WATER QUALITY ANALYSIS IN COAL WASHERIES

WATER QUALITY ANALYSIS IN COAL WASHERIES
WATER QUALITY ANALYSIS IN COAL WASHERIES
A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE
REQUIREMENTS FOR THE DEGREE OF
BACHELOR OF TECHNOLOGY
IN
MINING ENGINEERING
BY
Kolli Hareesh
111MN0520
DEPARTMENT OF MINING ENGINEERING
NATIONAL INSTITUTE OF TECHNOLOGY
ROURKELA - 769008
2015
WATER QUALITY ANALYSIS IN COAL WASHERIES
A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR
THE DEGREE OF
BACHELOR IN TECHNOLOGY
IN
MINING ENGINEERING
BY
Kolli Hareesh
111MN0520
UNDER THE GUIDANCE OF
PROF.D.P.TRIPATHY
DEPARTMENT OF MINING ENGINEERING
NATIONAL INSTITUTE OF TECHNOLGY
ROURKELA-769008
2015
NATIONAL INSTITUTE OF TECHNOLOGY
ROURKELA
CERTIFICATE
This is to certify that the thesis entitled “Water Quality Analysis in Coal Washeries”
submitted by Kolli Hareesh in partial fulfillment of the requirements for the award of Bachelor
of Technology degree in Mining Engineering at National Institute of Technology, Rourkela
(Deemed University) is an authentic work carried out by him under my supervision and
guidance.
To the best of my knowledge, the matter embodied in the thesis has not been submitted to any
other University/Institute for the award of any Degree or Diploma.
Date:
(PROF. D.P.TRIPATHY)
Dept. of Mining Engineering
National Institute of Technology
Rourkela – 769008
i
ACKNOWLEDGEMENT
I wish to express my profound gratitude and indebtedness to Prof. D. P. Tripathy,
Professor, Department of Mining Engineering, NIT, Rourkela for introducing the present topic
and for his inspiring guidance, constructive criticism and valuable suggestion throughout this
project work.
Also I would like to extend my gratitude to all our friends who have patiently extended all sorts
of help for accomplishing this undertaking.
Kolli Hareesh
111MN0520
Dept. of Mining Engineering
National Institute of Technology
Rourkela – 769008
ii
Contents
Sl. No.
1
2
3
Title
Page No.
Certificate
i
Acknowledgement
ii
Abstract
v
List of Tables
vi
List of Figures
vii
Introduction
1-4
1.1 Coal Washeries
2
1.2 Objectives of the study
4
Literature Review
5-15
2.1 Scholarly work of different researches
6
2.2 Impact of coal on water
13
2.3 Pollution associated with coal washeries for benefication of coal
14
2.4 treatability study of the washery effluent
15
Sampling and Measurement
16-27
3.1 Sampling Procedure
18
3.1.1 Collection of sample
18
3.1.2 Sample Volume
18
3.2 Sample collection from the washery
19
3.3 Measurement
20
3.3.1 Multi Water Quality checker U-50 series
21
3.3.1.1 Measurement of pH
21
3.3.1.2 Measurement of DO
22
3.3.1.3 TDS
22
3.3.1.4 Salinity
23
3.3.1.5 Measurement of Turbidity
23
3.3.1.6 Measurement of Oxidation-Reduction Potential
24
3.3.2 Flame Photometer 1382
24
iii
3.3.3 Determination of metals by Atomic Absorption
Spectroscopy
25
4
Results and Discussion
28-43
5
Conclusion
44-46
6
References
47-49
iv
ABSTRACT
Water is the most important element of eco-system and it is thus imperative to determine and
mitigate the effects of mining operation on the same. Also, contaminated water has adverse
physiological effects on human being and other animals. For this, it is important to identify the
critical parameters in the water sample which is the scope of the study.
Therefore an attempt made to analyze the characteristics of the effluent that comes from the three
coking coal washeries of Central Coal fields Limited in certain Kedla Coal washery, Rajrappa
Coal washery and Kargali Coal washery in Jharkhand state, India. For this study, raw water or
the intake water to the washery, fine coal jig water, coarse coal jig water and slurry lake water
were collected from the three washeries. Parameters illustrated in Ministry of Environment and
Forest (MoEF) Schedule VI Indian principles (2006) were determined along with the sodium,
potassium, magnesium, manganese, calcium in the washery effluent samples. The pH is observed
to be decreased in the process water. The concentrations of major elements in coal—Na, K, Ca
and Mg were found to be higher in process water than in raw water indicating that these elements
are transferred from coal to the water in washeries. However, only in the case of Mn, the
stipulated limit of the effluent standard was exceeded. Trace elements like As, Se, Cd, though
found to be present in coal, were absent in the process water indicating that these elements are
not released by coal during washing.
v
List of Tables
Table
Title
Page No.
Specifications of Flame Photometry used for the
25
No.
1
measurement
2
Suggested Wavelength for Different Metals during the use
27
of Atomic Absorption Spectrophotometry
3
Results of Kedla coal washery samples
29
4
Results of Rajrappa coal washery samples
30
5
Results of Bokaro and Kargali coal washery samples
31
vi
List of Figures
Figure No.
Title
Page No.
1(a)
Plot for the Sodium of Kedla Coal Washery
35
1(b)
Plot for the Potassium of Kedla Coal Washery
35
1(c)
Plot for the Calcium of Kedla Coal Washery
36
1(d)
Plot for the Magnesium of Kedla Coal Washery
36
1(e)
Plot for the Manganese of Kedla Coal Washery
37
2(a)
Plot for the Sodium of Rajrappa Coal Washery
38
2(b)
Plot for the Potassium of Rajrappa Coal Washery
38
2(c)
Plot for the Magnesium of Rajrappa Coal Washery
39
2(d)
Plot for the Calcium of Rajrappa Coal Washery
39
2(e)
Plot for the Manganese of Rajrappa Coal Washery
40
3(a)
Plot for the Sodium of Kargali Coal Washery
40
3(b)
Plot for the Potassium of Kargali Coal Washery
41
3(c)
Plot for the Magnesium of Kargali Coal Washery
41
3(d)
Plot for the Calcium of Kargali Coal Washery
42
3(e)
Plot for the Manganese of Kargali Coal Washery
42
vii
Chapter-1
INTRODUCTION
1
1. INTRODUCTION
The primary coal washery in India was introduced in the year 1951 by Tata Steel, at west
Bokaro, Jharkhand. From that point forward various washeries have come up fundamentally for
coking coal. Instantly 37 washeries are under operation in the nation. Out of these, 20 are coking
coal washeries and the remaining 17 are non-coking coal washeries. Water is the most wellknown medium for transporting material in beneficiation plants and consequently most coal
detachments happen inside this medium. Maybe the best and the most long-standing issue in coal
beneficiation plants is the transfer of gushing, which contains a suspension of fine solids.
1.1 Coal Washeries
Coal beneficiation is a physical process wherein the raw coal is crushed in crusher, screened and
separated through wet gravitation process in Batac jig. The rejects generated from the
beneficiation is part of the coal which contains more ash hence not used for metallurgical
process. The rejects consists of carbonaceous shale and coal which has less carbon percentage.
Rejects are collected in reject bunker in the Washery from where it is dispatched to dump area.
The Washery is also sells rejects in the open marked to minimize the reject disposal problem.
Installation of captive thermal power plant of MW capacity can be installed which utilizes for
power generation.
The physical and chemical analysis shows that ash constitutes a major portion of rejects and on
an average it above 55%. Ash is mainly refractory material and constitutes mainly carbonaceous
shale and silica. The chemical composition of the rejects is such that leachate would not form
heavy concentration of organic or inorganic pollutants.
Tailings from the process are collected in tailing ponds. Tailings (fine sludge) are being
recovered from tailing pond which is being mixed with rejects and disposed off.
The washeries are working on a closed circuit system and subsequently the effluent created from
the coal washeries containing suspended solids is pumped to settling lakes in which every single
fine strong progressively settle and the sensibly clean water is reused.
However the information accessible to date are inadequate to characterize the piece and amounts
of gushing as a component of coal sort or coal cleaning procedure varieties. The methodology
2
water and waste qualities of coal benefication plants rely on the specific procedure or
recuperation method utilized and the coal handled.
The run-of-mine coal is pulverized down to littler sizes in these washeries for simple taking care
of furthermore to free coal particles caught in extensive shale particles for development in
quality and amount of clean coal.
The various equipment used in the washeries are
1
Jigs
2
Heavy media cyclone
3
Froath flotation
Thickeners are utilized for dewatering. Jigs are in view of the guideline of gravity partition
overwhelming media typhoons utilize diffusive activity yet despite the fact that dealing with the
rule of gravity focus, it is not quite the same as jigging. Dances depend on stratification in a bed
of coal when the conveying water is beat. The coal is stratified by foaming air straightforwardly
through the coal-water reject mixture in this cleaning unit. In a tornado food is as mash
comprising of magnetite and coal slurry is presented underweight, which utilizes floatation
operators, for example, pine oil and diesel oil for benefication of better estimated coal(-0.5mm)
and is the most broadly acknowledged innovation for treatment of ultra-fines. The traditional
spiral thickener is contained a roundabout tank, into which a component comprising of a drive
head, shaft or confine and pivoting arms is fitted. The pivoting arms fill the double need of
passing on sedimented solids to a main issue of release impact subsequently packing the silt and
discharging water, in this way making a thick yet sensible sub-current slurry. The notable
highlights of both coking and non-coking washeries vary.
The tailings that are produced in the form of slurry are not allowed to be directly discharged
outside as per the Regulations of Indian Government
The effluent that is generated can contain the parameters that are entitled in the Ministry of
Environment and Forest (MoEF) Schedule VI Indian Standards [Central Pollution Control Board
(CPCB), 2001] namely manganese, nickel, copper, zinc, lead, cadmium, chromium, arsenic,
3
selenium and iron are to be estimated in water effluent samples to assess the potential pollutants
being transferred from the coal.
1.2 OBJECTIVES OF THE STUDY
Having mentioned the importance of assessing water quality, the work has been planned with the
following objectives:
Analysis of the water samples of washeries for water quality parameters and
Identification of the pollutants which are not desirable in water vis-à-vis water quality
standards and take remedial measures
4
Chapter-2
LITERATURE REVIEW
5
1. LITERATURE REVIEW
There’s no doubt that coal often contains a range of pollutants including uranium, thorium,
arsenic, mercury and other elements that are toxic at low concentrations. However these methods
of mining generates large amounts of waste which may decrease the water quality. The real
effects of mining courses of action is the sullying of water bodies through mine water seepage,
spillage of water presented to minerals, water from soil stacks. Water is the most imperative
component of eco-system and it is accordingly basic to focus and moderate the impacts of
mining operation on the same. Likewise, tainted water has unfriendly physiological impacts on
human and different creatures.
2.1 Scholarly work of different researches
The accompanying is a brief audit of work of different scientists on water quality studies because
of mining:
Singh (1997) did various investigations and concluded that the real effects of mining are water
contamination because of disintegration, oil, tainting of water bodies because of release of mine
water effluents, leachates from wash-off dumps, strong waste transfer locales, broken rocks,
harmful squanders, saltiness from mine flames, corrosive mine seepage and so on. He recorded
the real moderation routines as takes after: Overburden run-off gathering and treatment with
resulting control, Oil separators, Collection/stockpiling of leachates, drainages, wash-offs with
ensuing treatment, Proper sanitation and procurement of residential and sewage effluents
treatment, Treatment of mine water releases.
He recommended that as there is intense deficiency of water supply in mining ranges, growth of
underground pumped out mine water for different supplies can be given. This is monetarily
financially savvy and gives reserve funds towards water and vitality preservation while giving
natural and social advantages.
Cherry et al (1999) completed an integrative evaluation of water sheds affected by mines in
south-western Virginia, USA and Ely Creek, a tributary toward the North Fork of the Powell
6
River was chosen. The reason for the study was to explore the helpfulness of integrative bioevaluations, which utilize a few unique sorts of evaluation devices to get a wide, general photo of
the ecological effects of poisons in a given zone. The parameters utilized as a part of the study
incorporated: (1) water segment science; (2) residue metal science; (3) perpetual silt danger to a
cladoceran (Daphnia magna) and midge; (4) intense water section poisonous quality to another
cladoceran; (5) unending in situ lethality testing with Asian mollusks; (6) in situ benthic full
scale invertebrate examining; and (7) living space evaluation and eco-toxicological rating (ETR)
is dead set. They found that when pH was reliably at or beneath 3.0, in situ benthic full scale
organic entities are not very many. What's more, at Acid mine waste (AMD) locales where pH
extended from 3.5 to 6.0, a few endpoints were inhumane to natural anxiety. Their study
demonstrated that the abiotic inspecting strategies, (water science, living space appraisal and
metals examination) showed the degree of ecological anxiety.
Jarvis and Younger (2000) discovered that the effect of metal components releases from mines
and ruin loads on accepting streams is adverse. Oceanic greenery are profoundly bankrupted.
Their study plots the strategies for mine water sway evaluation utilized as a part of the UK. Their
technique is to measure mine water affects by selecting/organizing components as per their
impact. This was finished by measuring existing effects by means of synthetic, natural, and
visual clarification. The other methods include the following:
1. Method by the national rivers authority:
a. Physicochemical assessment of watercourse
b. Use of Benthic macro-invertebrates for second phase of assessment,
2. Chemical and ecological studies
Their study showed that the above were not adequate for evaluating the impact of underground
mining. The utilization of cutting edge hydro-geographical and geochemical demonstrating
systems is obligatory. They proposed that for any EIA a portion of the elements that are to be
considered are: Local learning that can give a significant knowledge into the beginnings of mine
water contamination and accurately taught neighborhood group individuals.
7
In the experience of the creators, a joint effort of expert architects and neighborhood group is an
appealing recommendation to potential subsidizing bodies. Likewise nearby groups can help
with development of remediation plans, and maybe all the more essentially can guarantee normal
support of such offices.
Roy et al. (2003) in the wake of completing various tests discovered that mining influences
colossal zone of the area and influence the nature of surface and underground water by including
contaminants and harmful mixes making it hazardous for drinking and mechanical use,
aggravating the hydrology of the region. They found that the significant wellsprings of fluid
effluents were: surface run-off, mine water pumped put amid seepage operation, spent water
from taking care of plants, dust extractors and dust concealment frameworks, effluents from
readiness and beneficiation plants, and drains/wash-off from waste/tailing dumps.
Additionally, as per their exploration Acid mine seepage is delivered at whatever point in a mine
of any sort penetrable arrangements interfaces with the water table, aquifer, or roosted water
body, or where surface water thinks that some way or another into a mine where sulfides
(especially pyrites) are show in the mineral or nation rock. Amongst shocking highlights of the
corrosive mine seepage are low pH and elevated amounts of sulfates, iron, and aggregate broke
up solids.
These drain oxygen level in water, build danger by rendering substantial metals solvent, and
make erosion issues. Corrosive mine waste can be viably controlled by keeping its development
at source, by weakening the corrosive mine seepage to adequate rich quality, and by utilizing
standard waste water treatment techniques for balance and evacuation of disintegrated solids.
Notwithstanding the corrosive mine waste, they guarantee another wellspring of water
contamination to be the convey off of the fine strong particles from the surface mining locales
and coal planning plants, particularly amid stormy seasons, into the streams and water-courses.
Once in a while the overburden is dumped along the banks of the streams and water-courses,
bringing about blockage of free stream and sullying of water. It has additionally created an
extreme harm to the products flooded by the stream water downstream.
8
Plant spillage, truck haulage, transport exchange focuses, and rail wagon stacking territories, are
normal sources contributing fines best the surface run-offs. Relinquished factory tailings, coal
decline piles, ruin stacks, and other waste dumps in mining territory contain huge measures of
broke down minerals, are ceaseless wellsprings of stream contamination, aside from displaying
blemish sights. Digging is additionally in charge of changing the hydrology of a territory from
numerous points of view. Subsidence because of underground mining influences underground
water, interruption of surface seepage examples and coming about commitment to stream
contamination. Infrequently it may change the stream course and release, there by influencing
the horticulture and verdure of the territory.
Lambert (2004) observed that in a few ranges of the Appalachian coal fields and in coal mining
areas of the UK, mine water sharpness and iron burden are most serious in the first years after a
release starts, however diminishes relentlessly and significantly with time. Their study was to
record the degree of water-quality changes in the Uniontown Syncline AMD releases, and to
explore geochemical and pressure driven elements in charge of the progressions. While in
operation, the benefit of these mines was the way that water did not pool and impede mining
exercises, yet rather went down incline and out of the mine. The release from Uniontown
Syncline Pittsburgh Coal crease stream into two noteworthy streams, or their tributaries: the
Youghiogheny River in the north piece of the Syncline, and Redstone Creek in the south part.
Anyhow, the strategy took after for this study included: Sample accumulation from 21 locales
and field estimations of pH, temperature, broke up oxygen, conductivity, ferrous iron and stream.
Results were recorded and contrasted and results from Scarlift study (1974). Hence Long-term
changes in the nature of surrendered underground coal mine releases were considered. The study
displayed clear confirmation for common change of the nature of seepage for deserted mine
releases. They proposed that the sort and size of water-quality changes that happened after some
time, predominantly relies on upon the level of flooding inside the mine voids adding to the
releases, and the time slipped by since mine relinquishment. In overwhelmed mines of the
Uniontown Syncline, acidic releases have gotten to be antacid in under 25 years. In the releases
from un-overflowed mines, M59 and others north of the Youghiogheny River, upgrades in water
quality have additionally happened more than 25 years, however to a littler degree than watched
9
for the overwhelmed mines. Consequently their study demonstrated that the accessibility of
oxygen for AMD generation is identified with the degree of flooding in the mine voids.
Heyden and New (2005) done various analyses and watched that the utilization of wetlands to
treat mine effluent has developed in fame in the course of recent decades, despite the fact that the
methods by which the common frameworks capacity are regularly inadequately caught on. This
field-scale examination uses day by day information over a 9-month period in evaluating the
courses of action prompting the remediation of mine emanating inside a characteristic wetland
on the Zambian Copper belt. The study separates emanating remediation through weakening
from poison maintenance. Diminished wetland outpouring convergences of SO4 and Na are
because of weakening just, while Co (50%) and particularly Cu (83%) are held inside the
wetland. Maintenance was connected to adsorption onto new or prepared surfaces amid a
beginning time of gushing discharge into the framework and to courses of action identified with
pH buffering to 7.5. The wetland's corrosive buffering limit was generally the aftereffect of
carbonate-rich groundwater release into the wetland. In spite of the fact that this buffering limit
likely shows minimal regular vacillation (20–80 k mole/day), the effect of acidic effluent enter
on the wetland itself presumably changes notably between seasons, inferable from the fleeting
and spatial qualities of release from the catchments aquifers. Evaluation of other characteristic
wetlands in the district demonstrated that some (around 15%) indicated comparable catchment
size, hydro chemical and hydrogeological qualities as those of the New Dam wetland, likely
exhibiting a comparative effluent remediation potential as that portrayed here.
Roy Choudhury and Starke (2006) appreciated and surveyed the potential risk of metal
contamination from dewatering of Grootvlei Gold Mine emanating into the Blesbokspruit, a
Ramsar confirmed wetland site, the Witwatersrand rock of this region contains sulfide minerals,
similar to pyrite pyrrhotite, chalcopyrite, gersdorffite, arsenopyrite, galena cobaltite, Fe, Ni, Pb,
Cu, Co, As and U-bearing leachable oxides (Scott). Groundwater leaks through the mineral reef,
consequently, has high Fe, SO4 and follow metal substance. Emanating pumping accordingly
brought about transfer and dispersal of follow metals in the surface water framework.
Blesbokspruit stream energizes the neighborhood dolomite aquifer. The poor water quality
consequently is prone to effect the freshwater assets in the range like Vaal River. The evaluation
10
was done by Surface water and silt inspecting, determination of Water science by pH, electrical
conductivity (EC), broke down O2 (DO), redox potential (Eh), temperature, particle
Chromatograph (DX500) and nuclear ingestion spectra-photometry test, which was trailed by
Leachate test utilizing ICP-MS., CHN analyzer to focus the natural C in the dregs. They
additionally surveyed the Sediment quality by deciding Enrichment variable (Ef), Geoaccumulation file, Metal contamination record (MPI) and Sediment quality rule list (SQG-I). For
follow component examination bunch investigation is performed. Bunch examination was
further used to recognize the aggregate versatility conduct of follow metals in Blesbokspruit
It was observed that the impact of mine water releases is nearly a littler source on the grounds
that (1) the pH of the water is commonly high from moving through the nearby dolomite aquifer,
and (2) the mine water experiences high thickness partition took after by lime treatment before it
is released. Both of these elements advance precipitation of metals instead of scattering and
hence the portability of follow metals is moderately low in the examined region. Additionally the
segment coefficient for the majority of the deliberate follow metals in Blesbokspruit is
discovered to be high, which prompts their collection in the wetland.
Chen et al (2007) researched the impact of corrosive mine seepage on the well water in the
neighborhoods Daboashan mine territory (Shangba town) and did a coordinated examination
venture. The study range is well known for copper, zinc, lead and iron mines. The vast majority
of the mines release their emanating into a mud holding impoundment (MRI) which is
manufactured for surge water. Since the MRI is flooded the mine release is going into a tributary.
Their evaluation strategy included examining from 112 well out of which 6 were chosen for long
haul studies. At that point pH, electrical conductivity test, test for Cu, Pb, Zn, Cd, Fe and Mn by
graphite heater nuclear assimilation spectrometry and Al estimation by inductively coupled
plasma-nuclear outflow spectrometry (ICP-AES) were completed. After wards poisonous quality
test utilizing Daphnia carinata was finished. Investigation on factual centrality of distinction
between means was performed utilizing pearson connection. The outcomes demonstrate that
every concoction parameter was variable amid the checking period. By and large, pH was 2.9 ±
0.3. Accordingly, centralization of different metals of potential harmfulness was additionally to a
great degree high and was in place Zn > Cu > Pb > Cd. The amassing of these metals in the
11
water was 1.6, 21, 1.76 and 13 times higher. Consequences of well water propose that the
groundwater in the Shangba floodplains have been influenced by the acidic watering system
water and the most reduced pH recorded in QL is inferable from its nearest nearness to the
inflowing watering system water of AMD source. Water gathered from the area nearest to the
acidic watering system water source was intensely dangerous to the test creature (Daphnia
carinata) even after 51 time weakening. It is likely that the amazingly high death rate of the
neighborhood populace reported for the study region is in any event halfway identified with the
large amounts of substantial metals, especially Cd in the drinking well water.
Balistrieri et al (2007) attempted to focus the synthesis of a stream that is affected by corrosive
mine waste, and to assess overwhelming physical and geochemical techniques controlling the
arrangement. They surveyed disintegrated metal speciation and poisonous quality utilizing a mix
of research center, field and displaying studies. They found that estimations of pH increments
from 3.3 to 7.6 and the aggregate of broke up base metal (Cd + Co + Cu + Ni + Pb + Zn) focuses
diminishes from 6270 to 100 mg/L in the dynamic blending and response zones, downstream of
the stream's conversion with corrosive mine seepage. Blending outlines and PHREEQC
estimations demonstrated that blending and weakening influence the convergences of every
broke up component in the span. Moreover, broke down Al and Fe focuses diminish because of
mineral precipitation, though disintegrated convergences of Cd, Co, Cu, Ni, Pb and Zn diminish
because of adsorption onto recently framed Fe encourages. The uptake of broke down metals by
sea-going living beings relies on upon the watery speciation of the metals and energy of
complexion responses between metals, ligands and strong surfaces. Diffusive slopes in slim
movies (DGT) method and the Biotic Ligand Model (BLM) are utilized to evaluate the metal
substance. Information from DGT units demonstrate that all broke up metal species are
inorganic. BLM studies affirmed the DGT results. Computed intense lethality focuses are
beneath LC50 values. Interestingly, labile Cu fixations surpass LC50 values for the life forms
and also Criteria Continuous Concentration and Criteria Maximum Concentration at destinations
<30 m downstream of the conjunction. These outcomes recommend that ecological conditions at
locales nearest to the juncture of the stream and corrosive mine seepage ought not to bolster solid
sea-going organic entities. Their study exhibited the significance of investigative demonstrating
12
strategy and incorporated geochemical water quality and danger lists to accomplish a
comprehension of natural effects in complex environment.
Bhuiyan et al (2010) surveyed the overwhelming metal focus in mine seepage (watering system
water) and groundwater frameworks in North-Western Bangladesh. They utilized contamination
records and diverse multivariate methodologies (PCA and CA) to distinguish the contamination
status and likely wellsprings of toxins in the study range. Their study included assessments of
overwhelming metal contamination file (HPI), substantial metal assessment list (HEI) and level
of pollution. In their evaluation they gathered thirty-two water tests, comprising of 20 from mine
waste and adjacent wetlands (prefixed seepage water (DW)), 10 groundwater tests from
boreholes, watering system pumps and hand-burrowed wells (prefixed groundwater (GW)) and 2
examples from coal mine unaffected territories (prefixed waterway water) and performed
temperature, pH and conductivity, DO, COD, AAS tests, in this manner deciding
physicochemical and basic properties of water. At that point contamination assessment records:
overwhelming metal contamination lists, Heavy metal assessment file, Degree of defilement
(Cd) were resolved which was trailed by Statistical examination. At that point the water tests
were ordered and contamination source was recognized. Spatial similitudes and testing site
gathering was done and connection lattice was framed.
2.2 Impact of coal on water
Water is an essential component in the process of preparation of coal, coal washing and dusting
suppression etc. To meet this requirement mines acquire surface or ground water supplies from
nearby agricultural or domestic users. These water resources ones used are rarely returned after
mining because of contamination from impurities present in the seam and also from the over
burden. The other impacts of using water are
Drainage of usable water from shallow aquifers
Lowering of water levels in adjacent areas
Contamination of usable aquifers below mining operation due to percolation of poor
quality mine water.
Increased run off of poor quality water and erosion from spoil piles
Poor quality water flow to nearby streams
13
Increases acidic or basic nature of water
Increased dissolved solids, that dissolved solids
Decreased BOD
Increased turbidity
Presence or increase in concentration of trace elements.
2.3 Pollution associated with coal washeries for benefication of coal
Coal seam in some of the nations has drift origin, brought about private blending of mineral
matter with coal, offering ascent to more powder substance. Coal washeries are to decrease
cinder substance in coal. For coking and non-coking quality change, coal washeries are utilized.
Coal having float starting point, coal-powder appropriation in the coal grid is so bury woven that
coal is basically needed to pulverize to littler sizes for better liberation of coal and slag particles.
Coal benefication generally relies on upon gravity contrast in the middle of coal and powder
particles in the wake of going through measuring.
Amid different operations in coal washeries a considerable measure of particulate matters and
vaporous toxins are produced bringing about a genuine air contamination issue in the range. In
addition, coal washeries discharge huge measure of solids and fluid waste creating genuine
ecological issues.
The washeries diminish fiery debris substance of coal to 17.5% or less. This procedure devours
clean water in the scope of 0.2 to 0.25 m3/ton of crude coal info.
The washeries are worked in the shut water circuit framework yet at the same time around 1218% of crude water is released as effluent. Despite the fact that emanating is dealt with in
settling tank however at times over-burdening results into disappointment of shut circuit
framework. The rejects (15 to 25% of data) are dumped close accessible area without watching
over steadiness of dump, thus dumps close to the stream bank cause disintegration of coal
particles amid blustery season and amassing of fine coal particles on the base of waterway.
14
Despite the fact that a large number of the washeries have sufficient settling tanks however
transfer of strong waste needed to be quickened, particularly in creating nations to check with the
contamination. Legitimate reject dump administration is obliged to minimize soil disintegration.
Another extremely helpful procedure of creating power with the assistance of washery rejects by
utilizing eco-accommodating Fluidized Bed Combustion innovation. By receiving innovation
which utilizes washery rejects, the transfer of fines and rejects can be used appropriately and
monetarily, as coal of float birthplace require to pound coal before benefication and subsequently
era of fines are more.
2.4 Treatability study of the Washery Effluent
According to the present environmental practice, it is necessary to treat the effluent water
coming out of the tailing pond to remove the suspended solids and be recycled preferably
without creating any pollution problem in the downstream water bodies and to maintain
satisfactory water balance. The size of the suspended solids in the washery effluent were found
to be less and they do not settle down easily. They tend to remain suspended in surface water for
an indefinite duration. The colloids are destabilized or destroyed by allowing them to
agglomerate or coagulate into larger ones and thus they can be removed effectively. The salt of
Al and Fe are found to be suitable for this purpose. The treatment for the removal of suspended
solid is based on the principle of an extended sedimentation.
15
Chapter-3
SAMPLING AND MEASUREMENT
16
2. SAMPLING AND MEASUREMENT
Water is the most well-known medium for transporting pulverized material in benefication plants
and thus most coal partitions happens inside this medium.
More intricate estimations are frequently made in a research center obliging a water test to be
gathered, saved, transported and dissected at another area. The procedure of water examining
presents two huge issues. The main issue is the degree to which the specimen may be illustrative
of the water wellspring of hobby. Numerous water sources shift with the time and area. The
estimation may fluctuate regularly or from day to night.
The second issue happens as the example is expelled from the water source and starts to create
substance balance with its new encompassing the specimen holder. Test holders ought to be of
materials with insignificant reactivity and pre-cleaning the holder is essential.
Sample preservation might part of the way resolve the second issue. A typical method is keeping
examples cool to moderate the rate of compound responses and stage change and dissecting the
example at the earliest opportunity; however this just minimizes the progressions as opposed to
counteracting them.
The goal of inspecting is to gather a part of material sufficiently little in volume to be transported
advantageously but sufficiently extensive for explanatory purposes while still precisely hating
the material being examined. This target suggests that the relative extents of every applicable
part will be the same in the examples as in the material being examined and that the specimen
will be taken care of in such a route, to the point that no critical changes in organization happen
before the tests are made.
Every now and again, the goal of inspecting and testing is to exhibit whether proceeding with
consistence with particular administrative prerequisites has been attained to. Tests are exhibited
to the research facility for particular determinations, with the sampler being in charge of
gathering a legitimate and delegate test.
Guarantee that the sample containers are clean and quality guaranteed before utilization.
Utilization sample compartments that are clean and free of contaminants. Fill test holders
without pre-rinsing with test; pre-rinsing results in loss of any included additive and infrequently
17
can predisposition comes about high when certain segments stick to the sides of the holder.
Contingent upon determinations to be performed, fill the holder full or leave space for air
circulation, blending, and so on. In the event that a container as of now contains additive, fare
thee well not to overload the jug, as additive may be lost or weakened.
Water and effluent tests were gathered, specifically, crude water information, fine coal dance
submerged, coarse coal dance submerged, and slurry lake water. The water/emanating examples
were gathered by prescribed strategies. The water tests were gathered in glass/plastic holders as
prescribed in the standard for distinctive parameters. The examples were filled in the cups totally
and stoppered in such a path, to the point that there was no air over the specimen. Spot
examining was finished. A percentage of the parameters, for example, pH, and temperature were
examined in situ and for investigation of different parameters, additives were included as
proposed in the standard.
3.1 SAMPLE PROCEDURE
3.1.1 Collection of sample:
It is guaranteed that all testing hardware is clean and quality-guaranteed before
utilization. Utilization test compartments that are clean and free of contaminants.
Sample containers were filled without pre-rinsing with sample; pre-rinsing results in loss
of any pre-added additive.
Special safeguards are vital for tests containing follow metals.
Since numerous constituents may be display at low fixations, they may be absolutely or
mostly lost or effortlessly tainted when legitimate examining and conservation methods
are not followed.
The followings were recorded during sample collection
o General information
o Sample identification number
o Location
o Sample collector
18
3.2 Sample Collection from the Washery
The samples from the washery are collected from different places in the washery and the flow
sheet of a general washery is given below followed by sample collection.
The Process Flow sheet of the Washery is as under:
Crushing of coal down to 40mm in two stages .Primary Crusher for crushing down to200 mm in double roll crusher and secondary crusher for crushing down to -40 mm in the
double roll crusher.
Stocking of 80-0 mm crushed coal in 10000 tone slit type bunker.
Screening of 80-0 mm Coal at 10 mm in vibratory screens to produce two fractions viz.
80-10- mm and 10-0 mm.
De-dusting of 10-0 mm coal in de-dusters to recover dry fines as far as possible. The
recovered fines are mixed with clean coal.
Preparation of 80-10 mm coal in a 480 TPH, 4 product Batac Jig to produce clean coal,
low ash middling, high ash middling and rejects.
De-sliming of 10- 0 mm de-dusted coal in de-sliming screen.
Preparation of 10-00 mm de-slimed coal in a 300 TPH, 4 product Batac Jig.
To produce clean coal, low ash middling, high ash middling and rejects. Dewatering of
clean coal from coarse coal Batac coal Jig dewatering screen.
Crushing of low middling in the size range 80-10 mm down to -10 mm in impact crusher.
The crushed middling are then fed to a set of HM Cyclones along 10-0.5 mm low ash
middling from small coal Batac Jig to produce clean coal and middling. A magnetite
arrangement has been provided for the purpose. The scheme also provides arrangement
for recovery of magnetite in two stage magnetic separator.
Dewatering of clean coal from small coal Batac Jig & HM cyclones initially in
dewatering screen sand finally in centrifuge.
Initial dewatering of high ash middling from small coal Batac Jig and HM cyclones
dewatering screen and finally in Centrifuge.
Thickening of 0.5 mm slurry in a radial thickener.
Preparation of 0.5 mm thickened slurry in flotation cells in disc filters and the filter cake
is mixed with clean coal.
19
Flotation tailings are fed to a vortex thickener, the underflow from which is charged to
tailings pond.
Arrangement for stocking of clean coal and middlings.
Stocking of reject in a 300 T reject bin and disposal by truck.
A total of 12 samples, 4 from each of the three different coal washeries are collected and
brought.
The four samples vary with their location in the washery. They are
1. Raw water
2. Fine coal Jig water
3. Coarse coal jig water
4. Slurry pond water
The three coal washeries selected for this study are of CCL washeries. They are
1. Kargali and Bokaro coal washery
2. Rajrappa coal washery
3. Kedla coal washery
The quantity of each sample is about 2 liters.
3.3 Measurement
Water quality is the physical, chemical and biological characteristics of water. In this study, the
parameters are tested and analyzed by the guidelines prescribed by American Public Health
Association (APHA, 1985) and Central Pollution Control Board (CPCB).
The characteristics of water or the parameters of water are widely placed in four categories,
namely Physical parameters, Metals, Inorganic Non-metallic contents or chemical compounds,
Organic parameters.
Physical Parameters: This deals primarily with measurement of the physical properties of a
sample. The determinations included here are Turbidity, Conductivity, Total Solids and
Temperature.
20
Metals: The effect of metals in water and wastewater range from beneficial through troublesome
to dangerously toxic. Some of the metals are required to be present; but some may be
unfavorable to the aquatic life. The toxicity or beneficiary of a metal depends on its
concentrations.
Chemical parameters and Inorganic Non-metallic Constituents: Acidity, pH, alkalinity,
various forms of chlorine, nitrogen and phosphorous are the considerable parameters while
analyzing for inorganic components present in water. These parameters may have the effect on
water quality in many number of ways.
Organic parameters: Direct determination of the Organic diversity and the ability of water to
sustain life are troublesome. Hence parameters like Dissolved Oxygen content, Bio- chemical
Oxygen Demand, Chemical Oxygen Demand and Total Organic Carbon content helps in
deducing inference regarding ability of the water to sustain life in it. So the above parameters are
to be determined with an equipment having utmost accuracy.
3.3.1Multi Water Quality Checker U-50 Series
pH, Oxidation and Reduction potential, Turbidity, Suspended Solids, Salinity, DO are the
parameters that are calculated by Multi Water Quality Checker U-50 Series.
The U-50 Series Multi Water Quality Checker highlights an incorporated control unit and
sensors. It is fit for making a most extreme of eleven synchronous estimations for different
parameters, and is ideal for utilization in the field. The U-50 Series is planned considering on
location convenience, gives a wide assortment of capacities, and can be utilized for water quality
estimations and reviews of stream water, groundwater, and waste water.
3.3.1.1 Measurement of pH
Principle of measurement of pH
U-50 arrangement utilize the glass cathode strategy for pH estimations. The glass electrode
strategy measures a potential contrast between the glass film for pH and the reference cathode.
21
3.3.1.2 Measurement of DO
Principle of measurement of DO
Dissolved oxygen (DO) alludes to the measure of oxygen that is contained in water. The
centralization of disintegrated oxygen is for the most part given as mg/L or as a rate esteem (the
broke down oxygen immersion proportion). Broken down oxygen is key for keeping up the selfdecontaminating capacity of streams and oceans furthermore for fish to live. The amassing of
broke down oxygen goes about as a marker of water quality. It is regularly measured when
handling waste water and overseeing water quality. The polarographic oxygen sensor is an
encased sensor wherein voltage is connected to a cathode made of a valuable metal, (for
example, gold or platinum) and an anode likewise made of a valuable metal, (for example, silver)
by means of an outside circuit, and a top with an oxygen penetrable stomach (film) is loaded
with electrolyte arrangement. The convergence of broke down oxygen can be measured by
measuring the present relative to the measure of diminished oxygen when oxygen that has
scattered through the oxygen porous stomach creates a reductive response on the surface of the
dynamic anode (gold). The technique for measuring disintegrated oxygen taking into account the
above guideline is known as the Membrane Electrode Method. Contrasted with the Chemical
Analysis Method, which requires entangled pre-processing to mitigate the impact of lessened
materials and oxidizing materials, this strategy permits disintegrated oxygen to be measured
effectively. It is likewise simple to expel undesired development from the silver anode by
cleaning and cleaning if a separator frames on it because of oxidation, making the technique
reusable.
3.3.1.3 TDS
TDS is short for Total Dissolved Solids and means the aggregate broke down strong sum. The
conductivity of an answer is influenced by the measure of saltiness, minerals, and broke up
gasses. That is, conductivity is a file that demonstrates the aggregate sum of all substances in the
arrangement. Of these substances, TDS demonstrates just the measure of disintegrated solids.
TDS can be utilized for an examination of the condition of substances made out of a solitary
segment, for example, NaCl. Be that as it may, the utilization of TDS for the examination of
arrangements of diverse sorts causes genuine lapses.
22
Conductivity and TDS are expressed by the following formulas.
Conductivity in SI units (S/m)....................... TDS (g/L) = L (S/m) × K × 10
TDS (g/L) = L (mS/m) × K ÷ 100
Conductivity in the old units (mS/cm).......... TDS (g/L) = L (mS/cm) × K
K = TDS coefficient
Initial settings use the values listed in the table (Page 80) that generally uses TDS coefficients.
For accurate TDS comparisons, find the TDS coefficient from measured conductivity values.
Then set the value thus obtained and make measurements.
3.3.1.4 Salinity
The U-50 arrangement is intended to ascertain saltiness and additionally alternate parameters.
Note that the "saltiness" here is the saltiness of ocean water. There is a steady connection in the
middle of conductivity and saltiness at specific temperatures. Along these lines, if information on
the conductivity and temperature are accessible, the comparing saltiness can be known. At the
end of the day, the saltiness estimation of the U-50 arrangement is in view of the guideline of
figuring the salt substance, making utilization of the deliberate estimations of conductivity and
temperature. Note consequently, that deliberate consequences of all substances whose
conductivity is recognized are shown as saltiness. Case in point, the deliberate result is shown as
NaCl focus, regardless of the possibility that indeed the specimen segment is, hydrochloric
corrosive (HCl).
3.3.1.5 Measurement of Turbidity
U-50 arrangement can perform adjustment utilizing formalin (NTU) or kaolin standard
arrangements as a turbidity standard arrangement. Nonetheless, units for the arrangement utilized
for alignment ought to be shown in estimations. Try not to utilize more than 400 mg/L of kaolin
standard arrangement in light of the fact that it expands precipitation rate, bringing about
estimation slip.
3.3.1.6 Measurement of Oxidation reduction potential (ORP)
Principle of ORP measurement
23
ORP is an abbreviation for oxidation-reduction potential. ORP is the energy level (potential)
determined according to the state of equilibrium between the oxidants (MZ+) and reductants M
(Z − N) + that coexist within a solution.
3.3.2 Flame photometer 1382
The parameters such as Sodium, Potassium, Magnesium and Calcium were carried out in Flame
Photometry apparatus.
This Flame photometer 1382 helps in the detection of sodium, potassium, calcium and lithium. It
uses the latest microcontroller technology and advanced engineering techniques for analyzing of
these parameters with highest accuracy.
Different features:
1. Microprocessor with printer interface
2. Multiple calibration of curve
3. Curve calibration programmability
4. Automatic gas cutoff system
5. Data storage facility
6. Auto flame failure detection unit
7. Setup data storage facility
8. Four parameters measurement in a single aspiration
9. Direct results in ppm and meq
10. Online help key
Principle and working:
The standard solution is suctioned through the Automiser unit. The solution, air and fuel are
blended inside the mixing chamber to change over into fine particles of fog then it is splashed
into the fire. The concentration of the components reflected through the change in color of the
lame. The radiation fire goes through the detecting unit and the narrow band of obstruction
channel which permits the particular portrayed radiation to the photo detector. It analyses the
radiation and showcase the output on the LCD screen.
24
Table: 1 (Specifications of Flame Photometry used for the measurement)
Mode
Range
Sensitivity
Resolution
Display
Flame system
Detector
Calibration
Gas cut-off
Flame failure
Automiser
Ignition system
Power
Dimension
Weight
General
Na: 0-100ppm
K : 0-100ppm
Ca: 0-100ppm
Li : 0-100ppm
Na:0.5ppm Li:0.5ppm K: 0.5ppm Ca: 15ppm
0.1 ppm
20 x 4 alphanumeric LCD with backlit
LPG and dry oil free air
Silicon photo Diode
Up to 5-Point calibration with curve fitting software
Automatic
Auto detection
Axial flow type
Auto ignition
230 V + 10% AC, 50 Hz
285 x 255 x 210 mm
7.5 kg in approx.
3.3.3 Determination of Metals by Atomic Absorption Spectrometric
Metal substance of water can be dead set through different routes, for example, Titration
Method, Phenanthroline Method, and Atomic Absorption Spectrometric Method. Out of which
the Atomic Absorption Spectrophotometry (AAS) is the most delicate, fast and advanced system.
The precision of this method is high. So in this work for determination of metals AAS is utilized.
Atomic absorption spectrophotometry: In flame atomic absorption spectrometry, a sample is
suctioned into a flame and atomized. A light beam is facilitated through the fire, into a
monochromatic, and onto a detector that measures the measure of light devoured by the atomized
part in the fire. For some metal, nuclear assimilation shows better sensitivity over flame outflow.
Since each metal has got its own retention wavelength a source light made out of the parts is
used, this indicate the strategy by and large far from ghostly or radiation impedance. Most
25
nuclear assimilation instruments moreover are arranged for operation in a discharge mode, which
may give better linearity to a couple of segments.
There is reliably a fix of "concoction obstruction" which rises when the fire is not adequately
solid to discrete the molecules realizing nonattendance of ingestion by iotas.
Apparatus and Reagents:
1. Atomic absorption spectrometer
2. Burner
3. Readout
4. Lamps
5. Pressure reducing valves
6. Vent
7. Air and acetylene
8. Metal free water
9. Standard solution
Procedure:
1. Sample is digested for the use during estimation.
2. Suitable hollow cathode light is introduced according to the metal whose substance is craved
to be discovered and fitting wave length is chosen for the distinctive metals. The table of
wavelength according to metal and sensitivity is given beneath.
3. Opening width is set by proposed setting for the component being measured and after that
current is turned on and balanced as recommended by the maker, and afterward the instrument is
left to warm-up until energy source settles for around 10 to 20 min.
4. Wavelength is streamlined by conforming wavelength dial until ideal energy increase is
obtained.
26
5. After introducing suitable burner head, and permitting air current according to greatest
sensitivity acetylene is permitted and fire is lighted.
6. Adjustment is performed by suctioning blank samples and standard examples and recording
the absorbance of the particular ones.
Table: 2 (Suggested Wavelength for Different Metals during the use of Atomic Absorption
Spectrophotometry)
Element
Wavelength (nm)
Al
328.1
Cd
228.8
Cr
357.6
Cu
324.7
Fe
248.3
Mn
279.5
Ni
232.0
Pb
283.3
Zn
213.9
7. In the wake of getting the adjustment plot in the middle of fixation and absorbance, sample is
analyzed for the specific metal.
8. The concentration of the metal is specifically recorded from the computerized show or read
out.
9. The fire is then quenched by turning off the acetylene initially took after via air.
Calculation:
The results are directly noted from the instrument.
27
Chapter-4
RESULTS AND DISCUSSIONS
28
4. RESULTS AND DISCUSSIONS
Processing of coal and minerals includes exchange of potential pollutants from one sector of the
environment into another. Changes happen in water quality amid coal beneficiation.
Transforming results basically underway of immense amounts of suspended material, other than
different pollutants in the effluent produced.
Washery name: Kedla Coal Washery (CCL)
Sample points: 1. Raw water
2. Fine coal jig water
3. Coarse coal jig water
4. Slurry pond water
Mg/l is taken as the unit for all the parameters until specified and BDL is below detectable limit
Sl.No
Parameter
Sample 1
Sample 2
Sample 3
Sample 4
1
2
3
4
Color
Odor
pH
Oxidation and
reduction
potential(mv)
Turbidity(NTU)
Total dissolved
solids(g/l)
Salinity(ppt)
DO
Arsenic
Lead
Cadmium
Iron
Nickel
Copper
Zinc
Chromium
Sodium
Potassium
Magnesium
Calcium
Manganese
Nitrate nitrogen
Acceptable
Acceptable
7.5
203
Acceptable
Acceptable
6.2
212
Acceptable
Acceptable
6.3
212
Acceptable
Acceptable
6.3
219
133
0.14
145
0.23
146
0.23
141
0.2
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Below
detection
limit
<0.01
0.7
0.7
0.7
0.7
6.8
7.1
7.2
7.2
BDL
BDL
BDL
BDL
<0.001
0.006
0.006
0.006
0.007
<0.001
BDL
BDL
BDL
BDL
<0.001
0.02
0.02
0.02
0.02
<0.001
0.003
0.003
0.003
0.003
<0.001
0.01
0.015
0.01
0.018
<0.001
0.003
0.004
0.005
0.004
<0.001
0.012
0.016
0.012
0.019
<0.001
12.6
20.8
20.8
20.6
<0.02
1.7
6.8
6.9
7.3
<0.02
24.3
58.7
55
27
<0.02
57
147
140
156
<0.02
BDL
2.4
2.3
2.1
<0.05
2.5
2.7
2.8
2.6
<0.01
Table: 3(Results of samples from Kedla Coal washery)
29
MoEFSchedule VI
Indian
standards
Acceptable
Acceptable
5.5-9.0
0.2
0.1
2.0
3.0
3.0
3.0
5.0
2.0
2.0
10.0
Washery name: Rajrappa Coal Washery (CCL)
Sample points
1. Raw water
2. Fine coal jig water
3. Coarse coal jig water
4. Slurry pond water
mg/l is taken as the unit for all the parameters until specified
BDL is below detectable limit
Table: 4 (Results of samples from Rajrappa Coal washery)
Sl.No.
Parameter
1
2
3
4
Color
Odor
pH
Oxidation and
reduction
potential(mv)
Turbidity(NTU)
Total dissolved
solids(g/l)
Salinity(ppt)
DO
Arsenic
Lead
Cadmium
Iron
Nickel
Copper
Zinc
Chromium
Sodium
Potassium
Magnesium
Calcium
Manganese
Nitrate nitrogen
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Sample 1
Sample 2
Sample 3
Acceptable
Acceptable
6.9
203
Acceptable
Acceptable
6.26
217
Acceptable
Acceptable
6.3
217
Acceptable
Acceptable
6.27
<0.01
219
116
0.135
131
0.93
137
0.891
110
0.809
0.6
6.6
BDL
0.012
BDL
0.033
BDL
0.006
0.014
0.006
13.7
2.3
6.35
25
0.017
2.3
0.6
7.16
BDL
0.016
BDL
0.033
BDL
0.014
0.016
0.006
24.3
7.1
43
138
2.1
2.8
0.6
7.15
BDL
0.014
BDL
0.037
BDL
0.014
0.015
0.006
21.6
7.4
28
138
2.0
2.5
0.6
7.19
BDL
0.014
BDL
0.037
BDL
0.008
0.016
BDL
21.3
7.1
46
132
2.4
2.6
30
Sample 4
Below
detection
limit
MoEFSchedule VI
Class ‘a’
standards
5.5-9.0
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.02
<0.02
<0.02
<0.02
<0.05
<0.01
0.2
0.1
2.0
3.0
3.0
3.0
5.0
2.0
2.0
10.0
Washery name: Kargali Coal Washery (CCL)
Sample points
1. Raw water
2. Fine coal jig water
3. Coarse coal jig water
4. Slurry pond water
mg/l is taken as the unit for all the parameters until specified
BDL is below detectable limit
Table: 5 (Results of samples from Kargali Coal washery)
Sl.No.
Parameter
Sample 1
Sample 2
Sample 3
1
2
3
4
Color
Odor
pH
Oxidation and
reduction
potential(mv)
Turbidity(NTU)
Total
dissolved
solids(g/l)
Salinity(ppt)
DO
Arsenic
Lead
Cadmium
Iron
Nickel
Copper
Zinc
Chromium
Sodium
Potassium
Magnesium
Calcium
Manganese
Nitrate nitrogen
Acceptable
Acceptable
6.7
210
Acceptable
Acceptable
4.44
278
Acceptable
Acceptable
4.4
278
Acceptable
Acceptable
4.3
<0.01
279
123
0.105
181
0.135
181
0.135
167
0.129
0.1
6.8
BDL
0.01
BDL
0.02
0.03
0.010
0.001
0.010
12.3
1.7
5
20.2
0.018
2.4
0.1
8.47
BDL
0.013
BDL
0.02
0.03
0.013
0.002
0.013
20.6
6.0
40
136
1.9
3.0
0.1
8.49
BDL
0.011
BDL
0.02
0.03
0.011
0.002
0.010
20.5
6.8
28.6
136
2.4
2.5
0.1
8.49
BDL
0.011
BDL
0.02
0.03
0.019
0.002
0.018
20.3
5.8
47.3
133
2.8
2.8
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
31
Sample 4
Below
detection
limit
MoEFSchedule VI
Class ‘a’
standards
5.5-9.0
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.02
<0.02
<0.02
<0.02
<0.05
<0.01
0.2
0.1
2.0
3.0
3.0
3.0
5.0
2.0
2.0
10.0
The washing operation to which the coal is subjected to decide the concentration of suspended
solids. In fine coal jigs, the coal undergoes to rough strengths which generates large number of
fines as observed in the three washeries. The process water that comes from the fine coal jig
contains more number of solids than the process water coming from coarse coal jig in the
washeries. In the Rajrappa coal washery this concentration of solids had large distinction from
raw intake water (135 mg/l) and fine coal jig water (930 mg/l) when compared to the other two
washeries, as it was negotiable in the both.
The washery tailings are pumped to the settling or slurry lakes, wherein the fine solids
continuously settle down and then the release of clear flood water is done. The concentration of
dissolved solids in the slurry lake fluctuates relying on the settling rate. It was discovered to be
129 mg/l on account of Kargali washery, 219 mg/l on account of Kedla coal washery and 809
mg/l on account of Rajrappa coal washery. The stream from the settling lakes now and again
contains tremendous measure of fines. This may be either because of deficient recovery or
because of recovery before the completion of sedimentation happening in the slurry lake.
Therefore, alongside the seepage from the coal stockpiling and refuse piles, flood from the
settling lakes additionally on occasion adds to contaminating the regular watercourse.
Thus, an endeavor is made in the washeries to boost water reuse keeping in mind the end goal to
diminish the amount of effluent released out from the washery. The innovation made to evacuate
dissolved material is the mechanical dewatering and sedimentation. For this method the
thickeners are utilized that assume the double part for purifying process water and thickening of
the fines as portrayed before. The flow which comes is directly pumped to the pressure or
vacuum filters which is then directed to the settling lakes from the thickener.
The properties of water are highly influenced by the dissolved minerals or salts. A few salts and
minerals, for example, sulfates and chloride of the antacid and soluble metals, promptly break up
in water which may essentially change the pH in this way.
As it is a known fact that the mineral matter decreases in the coal through the benefication
process but a few trace elements are also diminishing in this process. Trace elements are for the
most part diminished by this beneficiation where the degree is quite fluctuating for diverse
32
components. All in all, the components that connected with mineral matter are promptly
uprooted than that are fundamentally naturally bound. In normally utilized coal processing
systems, numerous follow components are amassed in overwhelming division. In this manner,
despite the fact that, uproot of some follow components are favorable, particularly those of
environmental importance, from a few coals, which results in an associative increment in the
rejects of the coal beneficiation process. Works are being carried in the US and in India
additionally to demonstrate the conveyance of follow components in the different particular
gravity portions of coal in research center environment.
The pH is decreased in all the three washeries when the process water and the raw water are
compared. The raw water intake of Kargali coal washery has the pH of 6.7 which is decreased to
4.4 of the effluent from the fine coal jig water. The raw water intake of Kedla coal washery has
the pH of 7.5 which is decreased to 6.2 of the effluent from the fine coal jig water. The raw water
intake of Rajrappa coal washery has the pH of 6.9 which is decreased to 6.26 of the effluent from
the fine coal jig water.
As the sulfides and pyrites displayed in coal are insoluble but their oxidation to ferrous sulfate
acids results in bringing down the pH of the process water and also can be a primary reason this
decrease in pH in the washeries. Then again, XRD examination was not carried out at this stage
to give the mineralogical investigation.
In the previous works the arrival or the dissolving of metals into water during the coal
benefication process has been accounted. The metals reported were Al, Co, Mn, Cu, Pb, Ca, Fe,
Ni, Mg, Zn and Pb. The following series gives us the draining rate the above mentioned metals;
Mn>Ca>Mg>Zn>Pb>Fe>Ni>Cu>Co>Al. Except iron, estimations of sodium, potassium,
magnesium, calcium were additionally have a large amount of variation when the values of the
three coal washeries, Kedla, Rajrappa and the Kargali coal washery are taken into consideration.
This consideration is done between the rejects of the washery and the fine coal jig water of the
washery. In Indian coal, for the most part the convergence of iron has high difference than the
33
components, which are sodium, potassium, magnesium and calcium. In Indian Manganese have
been accounted for as a minor component.
In the Kedla coal washery the manganese concentration was discovered to be more than the
allowable limit in the process water than the concentration of manganese found in the raw intake
water. The allowable limit of manganese as per standards is 2.0 mg/l, but the effluent from the
fine coal jig water has 2.5 mg/l and that in slurry lake was 2.1 mg/l which is more when
compared to the raw water intake having a manganese content of <0.5 mg/l. In the same way
when the other washeries are considered i.e. the Kargali and the Rajrappa, the Mn substance
introduce in process effluent was 2.8 and 2.5 mg/l which is higher than that present in raw water
(i.e. 0.018 mg/l) and is likewise higher than as far as possible.
As this substance, Manganese is a solvent from acidic to neutral pH because the free oxygen
responds to metallic components, we can say that manganese is getting dissolved in the process
water. This can also be explained from watching the pH of the process water which having less
than the raw water intake of the washery.
As it is a known fact that these Na, K, Mg, and Ca dissolve in water, the Na, K, Ca, and Mg
found to be higher in the process water than in the raw water. Figs. 1(a), (b), (c), (d), (e); 2(a),
(b), (c), (d), (e) and 3(a), (b), (c), (d), (e) are the plots of Kargali, Kedla and Rajrappa washery,
for Na, K, Mg, and Ca individually.
34
Na Analysis
25
2
20
2
15
1
10
1
5
0
Sodium
5
0
1
0
0 2
1
3
2
Sample
4 3
54
Sample
Fig: 1(a) Plot for the Sodium of Kedla Coal Washery of Kedla Coal Washery
8
7
6
5
4
3
2
1
0
8
7
6
5
4
3
2
1
0
K Analysis
0
1
2
3
Sample
0
1
2
3
Sample
Fig: 1(b) Plot for the Potassium of Kedla Coal Washery
35
4
5
Ca Analysis
160
140
120
100
80
60
40
20
0
0
1
2
3
Sample
4
5
Fig: 1(c) Plot for the Calcium of Kedla Coal Washery
Mg Analysis
50
45
40
35
30
25
20
15
10
5
0
0
1
2
Sample
3
Fig: 1(d) Plot for the Magnesium of Kedla Coal Washery
36
4
5
Mn Analysis
3.5
3
3
2.5
2.5
Mn Analysis
2
2
1.5
1.5
1
1
0.5
0.5
0
0
0
1
0 2
1 3
Sample Points
Fig: 1(e) Plot for the Manganese of Kedla Coal Washery
37
2 4
3 5
Sample Points
Na Analysis
25
2
20
2
15
1
10
1
5
0
Sodium
5
0
1
0
0 2
1
Sample
3
2
4 3
54
Sample
Fig: 2(a) Plot for the Sodium of Rajrappa Coal Washery
K Analysis
8
7
6
5
4
3
2
1
0
8
7
6
5
4
3
2
1
0
0
1
0
1
2
3
Sample
K
2
4
Sample
Fig: 2(b) Plot for the Potassium of Rajrappa Coal Washery
38
3
4
5
Mg Analysis
70
60
50
40
30
20
10
0
0
1
7
6
5
4
3
2
1
0
0 2
1Sample3
Mg
2
4 3
Sample
Fig: 2(c) Plot for the Magnesium of Rajrappa Coal Washery
Fig: 2(d) Plot for the Calcium of Rajrappa Coal Washery
39
54
Mn Analysis
2.6
2.5
2.4
2.3
2.2
2.1
2
0
1
2 Sample
3
Fig: 2(e) Plot for the Manganese of Rajrappa Coal Washery
Fig: 3(a) Plot for the Sodium of Kargali Coal Washery
40
4
Fig: 3(b) Plot for the Potassium of Kargali Coal Washery
Fig: 3(c) Plot for the Magnesium of Kargali Coal Washery
41
Ca Analysis
16
14
12
10
8
6
4
2
0
0
1
2
3
4
5
4
5
Sample
Fig: 3(d) Plot for the Calcium of Kargali Coal Washery
Mn Analysis
3
2.5
2
1.5
1
0.5
0
0
1
2
3
Sample
Fig: 3(e) Plot for the Manganese of Kargali Coal Washery
42
The increment of qualities in the water after beneficiation can be because of salts and minerals
exhibit as chlorides and sulfates of the salt that promptly break down in the water.
43
Chapter-5
CONCLUSION
44
5. CONCLUSION
The decrease of the pH from the raw water intake of the washery to the process water is within
the standard limits. MOEF Schedule VI Indian Standard (2006) specifies that it should be within
5.5-9.0.
After the processing of coal is done, the process water contains higher amount of significant
components of coal such as Na, K, Mg and Ca in the process water than that of the raw intake
water of the washeries. This explains that the complete or the maximum transfer of these
components is happening.
Follow components, for example, Ni, Cu, Zn, Cr, Mn and Pb were discovered to exhibit in the
water from the benefication process, other than Fe (a significant component). The Manganese
content is observed to be 2.4 mg/l(fine coal jig), 2.3 mg/l (coarse coal jig), 2.1 mg/l (slurry lake)
of the Kedla Coal washery has been exceeded its stipulated limits (2.0 mg/l) according to the
MoEF standards which requires dilution while releasing these water outside the washery. The
same has occurred in the other two washeries [Rajrappa coal washery 2.1 mg/l (fine coal jig), 2.0
mg/l (coarse coal jig), 2.4 mg/l (slurry lake) and for Kargali coal washery 1.9 mg/l (fine coal jig),
2.4 mg/l (coarse coal jig), 2.8 mg/l (slurry lake)] which has to be taken care for dilution of Mn
before releasing the water outside the washery.
So coming across from all the above conclusions we can infer that Mn should be dealt for better
decrease of contamination of water followed by the decrease in pH issue. The solids can be
evacuated by mechanical dewatering and sedimentation thickeners. For the Manganese issue we
can also change the pH of water that is making it more basic from acidic so that the water does
not allow to break down of Manganese.
Manganese concentration can also be decreased by oxidation or aeration with chlorine-dioxide,
chlorine, ozone, potassium permanganate or lime and lime-soda softening followed by filtration.
45
And also the elements such as Arsenic, Lead, Cadmium, Iron, Nickel, Copper, Zinc and
Chromium are observed to be within the limits in all the three washeries and they can be no harm
to the environment or the eco system.
46
REFERENCES
47
REFERENCES
1. Pandey, G.N and Carney, G.C. Environmental Engineering, Tata McGraw-Hill, 6th
Edition, New Delhi, 1995, pp. 252-271.
2. Holder, J., Environmental Assessment: The Regulation of Decision Making, Oxford
University Press, New York; For a comparative discussion of the elements of various
domestic EIA systems, see Christopher Wood Environmental Impact Assessment: A
Comparative Review. 2004.
3. Jay, S., Jones, C., Slinn, P. and Wood, C., Environmental Impact Assessment: Retrospect
and Prospect, Environmental Impact Assessment Review 27, (2007), pp.287-300
4. Lenzen M., Murray, S., Korte, B., Dey, C., Environmental Impact Assessment Including
Indirect Effects – A case study using input-output analysis, Environmental Impact
Assessment Review 23, 2003, pp. 263-282
5. Bhuiyan Md. A.H., Islam M.A., Dampare S.D., Parvez L and Suzuki S., Evaluation of
Hazardous Metal Pollution in Irrigation and Drinking Water Systems in The Vicinity of a
Coal Mine Area of North-Western Bangladesh, Journal of Hazardous Materials 179,
Elsevier, 2010, pp-1065–1077.
6. Singh, G., “Environmental Impact Assessment of Mining Projects”, The Indian mining
and Engineering Journal, 1997, Volume 36, pp.5.
7. Roy, M. P., Roy, S. K. and Singh, Dr. P. K., “Impact of mining on environment – An
appraisal”, The Indian mining and engineering journal, Volume 42, 2003, pp.11-12.
8. Nollet, L. M. L., “Handbook of water analysis”, Chapter-1, Sampling Methods in Surface
Waters, CRC Press, Second Edition, 2007, pp. 2-15.
9. Kori R, Parashar S., Basu D.D., “Guide Manual: Water and Wastewater Analysis”,
Central Pollution Control Board, Ministry of Environment and Forest, India.
10. Heyden, C.J.V.D. and New, M.G., “Differentiating dilution and retention processes in
mine effluent remediation within a natural wetland on the Zambian Copper belt”, Applied
Geochemistry, No. 20, 2005, pp-1241-1257.
11. Trivedi, R.C. (CPCB), “Key Note Address—Water Quality Standards”, International
Conference on Water Quality Management, New Delhi, Feb. 2003.
48
12. Ghose MK & Kumar A, Management of spoils and tailings from coal washery and
mineral benefication plant, JIAEM, 24 (1997), pp-63-67
13. Ghose MK, Environmental management for the disposal of spoils and tailings from
mines, Environ Ecolo, 15(1) (1997), pp-206-210.
14. Konar B.B., Banerjee S.B., Chaudhuri S., Chodhury A., Das N.S., Sen K. Coal
Preparation. Allied Publishers Ltd (Chapter 1), 1997.
15. Osborne, D.G. Coal Preparation Technology, vol. 2 Graham and Irotman Limited,
London/Boston (Chapter 19), 1988.
16. Abrahim G.M.S. and Parker R.J., “Assessment of Heavy Metal Enrichment Factors and
The Degree of Contamination in Marine Sediments from Tamaki Estuary, Auckland,
2008.
17. National Environmental Engineering Research Institute (NEERI), India. Manual on
Water & Waste Water Analysis, 1988.
49
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