Designing, Construction and Validation
of
Laboratory Type
Textile Effluent Treatment Plant
Designing, Construction and Validation
of Laboratory Type Textile Effluent
Treatment Plant
Prepared by:
Mohammad Israfil Alam
Pre-registration no.: 1299
TTH ID: SEU-04
Department of Textile Engineering
SOUTHEAST UNIVERSITY
Mobile: +88 01717123339
Email: [email protected]
Supervisor:
Dr. Arun Kanti Guha
Assistant Professor
Department of Textile Engineering
SOUTHEAST UNIVERSITY
Mobile: +88 01718833461
Email: [email protected]
Approval
This is to Certify that Mr. Mohammad Israfil Alam has completed a study under
my supervision entitled “Designing, Construction and Validation of Laboratory
Type Textile Effluent Treatment Plant” to submit an assignment to the authority of
Textile Talent Hunt Competition, 2010.
Table of Contents
Abstract ................................................................................................................................................. I
1. Introduction ................................................................................................................................... 1
1.1 Pollution by Textiles ............................................................................................................. 1
1.2 Characterization of Textile Wastewater of Different Areas of Bangladesh ...................... 3
1.3 Necessity of Laboratory Type Textile ETP ......................................................................... 4
2. Construction of Laboratory Type Textile ETP ........................................................................... 5
2.1 List of costs of accessories .................................................................................................... 6
2.2 Plant Layout: Drawing Design ............................................................................................. 7
2.3 Plant Layout: Image ............................................................................................................. 8
2.4 Capacity of Different Tank ................................................................................................... 9
2.5 Devices Used in ETP Model ............................................................................................... 10
3. Experimental ............................................................................................................................... 11
3.1 ETP Flow Chart ....................................................................................................................... 12
3.2 Treatment Processes ................................................................................................................ 13
3.2.1 Screening .......................................................................................................................... 13
3.2.2 Equalization ..................................................................................................................... 13
3.2.3 Primary Clarifier: ............................................................................................................. 14
3.2.4 Oxidation .......................................................................................................................... 15
3.2.5 Decoloring unit................................................................................................................. 15
3.2.6 Secondary Clarifier .......................................................................................................... 16
3.2.7 Sludge Processing Unit .................................................................................................... 16
3.2.8 Discharge .......................................................................................................................... 16
3.2.9 Experiment Results: Sample 01 ...................................................................................... 17
3.2.10 Experiment Results: Sample 02 ...................................................................................... 18
3.2.11 Experiment Results: Sample 03 ...................................................................................... 19
4. Results & Discussion .................................................................................................................. 20
5. Conclusion ................................................................................................................................... 23
6. Acknowledgements ..................................................................................................................... 24
7. References ................................................................................................................................... 25
Abstract:
The rapid growth of textile industries creates environmental pollution, mainly water pollution.
The reason of water pollution is lack of appropriate environmental management in textiles in
Bangladesh.[1] Wastewater is the major environmental issue of the textile industries besides other
minor issues like solid waste, residual waste etc. In Bangladesh most of the industrial units are
located along the banks of the rivers and they do not use Effluent Treatment Plant (ETP) for
wastewater. As a consequence, industrial units drain effluent directly into the rivers without
consideration of the environment. Department of Environment (DoE) has visited 466 factories
that produce harmful liquid wastes. Only 104 of them were found to have installed ETPs.
However, only 56 ETPs were found to be in use by the owners. The rest of the ETPs were either
closed to save operating cost or were out of order. Setup an effluent treatment plant is mandatory
for a factory today. But due to its high construction cost many factories directly discharge
effluent into the drain. In that case it is essential to know about textile wastewater management
from the beginning of our engineering life. To this view point a laboratory type textile effluent
treatment plant is constructed. We treat our laboratory wastewater in this ETP. Three samples
were collected from dyeing laboratory. Before treatment pH was 11, 10, and 9 and after
treatment pH is 7, 7 & 7 respectively. Before treatment color was deep blue, deep red & deep
yellow and after treatment color is pale blue, pale red & pale yellow respectively. BOD, COD,
TDS, TSS etc values could not be analyzed in laboratory due to unavailability of instruments.
These tests required high cost and could not manage. This ETP model can be used as practical
class for undergraduate textile students. The laboratory type ETP is essential in all laboratory of
textile engineering department of all universities. This will help to know how to treat textile
wastewater practically which is difficult to learn in factory.
1. Introduction:
In this industrialized age, environmental pollution is a matter of great concern. Surface water
pollution is one of the elements of environmental pollution. Chemical processing industries
especially textile processing industries are claimed to produce huge effluent to discharge in our
rivers. A complex mixture of hazardous chemicals both organic and inorganic is discharged into
the water bodies from all these industries, usually without treatment. It is well known that textile
mills consume large volume of water for various processes such as sizing, desizing, scouring,
bleaching, mercerizing, dyeing, printing, finishing and washing. Due to the nature of various
chemical processing of textiles, large volume of wastewater with numerous pollutants are
discharged everyday.
1.1 Pollution by Textiles:
Especially the chemical processing industries of textile like dyeing, printing, finishing &
washing are mainly responsible for water pollution whereas the spinning, weaving, knitting,
nonwoven, garment manufacturing etc have little or no contribution in water pollution.
A flow chart of textile manufacturing:
Figure 1. Textile Manufacturing Processes[2]
Table1. Volume of Effluent produced by different processing of textiles.[2]
Department of Environment issues the Environmental Clearance Certificate to the various
industries classified in categories of Green, Orange-A, Orange-B & Red in consideration of their
site and impact on the environment. As per The Environment Conservation Rules 1997, number
of categorized industries listed below:[2]
Textile wet processes are logically in red category. They have strong rules of these types of
industries including the preset up of Effluent Treatment Plant (ETP) plant in giving time period
Process Name Production per Day Amount of Effluent
produced per day (m3)
Weaving preparation 4.14 million meters/day 1118
Yarn dyeing 150 tones/day 16,500
Knit processing 1430 tones/day 1,28,700
Woven processing 3.84 million meters/day 84,500
Garment washing & dyeing 500000 pcs/day 8500
Category
Fact
ory
Figure 02. A column diagram of a plot of factory Vs. category reported by DoE, Bangladesh.
to get the Environmental Clearance Certificate which is obvious to get utility connection like
gas, water etc.
1.2 Characterization of Textile Wastewater of Different Areas of Bangladesh:[3]
We have to know pollution levels of different textile industrial zones. Textile wastewater
collected from different areas are analyzed in laboratory and found high pH and Total Dissolved
Solids (TDS) values in almost all areas. Maximum values of pH and TDS of different areas are
given below in column diagrams.
TDS
mg/
L
Figure 3. A column diagram of maximum values of TDS (mg/L) of wastewater of different areas
pH
p
H
Figure 4. A column diagram of maximum values of pH of wastewater of different areas
1.3 Necessity of Laboratory Type Textile ETP:
Laboratory type effluent treatment plant is a new concept in Bangladesh. Generally ETP setup
cost is high. The cost of ETP varies from Tk 1Cr to 5Cr depending upon the volume of
effluent.[2] Similarly, the processing cost of wastewater in ETP varies upon the processing
materials & process type. But a laboratory type ETP is easy & cheap to construct and treatment
cost is also cheap. Not also the textile industries produces wastewater, but also in every
university which have Textile Engineering Department & dyeing lab also produces effluents
during different dyeing practical classes. After practical classes generally the effluents are
discharged into the sewerage line. This effluent mixing with sewerage waste and increases the
pollution rate of drain water. If we use laboratory type ETP, firstly we can treat the effluent
produced from different practical classes and secondly we can easily learn how to operate ETP
as like as industry. We can also learn the total treatment process of ETP that could help our
future industrial job. We can collect effluents from different textile industry and treat it as like a
practical class of Effluent Treatment Plant. Even now Effluent Treatment Plant is mandatory to
setup of any new dyeing industry otherwise they will not get gas & electricity connection that’s
why it is important to know about ETP for future job life. ETP is also a part of textile
undergraduate engineering syllabus. So it is important to know about ETP and in that case a
laboratory type ETP can give all solution. Any research type activities related to wastewater can
be easily done in laboratory. A laboratory ETP construction cost is about Taka 5,000 to 6,000
with chemical cost. Its construction process is easy and operating cost is very low as compared to
industrial ETP.
2. Construction of Laboratory Type Textile ETP:
Construction of laboratory type textile ETP is an innovative work. At the beginning, most
important thing is make a layout plan according to model shape & area. Then calculate the
different tank areas according to its process. And after layout another important thing is
purchasing of construction materials. Construction materials are purchased from three different
places in Dhaka. Pumps and cork sheets are purchased from Kataban area, different plastic boxes
from old Dhaka and remaining materials from Badda area. Chemicals are purchased from
Hatkhola road. After collecting all raw materials, at first frame and boundary of plant was
constructed according to plan layout. After that cork sheets are placed inside the wood frame and
cut it according to different sizes of plastic box. Cork sheets are attached by adhesive & then the
boxes are placed inside the cork sheet. Air flow pipes and bubble creators are attached by joint &
adhesive respectively in different tank. At final stage a thin polyethylene sheet is attached on the
cork sheet as a waterproof surface.
Figure 5. Different steps of Construction of Laboratory Type Textile ETP.
2.1 List of costs of accessories:
Serial Product name Quantity Origin Unit price Amount (BDT)
01 Air pump 1 China 200 200
02 Filter pump 3 China 400 1200
03 Hard board 1 (8’ x 4’) Bangladesh 300 300
04 Ply Wood 5 Bangladesh - 150
05 Board pin 100 gm Bangladesh 15 15
06 Cork sheet 2 (4’ x 8’, 1”)
1 (4’ x 8’, 3/4”) Bangladesh
140
110
180
110
07 Hekso bleed 2 China 15 30
08 Measuring tape 1 China 25 25
09 Adhesive 2 India 60 120
10 Anti cutter 1 China 35 35
11 Polythin sheet 2 Bangladesh 15 30
12 Plastic box 7 Bangladesh - 280
13 Dropper 5 Bangladesh 5 25
14 Multi plug 1 China 300 300
15 Polyester net 1 Bangladesh 5 5
16 PVC pipe 2 (1/2 “ dia) Bangladesh 25 50
17 PVC Pipe joint 10 Bangladesh 5 50
18 Air flow pipe 5 yds China 8 40
19 Key & joint 10 Bangladesh 5 40
20 Air bubble creator 5 China 50 250
21 Making & other cost - - 300
Total 3735
Chemicals Cost/Kg (BDT)
Table 3. List of Costs of Chemicals
Table 2. List of costs of accessories*
*Prices may be changed as per market value.
Lime 150 Ferrous sulfate 200 Polyelectrolyte 800 De colorant 16 Hydrochloric acid 25
2.2 Plant Layout: Drawing Design
A Screening unit B Equalizing unit C Primary clarifier D Oxidizing unit E Decoloring unit F Secondary clarifier G Sludge processing unit H Storage tank I Outlet J Input power plug K Power unit L Air compressor pump
Water Pump
Liquid flow pipe
Overflow pipe
Power cord
Air flow pipe
Bubble creator pipe
Chemical dosing unit
L
A
B
C
D
G
F
E
H
K
J
I
2.3 Plant Layout: Image
5.0 L
2.5
L
7.0 L
1.5 L
0.5 L
0.5
L
105 cm
80
cm
2.4 Capacity of Different Tank:
Name Capacity
A Screening 1.0 L
B Equalization Tank 5.0 L
C Primary Clarifier 2.5 L
D Oxidation Tank 7.0 L
E Decoloring Unit 1.5 L
F Secondary Clarifier 0.5 L
G Discharge 0.5 L
H Sludge process unit 0.5 L
E
A
B
C D
F
G
H
2.5 Devices Used in ETP Model:
Oxygen pump:[4]
ü Long lasting performance
ü Two speed control system
ü Twin outlet
ü Energy saving design
ü Low noice and big output
Internal filter pump:
ü Long lasting performance
ü Suitable for fresh & salt water
ü Fully submersible
ü Energy saving design
ü Low noice and big output
Country of origin China
Manufacturer company Song Bao Electric Appliance Co. Ltd.
Model no. SB-348A
Input power AC 220-240V 5W
Output 2 x 4L/min
Pressure 0.02 x 2 Mpa
Country of origin China
Manufacturer company Song Bao Electric Appliance Co. Ltd.
Model no. WP-1200F
Input power AC 220-240V 15W
Output flow 880L/Hr (max)
Table 4. Specification of Oxygen Pump
Table 5. Specificaltion of Filter Pump
3. Experimental:
In laboratory, three samples were analyzed. Three samples were tested in three separate days. High
pH obtained in all samples and got standard results after treatment. To avoid contamination the ETP
cleaned properly before treatment of each new sample. pH, color & odor of samples were analyzed.
BOD, COD, TDS, TSS etc values could not be analyzed in laboratory due to unavailability of
instruments. These tests required high cost and could not manage.
Figure 6. Experiment with Laboratory type Textile ETP
3.1 ETP Flow Chart:
Screening Equalization
Tank
Primary Clarifier Oxidation
Tank
Decoloring Unit
Secondary Clarifier
Sludge processing
unit
Influent
Discharge
3.2 Treatment Processes:
Total treatment process contains following steps:
3.2.1 Screening:
The raw waste is passed through a manual bar screen to remove floating suspended matters like
polythene bags, rags etc. The bar screen is cleaned manually by hand. In this model collected
wastewater is passed through the screening unit to the equalization tank. Mainly there are no any
coarse particles used in laboratory.
3.2.2 Equalization:
The screened waste is then collected in the equalization tank. In equalization tank the wastewater is
kept 2 hours for cooling. The equalization tank is provided with air grids to keep the suspended solids
in suspension and to ensure proper mixing is achieved. The air grids are provided by bubble creator
connected to air blower.
Figure 7. Screening & Equalization tank
3.2.3 Primary Clarifier:
The equalized effluent is then pumped into the primary clarifier for coagulation, flocculation and pH
correction. The pump situated in the equalization tank & flows wastewater when switch on. In this unit
liquid waste is treated with lime, ferrous sulfate or alumn and polyelectrolyte so that sludge is
separated through coagulation and flocculation. Precipitated sludge is passed to sludge processing unit.
pH can be controlled by adding concentrated hydrochloric acid in between coagulation and
flocculation processes. The pH is kept around from 6.5 to 7.5. This tank is also provided with air grids
to keep the suspended solids in suspension and to ensure proper reaction of coagulation and
flocculation processes. The air grids are provided by bubble creator connected with air blowers. The
total reaction time is taken about 1.5 hours to 2 hours.
Steps Retention Time Chemicals Dosing
Equalization 2 hours Lime 1 g/L Primary clarifier 1.5 - 2 hours Ferrous sulfate 1 g/L Oxidation 1 hour Polyelectrolyte 1 g/L De coloring unit 1 hour De colorant 10 ml/L Secondary clarifier 2 hours Hydrochloric acid 20 ml/L
Figure 8. Primary Clarifier
Table 6. Retention Time & Chemical dosing
3.2.4 Oxidation:
The upper level liquid waste of secondary clarifier is passed to oxidation tank and precipitated sludge
is then separated to sludge processing unit by pump. The biological treatment is designed on extended
aeration principle. The aeration is provided with fixed type surface aerator for providing the required
oxygen for the biological degradation of organic pollutant. In our experiments we could not manage
bacteria & that’s why oxidation process was skipped from our experiments. In this unit the liquid
waste is kept about 1 hour for proper reaction of chemicals.
3.2.5 Decoloring unit:
After biological treatment the liquid waste is passed to the decoloring unit by pump. In this tank
required amount of decoloring agent is dosed to remove the organic color of wastewater. The reaction
time is about 50 to 60 minutes.
Figure 9. Oxidation Tank Figure 10. Decolorant Tank
3.2.6 Secondary Clarifier:
After decoloring unit the liquid waste is passed to the secondary clarifier. In secondary clarifier the
upper layer of the liquid waste remains stationary and liquid waste is passed from the lower level of the
secondary clarifier to the sludge processing unit so that remaining dissolved solids are separated as
sludge.
3.2.7 Sludge Processing Unit:
The sludge underflow from the primary and secondary clarifier is taken into sludge drying beds for
dewatering. The dewatered sludge is scrapped manually and disposed off suitably.
3.2.8 Discharge:
Over flow of liquid from the secondary clarifier is stored in discharge unit. This water is then drain out
to the environment.
Figure 11. Secondary Clarifier
Figure 13. Discharge Unit
Figure 12. Sludge Thickening Unit
3.2.9 Experiment Results: Sample 01
Parameters Before treatment After treatment Remarks
Color Deep Blue Pale Blue Decolorised
pH 11.0 7.0 pH maintained as
discharge limit Odor Odorless Odorless
Figure 15.Before Decolorization & after Decolorization
Figure 14.Before pH 11 & after pH 7.0
Table 7. Validation based on experimental results
3.2.10 Experiment Results: Sample 02
Parameters Before treatment After treatment Remarks
Color Deep Red Pale Red Decolorised
pH 10.0 7.0 pH maintained as
discharge limit Odor Odorless Odorless
Table 8. Validation based on experimental results
Figure 16.Before pH & 11 after pH 7.0
3.2.11 Experiment Results: Sample 03
Parameters Before treatment After treatment Remarks
Color Decolorised
pH 9.0 7.0 pH maintained as
discharge limit Odor Odorless Odorless
Figure 17.Before Decolorization & after Decolorization
Table 9. Validation based on experimental results
Figure 18.Before pH 11 & after: pH 7.0
4. Results & Discussion:
Treatment of effluent from textile dyeing industries is required to meet the national and international
effluent discharge standard. It is required to meet the national standard to abide by the rules set up by
the Government and to meet the international standard to comply with the standard setup by the
buyers. In Bangladesh, Department of Environment is the regulatory body to monitor and control the
pollution from the industrial discharge. It has set up the industrial discharge standards for the
industries.
Table 10. Inland Surface Limits for textile liquid waste according to the National Effluent Quality
Standards (NEQS) guided by DoE of Bangladesh.[5]
Parameters Limits
pH 6.0-9.0
BOD5 (20oC) 50 mg/L
COD 200 mg/L
TSS 100 mg/L
TDS 2100 mg/L
Oil & Grease 10 mg/L
DoE has not set up any color standard for the industries. Although as a health and environmental issue
color is less of a concern than many of the other parameters, it is an issue in dye house effluent because
unlike other pollutants it is so visible. Reducing color is therefore important for the public perception
of a factory.
Figure 19.Before Decolorization & after Decolorization
Our laboratory experiments got standard limits after treatment in each sample. Laboratory treatment
has given result on pH, color, temperature & odor of samples. TDS, TSS, BOD, COD was not found
because of unavailability of instruments.
Table 11. Lab Experiment Result Based on pH.
Sample No. pH
Remarks Before Treatment After Treatment
Sample 01 11.0 7.0 Satisfactory
Sample 02 10.0 7.0 Satisfactory
Sample 03 9.0 7.0 Satisfactory
Table 12. Lab Experiment Result Based on color.
Sample No. Color
Remarks Before Treatment After Treatment
Sample 01 Deep Blue Pale Blue Satisfactory
Sample 02 Deep Red Pale Red Satisfactory
Sample 03 Deep Yellow Pale Yellow Satisfactory
High pH values were obtained in every sample before treatment in ETP model and after treatment in
this model standard limits were found on each sample. It proves that the treatment process was
correctly done as like factory.
Now a day it is essential to know about textile wastewater management as a textile engineer. To this
view point a laboratory type textile effluent treatment plant can be a good solution to know about
textile wastewater management system. By this ETP model any kinds of wastewater related treatment
can be done.
Practical Classes: By this ETP model practical classes about textile wastewater management can be
taken. It is helpful for a student to know easily how textile wastewater is treating. In fact now a day
textile wastewater management is a part of syllabus of undergraduate student. That’s why every
university which has Textile engineering department is essential to have an ETP model in their
laboratory.
Dyeing wastewater treatment: Wastewater from textile dyeing laboratory is directly discharged on
sewerage line during practical classes. This effluent mixing with sewerage waste increases the
pollution rate of drain water. But this wastewater can be stored in a drum and can treat by this ETP
model in laboratory.
Research on wastewater: Any research type activities related to wastewater can be easily done in
laboratory by using this ETP model. Wastewater collected from different areas can be analyzed by this
model.
5. Conclusion:
In the way of employment-intensive industrialization, textile industries are playing an utmost
important role offering tremendous opportunities for the economy of Bangladesh. But hasty and
unplanned clustered growth of industries leads to adverse environmental consequence in an alarming
way. Large quantity of water associated with the production of a number of dyeing and textile
industries releases toxic wastewater rich in dye and chemicals to the environment that result in sever
water body pollution. For undergraduate studies in Textile Engineering there are several Universities in
public and private sectors launched B.Sc in Textile Engineering program. At the department of Textile
Engineering dyeing laboratory is essential for practical classes in wet processing technology. Effluent
is generated after dyeing lab classes in Universities. It is also essential to treat this effluent. So
laboratory type ETP is mandatory in these universities to treat wastewater generated after practical
classes. This type of ETP designing, construction and validation methods reported in this assignment.
So it would be nice if this type of innovative laboratory type ETP is constructed and used for lab
wastewater treatment.
6. Acknowledgements:
By the name of Allah at first I would like to thank Bangladesh Textile Today for arranging such a
challenging competition. It is a great opportunity for me to participate in this competition.
In this second step of Textile Talent Hunt, my paper design subject is “Designing, Construction and
Validation of Laboratory Type Textile Effluent Treatment Plant”. It is a good subject and
awareness for people who are thinking about the textile wastewater management system. I would like
to give thank my Supervisor Dr. Arun Kanti Guha for his support to make this paper successful.
Without his support it will more difficult to make this paper successful. I am also grateful to Prof.
Fakhrul Hasan Murad, Chairman, Department of Textile Engineering for financial and moral support
to complete this work. After him I would like to give thank our laboratory teacher Mr. Yeamin Sarker.
He helped me a lot to collect wastewater. In this paper I have tried to give my best performance to
make this paper successful.
Again thank to Bangladesh Textile Today for arranging Textile Talent Hunt -2010. I think in future
they will organize more programs which will help us in our future life.
7. References:
1. Arun Kanti Guha, Md. Shariful Islam, “Environmental Management in Textile”, Bangladesh
Textile Today, 2(1), 43-48
2. A.S.M. Tareq Amin, Md. Ershad Khan, “Surface Water Pollution: Contribution of Textile
Sector and Way Out”, Bangladesh Textile Today, 2(3), 16-20.
3. Md. Imdadul Haque, Arun Kanti Guha, “Characterization of Textile Wastewater of Different
Areas of Bangladesh”, Bangladesh Textile Today, 3(1), 28-31.
4. http://www.newsobo.com
5. http://www.doe-bd.com
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