The document summarizes the implementation of an effluent treatment plant (ETP) at Niagara Textile Industry Ltd. in Bangladesh. It describes the ETP's physico-chemical treatment process which includes screening, sedimentation, filtration, pH control, coagulation, flocculation, and aeration. The ETP treats about 120m3 of wastewater per hour. While the ETP aims to treat wastewater, the quality of its discharged water remains poor with visible color and odor, potentially harming the local canal waters. Untreated textile wastewater from industries pollutes Bangladesh's environment through high levels of biochemical and chemical oxygen demand. Proper implementation and maintenance of ETPs is needed
Introduction to ArtificiaI Intelligence in Higher Education
Implementation of ETP & effect of Textile waste water on environment
1. Implementation of Effluent Treatment
Plants for Waste Water & Effect of
Untreated on Environment
Rois U. Mahmud1
(G.L),Ashfaq R2
,Main Uddin3
,Tariqul Islam4
,Rashedul
I5
,Anupam Das6
,Sane Malum7
Students (1-7) of “Department of Textile Engineering”. BGMEA
University Of Fashion & Technology.
Email:roisuddinhridoy@gmail.com
Name of industry: Niagara Textile Industry Ltd.
Date of site visit:08/06/2015
2. Acronyms and Abbreviations
AS Activated Sludge
ASP Activated Sludge Plant
BOD Biochemical Oxygen Demand
BOD5 5-day Biochemical Oxygen Demand
CO2 Carbon dioxide
COD Chemical Oxygen Demand
DFID Department for International Development
DO Dissolved Oxygen
ETP Effluent Treatment Plant
MLSS Mixed Liquor Suspended Solids
NaOH Sodium Hydroxide
SVI Sludge Volume Index
TDS Total Dissolved Solid
TSS Total Suspended Solid
Lime Calcium carbonate
ABSTRACT
The work is aimed on the implementation process of textile industries effluents & the present
pollution scenario in Bangladesh due to textile effluent and the consequent solution of the
problem by installation of effluent treatment plant.Despite of having ETP equipment almost all
industries in Bangladesh most of them don’t implement the system because of huge expenses.
On other hand the increasing industrialization is contributing severe pollution to the
environment by the toxic waste discharge. The liquid effluents from industries are causing a
major havoc to the environment, ecology, agriculture, aquaculture and public health since the
development of textile industries in the country. It had become a prerequisite to set up ETP in
each industrial establishment, particularly at dyeing industries that were discharging huge
3. amount of liquid waste to the rivers every day. But, for the successful implementation of ETPs,
industry owners will have to be socially responsible and at the same time, government should
provide the factory owners with logistic supports and relaxed timeframe to set up ETPs.
Keywords: Implementation process, Industrial Effluents; Water Quality; BOD; COD; TSS.
Introduction
Industrialization is an inevitable feature of economic intensification in a developing country. In
the way of employment-intensive industrialization, textile industries are playing an utmost
important role offering tremendous opportunities for the economy of Bangladesh. With the
industrial development in Bangladesh, the waste management systems did not develop
accordingly. Despite of having ETP equipment almost all industries are seen to discharge their
wastes into water and on land without any treatment or after partial treatment. Of the
environmental elements, water is the most affected as the big industries are usually situated on
the river banks and due to continuous receiving of the effluents the toxicity of these river water
increases day by day. The environmental pollution created by the industries has now become a
burning issue of the nation (Bhuiyan, M.A.H. et. al., 2011) (Islam and Jolly, 2007) (Jolly and
Islam, 2006). The major polluting industries like textile and dyeing, paints, tanneries, oil
refineries, chemical complexes, fish processing units, fertilizer factories, cement factories, soap
and detergent factories including light industrial units of Bangladesh discharge directly
untreated toxic effluents in the rivers (Jolly, Ph. D.thesis, 2011). The textile dyeing wastes
contain unused or partially used organic compounds, and high biochemical oxygen demand
(BOD) and chemical oxygen demand (COD).
It is a positive sign that many industries are also making progress in establishing and operating
their own ETPs to comply with national and international requirements, and also because of
increased personal awareness of the negative impacts of industrial effluent.
Objectives
1.To find out the implementation process of Effluent Treatment Plants of textile industries
2.To find out the used chemicals data in ETP
3.To find out the capacity of effluent treatment
4.To find out the effect of untreated water on environment
4. Literature Review
For making a Research paper on the implementation process of ETP & effect of untreated water
on environment under our Lecturer Mr.Rakib we made a visit at Niagara Textile LTD in
Chandra,Gazipur.After went there one disappointing matter we faced that the authority didn’t
give us any permission to take photo of ETP processes & units. We don’t know why they did
that may be for their security purpose.Then we went to ETP plant & the instructor of ETP told
us their ETP is a physico-chemical ETP plant.
With physico-chemical treatments generally used in Bangladesh (coagulation and flocculation)
it is possible to remove much, possibly all of the color depending on the process used. It is
however difficult to reduce BOD and COD to the value needed to meet the national effluent
discharge standard, and impossible to remove TDS. The removal rate is dependent on the
influent wastewater quality. The removal efficiency of this type of treatment has been found to
be 50% and 70% for BOD and COD respectively.After that we knew about the process flow chart
of the ETP and that is respectively screening, equalization tank, Sedimentation and Filtration,
Chemical Unit Processes,PH
controller, Aeration Tank, Coagulation and Flocculation, Secondary
Clearifier & sludge collection Tank & Discharge Treated Water.We also know about the all
chemicals are used to treat the waste water in Niagara. These are Fe(SO4),Ca(CO3),HCL &
electro-polymer.We also collect the capacity of ETP. They treat about 120m3
water per
hour,that mean they treat about 2880m3
water per day.At the final stage we saw the discharge
& sludge tank and we collect the Data of discharge quality. After collecting the Data and
monitoring the discharge water color & odor we have reached a decision on that the quality of
discharge of Niagara is not so good. May be their waste water treatment is just like an Eye
wash. And they give up the discharge into the local cannel.That’s why their low quality treated
water may harm the cannel’s water.So that the authority should maintain the plant very
carefully to treat the water purely.
We also know about another important matter that whole water source of Niagara is
underground water. This is a really big matter of concern for our environmental balance of
underground water. And another matter is, Niagara authority do not use the used water by
recycling. So that day by day we may be loose our underground water level. So we recommend
here to the authority to use the treated water by recycling. So that our water level may not go
down day by day.
5. Methodology
In order to achieve the objectives of the study, an intensive field survey was conducted in
Niagara textile industry in chandra, Gazipur.At starting point of our visit we first saw the dyeing
process of the industry.Here we saw their conventional & modern dyeing machines used to dye
the fabric. We informed here as for conventional machine they use 150L water per Kg fabric for
dyeing & for modern machine they use 60to75L water per Kg fabric.And we also know about
the capacity of their effluent treatment plant. Then we went to see the ETP and here we talk
with the ETP instructor. He told us about their systems and processes of effluent treatment. He
also told us about the chemicals they use for treating effluent. After that we went to see the
whole process of ETP by our eye. At the end of the site we have examined the final water
sample produce through ETP system(color) & how they manage that water and sludge.From the
whole visit we collect the standard implementation process of ETP, Data of chemical they
used,their management,standard rate of their final treated water& also findout how useful that
water is for the environment etc.
Pollution Scenario Due to Textile Effluent
In Bangladesh, industrial units are mostly located at waterside. A complex mixture of hazardous
chemicals, both organic and inorganic, is discharged into the water bodies from all these
industries, usually without treatment. Thus, industrial units drain effluents directly into the
rivers without any consideration of the environmental degradation.
Textile and dyeing industries produce wastewater, or effluent, as a bi-product of their products,
which contains several pollutants originated from sizing, bleaching, mercerizing, fancy dyeing,
screen printing, yarn dyeing and finishing. Chemicals used in these industries include
acrylonitrile, chlorinated phenols, salicylanilide, organic mercurial compounds, and copper
ammonium carbonate(3). Organic components degrade water quality during decomposition by
depleting dissolved oxygen. The non- biodegradable organic components persist in the water
system for a long time and pass into the food chain. In-organic pollutants are mostly metallic
salts, and basic and acidic compounds. These inorganic components undergo different chemical
and biochemical interactions in the river system, and deteriorate water quality.
In knit dyeing, the local textile dyeing industries higher amount of wastewater which varies
from 150 - 330 liter per Kg of fabric, whereas the recommended amount of wastewater that
can be discharged from composite textile dyeing industries is 100 liter per Kg fabric as per
Environmental Conservation Rules, 1997 [4]. Disposal of these large amounts of wastewater
with highly toxic compounds to water body and irrigable land is extensively threatening to the
ecosystem and aquatic life and it also enters in our food chains. These lead to diminish the
fisheries and agricultural economy day by day. The pollution leads to yield of poor quality of fish
6. with the smell of chemicals. In general, pH of the effluent is found to above 11, which become
lethal to all species of fish.
Again, the textile industries dispose large quantities of sulphates in their wastewater; this can
be converted in the environment to hydrogen sulfide, a very poisonous gas. In addition, there is
a large body of evidence that shows that residual textile dyes which go along with the waste-
water can act as respiratory sensitizers and can lead to coughs, respiratory tract irritation ad
asthma [4].
It is to be noted that, textile effluent comprises of large quantity of salt along with wastewater
as dissolved solid. This salinity of the effluent is not removed by the conventional treatment of
the effluent. So, with or without treatment, this wastewater disposed to the water system leads
to increasing the salinity of water severely.
Thus, this indiscriminate discharge of untreated effluent to river deteriorates river water quality
to unacceptable level and heavily impacts on water supply, human health, fisheries and
agriculture. Recently, Government of Bangladesh (GoB) has conducted a study on survey of
environmental pollution from industries in greater Dhaka, with the assistance of the United
Nations Environmental Program (UNEP). Under the project, six clusters (Savar, Konabari,
Tejgaon, Tongi, Hazaribagh and Narayangonj) are classified to undertake sampling and analysis
the data to characterize wastewater.
7. Findings of the Study
## Implementation
# Effluent treatment methods:
At first we work with the method of effluent treatment method. Methods of effluent treatment
may be classified into three main categories: physical, chemical and biological, as listed in Table
[1]. Primary stages of treatment are mainly physical and include screening, sedimentation,
flotation and flocculation to remove fibrous debris, undissolved chemicals and particulate
matter. Primary treatment does not significantly remove color. Secondary stages are designed
to eliminate the organic load and consist of a combination of physico-chemical separation and
biological oxidation. Biological treatment does not remove sufficient color, COD and
electrolytes to be satisfactory on its own but is often the least costly method of treatment.
Physico-chemical separation depends on the forces of chemisorption to extract the colloidal
organic compounds from the liquid phase. Tertiary stages of treatment have become more
important but they make a major contribution to treatment costs. This stage is important for
the removal of color and no one treatment will deal with the removal of all types of color.
Biological processes must be protected from shock loads of industrial pollutants, especially
those containing toxic constituents. Preliminary stages include equalisation, neutralization and
disinfection. Major reasons for poor results from settling tanks include significant fluctuations
in flow, temperature and composition of waste liquors which cause convection currents and
stratification in the tanks and interfere with normal sedimentation. Balancing of flow and
composition together with cooling or heat recovery is necessary. Disinfection with chlorine may
protect the micro-organisms in the biological stage from toxic contamination.
8. Table 1 – Methods of effluent treatment
Our work site on which we work is a Physico-chemical Treatment Plant.
The basic units needed for a stand-alone physico-chemical treatment plant are screening, an
equalization unit, a pH control unit, chemical storage tanks, a mixing unit, a flocculation unit, a
settling unit and a sludge dewatering unit (Figure 1).
Figure 1: Typical Flow Diagram of a Physico-chemical Treatment
Plant in Bangladesh.
Physical Chemical Biological
Sedimentation
Filtration
Flotation
Foam fractionation
Coagulation
Reverse osmosis
Solvent extraction
Ionising radiation
Adsorption
Incineration
Freezing
Distillation
Neutralisation (HCL)
Reduction
Oxidation
Catalysis
Ion exchange
Electrolysis (Polymer)
Stabilised ponds
Aerated lagoons
Trickling filters
Activated sludge
Anaerobic digestion
Fungal treatment
9. Now we describe about the processes of our visited site plant by following site
authorities flow chart:-
1.Screening: Screening is a mechanical process that separates particles on the basis of size.
There are several types, which have static, vibrating or rotating screens. Openings in the
screening surfaces range in size depending on the nature of the waste. In the case of textile
dyeing industries they should be small enough to catch pieces of cloth, which may damage
process equipment, reduce the effectiveness of the ETP or contaminate waterways.
2. Equalization/Collecting Tank:
The many steps in the textile dyeing process (pre-treatment, dyeing and finishing) mean that
wastewater quality and quantity varies considerably over time, however ETPs are usually
designed to treat wastewater that has a more or less constant flow and a quality that only
fluctuates within a narrow range. The equalization tank overcomes this by collecting and storing
the waste, allowing it to mix and ensuring that it becomes less variable in composition before it
is pumped to the treatment units at a constant rate. The purpose of equalization for industrial
treatment facilities are therefore:
• To minimize flow surges to physical-chemical treatment systems and permit chemical feed
rates that are compatible with feeding equipment.
• To help adequate pH control or to minimize the chemical requirements necessary for
neutralization.
10. • To provide continuous feed to biological systems over periods when the manufacturing plant
is not operating.
• To prevent high concentrations of toxic materials from entering the biological treatment
plant.
Mixing usually ensures adequate equalization and prevents settle able solids from depositing in
the tank. In addition, mixing and aeration may result in the oxidation of reduced compounds
present in the waste-stream or the reduction of BOD.
3.Sedimentation and Filtration:
The flocs formed in flocculation (see chemical unit processes for a description of flocculation)
are large enough to be removed by gravitational settling, also known as sedimentation. This is
achieved in a tank referred to as the sedimentation tank, settling tank or clarifier.
11. Sedimentation is also used to remove grit and suspended solids, to produce clarified effluent,
and to thicken the sludge produced in biological treatment. Flocculation and sedimentation
should remove most of the suspended solids and a portion of the BOD.
4. Chemical Unit Processes:
Chemical unit processes are always used with physical operations and may also be used with
biological treatment processes, although it is possible to have a purely physico-chemical plant
with no biological treatment. Chemical processes use the addition of chemicals to the
wastewater to bring about changes in its quality. They include pH control, coagulation, chemical
precipitation and oxidation. Niagara authority use Fe(SO4), Calcium carbonate(lime),HCL,
Electrolyte(polymer).
5. pH Control:
Waste from textile industries is rarely pH neutral. Certain processes such as reactive dyeing
require large quantities of alkali but pretreatments and some washes can be acidic. It is
therefore necessary to adjust the pH in the treatment process to make the wastewater pH
neutral. This is particularly important if biological treatment is being used, as the
microorganisms used in biological treatment require a pH in the range of 6-8 and will be killed
by highly acidic or alkali wastewater. Various chemicals are used for pH control. For acidic
wastes (low pH) sodium hydroxide, sodium carbonate, calcium carbonate or calcium hydroxide,
may be added among other things. For alkali wastes (high pH) sulphuric acid or hydrochloric
12. acid may be added. Acids can cause corrosion of equipment and care must be taken in choosing
which acid to use. Hydrocholoric acid is probably better from an environmental view point but
can corrode stainless steel therefore plastic or appropriately coated pumps and pipes must be
used.
6. Aeration Tank:
Aeration is required in biological treatment processes to provide oxygen to the microorganisms
that breakdown the organic waste. It may also be applied in the equalization tank to provide
mixing and to reduce oxygen demand by oxidizing the compounds present in wastewater. Two
main methods are used for this: either mechanical agitation of the water so that air from the
atmosphere enters the water; or by introducing air into the tank through blowers (to supply air)
and diffusers (to diffuse the air uniformly).
13. 7. Coagulation and Flocculation:
Coagulation is used to remove waste materials in suspended or colloidal form. Colloids are
particles over a size range of 0.1 – 1 nm (10-8
– 10-7
cm). These particles do not settle out on
standing and cannot be removed by conventional physical treatment processes. In a small
sample of wastewater there will be both settleable solids and dispersed solids. A significant
portion of these non-settleable solids may be colloidal. Each particle is stabilized by negative
electric charges on its surface, causing it to repel neighboring particles, just as magnetic poles
repel each other. Coagulation is destabilization of these colloids by neutralizing the forces that
keep them apart so that they can agglomerate 2
,3
(come together). This is generally
accomplished by adding chemical coagulants and mixing. Figure 2 illustrates how
these chemicals reduce the electric charges on colloidal surfaces.
Fig:2
14. The term ‘flocculation’ may be taken to cover those processes whereby small particles or small
groups of particles form large aggregates. Flocculation during wastewater treatment converts
finely divided suspended solids into larger particles so that efficient, rapid settling can occur.
The term is also used for the dramatic effect when polyelectrolytes are added and large stable
flocs are formed very quickly (Figure 3).
Fig:3
8.Secondary Treatment/ Secondary Clearifier:
The objective of secondary or biological treatment of industrial wastewater is to remove, or
reduce the concentration of, organic and inorganic compounds. Biological treatment processes
can take many forms but all are based on microorganisms, mainly bacteria. These
microorganisms use components of the effluent as their “food” and in doing so break them
down to less complex and less hazardous compounds, thus decreasing the BOD and COD. In the
process the microorganisms increase in number.The two most common forms of biological
treatment are:
• Activated sludge plants (ASPs)
• Biofilm based systems (often these are trickling filter systems).
Activated sludge (AS) is an aerobic flocculent slurry of micro-organisms which remove organic
matter from wastewater and are then removed themselves, usually by sedimentation.
Activated sludge is best suited to the removal of soluble organic matter because insoluble
15. organic matter can usually be removed more economically by physico-chemical means. Often,
however, wastewaters will contain both soluble and insoluble organic mater.
AS leaves the reactor with the treated effluent but is settled out in a clarifier and returned to
the aeration unit to recycle the bacteria. The amount of AS required for effective operation
varies according to the design of the ASP and the concentration and nature of the effluent
being treated. Suppliers of ASPs should be able to advise on the optimum amount of AS in the
system. The ratio of the amount of effluent in terms of BOD and the amount of AS (known as
the f/m ratio) is an important design and operating parameter and sometimes ASPs are
operating so as to maintain a fixed f/m ratio. If there is more AS in the ASP than desired a
portion is removed (this is called wasting) and disposed of.
In the ‘traditional’ trickling filter, the effluent is tricked over the surface of the slime-covered
media and the space between the particles of media is occupied by air which passively diffuses
through the filter (Figure 3). In the more recent design of the submerged fixed film reactor, the
particles of media are submerged in the effluent and the air is blown into the reactor from
below.
Both activated sludge and fixed film systems can produce high quality effluent but both have
advantages and disadvantages. In the AS process the settling and recycling of AS to the aerobic
reactor is vital, but the settling process can be difficult to accomplish. Fixed film systems do not
require recycling of biomass and so do not present this problem. Surplus AS needs to be
disposed of: this material must be disposed of appropriately so that the pollutants now present
in this sludge do not enter the water cycle (see the briefing note “Management of Textile
Dyeing Sludge” produced as part of this series for more information on this). The treated liquid
is discharged to the environment or taken for further treatment depending on the desired
standard of effluent quality or the required use of the wastewater.
16. 9.sludge collection Tank & Discharge Treated Water:
Sludge is produced from the treatment of wastewater in on-site (e.g. septic tank) and off-site
(e.g. activated sludge) systems. This is inherently so because a primary aim of wastewater
treatment is removing solids from the wastewater. In addition, soluble organic substances are
converted to bacterial cells, and the latter is removed from the wastewater. Sludge is also
produced from the treatment of stormwater , although it is likely to be less organic in nature
compared to wastewater sludge. In Niagara they collect the sludge in the sludge bad and they
store it at least 3 to 4 month.After that they put that sludge in small packet and transfer that
packet at another place where they had planted these in the ground.
On another hand they dis charge their final treated water into the local cannel.They don’t use
the water by recycling . They told us for their lacking of modern technology of ETP they can’t
use the water by recycling.
17. Results and Discussion:
For all industries use ETP should follow a National Standards – Waste Discharge Quality
Standards for Industrial units & projects.
By law factories must monitor the quality of their wastewater and stay within national limits for
pollution. The Environment Conservation Rules, 1997 provide national standards for the quality
of industrial wastewater being discharged into certain places including open water bodies,
public sewers and irrigated land. They also provide specific discharge quality standards for key
parameters from certain industries, including the textile dyeing industry.
*Product Quality Checked:
Biological Oxygen Demand (BOD)
Chemical Oxygen Demand (COD)
Total suspended solids
Total dissolved solids
Color
pH et.
18. Table: Discharge Quality Standards for Classified Industries – Composite Textile Plant
In Niagara,they use 4 chemicals in their ETP.
*Required Chemicals and Their Functions in ETP:
HCL:
Function: Neutralize the waste water controlling the PH. It is auto dispensed in the
neutralization tank.
19. Polyelectrolyte:
Function: Used for sedimentation / sludge coagulation and also killing bacteria.
De-colorent(caco3):
Function: Used for removing color. It is used auto / manually in the sedimentation feeding tank.
ferrous sulphate:
Function: It is used to kill the harmful bacteria. It is used in the biological oxidation tank.
*Capacity of effluent treatment in Niagara:
Our visited site industry’s effluent treatment capacity is – 120m3
/hour
That mean their capacity per Day is – 2880m3
/day
*Data of discharge quality of our visited site:
Table: Physicochemical Characteristics(Approximate)
Physicochemical
Characteristics
Untreated Effluent Treated Effluent
Color Dark- Blue Light-blue
Odor Unpleasant Small Odor
BOD Above 200 Around 100
COD Above 350 Around 250
PH
9.8 7.2-7.4
TDS 3300 1590
TSS 200 133
Temperature 430
c 350
c
20. At our visiting time we also find out one important matter that the whole industry use
*underground water* for their dyeing,finishing etc! And they also don’t use that used water by
recycling! They discharge the water into the cannel or River.
Recommendation
Here at first we would like to give thanks to prof.Engg.Dr. Ayub Nabi Khan(pro-vice of BUFT)for
managed the industry, Mr.Diamond sir for giving us the chance to visit Niagara&
Mr.Zahir(Trainee) to help us by giving his valuable time. On the other hand,at our visiting time
we knew that whole water source of Niagara is underground water. This is a really big matter of
concern for our environmental balance of underground water. And another matter is, Niagara
authority do not use the used water by recycling. So that day by day we may be loose our
underground water level. So we recommend here to the authority to use the treated water by
recycling. So that our water level may not go down day by day.Other matter is we don’t think
the ETP of Niagara is much modern for treating the effluent purely and also they may not treat
the effluent of factory at standard way. Because we saw the final treated water color is not
good as standard and discharge water have also much odor too. And authority discharge that
water into local cannel or River.So that this low quality treated water may harm the quality of
the cannel or river’s water and also harm the Environment badly.
Conclusion:
The recent awareness on the ETP requirement should be directed in a constructive way. We
realize that industrial effluent should be treated before drainage. Upon dis- cussed novel
methods can be applied to remove different dye also hazardous materials from industrial
effluents. The Government must come forward to facilitate ETP installation with technical
guidance and also with fi- nancing. Consideration for Common ETP can be made by the
Government, which will encourage small-scale industries to establish ETPs within their cost
limitations. Government’s recent stringent role against industry owner may pressurize them to
come up with compliance meas- ure regarding ETP installation, but in the long run, a good
result from the concept of ETP installation can only be ensured by proper monitoring and
environmental audit by Government afterward. Neither industry and private sector nor public
sector alone can be left responsible for realization on the intensity of the problem. Government
and the private sector should come into with its full glory to solve the problem mutually, which
aims at burning issue like environmental conservation.
21. REFERENCES:
1. Government of People’s Republic of Bangladesh, Ministry of Environment and Forests, The
Environment Conversation Rules 1997, Schedule 10, Rule 13 (Un-official English Version)
2. Islam, A. and Jolly, Y.N. (2007): Heavy metals in water and fishes of the tannery affected
vicinity of the river Buriganga, J. Bang., Aca, Sci., 31(2), 163-171.
3. Jolly, Y.N. and Islam, A. (2006): Heavy Metals in Water and Fishes of the River Shitalakkha,
Nuclear Science and Application, 15(20:13-20.
4. Jolly, Y.Nb., Ph.D. thesis, (2011): Evaluation of industrial effluents for irrigation, Dept. of
Applied Chemistry and Chemical Engineering, University of Dhaka, Bangladesh. pp. 174-178
5. Bhuiyan, M.A.H.; Suravi, N.I.; Dampare, S.B.; Islam, M.A.; Qurashi, S.B.; Ganyaglo, S. and
Suzuki, S. (2010): Investigation of the possible sources of heavy metal contamination in lagoon
and canal water in tannery industrial area in Dhaka, Bangladesh, Environ Monit Assess, 175,
633-649.
6. Web: www.bcas.net
7. Journal of Environmental Protection, 2013, 4, 301-308
http://dx.doi.org/10.4236/jep.2013.43035 Published Online March 2013
(http://www.scirp.org/journal/jep)
8. Guide for Assessment of Effluent Treatment Plants in
EMP/EIA Reports for Textile Industries. Department of Environment
Ministry of Environment and Forest, Bangladesh.