chemical oxygen demand and colour removal from …

CHEMICAL OXYGEN DEMAND AND

COLOUR REMOVAL FROM THE

TEXTILE EFFLUENTS BY USING LOW-

COST ECO- FRIENDLY ADSORBENTS

Aravind G

Department of Civil Engineering

SRM Institute of Science and Technology, Kattankulathur- 603203, Tamil Nadu, India

Prasanna k

Department of Civil Engineering

SRM Institute of Science and Technology, Kattankulathur- 603203, Tamil Nadu, India

Abstract- Textile Wastewater is a type of wastewater that contain a large variety of dyes and chemicals which pose a

high risk to both Living and Non-Living Environment when discharged untreated. The textile wastewater contains

COD, BOD, Nitrogen, Heavy metals, Dyes and Colorants and for the treatment of any textile wastewater it is

necessary to eliminate these parameters. Fly Ash and Coconut Shells having the largest carbon content has the

tendency to adsorb parameters in any wastewater sample. The adsorption process was Batch Adsorption Process and

it can be explained on the basis of Freundlich and Langmuir adsorption isotherm model. Maximum removal of COD

was 85% and Colour of 89% was found at a mean adsorbent dosage of 400 mg/l for Fly Ash with a contact duration

of 60 minutes and agitator speed of 400 rpm. The Maximum removal of COD was 76% and Colour of 86% was found

at a mean adsorbent dosage of 400 mg/l for Coconut shells with a contact duration of 60 minutes and agitator speed

of 400 rpm. Finally, from the study of two low- cost adsorbents it is found that the Fly Ash has the maximum removal

efficiency. Fly Ash and Coconut Shells are the main key in this study.

Keywords: COD, Colour, Fly Ash, Coconut Shells, Adsorption.

I. INTRODUCTION

The Textile Industry is mainly dealing with the design, production, distribution of yarn, cloth and clothing. The

Raw Materials of any Textile Industry are Natural or Synthetic components. Natural Components include

Cotton, Jute, etc. and the Synthetic components include Nylon, Polyester, etc. India is one of the largest

producers of Textiles in the world and it also produces large amount of wastewater mainly textile wastewater.

Depending upon the locally available raw materials that are used can cause a high impact to the environment

and the main cause of such an impact to the environment is mainly due to the parameters of COD, BOD, Dyes,

TDS, TSS and etc. When compared to other Parameters COD, BOD and Dyes pose a high to not only the

Environment but also to the Living Beings. Colour Removal is risky and hence Colour Removal and COD

Removal is studied.

Currently there are various treatment processes involved for the treatment of any Textile Wastewater.

Oxidation, Coagulation, Filtration, Ozonation, Membrane Filtration, Treatment using Hydrogen Peroxide and

Reverse Osmosis are some of the treatment processes. The above-mentioned process is mostly effective for the

treatment but the major disadvantages are the high cost of treatment and the disposal problems. To overcome

this, Adsorption process is used mostly for the treatment. The Adsorption process poses as an alternative

approach for the treatment of textile wastewater mostly for the removal of COD, BOD and Colour by using Eco-

Friendly Low- Cost Adsorbents. The use of Low- Cost Adsorbents contributes to the Sustainable Environment.

The Fly Ash and Coconut Shells are readily available in the Environment. Coconut shells are mostly discarded

as unwanted and it pose a very good Adsorbing medium. Other readily available Eco- Friendly Adsorbents are

Rice Husk, Saw Dust, Wheat Barn, Almond Shell, Banana Pith, etc. COD and Colour removal is the main target

in this study and Fly Ash and Coconut Shells can easily remove these parameters. In the present study Batch

Adsorption Technique is used by using Fly Ash and Coconut Shells as an Adsorbent with respect to the Effect

of pH, Contact Time, and a mean Adsorbent Dosage of 400 mg/l. The Wastewater was collected from the CETP

and KPR Mills, Tirupur and the Experiment was performed at a Private Laboratory at Coimbatore.

Journal of Xi'an University of Architecture & Technology

Volume XIII, Issue 6, 2021

ISSN No : 1006-7930

Page No: 120

2.1 Material and Methods -

Materials are very much important to perform any experiment. The

characteristics and the environment they are collected from and it is important to prevent it from any further

substances so need to be stored properly. The naturally available adsorbents are chosen because it’s easi

available in the environment and is of low cost. At times they are used for other purposes and are thrown as

useless or unwanted. Fly Ash was collected at a local Fly Ash producing mill at Coimbatore and the Coconut

shells was collected from a local Farm at Coimbatore (

grinded and sieved through a mesh of size 0.5 mm and then washed and grinded and oven dried for 24 hours for

103°C. Wastewater Samples was collected from four Textile Wastewater Outlets

collected from CETP, Veerapandi, Tirupur and One sample was collected from KPR Mills, Arasoor, Tirupur.

The Textile Wastewater contains large variety of colourants which is nothing but the dyes. The presence of

colour in a fabric helps in a good aesthetic view. The presence of colour is the only reason why the COD is in

high amount in any Textile Wastewater Sample.

Figure 1. Coconut Shells.

2.2 General Procedure -

The naturally available adsorbents are chosen because it’s easily available in the environment and is of low cost.

At times they are used for other purposes and are thrown as useless or unwanted. The Textile Wastewater

contains large variety of colourants which is nothing but the dyes. The pres

good aesthetic view. The presence of colour is the only reason why the COD is in high amount in any Textile

Wastewater Sample. The adsorbents were heated, grinded and sieved through a mesh of size 0.5 mm and then

washed and grinded and oven dried for 24 hours for 103

step is the characterization of the textile wastewater under various parameters of pH, BOD, COD, Colour and

TSS. The Second step of the experiment is the

reduce the initial parameters of pH, BOD, COD, Colour and TSS. The Fly ash was collected from a local Fly

Ash mill and the Coconut shells was collected from a local Farm. Initially, the adsorbents

grinded and made to a powder form. They are collected and then sieved through a mesh of size 0.5 mm and then

washed with distilled water in order to remove unwanted impurities. The adsorbents are oven dried for 24 hours

for 103°C. The collected wastewater samples were treated with the adsorbents with an adsorbent dosage of 6 g/l

initially.

The Experiment as per the procedure is followed and the results for the Initial Parameters and the Wastewater is

tested with the adsorbents for various effects of Effect of

Time.

3.1 Initial Parameters of the Collected Textile Wastewater Sample

The testing of the Initial Parameters of any wastewater sample is important as it gives sufficient results for the

Experiment to take place. The various parameters are pH, COD, BOD and TSS

results are tabulated (Table -1).

II. EXPERIMENTAL

Materials are very much important to perform any experiment. The materials that are used depend upon the


substances so need to be stored properly. The naturally available adsorbents are chosen because it’s easi



m at Coimbatore (Figure 1 and Figure 2). The adsorbents were heated,


Wastewater Samples was collected from four Textile Wastewater Outlets of which three samples were



c helps in a good aesthetic view. The presence of colour is the only reason why the COD is in

high amount in any Textile Wastewater Sample.

Coconut Shells. Figure 2. Fly Ash.

chosen because it’s easily available in the environment and is of low cost.


contains large variety of colourants which is nothing but the dyes. The presence of colour in a fabric helps in a



d and grinded and oven dried for 24 hours for 103°C. This study was conducted in two steps. The first


TSS. The Second step of the experiment is the treatment of Physicochemical parameters like adsorption to


Ash mill and the Coconut shells was collected from a local Farm. Initially, the adsorbents were heated and



cted wastewater samples were treated with the adsorbents with an adsorbent dosage of 6 g/l

III. RESULTS AND DISCUSSION


tested with the adsorbents for various effects of Effect of pH, Effect of Adsorbent Dosage and Effect of Contact

f the Collected Textile Wastewater Sample -


. The various parameters are pH, COD, BOD and TSSof the wastewater sample

materials that are used depend upon the


substances so need to be stored properly. The naturally available adsorbents are chosen because it’s easily



. The adsorbents were heated,


of which three samples were



c helps in a good aesthetic view. The presence of colour is the only reason why the COD is in

chosen because it’s easily available in the environment and is of low cost.


ence of colour in a fabric helps in a



This study was conducted in two steps. The first


treatment of Physicochemical parameters like adsorption to


were heated and



cted wastewater samples were treated with the adsorbents with an adsorbent dosage of 6 g/l


pH, Effect of Adsorbent Dosage and Effect of Contact


of the wastewater sample and the



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Table-1 Initial Parameters of the Collected Wastewater Sample

Samples

S1 S2 S3 S4 S5 S6 S7 Initial

Parameters

pH 8.9 15 9 13 6 13 7

BOD5 (mg/l) 430 542 630 520 380 530 400

COD (mg/l) 790 1430 890 720 400 1530 650

TSS (mg/l) 3200 1650 1200 1550 2800 1280 1300

Colour Brown Dark

Brown

Brownish

Green Purple Brown

Dark

Brown Brown

3.2 Effect of pH -

pH is defined as the logarithmic of the Hydrogen Ions Concentration. It is the measure of how acidic or basic the

water is. pH of the samples indicate that pH increases COD removal value decreases. Maximum COD removal

occurs at a pH of 14.

3.2.1 Effect of pH by using Coconut Shells as an Adsorbent -

Initially 200 ml of a wastewater sample was collected in a 5 Conical Flask by varying the pH in the order of 3,

6, 9, 12 and 14 by using Coconut Shells as an Adsorbent. Before the process the adsorbents are well maintained

at a constant temperature after treating it with a distilled water. The adsorbent dosage was maintained at 400

mg/l. The samples were stirred with the help of a stirrer and it was placed at an agitator for about an hour at 400

rpm. After 60 mins, the sample was taken out and then filtered by using a filter paper. It is seen that the

optimum COD removal was found at a pH of 14. The maximum COD Removal was around 53% for Coconut

Shells as an Adsorbent (Figure 3).

Figure 3. Effect of pH by using Coconut Shells as an Adsorbent

3.2.2 Effect of pH by using Fly Ash as an Adsorbent -

Initially 200 ml of a wastewater sample was collected in a 5 Conical Flask by varying the pH in the order of 3,

6, 9, 12 and 14 by using Fly Ash as an Adsorbent. Before the process the adsorbents are well maintained at a

constant temperature after treating it with a distilled water. The adsorbent dosage was maintained at 400 mg/l.

The samples were stirred with the help of a stirrer and it was placed at an agitator for about an hour at 400 rpm.

After 60 mins, the sample was taken out and then filtered by using a filter paper. It is seen that the optimum

COD removal was found at a pH of 14. pH is defined as the logarithmic of the Hydrogen Ions

Concentration.The maximum COD Removal was around 63% for Fly Ash as an Adsorbent (Figure 4).

3 6 9 12 14

pH (Sample 1) 750 680 539 450 400

pH (Sample 2) 1426.89 1367 1245 935 858.5

pH (Sample 3) 885 780 645 575 430

pH (Sample 4) 710 650 645 530 400

pH (Sample 5) 378 365 280 250 200

pH (Sample 6) 1510.3 1480 1440.35 1380.5 1330

pH (Sample 7) 645 620 580 567 545

0

200

400

600

800

1000

1200

1400

1600

CO

D (

mg

/l)

pH

pH (Sample 1)

pH (Sample 2)

pH (Sample 3)

pH (Sample 4)

pH (Sample 5)

pH (Sample 6)

pH (Sample 7)



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Figure 4. Effect of pH by using Fly Ash as an Adsorbent

3.3 Effect of Adsorbent Dosage -

Adsorbents used in this study are Fly Ash and Coconut Shells. The Adsorbent Dosage is usually done to know

how the adsorbents are used to adsorb the Wastewater to treat the textile wastewater. This takes place with the

procedure. The following procedure is followed to know the exact amount of These adsorbents were heated,

made into powder form, oven dried and was washed with distilled water and again was oven dried for 24 hours

for about 103°C. The samples show that increase in Adsorbent Dosage will reduce the COD Concentration.

3.3.1 Effect of Adsorbent Dosage by using Coconut Shells as an Adsorbent -

Initially 200 ml of a wastewater sample was collected in a 5 Conical Flask by maintaining at a pH of 14 and

varying the Adsorbent Dosage in the order of 4, 6, 8, 10 and 12 for the adsorbent Coconut Shells. The samples

were agitated by placing in an agitator for about an hour at 400 rpm. After 60 mins, the sample was taken out

and then filtered by using a filter paper. It is seen from both the adsorbents that the optimum Adsorbent Dosage

was 12 mg/l for the maximum COD and Colour removal at a constant pH of 14. At the maximum Adsorbent

Dosage, the maximum COD Removal was around 62% for Coconut Shells as an Adsorbent (Figure 5).

Figure 5. Effect of Adsorbent Dosage by using Coconut Shells as an Adsorbent

3 6 9 12 14

pH (Sample 1) 750 680 539 450 400

pH (Sample 2) 1426.89 1367 1245 935 858.5

pH (Sample 3) 885 780 645 575 430

pH (Sample 4) 710 650 645 530 400

pH (Sample 5) 390 370 350 335 275

pH (Sample 6) 1525.35 1485 1450 1400 1367.35

pH (Sample 7) 648 620 590 575 548

0

200

400

600

800

1000

1200

1400

1600

CO

D (

mg

/l)

pH

pH (Sample 1)

pH (Sample 2)

pH (Sample 3)

pH (Sample 4)

pH (Sample 5)

pH (Sample 6)

pH (Sample 7)

4 6 8 10 12 14 16 18

Adsorbent Dosage (Sample 1) 280 400 580 654 776

Adsorbent Dosage (Sample 2) 825 933.25 1128 1260 1356.46


Adsorbent Dosage (Sample 4) 320 470 535 610 695.2

Adsorbent Dosage (Sample 5) 230 250.25 290 295.45 320.2 350 365 370

Adsorbent Dosage (Sample 6) 1428.56 1445 1450 1470 1489.2 1505 1518.45 1520

Adsorbent Dosage (Sample 7) 520 540 570 588 602 610 628 640

0

200

400

600

800

1000

1200

1400

1600

CO

D (

mg

/l)

Adsorbent Dosage (mg/l)

Adsorbent Dosage

(Sample 1)Adsorbent Dosage






(Sample 7)



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3.3.2 Effect of Adsorbent Dosage by using Fly Ash as an Adsorbent -


varying the Adsorbent Dosage in the order of 4, 6, 8, 10 and 12 for Fly Ash. The samples were agitated by

placing in an agitator for about an hour at 400 rpm. After 60 mins, the sample was taken out and then filtered by

using a filter paper. It is seen from both the adsorbents that the optimum Adsorbent Dosage was 12 mg/l for the

maximum COD and Colour removal at a constant pH of 14. At the maximum Adsorbent Dosage, the maximum

COD Removal was around 68% for Fly Ash as an Adsorbent (Figure 6).

Figure 6. Effect of Adsorbent Dosage by using Fly Ash as an Adsorbent

3.4 Effect of Contact Time -

Contact Time is an important parameter for an adsorbent to be considered for treating any wastewater including

Textile Wastewater with the presence of Fly Ash and Coconut Shells as an Adsorbent. From the Effect of pH

and the Effect of Adsorbent Dosage, the Contact Time was found to be around 60 minutes. It is also seen that

the contact time increases with the agitator speed for about 400 rpm for both the adsorbents. The Contact Time

will also deal with the colour removal. It will be seen that if Contact Time increases, COD and Colour reduction

increases.

3.4.1 Effect of Contact Time by using Coconut Shells as an Adsorbent -


constant Adsorbent Dosage as 12 mg/l for the adsorbent of Coconut Shells. When compared to Fly Ash,

Coconut Shells have lesser adsorbing capacity as per studies. Contact Time is an important parameter for an

adsorbent to be considered for treating any wastewater including Textile Wastewater with the presence of Fly

Ash and Coconut Shells as an Adsorbent. The samples were agitated by placing in an agitator for different time

intervals of 30, 60, 90, 120 and 150 minutes at 400 rpm. After the time interval, the samples were taken out and

then filtered by using a filter paper. At Optimum Contact Time, COD Removal occurred at 76% for Coconut

Shells as an Adsorbent and Colour Change from Dark Brown to Moderate Brown for Coconut Shells as an

Adsorbent. And the maximum colour removal was found to be at Sample 2 when using Coconut Shells as an

Adsorbent. It is also seen that the contact time increases with the agitator speed for about 400 rpm for both the

adsorbents. The Contact Time will also deal with the colour removal. Contact Time is an important parameter

for an adsorbent to be considered for treating any wastewater including Textile Wastewater with the presence of

Fly Ash and Coconut Shells as an Adsorbent. From the Effect of pH and the Effect of Adsorbent Dosage, the

Contact Time was found to be around 60 minutes. It is also seen that the contact time increases with the agitator

speed for about 400 rpm for both the adsorbents. The Contact Time poses as the main reason in COD and

Colour Removal. It will be seen that if Contact Time increases, COD and Colour reduction increases (Figure 7).

4 6 8 10 12 14 16 18





Adsorbent Dosage (Sample 5) 250 270 290.5 300 328.2 368.25 375.45 395

Adsorbent Dosage (Sample 6) 1400 1450 1468 1480 1493 1503.45 1510 1527

Adsorbent Dosage (Sample 7) 480 520 550 578 590 610 635 648

0

200

400

600

800

1000

1200

1400

1600

CO

D (

mg

/l)

Adsorbent Dosage (mg/l)

Adsorbent Dosage

(Sample 1)

Adsorbent Dosage

(Sample 2)

Adsorbent Dosage

(Sample 3)

Adsorbent Dosage

(Sample 4)

Adsorbent Dosage

(Sample 5)

Adsorbent Dosage

(Sample 6)

Adsorbent Dosage

(Sample 7)



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Figure 7. Effect of Contact Time by using Coconut Shells as an Adsorbent

3.4.2 Effect of Contact Time by using Fly Ash as an Adsorbent -


constant Adsorbent Dosage as 12 mg/l for the adsorbent Fly Ash. The samples were agitated by placing in an

agitator for different time intervals of 30, 60, 90, 120 and 150 minutes at 400 rpm. After the time interval, the

samples were taken out and then filtered by using a filter paper. At Optimum Contact Time, COD Removal

occurred at 80% for Fly Ash as an Adsorbent and Colour Change was found to be from Dark Brown to

Moderate Brown for Fly Ash as an Adsorbent. It is seen that the Sample 2 has the highest Colour Removal for

Fly Ash as an Adsorbent (Figure 8).

Figure 8. Effect of Contact Time by using Fly Ash as an Adsorbent

30 60 90 120 150

Contact Time (Sample 1) 345 480 560 690 720

Contact Time (Sample 2) 780 857.9 990 1225 1385



Contact Time (Sample 5) 250 253.5 280 300 350

Contact Time (Sample 6) 1460 1490 1508.45 1514 1527


0

200

400

600

800

1000

1200

1400

1600

CO

D (

mg

/l)

Contact Time (mins)

Contact Time

(Sample 1)Contact Time






(Sample 7)

30 60 90 120 150

Contact Time (Sample 1) 350 500 580 680 789.67





Contact Time (Sample 6) 1447.3 1480 1505.5 1510 1530


0

200

400

600

800

1000

1200

1400

1600

CO

D (

mg

/l)

Contact Time (mins)

Contact Time







(Sample 7)



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IV. CONCLUSION

The Outcome of this paper is to reduce the COD and Colour from the collected textile wastewater by using Fly

Ash and Coconut Shells as an Adsorbent. It is seen from the experimental work that the maximum Optimum

COD removal for Fly Ash as an Adsorbent was at 85% and the maximum Optimum COD removal for Coconut

Shells as an Adsorbent was at 76%. The Colour removal was found to be from Dark Brown to Light Brown for

Fly Ash and from Moderate Brown to Light Brown for Coconut Shells as an Adsorbent.

From the experiments using Eco- Friendly Low- Cost Adsorbents such as Fly Ash and Coconut Shells in the

treatment of textile wastewater, it is seen that the experiment is cost effective comparative to other treatment

methods. By comparing two adsorbents it is seen that the Fly Ash has the greatest removal capacity of COD and

Colour.

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