP)
Biological – fixed film bioreactor
Additional treatment required for water to be
used for non-potable water
0.5 – 360 kL/d
(2 - 1800 EP)
Subsurface wetland with a
vertical recirculating filter
0.5 – 360 kL/d
(2-1800 EP)
Subsurface flow wetland
followed by a vertical filter
UV disinfection is required to reduce pathogen
2 – 10 kL/d
(20-100 EP)
Biological system – primary
settling followed by
recirculating media filtration
Suitable for smaller communities and cluster
developments with land available
7.5 – 1300 kL/d
(30 -6500 EP)
Primary separation in septic
tank, filtered and then
evapotranspiration
Additional treatment required for water to be
used for non-potable water. Suitable for
developments with land available for irrigation.
(see page 61)
10 – 100 kL/d
(50 - 500 EP)
Onsite primary & biological
treatment with centralised
effluent treatment (recirculating
textile filtrater)
Small diameter sewer minimises exfiltration
protecting the environment. Water reuse can
be achieved by including further disinfection.
Packaged
Environmental
12.5 – 100 kL/d
(50 - 400 EP)
Biological treatment followed by
membrane filtration
Nubian
(see page 53)
Perpetual Water
(see page 56)
Clearwater Aquacell
(see page 47)
Biolytix
(see page 42)
Biolytix (+UF)
(see page 42)
Novasys – BIOSYS
(see page 44)
Rootzone (vertical filter
– greywater wetland)
(see page 41)
Rootzone (horizontal
wetland)
(see page 45)
WaterPac
(see page 43)
KEWT
(see page 46)
Innoflow
Typical scale
7
3
5 + installation
Operating costs
(per year)
Low
1.5
6.5 + installation
$365
1.2 – 124
13 (single house)
100 (500 EP)
$500 (6 EP)
$5500 (500EP)
$10,000 (1000EP)
13 per house
$400
35 – 500
30 for 50 EP
$1,200
2
-
-
2 - 800
5 (single house)
40 (100EP)
4 – 1600
1000 (2000EP)
Restricted irrigation
20 – 200
10 (10-20 EP)
60 (40 EP)
120 (100 EP)
$500 - $2,500
Restricted or
subsurface irrigation
200
30 – 50 (50EP)
-
160 + onsite
intercept
500 (100EP)
includes
reticulation
$400 + periodic
maintenance
60
350
Subsurface irrigation
Restricted irrigation.
Land intensive treatment process
2.4 – 16
$2,000 (100 EP0
Clustered
development
Disinfection required
8
Key :
Wastewater reuse in the Urban Environment: selection of technologies
Capital
expenditure
($’000)
Disinfection required
EP is defined as “equivalent person” as 200 L/p/d. Typical operating range describes indicative operating ranges
suitable for outdoor uses;
Footprint
(m2)
Single
households
7
suitable for toilet flushing;
Water quality
suitable for 8 :
Disinfection required
$25,000 (400EP)
Localised
development
suitable for cold washing machine tap
37
Water treatment
technology
Treatment technology
Other information
Water quality
suitable for 8 :
43 - 1000 kL/d
(300 - 3000 EP)
Disinfection by a high velocity
sonic disintegrator, then
Struvite crystalliser coupled
with filtration
Higher quality water can be attained with
ultrafiltration or reverse osmosis
Restricted or
subsurface irrigation
15 – 300 kL/d
(80 – 1500 EP)
Membrane bioreactor
Disinfection required.
Typical scale
7
Footprint
(m2)
Capital
expenditure
($’000)
Operating costs
(per year)
32
-
-
50 – 180
150 – 1,000
$5,800 (80 EP) $21,000 (1500 EP)
$15,000 - $23,000
(100 kL/d)
$35,000 - $45,000
(300 kL/d)
Solutions (ISWETS)
(see page 54)
Water Fresh
(see page 39)
COPA – ReAqua MBR
(see page 55)
Aquatec-Maxcon –
Kubota
(see page 51)
Port Marine
(see page 48)
Ludowici – Zenon
(see page 49)
Veolia
(see page 50)
Memcor – Memjet
Xpress
(see page 52)
NuSource Water
(see page 60)
COPA (ReAqua
HBNR)
(see page 40)
Memcor CMF, AXIM
(see page 59)
COPA – ReAqua CAS
(see page 57)
Baleen
(see page 58)
100 – 300 kL/d
(500 – 1500 EP)
Membrane bioreactor
Kubota membrane. Disinfection required.
20 - 70
380 – 452
40 – 1600 kL/d
(200-8000 EP)
Membrane bioreactor
UV disinfection is required for non-potable
urban uses.
Small
590
5 – 1000 kL/d
(50-4000 EP)
Membrane bioreactor
Disinfection required.
56-150
50 – 1400
$30,000 (50 kL/d)
$100,000 (200kL/d)
100 – 500 kL/d
(500 – 2500 EP)
Membrane bioreactor
Disinfection required.
200
540 - 1400
$0.55/kL
$20,000 (100 kL/d)
$100,000 (500 kL/d)
100 – 400 kL/d
(500-2000 EP)
Membrane bioreactor
Disinfection required
50 - 100
500 (100 kL/d)
800 (400 kL/d)
$55,000 (100 kL/d)
$82,000 (400 kL/d)
50 – 2000 kL/d
(200-8000 EP)
Membrane filtration
This sewer mining process can respond
quickly to changing water demands, hence
little onsite storage is required to cater for
seasonal demand, for example irrigation.
30
650 (50 kL/d)
1100 (200 kL/d)
$37,000 (50 kL/d)
$84,000 (200 kL/d)
6.2 – 7000 kL/d
(30 – 35000 EP)
Biological process –
intermittently decanted
extended aeration
Disinfection required.
200 (30 EP) –
1000 (2000 EP)
$5,000 (30 EP) $25,000 (2000 EP)
7 - 13
AXIM
250 (40 kL/d)
350 (500 kL/d)
AXIA
450 (500 kL/d)
2600 (3000 kL/d)
AXIM
$8,000 (40 kL/d)
$27,400 (500 kL/d)
AXIA
$22,000 (500 kL/d)
$55,000 (3000 kL/d)
14 for 4500
EP
600
$77,000 (500 kL/d)
$150,000 (1000 kL/d)
3.5 – 9
24
$0.65/100kL
40 – >3000 kL/d
(200->15000 EP)
Membrane filtration
Tertiary treatment processes designed to
upgrade secondary effluent. Additional front
end treatment processes required. Systems
greater than 3000kL/d are custom designed.
500 – 5000 kL/d
(2000-25000 EP)
Fine solids separator (FSS)
followed by biological process.
Further disinfection is required.
The FFS is an excellent solid-liquid separator
for processes such as sewer mining.
9000 – 38000 kL/d
(45000-200000 EP)
Filtration
Additional treatment required to attain nonpotable urban water uses
Wastewater reuse in the Urban Environment: selection of technologies
Further treatment
required
$66,125 for 30 kL/d
Localised
residential
development
e.g. multi-unit
dwellings
Localised
development
Large scale
residential
development
38
4.1
4.1.1
Chemical
WaterFresh – Struvite Crystalliser
Process description: Disinfection with a High Velocity Sonic Disintegrator and Chemical treatment
(with MgO), filtration (zeolite).
Screened sewage is dosed with Cl02 in a mixing tank and introduced to a Cell Detention Unit (CDU)
where it is disinfected with a High Velocity Sonic Disintegrator. It is then dosed with Magnesium,
nutrients are removed by the production of Struvite (MgNH4PO4.6H2O) which forms in the crystallizer.
Oil and grease is also absorbed by the MgO. Zeolite replacement filters remove the Struvite crystals
and remaining MgO. Low pressure in the zeolite filter absorbs any remaining ammonia. Ultrafiltration
or RO can be used depending on water reuse application. The saturated zeolite filter medium can be
used as a soil improver / slow release fertiliser.
Expected performance would meet class A standards, with BOD5 <5mg/L, SS <5 mg/L, E.Coli <
1/500mL and log5 virus reduction. Phosphorus reduction to 0.2mg/L and Nitrogen to 4mg/L.
Operating range: 300 – 3000 EP, (43 kL/d - 1000 kL/d)
Indicative costs: Capital costs and operational costs are not available.
Operational costs are ‘low’.
Maintenance Requirements: Contractors check plants periodically to ensure the performance of the
plant, top up chemicals and remove byproducts. Regular monitoring requirements can carried out on
site by an appropriately trained individual.
Examples include: EPA Licensed, Council Approved (Miriam Vale Shire), WaterFresh plant at 1770
and Agnes Waters communities. A 180 litre per minute (260kL/d) plant has been built at ‘Sunrise’ at
1770, Queensland, Australia.
Footprint: low, ~ 0.1m2/EP.
32m2 for typical 300+ EP system.
Power consumption:
No information provided.
For more information see:
www.waterfresh.com.au
Wastewater reuse in the Urban Environment: selection of technologies
39
4.2
Biological
4.2.1
COPA Water – ReAqua HBNR
Process Description: Biological Nutrient Removal (BNR) process followed by physical multi media
filtration and disinfection. BNR is an intermittent activated sludge treatment system with aeration,
settling and decant in the same reactor. This is followed by multi-media filtration, UV disinfection,
sodium hypochlorite dosing for residual chlorine and sludge storage and thickening.
The expected performance would meet class A standards, with BOD5 < 10 mg/L, SS< 10 mg/L,
turbidity < 2 NTU. Nitrogen reduced to about 10 mg/L, chemical phosphorus removal if required to
<1mg/L. Pathogen removal with UV treatment is required to achieve the desired treatment.
Operating range: Plants can be designed for flows 6.2 – 7,000 kL/d (30 – 35,000 EP)
For EP range 30 - 400, a single tank BNR process is generally used. For 400 – 35,000 EP a hybrid
BNR plant would consist of two tanks for enhanced treatment with an Aerobic-Anoxic Tank and an
Intermittent Aeration Tank.
Indicative Capital costs: Capital costs range from approximately $200,000 (30 to 100 EP) to
$1,000,000 (2000 EP) depending on site specifics and automation requirements.
Indicative Operation & Maintenance costs: Operational Costs are estimated at $5,000 for a 30 EP
plant, and $25,000 for a 2000 EP plant. These costs include operational costs (electricity, etc.) and
operator costs (labour) with typical maintenance requirements of one visit (2-4hrs) per week.
Energy consumption: Typically 10 to 12 c/kL (12c per kWh).
Footprint: The 6.2 kL/d plant approximately 50m2 and the 400 kL/d plant approximately 300m2.
Life Cycle: 25 Years
Examples include:
•
•
•
•
underground plant at Twelve Apostles Visitor Centre (VIC) for 150EP,
Rosewood STP 600kL/d (QLD),
Burrum Heads STP 325 kL/d (QLD) and
Dunsborough STP 2000 kL/d (WA).
For more information about the ReAqua HBNR: www.copawater.com.au
Wastewater reuse in the Urban Environment: selection of technologies
40
4.2.2
RootZone – Greywater Vertical Treatment Unit
Process Description: RootZone’s vertical filter treats greywater through biological processes (biofilm
on media surface) and physical process (filter media) followed by UV disinfection. The unit contains a
filter media which is porous, irregularly shaped for enhanced surface area and increased biological
treatment efficiency. The raw feed is pumped in 200L cycles to the vertical filter bed which is an open
round tank planted with reeds to keep the surface of the media open and prevent clogging or ponding.
Expected performance can meet class A standards, with BOD5 < 10 mg/L, NTU < 2. Nitrogen reduced
to about 50%, phosphorus removal around 75%. Pathogen removal with UV treatment to E Coli<1.
Operating range: Plants can be designed for flows 0.5 - 360 kL/d (2 – 1800 EP).
Indicative costs: Capital costs are approximately $5,000 for a household system and $40,000 (100
EP). Operational costs are estimated at $2,000 for a 100 EP plant (excluding remote data capture and
monitoring costs). The significant operational costs are operation of the UV disinfection unit and
irrigation pumps, maintenance visits and effluent quality monitoring.
Maintenance Requirements: Typical maintenance visits 4 times per year, these involve checking the
UV unit, monitoring equipment, alarms and chlorine dosing.
Energy consumption: Very low; small pumps (5minutes/day when required) and UV system (lamps
20-40W for household, 150-200 W for unit block)
Footprint: 2m2 (household), 8m2 (30 EP system), 800m2 (1800 EP system)
Examples Include: Treatment plants;
800m2 vertical filter in 17 Mile Rocks (QLD) follows a subsurface wetland as the third stage in
treatment for 360 kL/d sewer mining application,
• 8m2 vertical filter for 12 units in Brunswick (VIC): 32 EP, 1500 kL/d application.
• Numerous domestic applications 1-4m2 filter beds in Wingecarribee (NSW)
For more information see: http://www.rootzone.com.au/index.html
•
Wastewater reuse in the Urban Environment: selection of technologies
41
4.2.3
Biolytix with ultrafiltration
Process description: The Biolytix system is a biological fixed growth treatment system, using a living
humus media. Physical separation processes (entrapment and filtering) occur in the soil media.
Further treatment can be achieved with an add on ultrafiltration membrane process train integrated
with the Biolytix filter.
"Biolytix" humus filters are suitable for decentralised wastewater treatment, typically supplying water
for subsurface irrigation. They provide passive aerobic treatment using a robust organic soil
ecosystem (humus) which uses the waste material and filters the water.
Expected performance with BOD5 ~5 mg/L, SS ~5 mg/L from the Biolytix system and BOD5 ~2 mg/L,
SS ~0.55 mg/L after ultrafiltration. Nitrogen reduced to 30-50mg/L (or 5mg/L if required), 20% of the
phosphorus load in the influent would be removed by the Biolytix filter. Further phosphorus removal is
possible. Pathogen removal with ultrafiltration to achieve the desired treatment, chlorination prior to
the membrane is possible.
Operating range: The Biolytix Filter modules are designed to treat 1.6, 3.3, 6.6 and 10 kL/d domestic
sewage. For larger flows networks of Biolytix modules can be linked. The ultrafiltration module is
designed to treat 12 kL/d, but can be designed for 3 - 100kL/d.
Indicative costs: Capital costs for the Biolytix Filter with ultrafiltration range from approximately
$13,000 (household) to $30,000 (10kL/d, ~50 EP) excluding online monitoring requirements.
Operational Costs are estimated at $500/yr (household) to $2,200 (10kL/d plant). Larger systems are
available upon request.
Maintenance Requirements: Standard maintenance visits each year (provided by Biolytix), humus
removal approximately each 4 years, sediment removal every 10 years, replacement of parts for pump
every 6 - 20 years and ultrafiltration membrane replacement every 6 years approximately.
Energy consumption: Very low energy requiring only 0.25 kWh/kL (varies slightly subject to
treatment plant configuration and loading rate).
Footprint: 2.4/5m2 (household), 16/20m2 (10 kL/d system) for standard system/filter with ultrafiltration
respectively.
Examples: Many households, eco-resorts, hotels and five star lodges in New Zealand, Australia and
South Africa. On Macleay Island (QLD), treatment for 20 houses supply irrigation for the nearby golf
course. Two cluster plants linked with some smaller plants treat over 240kL/d plant in South Africa.
For more information see:http://www.biolytix.com/index_html
Wastewater reuse in the Urban Environment: selection of technologies
42
4.2.4
Waterpac – NatureFlow Systems
Process description: The NatureFlow system is a biological treatment system. Primary chambers
are used to settle out solids, like a conventional septic tank. The effluent is further treated in a media
filter and UV disinfection with self cleaning UV lamp (‘spinning turbine cleaner’).
The media filtration is either a sand media filtration or a media filtration – dependent on the site
application.
The treated effluent is disposed by land irrigation typically via subsurface irrigation or through
restricted access irrigation.
Operating range: Plants can be designed for flows from 2 to 10 kL/d (10 – 100 EP)
Indicative costs: Capital costs range from approximately $10,000 (10-20 EP), $60,000 (40 EP) to
$120,000+ (100 EP) depending on site specifics and automation requirements. Operational Costs are
estimated at $500 for a domestic application, and $2,500 for a 100 EP plant.
Maintenance Requirements: Standard maintenance service 4 times per year, replacement of UV
lamps 1/yr, sludge removal 1/5-7yrs, replacement of pump 1/2-3yrs.
The NatureFlow is yet to attain accreditation in NSW.
Energy consumption: low; gravity discharge systems ~ 0.4 kWh/kL, pumped irrigation dispersal
systems ~0.6-0.7 kWh/kL. The system uses only small pumps and UV lamps. This consumption
corresponds to approximately $15/EP/year.
Footprint: 2m2/EP (200m2 for 100 EP). The systems are suited to residential cluster developments
and smaller communities.
Examples include
•
•
•
Roslyn Lodge 100EP, (QLD)
Peppers Hidden Vale Resort 100 EP (25 kL/d), (QLD) and
Karawatha Church 40 EP (QLD).
For more information see: http://www.waterpacaustralia.com/
Wastewater reuse in the Urban Environment: selection of technologies
43
4.2.5
Novasys – BIOSYS
Process description: Biological treatment in a compact bioreactor containing small polymer foam
cube media ‘Variopor’, followed by optional membrane filtration (the membrane filtration is required to
meet Class A).
Wastewater is screened, the fine solids are separated before being fed to the BIOSYS compact
bioreactor. The bioreactor contains carrier material for biological treatment. An optional membrane
system can be installed and is required to meet Class A. Disinfection is required for Class A with either
UV or chlorination.
Expected performance of the bioreactor is for Class B effluent, and with UV or chlorine disinfection
effluent would meet Class A standards.
From the bioreactor BOD5 < 10 mg/L, total N <10mg/L.
Pathogen removal to meet requirements can be achieved with UV or Chlorination.
Operating range: Plants can be designed for flows up to 1 - 150 kL/d (5 – 1000 EP)
Indicative costs: Costs are available from the manufacturer.
Maintenance Requirements: A 100 EP module produces 50L of sludge/week. Typical maintenance
requirement is 1 hour per week. The carrier media has a 6 year warranty, the pumps and blowers
have a 2 year warranty.
Energy consumption: pumps, blowers and UV lamp.
Footprint: very small 0.02m2/EP (1.6 x 1.3m for 100 EP) – excluding fill tanks and blowers.
Examples include: plants using the ‘Variopor’ carrier media;
• Dusseldorf STP 80,000 EP (Germany)
• Aachen STP 87,000 EP (Germany)
• Freising STP 110,000 EP (Germany)
For more information see:
http://www.novasys.com.au/efftreat.htm
http://www.butec-umwelt.de/index-E.html
Wastewater reuse in the Urban Environment: selection of technologies
44
4.2.6
RootZone – All wastewater Horizontal Subsurface Wetland
Process Description: The Rootzone Subsurface Flow Wetland treats all wastewater (black and
greywater) in a biological process (subsurface flow wetland) and physical process (filter media), which
is followed by UV disinfection. Further treatment is provided by the 'Vertical Rootzone Filter' (which is
the same as the unit used for greywater treatment, 2.2.2).
The Horizontal Filter is an adapted subsurface flow constructed wetland. The media has a much
greater specific surface area and adsorption capacity for phosphates and heavy metals, as well as a
high hydraulic capacity. Raw feed enters a two chamber septic tank followed by the 'Horizontal
Rootzone Filter', then a 'Vertical Rootzone Filter' containing a filter media (porous, irregularly shaped
for enhanced surface area and increased biological treatment efficiency), planted with reeds which
keep the surface of the media open and prevent clogging or ponding.
Performance reports BOD5 < 10 mg/L, NTU < 2. Phosphorus and nitrogen reduced by about 75%.
Pathogen removal with UV treatment to E Coli<1.
Operating range: Plants can be designed for flows 0.5 - 360 kL/d (2 – 1800 EP).
requirement is based on BOD load per person per day, rather than a volume of water.
The area
Indicative costs: Capital cost is approximately $1,000,000 (2000 EP). Operational costs are minimal,
with low labour requirements, no chemical costs, minimal power (predominantly the third pipe reuse
pump requirement) and minimal sludge production – septic tank desludge approximately every four
years.
Maintenance Requirements: Typical maintenance requirement is 8hr/yr (4 trips/yr).
The
maintenance visits involve checking UV unit, monitoring equipment, alarms, chlorine dosing if fitted.
Maintenance is minimal (two people could maintain 50 systems of 2000EP). No chemical costs, low
power costs (only a pressure pump for third pipe/irrigation). Desludging the septic tank would be
required approximately every 4 years.
Energy consumption: Very low; small pumps (5 minutes/day when required), UV lamps, third pipe
recycling
pump
requirements.
Footprint: 2m2/EP
Examples include:
•
2500m2 full system
for
unrestricted
public open space
irrigation at 17 Mile
Rocks
•
Numerous domestic
applications in
Wingecarribee
(NSW)
For more information see:
http://www.rootzone.com.au/index.html
Wastewater reuse in the Urban Environment: selection of technologies
45
4.2.7
KEWT – GBG Project Management
Process description: The Effluent and Wastewater Treatment (KEWT) process consists of septic
tank, zeolite filter followed by evapotranspiration beds. Each ‘concrete pot or bed’ contains a
transpiration bed with suitable vegetation (rhizofiltration). The pots ensure no interaction with ground
water and make treated water available for reuse.
Expected performance would require additional treatment to meet Class A standards, with BOD5
<20mg/L, SS <30 mg/L. With additional disinfection, Class A standards could be met.
The technology is suitable for areas where land is available. Examples include golf courses, rural
developments, remote or outer suburban communities with sufficient land area for underground
treatment and disposal (irrigation or reuse).
Operating range: Typically 30EP, with plants designed for 30-6500 EP, (flows 7.5-1300 kL/d)
Indicative costs: Ranging from ~$600 to $2,000/EP depending on the type of installation (e.g. sewer
mining, domestic or commercial) and site constraints.
Maintenance Requirements: A 20 year maintenance plan with associated costs is provided for each
project. The key tasks include solids removal after 5 years, Zeolite removal after 8 years, pruning
twice a year, Soil & Plant replacement after 10/15/20 years and General Pump Servicing. These tasks
would be done by the Local Authority, responsible under the EPA licence for management of the
system.
Energy consumption: The power requirements for the technology are minimal with energy use is
solely for pumps and UV disinfection.
Footprint: 2-4 m2/EP. For example a 50EP requires ~ 200m2: 80m2 for tanks and treatment pots,
100+m2 for irrigation area.
Examples include trials at seven sites throughout Queensland, including industrial sites, camping
grounds, amenities blocks and domestic dwellings. In particular Comet River Hotel, Burpengary Child
care centre, Greenbank State School, Gem Air Caravan Park as well as the 7 test sites throughout
Central Qld.
For more information see:www.gbgprojects.com
Wastewater reuse in the Urban Environment: selection of technologies
46
4.3
4.3.1
Hybrid systems
Clearwater Aquacell
Process description: The AqucaCell is designed to cater for single household to larger scale
applications including multi-unit dwellings. The modular system is a membrane bioreactor – a
combination of physical and biological processes for grey water treatment (‘Aquacell G-series’). Water
is collected in a storage tank, then aerobic digested treatment before ultrafiltration. Nutrient reduction
is achieved with a biological membrane; contaminant removal through physical removal and microbial
induced aerobic degradation. The water can be reused for toilet flushing, car washing, irrigation.
Systems are also available for sewer mining applications (‘Aquacell S-series’ for all wastewater).
Expected performance would meet Class A standards; with BOD <5mg/L, SS <1mg/L, TN <5-15mg/L
if required, Turbidity <1 NTU, 4-6 log pathogen removal and 99.9999% removal viruses.
Operating range: from 0.5 – 100 kL/d (2-500 EP) for residential and 200kL/d (1000EP) for
commercial.
Indicative costs: Capital costs of $500 per person for Commercial (1000EP = $0.5million). $200 per
person for Residential application (500EP = $100k). For a household system the cost is $8.8k plus
installation costs. Plant life expectancy of more than 30 years is expected.
Operational costs $10 per person for Commercial (that is $10k for 1000EP) and $11 per person for
Residential applications (that is $5.5k for 500EP).
Maintenance Requirements: Maintenance is covered by an Essential Service Contract. This service
contract includes a monthly service visit, emergency call out, phone support etc.
Energy consumption: Estimated power consumption ~ 0.8 kWh/kL.
Footprint: small, 1.2 - 124 m2 including storage (0.15 m2/EP, 0.6 m2/kL).
Examples include: Domestic applications in NSW and larger scale applications currently being
commissioned in Victoria.
For more information see: http://www.clearwatertechnology.com.au/cwaquacell.htm
Wastewater reuse in the Urban Environment: selection of technologies
47
4.3.2
TCI Port Marine – ROCHEM Bio-Filt
Process description: The ''ROCHEM Bio-Filt” is a biological (suspended) and physical (membrane)
process, using a patented membrane bioreactor, with ultrafiltration. The biological decomposition of
waste is achieved through microbial growth in mixed liquor, physical removal of contaminants and
microbial induced aerobic degradation. The membranes are not immersed in mixed liquor. UV
disinfection is included for pathogen reduction.
Expected performance would meet Class A standards; with BOD <10-15mg/L, pH 6-8, TSS <15-20
mg/L, TC < 1000MPN/100mL, FC 0. Note typical application performance BOD <30mg/L and TSS <
40mg/L.
Operating range: modules of 40 kL/d.
Indicative costs: Capital costs $590k.
Operational costs $66,125/yr for 30kL/d treatment (including $850 in chemical costs and
transportation, $51,191 for electricity, $ 4224 in operational and maintenance costs, $5400 in
replacement costs, $500 in traveling costs and $4000 in sludge handling).
Maintenance Requirements: Every few months the membranes must be treated with cleaning
agents at defined intervals.
Energy consumption: High energy consumption. Estimated energy consumption 47 kWh/kL, with
operational electricity costs per annum of $51,191 for 30kL/d operation. (assumes $0.1/kWh).
Footprint: small, 13 m2 (0.08 m2/EP, 0.3 m2/kL). The small footprint enables equipment to be located
in an underground carpark.
Examples include: Russian technology, particularly used in marine applications (ocean liners).
Suitable for high-rise developments, both residential and commercial.
For more information see: English page on the Russian manufacturer site:
http://www.rochem.ru/en.php
Wastewater reuse in the Urban Environment: selection of technologies
48
4.3.3
Ludowici Zenon
Process description: Ludowici Environmental is the distributor in Australia for the 'Zenon' membrane
bioreactor between 5 and 1000 kL/d. It is a hybrid process involving both biological (suspended) and
physical (membrane) treatment. Biological treatment occurs in aerobic and anoxic zones; chemical
removal of phosphorus can be added if required. Contaminant removal through physical removal and
microbial induced aerobic degradation.
Expected performance would meet Class A standards; with BOD <10 mg/L, TSS <10 mg/L, TN <
12mg/L.
Operating range: 5 - 1000 kL/d (typically 50- 4,000 EP)
Indicative costs: Capital costs vary with site specifics and requirements, typically $1000/EP. Capital
costs for recent projects range from $50,000 to $1.4 million. Operational costs vary and details are
unavailable.
Maintenance Requirements: The mechanical items (pumps, mixers, blowers) require periodic
maintenance, membranes are maintained through automated cleaning. Membranes would need to be
replaced every 7 - 10 years, at a cost of $30,000 for a 50kL/d plant and $75,000 - $100,000 for a 200
kL/d plant. The average plant has a life of 35-40 years.
Energy consumption: Estimated power consumption and electricity operational costs are not
available. Pumps are required for flow balancing, and recycle streams and mixing for biological
treatment, and additional energy requirements for blowers.
Footprint: small, 56 m2 – 150m2 including storage requirements for plants treating 50-200 kL/d. (~0.2
m2/EP, 0.7-1 m2/kL).
Examples include: Sewage Treatment Plants for resorts (Couran Cove, Iririki Island, Double Island),
Schools (Beechmont, Bodalla, Sheldon), Mining applications (Burton Coal, Coppabella Mine, and
Milmerran Power Station), as well as for McWilliams winery, Hexham Bowling Club and Kurrajong golf
club.
NB – not all of these applications are for Zenon membrane bioreactors.
For contact email details see: www.ludoenviron.com
Wastewater reuse in the Urban Environment: selection of technologies
49
4.3.4
Veolia
Process description: The 'Biosep' immersed membrane bioreactor is a biological (suspended) and
physical (membrane) process. Membranes are placed in direct contact with the biomass during
biological treatment (Mixed Liquor). The raw water requires screening (1-2mm) before it enters the
membrane bioreactor. There is no need for clarifiers and sand filtration and UV disinfection. Biological
decomposition of waste occurs through microbial growth in mixed liquor, and contaminant removal
through physical removal and microbial induced aerobic degradation.
Expected performance would meet Class A standards; with BOD < 5mg/L, Suspended solids are
undetectable, TN 10-15mg/L, TP 0.5 - 2 mg/L. UV disinfection provides TC > 6 log removal, same for
fecal coliforms and Enterococcus.
Operating range: 100-1500 kL/d (500 - 7500 EP)
Indicative costs: Capital costs $540,000 to $1.83M. Operational costs $0.55/kL, that is approximately
$20,000 - $100,000/yr for plants treating 100-500 kL/d. The average life of the structures is greater
than 10 years. Membranes are warranted for about 2 years.
Maintenance Requirements: The system would require 1-2hr/d operational support, and four days
labour each year for general maintenance.
Energy consumption: 1.2 – 1.5 kWh/kL for water produced (includes biological system and the
Biosep system).
Footprint: small, 200 m2 for 500kL/d Biosep process with chlorine dosing (0.4 m2/kL).
Examples include: Veolia Water/Generale des Eaux operate ~15 wastewater treatment plants using
membrane bioreactors – predominantly in France. Veolia Water System as and Anjou Recherche
R&D have been involved in the design and construction of more than 30 MBR plants since 1991.
There are 22 Biosep plants operating worldwide.
Process schematic of Veolia’s membrane bioreactor
For more information see: www.veoliawater.com.au
Wastewater reuse in the Urban Environment: selection of technologies
50
4.3.5
Aquatec-Maxcon: Kutoba
Process description: The Kubota Submerged Membrane Bioreactor (MBR) uses a flat sheet
submerged membrane unit. Typical installations include a balance/storage tank, fine screen, grit
removal, anoxic tank, if required alum is added for phosphorus precipitation, aeration and MBR. This
is followed by UV disinfection and/or sodium hypochlorite dosing to provide chlorine residual.
Expected performance would meet Class A standards; with BOD 10 mg/L (typically 10 – 20mg/L),
Suspended solids <2 mg/L, Turbidity <2 NTU, TN 15mg/L, Ammonia 0.5 – 2mg/L, TP 1 – 5mg/L. UV
disinfection is included to provide an additional barrier to pathogens.
Operating range: Package plants are available from 30-300 kL/d (EP 150+), typical plant size 100300 kL/day (500-1500 EP). Above 300kL/d plants can be custom designed and built.
Indicative costs: Capital costs range from $380,000 to $452,000 (excluding GST) for plants treating
100-300 kL/day, with plant life expectancy of 20 years.
Operational costs for a 100kL/d plant are $15,000/yr in the first 4 years, $23,000 after the first four
years; for a 200kL/d plant $25,000/yr then $35,000 after the first four years; and for a 300kL/d plant
$35,000/yr then $45,000 after the first four years. These costs include the whole of plant maintenance
inclusive of pumps and electrical maintenance, labour (10 hours per week), and alkalinity dosing of
approximately $8000 per year. After 4 years the costs of mechanical/electrical equipment replacement
requirements increase due to general wear and tear. These costs do not included sludge and
screenings disposal and membrane module replacement (typically replaced after 10 to 12 years of
operation).
Maintenance Requirements: The system requires in situ membrane cleaning every 6 months and
normal maintenance of typically 10 hours per week. Membranes are expected to have a lifetime of 10
to 12 years with a 0.5% membrane replacement.
Energy consumption: Estimated energy consumption is 1.25 kWh/kL, including inlet pumping
station, anoxic recycle, mixers, odour control and UV disinfection. Pumps are required for flow
balancing, and recycle streams and mixing for
biological treatment.
Footprint: small, 20 - 70 m2 for 100 - 300kL/d
plants (0.2m2/kL), excluding area for balance tank
storage requirements.
Examples include: Tirau, Turangi and Te Aroha in
New Zealand (2005). A 2000 EP plant at Picnic
Bay, Magnetic Island, and a 20 000 EP plant at
Victor Harbour, SA.
For more information see:
http://www.aquatecmaxcon.com.au/
Wastewater reuse in the Urban Environment: selection of technologies
51
4.3.6
Memcor MBR, Memjet Xpress
Process description: The package membrane bioreactor is a biological treatment with integrated
membrane filtration. Aerobic and anoxic treatment uses an activated sludge plus coagulant addition
for P removal.
Expected performance would meet class A standards; BOD < 5mg/L, SS <2 mg/L, 0.2 NTU, E.coli <1
org/100mL, total coliforms <10 org/100mL and up to 3 log reduction of viruses. Phosphorus reduction
to <1mg/L.
Operating range: from 100 – 400 kL/d (typically 500 – 2,000 EP)
Indicative costs: Capital costs range from $500,000 for 100 kL/d plant to $800,000 for 400 kL/d
system. The plant life expectancy is 20 years.
Operational costs include power, chemicals, membrane replacement and maintenance. The power
costs are between $0.21/kL - $0.80/kL for MBR Xpress (100 – 400 kL/d). The total operational cost is
between $500/MLD and $1500/MLD, ($150 - $225/day, $55,000 – $82,000/year).
Maintenance Requirements: The maintenance costs are included in the operational cost. The
membranes are guaranteed for 3 years and are expected to have a life of 5 years.
Energy consumption: Estimated power costs range from $0.21/kL - $0.80/kL for MBR Xpress (100 –
400 kL/d). The average power requirements range from 15 – 30 kW, correlating to 1.8 – 3.6 kWh/kL.
Footprint: small, ~ 50 - 100 m2 for MBR Xpress (100 – 400 kL/d), 0.25-0.5m2/kL.
Examples include: Numerous locations world wide including North Head STP (Sydney) providing
water for process cleaning operations., Bao Steel China, Cebu Philippines, Southern Cross and Urban
Workshop Buildings, Melbourne.
For more information see:
http://www.usfilter.com/water/Business+Centers/Memcor_Products/Memcor_Products/axim_cmf_L_pr
oduct.htm
Wastewater reuse in the Urban Environment: selection of technologies
52
4.3.7
Nubian
Process description: The Nubian Domestic Greywater Treatment System (DGTS) is a hybrid
treatment system involving biological and physical treatment processes. The system comprises a
balance tank, treatment column, and treated water storage tank. Screens remove lint and coarse
material before it flows into the balance tank. The water is pumped to the treatment column where it
flows down through a vertical treatment column with a non-static bed of proprietary media. Pathogen
removal is achieved with UV disinfection.
Treated water quality meets Class A standards. Further treatment is available with the addition of
optional membrane filtration.
Operating range: The modular nature of the system allows it to treat water from a single and multi
dwelling residences. Operating flowrate for one module is 100 – 1200 L/day with the capacity to treat a
maximum flow of 2000 L/day. Addition of each module provides a further 1200 L/day capacity
(approximately 2-6 EP).
Indicative costs: Capital costs are approximately $6,000 plus site specific installation and reuse
requirements. Monthly monitoring and maintenance cost are $45 which includes annual replace of the
treatment cartridge, automatic water quality monitoring and bi-annual inspections.
Maintenance Requirements: Domestic applications require biannual maintenance (as per NSW
Health Guidelines for remotely monitored systems). Industrial and commercial applications would
require more frequent maintenance. Telemetry is used for immediate response to system failure.
Energy consumption: The treatment system is modular in design. Addition of further components for
higher flow ranges (eg multi dwelling applications) reduces power consumption per kL (4.55 kWhr/kL
for single dwelling applications).
Footprint: Single module household systems 2305 mm (width) X 450 mm (depth). Storage tanks can
be situated above or below ground to minimise overall footprint of the facility. The treatment cabinet is
1005 mm (width) X 450 mm (depth). The treatment facility can be specially designed for multi dwelling
applications requiring < 0.4 m2/kL.
Examples include: The system is currently under accreditation (6 month process beginning
September 2005) with the NSW Health Department for single and multi dwellings.
For more information see: http://www.nubian.com.au/
Wastewater reuse in the Urban Environment: selection of technologies
53
4.3.8
Packaged Environmental Solutions (ISWETS)
Process description: The ISWETS (Integrated Sensitive Waters Effluent Treatment System) is a
combination of treatment processes, presented by Packaged Environmental Solutions (PES) for
producing Class A water. The biological treatment is with the Kelair-Blivet™ stand-alone packaged
STP (sewage treatment plant) comprising primary settlement, aerobic zone, final settlement (humus
tank) and sludge storage. This is followed by microfiltration, and thermal disinfection with an energy
efficient ‘Fluid Disinfection System’ (FDS).
Expected performance: BOD5 <10 mg/L, SS <15 mg/L, 5 NTU. Nitrogen reduced to 10-12mg/L,
phosphorus removal to <1mg/L. Pathogen removal with ultrafiltration to achieve the desired
treatment, chlorination prior to the membrane is possible.
Operating range: Plants can be designed for flows 12.5 – 100 kL/d (50 – 400 EP)
Indicative costs: Capital costs are approximately $350,000 for 400 EP plant.
Operational Costs are estimated at $25,000/yr for 400 EP plant.
Maintenance Requirements: The system would require maintenance equivalent to 54 hours each
year: 30 minutes weekly, 1hour each month, 3 hours quarterly and 4 hrs annually.
Energy consumption: Low power usage for Blivet STP (roughly $1 per day with max 0.75kW Pump
and motor; ~0.1 – 0.7 kWh/kL). Small, quiet compressor for the microfiltration unit. FDS can run on
gas or electricity or waste heat: only 2% heat loss so extremely efficient.
Footprint: 60m2, (0.6m2/kL, 0.15m2/EP).
This includes 3 x 22kL tanks ~7m2 (sewage surge, aerated zone, anoxic), Kelair Blivet 11-25m2, 10kL
recycle tank and microfiltration, FDS, low dosage residual Chlorine dosing and irrigation storage tank.
Examples include: Aanuka Island Resort, Fiji will be using the Fluid Disinfection System for one of
their resorts.
For more information see: www.pescorporation.com
Wastewater reuse in the Urban Environment: selection of technologies
54
4.3.9
COPA Water – ReAqua MBR
Process Description: Biological membrane process followed by UV disinfection. The Clereflo MBR
range is available as a below ground or above ground membrane bioreactor process that incorporates
the Kubota flat sheet membranes into compartmentalised tanks.
The plant consists of a number of stages:
• A balance tank to ensure equalised flow and load is passed into the next stages
• An Anoxic reactor
• A baffled primary settlement tank or a primary screen for the removal of gross solids
• A membrane bioreactor zone
• A permeate holding tank
The performance would meet class A standards, with BOD5 < 10 mg/L, SS< 5 mg/L, turbidity <2 NTU.
Operating range: Standard plants sizes cater for flows from 15 to 300 kL/d (75 – 1500 EP) and
customized plant for flows in excess of 300 kL/d.
Indicative Capital costs: Capital costs range from approximately $150,000 for the smallest plant
increasing to approximately $1.0m for the 300 kL/d plant depending on site specifics and automation
requirements.
Indicative Operation & Maintenance costs: Costs are estimated at $5,800 for an 80 EP plant, and
$21,000 for a 1500 EP plant. These costs include includes operational costs (electricity etc.) and
operator costs (Labour) with typical maintenance requirements of one visit per week (2hrs) with an
additional scheduled maintenance requirement of 4 full day visits per annum.
Energy consumption: Typically 14 to 16 c/kL (12c per kWh).
Footprint: The 15 kL/d plant is approximately 50m2 and the 300 kL/d plant is approximately 180m2.
Life Cycle: 25 Years
Examples include:
• 60+ MBR installation in the UK and Europe
• New Farm Park Sewer mining, Brisbane Water (Qld)
For more information about the ReAqua MBR: www.copawater.com.au
Wastewater reuse in the Urban Environment: selection of technologies
55
4.4
4.4.1
Physical
Perpetual Water – Perpetual Water - Home™ Grey Water Purification System
Process description: Perpetual Water’s system is modular system designed to treat greywater from
a typical domestic residence. The first stage in the process is a physical (sedimentation) followed by
an electrostatic attraction (Active Adsorption Filtration). The fully automated system processes up to
720 litres of grey water per day.
Grey water is collected in an underground sump where coarse hair and lint is removed by a filter. The
water is transferred to a settling tank, operating in a batch process each evening to allow 7hrs settling.
The solids are discharged to the sewer, the supernatant pumped to the filter bank. The filter is an
‘Active Adsorption’ process which targets dissolved contaminants, viruses and bacteria. Treated water
is stored in a rainwater tank.
Expected performance would meet class A standards, with BOD5 <2mg/L, SS <2 mg/L and E.Coli 0
cfu/L.
Operating range: 2 – 6 EP (0 – 0.72 kL/d)
Indicative costs: $5,900 plus installation and clean water storage tank. Operational costs are
approximately $335/yr (including electricity costs and one annual maintenance visit valued at $300 (ex
GST)). Plant life expectancy is ~15 years.
Maintenance Requirements: The system is a completely automated self cleaning unit. Annual
maintenance will be required, to be provided by an accredited maintenance contractor.
Energy consumption: Electricity is 365 kWh/yr, 1.3 kWh/kL. The system employs three pumps for
water transfer and reuse and some additional minor electrical components however these typically
operate either on demand or for limited periods. As a result, electricity consumption is minimal.
Footprint: ~ 0.2-1 m2/EP.
1-2 m2 for the typical household system.
Examples include: Household models are operating in the ACT.
For more information see: www.perpetualwater.com.au
Wastewater reuse in the Urban Environment: selection of technologies
56
4.4.2
COPA Water – ReAqua CAS
Process description: The ReAqua Chemically Assisted Separation process is a physical separation
process (coagulation addition for fine solids separation) followed by a biological process (typically
either a submerged aerated filter or hybrid BNR). Further polishing is attained through a sand filter.
The water is disinfected by UV and chlorinated.
Target applications are the clean-up of sewer overflows, peak load reduction in sewerage and the
extraction of water from sewers for reuse purposes.
The performance of the complete ReAqua CAS process would meet class A standards, with BOD5
<10 mg/L, SS <5 mg/L, turbidity <2 NTU.
Operating range: Plants can be designed for flows up to 5 ML/d (20000 EP)
Indicative Capital costs: Capital costs range from approximately $750,000 for a 500 kL/d plant
increasing to $1.5m for a 2000 kL/d plant and is inclusive of the FSS, biological, sand filtration and UV
disinfection.
Indicative Operation & Maintenance costs: Operational Costs (for power and chemicals only) are
estimated at 35 to 45 c/kL. Labour costs are additional and are similar for all plant sizes. Typical
requirements are 2 to 3 visits (3-6 hrs) per week which, would include, routine monitoring and the
topping up of the chemicals used in the process - alum and polymer. There should also be
approximately two full days of shutdown inspection and maintenance checks per year.
Energy consumption: Typically 6 to 8 c/kL (12c per kWh).. Energy use is predominantly for pumps,
blowers and UV disinfection.
Footprint: The 500 kL/d plant is approximately 150m2 and the 2000 kL/d plant is approximately
500m2.
Life Cycle: 25 Years
Examples include:
•
•
•
•
•
Mornington STP, South East Water (Vic)
Ocean Grove peak load reduction, Barwon Water (Vic)
Brushy Creek, Yarra
Valley Water (Vic)
Cranbourne
STP,
South East Water
(Vic)
Kogarah Golf Course
sewer mining, (NSW)
For more information about
the
ReAqua
CAS:
www.copawater.com.au
Wastewater reuse in the Urban Environment: selection of technologies
57
4.4.3
Baleen Filters
Process description: Physical (Screening) and chemical addition if required. Initially a coarse
screening to 250 μm with a double spray system (one high pressure and one low volume) to keep the
filter zone clear which is followed by a micron screening to less than 100 μm (sub 5 μm possible with
chemical assistance). Removal inline to 25 μm, effective removal of colloidal substances to less than 5
μm when coupled with chemically assisted filtration (CAF) techniques (such as flocculation and
precipitation) to substantially reduce turbidity, nutrient and pathogen levels.
Expected performance would not meet Class A standards without additional associated secondary
treatments and pathogen control. Suspended solids removal is very effective ( to 25 μm without
chemical assistance, and as low as 3 μm with chemical assistance). BOD associated with TSS will be
removed. Disinfection is also required.
Operating range: 9 – 38+ ML/d.
Indicative
costs:
Capital
cost
from
$24,000
plus
disinfection
costs.
Operational costs include electricity for an air compressor and water pump as well as chemical costs.
These costs are highly dependent on usage rates / throughput, typically less than $0.65 per 100kL of
filtered water.
Maintenance Requirements: The system would require daily inspection and cleaning (using
automated spray), weekly wash and clean with a high pressure spray hose, monthly inspection,
cleaning and maintenance for pumps, air cylinders and suction filters.
Energy consumption: Each Baleen filter uses approximately 5 cfm of compressed air at 5 to 7 bar,
and each filter uses an electric motor for the water pump at around 2kW/hr. The peak utility
requirements for the filter are mains and/or recycled water, compressed air 5 cfm at 6 bar and power
to 3.0 kWh per unit.
Footprint: very small, 3.5-9 m2 for systems 9 – 38 ML/d.
Examples include: This self-cleaning filter, originally patented by the University of South Australia
has been critically tested by industry and is now distributed from South Australia and Queensland for
waste treatment in various industries including food processing and packing, the wine industry, and
animal waste treatment.
For more information see: http://www.baleenfilters.com/product.asp
Wastewater reuse in the Urban Environment: selection of technologies
58
4.4.4
Memcor AXIM and AXIA CMF-S
Process description: The Memcor systems are tertiary membrane filtration of secondary wastewater.
Primary and secondary treatment must be provided by other processes. Suitable for influent with SS
up to 150 mg/L (typically clarified secondary effluent).
Expected performance would meet Class A standards with appropriate pretreatment; BOD < 2mg/L,
SS <0.5 mg/L, 0.2 NTU, E.coli <1 org/100mL, 4 log pathogen removal and up to 3 log reduction of
viruses. Phosphorus reduction to < 1mg/L.
Various systems for particular operating ranges: either AXIM Memcor CMF-L System (40 – 500 kL/d)
or the AXIA Memcor CMF-S System (submerged membrane system) (500 – 3000 kL/d), or the.
Operating range: from 40 – 3000 kL/d (200 – 15000 EP) (>3000 kL/d are custom designed systems)
Indicative costs: Capital costs for:
• AXIM Memcor CMF-L System $0.25 - $0.35 million (for plants ranging from 40 - 500 kL/d).
• AXIA Memcor CMF-S System $0.45 - $2.6 million (for plants ranging from 500 – 3000 kL/d).
Operational costs for;
• AXIM Memcor CMF-L System, $8,000 (40 kL/d) to $27,400 (500 kL/d).
• AXIA Memcor CMF-S System, $22,000 (500 kL/d) to $55,000 (3000 kL/d).
Maintenance Requirements: The maintenance requirements are reflected in the operating costs.
Examples include: Greater than a thousand locations world wide both for potable water and
wastewater treatment: Bendigo (Vic), USA, Jordan and UK.
Footprint: small, typically 7-13 m2 for 100 – 3000 kL/d plants.
Energy consumption:
• AXIM – 350 to 120 kWhr/ML treated water (40 to 500 kL/d)
• AXIA – 120 to 80 kWhr/ML treated water (500 – 3000 kL/d)
For more information see: www.usfilter.com./en/Product+LInes/Memcor_Products
Wastewater reuse in the Urban Environment: selection of technologies
59
4.4.5
NuSource Water
Process description: Physical process, membrane filtration. Membrane Water Reuse (MWR) is a
sewer mining process where waste water passes via an engineered filtration system to separate water
from solid waste. Class A water is produced for re-use and solids are returned to the sewer. Three
stage filtration: 200 m pre-screen, dual membrane microfiltration / ultrafiltration and reverse osmosis.
Expected performance would meet class A standards; BOD <2mg/L, SS 0mg/L: TDS 12mg/L, TKN 5.5
mg/L, TP 0.03 mg/L, FC<0.1cfu/100mL. RO to greater than 6 log removal of pathogens.
Operating range: from 200 - 8 000 EP, 50 – 2000 kL/d.
Indicative costs: Capital costs range from $0.65M (50kL/d), $0.8M (100kL/d), $1.1M (200kL/d) with
plant life expectancy of ~20 years.
Operational costs include power, chemicals, membrane replacement and maintenance. The
operational costs are between $2.20/kL - $1.00/kL for plants 50 – 2,000 kL/d which equates to
$40,150– $73,000/year respectively.
Maintenance Requirements: The system requires maintenance visits 2-4 times each year. These
are done by a fleet of service teams from NuSource Water with a long term client service contract.
Energy consumption: Estimated electricity costs range from $0.30/kL (200 kL/d) to $0.60/kL for 50
kL/d plant. Energy requirements range from ~3 – 6 kWh/kL.
Footprint: small, ~ 30 m2 (0.01 m2/EP, 0.3 m2/kL).
Examples include: Wastewater treatment and recycling for flushing and cooling systems in the CH2
office building in Little Collins Street, Melbourne, to realise 80% reduction in potable water use.
Flemington Racecourse, Melbourne (VIC), uses a 50kL/d MWR plant for irrigation.
Suitable for any project with a sewer in the vicinity, from commercial and municipal developments,
schools and institutions to hotels, process plants and golf courses. Class A water suitable for irrigation,
industry, cleansing and waste disposal.
For more information see: http://www.syfon.com/nusource/how.asp
Wastewater reuse in the Urban Environment: selection of technologies
60
4.5
Alternative sewer technologies
4.5.1
Innoflow - Interceptor Tank , Orenco Sewer and AdvanTex Treatment Pods
Process description: Physical Separation and anaerobic decomposition in household Interceptor
Tank "Biotube" effluent filter which provides primary pre-treatment. Transport in small diameter
Orenco Effluent Sewer to centralized treatment with AdvanTex Treatment Pods (recirculating textile
packed bed reactor process) and final UV disinfection.
Sewage flows to an interceptor tank in each dwelling for
primary pre-treatment. The pretreatment Biotube effluent
filter reduces TSS to 30pppm with typical tank size of
4.5m3 per dwelling. Solids and scum are intercepted with
the remaining flow pumped or gravity fed to the treatment
plant through a water tight small diameter 'Orenco' sewer.
Flows are either gravity fed or pumped from the tank to
the treatment plant.
Expected performance with BOD5 < 10 mg/L, TSS< 10 mg/L. Nitrogen reduced by typically 70%.
Phosphorus removal would require additional treatment. Pathogen removal with UV treatment to <
100 cfu/100mL.
Operating range: Systems are available for individual lots to small townships (0.8 – 100kL/d);
typically applications are for flows 30 – 60 kL/d (120 – 250 EP)
Indicative costs: Capital costs for 100EP, 45 houses: ~$500,000. (Treatment plant ~ $170k, House
interceptor tanks ~ $200k, chlorination ~ $40k, land irrigation applications $50k, Orenco sewer $27k
depending on site specifics and automation requirements).
Capital costs per lot 10 – 12k, house interceptor tanks $4,500 - $7,500.
Operational Costs are estimated at $400 for electricity (UV and pumps) + cost for annual servicing and
maintenance.
Maintenance Requirements: The system is well automated: annual servicing is required for domestic
AdvanTex treatment plants, quarterly servicing for commercial / township systems.
Energy consumption: 0.2-0.4 kW/d for each STEP interceptor tank, 40 kWh/lot/yr for electrical
consumption at the treatment plant and 35-40 kWh/lot/yr for UV.
Some examples include:
•
•
•
Solan Estate Subdivision – Rodney District (NZ); 23kL/d
Furneax Lodge – Malborough Sounds (NZ) ~10kL/d
Golden Valley Subdivision Kuaotuna Coromandel (NZ); 22kL/d
Footprint: 1.6m2/EP, 160m2 for 100EP.
For more information see: http://www.innoflow.co.nz/
Wastewater reuse in the Urban Environment: selection of technologies
61
4.5.2
Mono-Pumps - small diameter sewer
Process description: Macerating pump units are used to facilitate use of Pressure Sewer Systems
using small bore pipes that follow the natural ground contour at shallow depths as opposed to large
bore gravity sewers that must often be laid at considerable depth for grade. Pipework material is
usually polyethylene (PE) or UPVC pressure pipe with welded or solvent welded joints. Pressure
Sewer Systems are particularly suited for sewerage in:
•
Mountainous or hilly land
•
Flat land
•
Clay or rocky soil or areas of shallow top soil
•
Environmentally sensitive areas
•
Built up areas
•
Areas of low population density
•
Areas with high ground water tables
The system Components include a pump unit, collection
well, sensor control system, and a small bore rising main
network of poly pipe laid in shallow trenches. The Pump
Unit
–
Mono
G60
Grifter
–
a
positive
displacement/macerating pump system that reduces raw
domestic sewage to a finely ground watery slurry.
Flow = 0.85 L/s TDH = 60m.
The collection well is a HDPE tank 1-1.5kL holding the raw sewage in a wetwell and the pump unit (in
dry well). The high pressure capabilities of the G60 pump unit enables pumping over distances of up
to several kilometres.
Operating range: The systems can be employed on residential, commercial and public authority
applications. Generally, when employed on residential applications there is one system per residence.
However, multiple connections can be made depending on incoming flow loadings.
Indicative costs: Capital Cost for 1000 L system is $4,000.00 + GST and for the 1500 L system is
$4,400.00 + GST. Operational cost is $12 per annum (approx) and maintenance cost is $21 per
annum (parts/labour averaged over 20 year period).
Maintenance Requirements: Maintenance requirements are minimal. General maintenance relates
more to cleaning activities (tank, level sensors). The main wearing components are the rotor and
stator (both located within the pump unit). Wear rates are mainly dependent on the grit content of the
sewage, however, if this is minimal then component life in the order of 7-10 years can be expected.
The life cycle of the system is 20-25 years.
For more information see: http://www.mono-pumps.com/mono/home.nsf/p/home_au
Wastewater reuse in the Urban Environment: selection of technologies
62
4.5.3
FLOVAC – Vacuum sewer system
Process description: The FLOVAC system is a vacuum sewer system. Each household drains to a
small sump by gravity. When 40L has accumulated, the valve automatically opens and the differential
air pressures forces the blackwater through the sewer system. The valve is pneumatically controlled
and operated.
A centralised pumping station collects the blackwater for transfer to a treatment plant or a gravity
sewer main. Treatment is required for the blackwater collected.
Vacuum sewers enable steep terrain and areas in sensitive environmental areas to be developed. The
small diameter sewers (typically ranging from 125-250 mm diameter) require only shallow and small
trenches and so are suitable for steep terrain and protect the environment by minimising infiltration
and exfiltration.
Operating range: Systems available range from small communities to residential subdivisions.
Indicative costs: 1000 lots: $1,500 to $2,000 per lot; 500 lots: $4,500 to $5,000 per lot; 100 lots:
$9,000 to $10,000 per lot. Each system requires a centralised vacuum pump station for $400,000 (this
is included in the calculations). Energy Costs vary per project, but on average it comes to about $3 per
house per year.
Maintenance requirements: The system is well automated: monthly servicing is required to ensure
the system is operating correctly.
The minimum life span is 50 years under Australian Standards for Vacuum interface valves with an
expected overall project scheme with a 100 year plus life expectancy.
Some examples include:
• Tea Gardens NSW
• Coomera Waters Queensland
• Couran Cove Eco Resort Queensland
• Kurnell NSW
For more information see: www.flovac.com
Wastewater reuse in the Urban Environment: selection of technologies
63
5 References
Australian and New Zealand Environment and Conservation Council (ANZECC) and Agriculture and
Resource Management Council of Australia and New Zealand (2000) National Water Quality
Management Strategy – Paper No. 4 - Australian and New Zealand Guidelines for Fresh and
Marine Water Quality
Australian and New Zealand Environment and Conservation Council (ANZECC) and Agriculture and
Resource Management Council of Australia and New Zealand (2000) National Water Quality
Management Strategy – Paper No. 14 – Guidelines for Sewerage Systems – Use of Reclaimed
Water
Australian Greenhouse Office (2004) AGO Factors and methods workbook, August 2004, Australian
Government.
Crites, R. and Tchobanoglous, G. (1998) Small and decentralised wastewater management systems,
McGraw-Hill.
Department of Environment and Conservation (NSW) (2004) Environmental guidelines – use of
effluent by irrigation
Environment Protection and Heritage Council and the Natural Resource Management Ministerial
Council (2005) National Guidelines for Water Recycling – Managing Health and Environmental
Risks, Draft for public consultation, October 2005.
Fane, S. A., N. J. Ashbolt, S. B. White (2002) Decentralised urban water reuse: The implications of
system scale for cost and pathogen risk, Water Science and Technology 46 (6-7) 281 - 288.
Hawken, P., Lovins, A., Lovins L. H. (1999) Natural Capitalism, Back Bay Books, New York
NSW Health (2000) Greywater reuse in sewered single domestic premises
NSW Health (2005) Domestic Greywater Treatment Systems Accreditation Guidelines
Po, M., Kaercher, J. and Nancarrow, B. E. (2004) Literature review of factors influencing public
perceptions of water reuse, Australian Water Conservation and Reuse Research Program,
CSIRO Land and Water
Wastewater reuse in the Urban Environment: selection of technologies
64
Appendix A – Water quality treatment
The NWQMS Guidelines for Sewerage Systems - Use of Reclaimed Water provides an overview of water quality required for sewerage reuse and
summarised in Table 8 below.
Table 8. Effluent quality standards for reuse
3
3
Reuse
Suggested Treatment
Level
Reclaimed Water Quality
Monitoring
<3ML/Year
Monitoring
>3ML/Year
Controls/Notes
Municipal irrigation, dust
suppression, ornamental
waterbodies – uncontrolled
public access (except for
sub-surface irrigation – see
below)
Secondary + pathogen
reduction by
disinfection, ponding or
filtration
Thermotolerant coliforms median value of
<10 cfu/100 ml
Weekly initially for 3
months, then monthly
Weekly initially for 3
months, then monthly
1 mg/L Chlorine residual after 30
min or equivalent level of
pathogen reduction4
Weekly
Daily
pH 6.5 - 8.0 (90% compliance)
Weekly
Weekly
Systems using detention only do not provide
reduction of thermotolerant coliform counts to
<10 cfu/100 ml and are unsuitable as sole
means of pathogen reduction for high contact
uses.
Note: Thermotolerant coliforms value is to be
reviewed for the ARMCANZ, ANZECC,
NHMRC Guidelines on which this Table is
based in view of the fact that the median
value for primary contact recreation is
150 cfu/100 ml
2
As required
Continuous
Municipal irrigation, dust
suppression - controlled
public access
Secondary + pathogen
reduction by disinfection
or ponding
Thermotolerant coliforms median value of
<1000 cfu/100 ml
3 Monthly
Monthly
Sub-surface Irrigation for all
purposes.
Secondary
1 mg/L Chlorine residual after 30
min or equivalent level of
pathogen reduction
Weekly
Daily
Horticulture
Secondary
Suspended Solids or Turbidity
Monthly
Monthly
pH 6.5 - 8.0 (90% compliance)
Monthly
Monthly
2NTU
Wastewater reuse in the Urban Environment: selection of technologies
65
3
3
Reuse
Suggested Treatment
Level
Reclaimed Water Quality
Monitoring
<3ML/Year
Monitoring
>3ML/Year
Controls/Notes
Residential:
Garden watering
Toilet flushing
Car washing
Path/wall washing
Secondary + filtration +
pathogen reduction
Thermotolerant coliforms median value of
<10 cfu/100 ml
Weekly initially for 3
months, then monthly
Weekly
1 mg/L Chlorine residual after 30
min or equivalent level of
4
pathogen reduction
Weekly
Daily
Plumbing controls
Note: Thermotolerant coliforms value is to
be reviewed for the ARMCANZ, ANZECC,
NHMRC Guidelines on which this Table is
based in view of the fact that the standard
for primary contact recreation is 150
cfu/100 ml.
pH 6.5 - 8.0 (90% compliance)
Weekly
Weekly
As required
Continuous
2NTU
2
1Source:-NWQMS Guidelines for Sewerage Systems - Use of Reclaimed Water, ARMCANZ, ANZECC, NHMRC.
2 Limit met prior to disinfection. 24 hour mean value. 5 NTU maximum value not to be exceeded.
3 These are the recommended maximum monitoring regimes only. The adoption of best management practices, demonstrated effluent quality and the risk to public health will be taken into account
by the relevant authorities to determine the level of monitoring required.
4 Chlorine residual of 1 mg/L after 30 min of chlorine contact ensures adequate disinfection. Where there is the potential to discharge to receiving waters effluent should be either dechlorinated or
held until chlorine residual is <0.5 mg/L.
Wastewater reuse in the Urban Environment: selection of technologies
66
A1. Guidance for residential development
NSW guidance for water reuse within the urban environment is specified in NSW guidelines for Urban
and Residential Use of Reclaimed Water (NSW Recycled Water Coordination Committee, 1993) and
are reproduced in the Table 9. National guidelines for use of reclaimed water and presently being
upgraded and will be released before the end of 2005. The anticipated performance expectations are
a 6-7 log reduction (i.e. 10-6 to 10-7) of pathogens based on a risk based approach. This high level of
pathogen removal reflects the high exposure risk associated with the use of recycled water in
residential development.
Table 9. Water quality requirements for water reuse in urban development
Parameter
Microbial quality
Faecal coliforms
Coliforms
Virus
Parasites
Physical quality
Turbidity
pH
Colour
Chemical
Residual chlorine
Present guidelines
< 1/100 mL
<10/100 mL
< 2 in 50 L
< 1 in 50 L
< 2 NTU geometric mean
< 5 NTU in 95% of samples
6.5 to 8.0
< 15 TCU
Should not exceed 0.5 mg/L at point of
use
Wastewater reuse in the Urban Environment: selection of technologies
67
A2. Guidance for multi-unit dwellings
NSW has further refined the standards and their water quality expectations for multi-unit dwellings and
these are detailed in Circular 2004/71 Interim Guidance for Greywater and Sewage Recycling In MultiUnit Dwellings and Commercial Premises. For convenience they are reproduced in Table 10.
Table 10. NSW Health guidance for final water quality
Parameter
E.Coli or thermotolerant
coliforms
Total coliform
Virus 9
Cryptosporidium
Giardia
Turbidity
Disinfection effectiveness
pH
Biochemical
Oxygen
Demand (BOD5)
Suspended solids
Compliance value
Sampling frequency
Validation process
Ongoing
< 1/100 mL
Bi-weekly
Monthly
< 10/100 mL
< 2/50 L
< 1/50 L
< 1/50 L
< 2 NTU
0.5 mg/L free chlorine 10
6.5 – 8.0
Bi-weekly
Monthly
Weekly
Weekly
Continuous on-line
Continuous on-line
Continuous on-line
Not required
Not required
Not required
Not required
Continuous on-line
Continuous on-line
Continuous on-line
< 10 mg/L
Weekly
Not required
< 10 mg/L
Weekly
Not required
A3. Guidance for onsite systems
Clear guidance is also provided for smaller scale, onsite treatment, systems. Historically this has
evolved from septic and sullage systems. NSW Health provides the following guidance for onsite
sewerage systems and greywater treatment systems.
•
Septic Tank and Collection Well Accreditation Guidelines (NSW Health, 1999).
•
Greywater reuse in sewered single domestic premises (NSW Health, 2000).
•
Domestic Greywater Treatment Systems Accreditation Guidelines (NSW Health, 2005).
More detailed information is available from NSW Health’s website:
http://www.health.nsw.gov.au/public-health/ehb/general/wastewater/wastewater.html
A4. Guidance for environmental systems
Australian standards are reported in the national ANZECC guidelines. Water quality parameters are
established for the use of reclaimed water and are previously described on Page 19.
NSW’s Department of Environment and Conservation (2003) Environmental Guidelines – Use of
Effluent by Irrigation provide clear guidance for the beneficial use of reclaimed water. The guidelines
focus on the reuse of water for:
9
10
•
landscaping watering
•
Irrigation of pasture, crops, orchards, vineyards, plantation forests and rehabilitated sites, and
•
irrigation of golf course, racecourses and other recreation grounds.
Testing should include Enterovirus, Adenovirus, Reovirus, Hepatitis A, Norovirus and Rotavirus
Sufficient to maintain a chlorine residual of 0.5 mg/L throughout the system
Wastewater reuse in the Urban Environment: selection of technologies
68
The Department of Conservation’s guidelines provides a detailed methodology for the long term site
assessment and suitability for effluent irrigation.
A5. Guidance for approval
Currently the Protection of the Environment Operations Act 1997 (POEO Act) requires environmental
protection licenses for certain activities listed in Schedule 1 of the Act. This includes wastewater
management which water reuse is classified.
Sewage treatment systems are defined as “…an intended processing capacity of more than 2,500
persons equivalent capacity or 750 kL/day and that involve the discharge or likely discharge of wastes
or by-products to land and waters.”
Clearly DEC (EPA) approval is only required for large systems (greater than 2,500 EP) where there is
a discharge to the environment for example irrigation. In systems where there is no discharge, for
example water reuse within a high-rise building for toilet flushing, a license is not required from the
EPA.
Smaller systems (less than 2,500 EP) are the jurisdiction of the local government. Under the
provisions of Division 6 (Clauses 42 and 43) Local Government (General) Regulation 2005, a local
council has the responsibility of the approval of water reuse systems. Onsite systems require
accreditation by the NSW Department of Health. This is the only statutory role of NSW Health in onsite single domestic wastewater management. The government is currently establishing guidance for
systems between onsite scale and less than 2500 EP.
Wastewater reuse in the Urban Environment: selection of technologies
69
Appendix B – Contact list of all treatment technologies
Company
First name
Last name
Address
Suburb
State
Phone number
Fax number
Email
FLOVAC
John
Radinoff
32 Punch Street
ARTARMON
NSW
2064
(61 2) 9438 4900
(61 2) 9438 4944
info@flovac.com
Aquagenics
Bill
Day
Smithfield
NSW
2164
(02) 9757 1922
(02) 9757 1238
bdaqua@bigpond.net.au
Aquatec-Maxon
Baleen Filters Pty
Limited
Sharon
Bay
1/101 Percival Road
1st Floor,
221 Eastern Valley
Way
Middle Cove
NSW
2068
(02) 9958 8029
(02) 9958 5414
sharonb@aquatecmaxcon.com.au
Kevin
Jones
28 Phillips Street
Thebarton
SA
5031
+61 8 8354 4511
+61 8 8354 4522
kevin@baleenfilters.com
Biolytix
Gary
Inghram
429 Sandy Bay Rd
Clunies Ross Street
PO Box 6, Seven Hills
NSW 1730
Sandy Bay
TAS
7018
(03) 6225 0739
(03) 6225 4354
garyi@biolytix.com
Prospect
NSW
2148
(02) 9840 2322
(02) 9840 2344
angela.laloggia@boral.com.au
(02) 4782 3300
(02) 4782 3211
colinf@clearwatertechnology.com.au
prabha.neni@copawater.com.au
Boral Masonry Limited
Angela
La Loggia
Clearwater Technology
Colin
Fisher
2 Ashwood Avenue
PO Box 85
Postcode
Copa Water
Prabha
Neni
Milperra
Fairfield
Gardens
NSW
2214
(02) 8707 7700
(02) 9773 1496
EcoDesign
Jonathon
Berry
Enviroflow Water
Technologies
Mike
Davis
GBG Project
Management
Grahram
Doyle
PO Box 2000
1/6 Overlord Place
PO Box 127
Archerfield Qld 4106
11B Marwarra
Crescent
PO Box 163
QLD
4103
(07) 3342 4497
(07) 3342 4496
Acacia Ridge
QLD
4110
(07) 3711 7053
(07) 3711 6312
HydroCon
John
Wells
53 Balfour St
Ferney Hills
QLD
4055
(07) 3851 4266
(07) 3851 4277
Chippendale
NSW
2008
Hydrosmart
Innoflow Technologies
NZ Ltd
Irrigation and Water
Technologies
Paul
Pearce
Andrea
Houltham
P O Box 300-572
Owen
Matteson
344 Annangrove Road
Rouse Hill
NSW
2155
Ludowici Environmental
Kurt
Dahl
12 Victoria Ave
NSW
2154
Memcor Australia
Mark
Thompson
1 Memtec Parkway
Castle Hill
South
Windsor
NSW
2756
(02) 4577 0054
Wastewater reuse in the Urban Environment: selection of technologies
Albany
Auckland
graham@gbgprojects.com.au
jwells@hydrocon.com.au
(08) 8357 3334
New
Zealand
sales@enviroflow.com.au
09 426-1027
info@hydrosmart.com.au
09 426-1047
AndreaH@innoflow.co.nz
(02) 9679 0111
(02) 9679 0122
owen@iwtech.com.au
(02) 9634 0016
(02) 9634 2160
k.dahl@ludoenviron.com
(02) 4577 0078
mark.thompson@memcor.com.au
70
Company
First name
Last name
Mono-pumps
Craig
Kennedy
Novasys Groups Pty Ltd
Nubian Water Systems
(GHD)
Harvey
Gough
Luke
Opray
25-27 Whiting St
Artarmon
NSW
NuSource Water
Packaged
Environmental Solutions
(PES)
Peter
Cooper
22 Hargreaves St
Huntingdale
VIC
Cornell
Huysse
P.O. Box 127
Wahroonga
NSW
2076
1300 88 2370 or
(02) 9481 0013
02 9481 7889
Perpetual Water Pty Ltd
Craig
Richmond
(02) 6162 0650
(02) 6162 0651
Redo Water Systems
Peter
Unkles
PO Box 937
Mt Eliza
VIC
3930
(03) 9708 8762
(03) 9708 8566
Rootzone
TCI Port Marine /
Intelligent Solutions
Tony
Towndrow
PO Box 414
Picton
NSW
2571
(02) 4632 7566
(02) 4632 7344
rootzone@unwired.com.au
Jason
Meyers
(02) 9333 6396
(02) 9333 6398
jason.myers@tciltd.com.au
Ultimate Heatlh
Stafford
Lowe
Veolia Water Systems
Vas
Suresh
WaterFresh
Barbara
Cush
Waterpac Australia
Ken
Zenon
Sada
Address
Mono Pumps (Aust)
Pty Ltd – A National
Oilwell Varco Co.
P.O. Box 213
31/756 Burwood
Highway
PO Box 1150,
Mountain Gate
Unit 19
46 Abel St
Level 4, Bay Centre
65 Pirrama Rd
Suburb
State
Sutherland
NSW
Ferntree Gully
VIC
Postcode
Phone number
Fax number
Email
2232
(02) 9521 5611
(02) 9542 3649
ckennedy@mono-pumps.com
3156
(03) 9752 3766
(03) 9752 3977
sales@novasys.com.au
2064
(02) 9438 5522
(02) 9437 5244
3166
(03) 9542 6001
peter.cooper@nusourcewater.com
chuysse@pescorporation.com.au
craig.richmond@perpetualwater.com.
au
Penrith
NSW
2750
(02) 4732 5811
(02) 4732 5833
stafford@ultimatehealth.com.au
NSW
2009
(02) 8572 0400
(02) 8572 0410
systems@veoliawater.com.au
QLD
4073
(07) 3279 3974
(07) 3279 3978
bcush@waterfresh.com.au
Bryer
16 Sinnamon Road
Cnr Mt Lindsey Hwy &
Greenbank Rd
PO Box 189,
Jimboomba
Pyrmont
Seventeen
Mile Rocks
North Maclean
QLD
4280
(07) 5546 9833
(07) 5546 9566
enquiries@waterpacaustralia.com
Krishnan
15 Jordan St
Wentworthville
NSW
2145
Wastewater reuse in the Urban Environment: selection of technologies
skrishnan@zenon.com
71
Appendix C - Additional technologies and systems
DISINFECTION
IRRIGATION & DIVERSIONS
UltraViolet
Subsurface irrigation + bio fixed film bed
- Aquatec (Trojan
- RootZone: subsurface wetland
UVLogic)
Thermal
- PES (FDS)
Subsurface irrigation (barrier to groundwater)
STORMWATER
HARVESTING
Paving / Pipe Treatment
- HydraPave
- Boral
- KEWT
Irrigation
Other
- KISSS : Sub-surface Capillary Irrigation.
- Redo Water
Grey Water Diversion
- Ultimate Health
- Ecodesigns (Grey Water Diversion)
Figure 9. Additional technologies and systems
The irrigation and diversion systems collate a suite of technologies that utilise a form of land disposal
systems. KISSS is a subsurface irrigation system and is not discussed further in this report.
The disinfection systems are typically incorporated into the process treatment train and those listed
above are not discussed further in this report. Stormwater treatment systems were also included in this
section, though no further analysis is provided. These additional technologies and systems are not
considered in detail in this report. Where appropriate, their application is identified and their benefits to
urban development highlighted.
Wastewater reuse in the Urban Environment: selection of technologies
72
Hydrosmart
Process description: Hydrosmart’s system temporarily alters the ionic charge within the water. The
system utilises a series of resonance frequencies to temporarily alter the polarity of charged species.
The system is effectively prevents pipe fouling from crystalline and salt substances.
Limited independently verified scientific research is available detailing Hydosmart’s mechanism.
Further research is required to access the system’s efficacy.
Operating range: Claimed to operate over a range of scales.
Indicative costs: Site specific.
Examples include: Units are installed vineyards, ships e.g. The Spirit of Tasmania and other selected
examples.
Footprint: The footprint is small and can be retrofitted within typical irrigation systems.
Power consumption:
For more information see: www.hydrosmart.com.au
Wastewater reuse in the Urban Environment: selection of technologies
73
Boral Masonry Limited
System Name
Hydrapave
Water Type Treated
Stormwater runoff
Process Description : Stages
Rainwater infiltrates through small channels at the end of concrete pavers
suitable for pedestrian paths, carparks and driveways. The water passes
through a geotextile and through a bed of clean crushed aggregate. An
impermeable membrane base ensures water can be collected for reuse or
discharge through a drain (wrapped in a geotextile).
Method of Nutrient
Pathogen reduction
Organic matter is trapped in the geotextile and aggregate. Oils and heavy
metals are adsorbed onto the surface of organic matter and aggregate.
Natural microbial filament growth digests low level hydrocarbon pollution. The
layers of aggregate and geotextile are similar in process to trickling filter
sewage treatment plants: biological fixed film treatment. At least 70g of oil per
m2 per year can be digested by naturally occurring microbes in the sub-base.
Application of slow release fertiliser can assist with treatment of water severely
contaminated with hydrocarbon pollutants!
and
Other Info
Benefits include: low capital cost and low maintenance, onsite natural
treatment of pollutants, control of run-off to reduce flooding, reduces surface
ponding and erosion. Safer collection and detention compared to open drains
and pits. The pavers are 80mm thick concrete and have a vertical drainage
channel at the end of the paver to collect and direct stormwater to the subbase. Beneath the pavers there is 50mm depth of bedding course of 5mm
single size crushed aggregate, a geotextile and 350mm depth of sub base of
crushed aggregate (typically 40mm with 30% void space) above an
impermeable membrane. Hydrapave reduces rainfall runoff and downstream
flooding, reduces the size or need for detention tanks, helps to recharge or
maintain natural groundwater and traps pollutants and breaks down
hydrocarbon contaminants.
Cost – capital
The Hydrapave LT paving system would cost approximately $130-$150/m2,
with additional costs for site preparation, excavation and levelling. Price may
also vary depending on site access, size of project, degree of site preparation
necessary, location of job site and other variables.
Control
and
procedures and
outlined
operation
practices
The infiltration rate of the Hydrapave system is 1.25L/s (4500mm/hr). Even if
80% of the permeability is lost due to silting the surface will still allow infiltration
of 0.25 L/s (900mm/hr). The capacity of the sub-base reservoir is 30%: a
10m2 area with sub-base depth of 0.35m will store 1m3 of treated water.
Impermeable surfaces drained to a Hydrapave area should not be more than
twice the area of hyrodpave used for collecting the runoff.
For more info: http://www.boral.com.au/mdg/hydrapave/index1.html
Ultimate Health
System Name
Eurostel and Envirolyte
Water Type Treated
Applications for poultry industry, veterinary, cooling towers, horticulture,
agriculture, swimming pools, effluent treatment
Process Type
Sterilisation and disinfection of water to eliminate pathogens (bacteria, viruses,
spores, mould and fungi, and removes heavy metals). The properties of the
electrochemically treated water depend on the composition of mineral salts in
the source water and on the type and mode of electrochemical exposure
(including the design and electrochemical parameters of the reactor).
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Process Description : Stages
A brine solution is electrolysed (anode and cathode chambers separated by a
diaphragm). Solutions of various pH can be extracted from the unit, suitable for
specific applications. The acidic anolyte solution is suitable where corrosion is
not a problem. It has a pH of 2.0 - 3.5 with an active chlorine equivalent of 500700 mg/L and is effective against bacteria, viruses and algae even when diluted
in water or sprayed in the air. The Neutral Anolyte can be used if corrosion may
be a problem and where possible evaporation of active chlorine can not be
avoided. The pH is 7.5 - 8.5 with an active chlorine equivalent of 500-700 mg/L.
It is used for disinfecting swimming pools, drinking water and sterilisation of
floors, walls, tools, food stuff etc. The Catholyte alkaline solution can remove
heavy metals from water through precipitation and is also used as a washing
liquid. It has a pH of 11 - 13 and can be used when the pH of the water to be
treated needs to be increased.
Method of Nutrient
Pathogen reduction
Generation of HClO and OCl- and other disinfecting ions.
Other Info
and
Technology from Estonian and Russian background - distributed worldwide.
http://www.envirolyte.com/systems.shtml
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Irrigation and Water Technologies
KISSS – Capillary, subsurface irrigation system
For more information refer to: http://www.kisss.net.au/
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Aquagenics
Process description: Physical process with dissolved air filtration (DAF) as the key removal
mechanism. The Aquagenics DAFF package plant consists of a dual media gravity filter with combined
air water washing. Phosphorus reduction is achieved by precipitation with aluminium addition followed
by filtration. Organic concentration is reduced by reduction with aeration and in media microorganisms. Additional oxidation of organics with Chlorine or Permanganate with a pre-oxidation tank.
Expected performance would not meet class A standards; marginal reduction of BOD, removal of
particles >2 m, no reduction in nitrogen, TP to 0.1 mg/L, typically 2-3 log removal of pathogens.
Operating range: from 500 – 6000 kL/d.
Indicative costs: Capital costs $3 000 000 + GST (for 5ML/d plant (including civil works and turnkey
operation).
Operational costs $455/d for 5ML plant (Electricity costs $0.01/kL, Chemical $0.056/ kL, Labour
$0.015/kL, Maintenance $0.01/kL). Note that Chemical consumption and cost will increase with TP <
10mg/L).
Maintenance Requirements: The maintenance requirements are reflected in the operating costs.
Examples include: DAFF is often used for drinking water treatment systems. Numerous locations
particularly for potable water treatment: Woodend, Marriages 3.6ML/d DAFF Water Treatment Plant
(Vic), Bicheno 4ML/d DAFF Water Treatment Plant (Tas) and Moore Park 2.5 ML/d DAFF Water
Treatment Plant (QLD).
Footprint: small, 400 m2 for 5ML/d plant (0.08 m2/kL).
Power consumption: Estimated energy consumption $0.01/kL for 5000 kL/d, correlating to ~0.1
kWh/kL.
For more information see: http://www.aquagenics.com.au/
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EcoDesigns – Grey Water Diversion
Process description: A biological treatment (earthworm aerobic grease filter, soil organisms) and
physical treatment (filtration) followed by a land disposal system. The systems directs water by gravity
through initial filtration and then a subsurface irrigation system for distribution and shallow, subsurface,
trickle irrigation system for immediate reuse (no storage). Irrigation distribution to aerobic topsoil of
irrigation area. Aerobic grease filter, AGF, removes food scraps, fats and oils from the kitchen
greywater. Earth worms are added to the filter medium and consume the kitchen scraps and aerate
the grease filter.
This Greywater Diversion Device for a single dwelling (with no storage of water, subsurface irrigation)
does not require accreditation from NSW Health but local council approval to operate a GDD and for
the land application facility (irrigation areas). It would not meet class A standards. The water is used
for irrigation on site – not available for other reuse demands.
Operating range: The system is designed for single households. The modular system can be scaled
for larger systems where the quantity of greywater produced can be matched with a suitable irrigation
area. Up to 10EP, 1400 L/d requires 70m2.
Indicative costs: Capital costs of approximately $2000 to $2500. Operational Costs are minimal –
excluding local government annual inspections if required.
Maintenance Requirements: There are only minor tasks required to maintain the system. These
would take approximately 2hr/year and include regular inspection of aerobic grease filter and
distribution outlet housings, addition of mulch for the grease filter (0.1m3 of bark, wood chips or leaf
litter / year), removal of sprouted seeds growing in the worm castings and removal of excess
vermicast. Annual clearing of the distribution outlets of soil and roots / blockages. Pipe diameter (min
42mm) is designed to minimise blockages, but a hose can be used to flush blockages out if required.
Power consumption: minimal / zero.
Footprint: high 15-35m2/EP. House hold system requires typically 70m2 for irrigation area (kitchen
14m2, bathroom 28m2, laundry 28m2)
Examples include: household systems in approximately 20 local government areas, primarily in
Queensland.
For more information see: www.greywater.com.au
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