JeradDLId0124vol001issue002.pdf

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Journal of Environmental Researh And Development Vol. 1 No. 2, Oct.-December 2006

124

COMMON EFFLUENT TREATMENT PLANT- A BLESSING

FOR SMALL SCALE INDUSTRIES AT

SACHIN INDUSTRIAL AREA, SURAT (INDIA)

D. J. Naik, K.K. Desai1, R. T. Vashi*2 and K.C.Desai3

1. Department of Chemistry, Veer Narmad South Gujarat University, Surat (India)

2. Department of Chemistry, Navyug Science College, Surat (India)3. Department of Chemistry, P. T. Science College, Surat (India)

Received April 15, 2006 Accepted October 15, 2006

ABSTRACT

Many dyestuff and dye intermediates manufacturing industries are small scale and

they cannot afford to the treat their effluents individually so they set up CETP.

Waste water discharging from dyeing house and dye manufacturing unit contain

higher amounts of BOD, COD,TDS and SS which is objectionable to the public for health

reason. Treated waste water from CETP reduces the mean level of BOD, more than 93% and

COD reduction was 90%, reduction of TDS and SS was 45 and 30% respectively. Mean

reduction of phenolic compound, nickel, oil and grease up to 50%, which is below the GPCB

permissible limit.

In this paper, the crucial role played by CETP for industrial wastewater from dyeing

industries situated at Sachin in South Gujarat is taken as a case study. Further, it is emphasized

that CETP can help industrial estates towards its sustenance and development.

Key Words : CETP, Dyes industries, Effluents, Phenolic compound Waste Water.

INTRODUCTION

India is among one of the major

producers of dyes and dyes intermediate from

Asian region and can meet the requirement of

the world at large. Dye is a major industry,

which contributes water pollution by discharging

large volume of coloured and toxic effluent.

These waste water are dumped into different

water bodies and spoil the aquatic life and

aesthetic value of the receiving water bodies.1

Dyes effluent contains heavy load of pollutants

*Author for correspence

like colour, high SS, TDS, BOD, COD and

some of them are carcinogenic and mutagenic.2

Industrial wastes primarily contain

chromium in the hexavalent form, as chromate

and dichromate. Hexavalent chromium is used

in the manufacture of inks ,industrial dyes and

paint pigments . Hexavalent chromium at

10 mg/kg of body weight will result in liver

necrosis, nephritis and ultimately death in

humanbeings.3Most of dyeing industries are

in small scale sector, existing in clusters and


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not having enough land and financial capability

for setup their own Common Effluent

Treatment Plant (CETP). As an integrated

approach, a group of about 30 dye

manufacturing industries waste treatment to setup CETP and it was in operation since 2001.

G.L. Rao4 studied the role of CETP at

Jeedi melta industrial estate in Andhra Pradesh

and S.Rajmani et al.5 studied the CETP for a

group of 14 tanneries in Bangalore and

considered CETP as appropriate and viable in

technical, environmental, social and commercial

angle. Based on preceding data, design of the

CETP was finalized. It was observed that the

combined wastewater had high COD, BOD,

TDS, ammonical nitrogen and chloride. Effluent

was found highly acidic, so it was decided that

the CETP will receive effluent from each

industry after it is neutralized. CETP has no

tertiary treatment plant, at present.

The dyes manufacturing units situated

in Sachin industrial area have an average

production capacity of about 4 metric tonnes/

month depending on their size. The quantity of

water consumed by dyes manufacturing units

ranges from 5,000 to 30,000 L/day depending

upon their production capacity. The source of

inlet water is either the bore-well or GIDCwater supply. The quantity of wastewater

generated from these industries ranges from

2,000 to 18,000 L/day.

MATERIAL AND METHODS

In the present study, ten dyes and dye

intermediates manufacturing industries were

selected for the collection of their primary

treated effluent samples. For each unit, the

pr ima ry trea ted effluent sa mples wer e

collected from tankers coming to CETP, six

times within a span of one year i. e., betweenDecember 2001 to December 2002. Water

samples of untreated and treated water from

CETP were also collected at the same time

for analysis.

The effluent water samples were

collected one litre of previously rinsed with

double distilled water polythene bottles. The

samples were analysed according to the

procedure mentioned for standard methods.6

Every time three samples were taken fromequilization tank and their analysis was also

done. Average of three analysis is reported in

Table-1. Five samples of water, treated in

CETP were taken every month and analysed.

Average results of these five analysis are given

in Table-1.

To study the characterization of primary

treatment water from each unit from

equalization tank and treated waste water from

CETP different parameters like pH, COD

(Chemical Oxygen Demand), BOD (Bio-

chemical Oxygen Demand), SS (SuspendedSolid), TDS (Total Dissolved Solids), chlorides,

phenolic compound, Ammonical nitrogen,

Hexavalent chromium, Nickel as well as oil and

grease etc. are taken. In the present study

soluble hexavalent chromium is determined

spectrophometrically by complexing with

diphenyl carbazide. Take an aliquot of the acid

digested sample and filter if necessary. Add

ammonium hydroxide or dilute sulfuric acid to

make the solution neutral and dilute it to

100 ml and add 2 ml of diphenyl carbazide

solution , mix and allow to stand for 10 minutes

for full colour development .Mesuare the

absorbance at 540 nm. Prepare a calibration

curve using standard chromium (VI) solution.6

RESULTS AND DISCUSSION

Based on the field inventory, dyeing

processes adopted by the ten dyeing industries,

water usage and wastewater discharge pattern,

characterization of wastewater, regulations of

GPCB etc., the following design components

for CETP were adopted as shown in Table-2and the flow diagram of the CETP is presented

in Fig. 1. The evaluation of the performance of

all the units in the treatment plant is carried out

regularly and the plant performance data is

given in Table-2.


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Table 1. Mean Values of Wastewater Characteristics at Different Stages ofTreatment in CETP

Sr. Parameter Industrial Waste water Treated Permissible

No. wastewater from waste water limit of after primary Equalization GPCB

treatment tank Mean S.D. Mean S.D. Mean S.D.

1. PH 6.9 8.2 7.2 7.9 7.1 7.5 6.5-8.5

2. COD 2705 889 2935 232 262 15 250

(247-284)

3. BOD (3 days 857 285 896 84 56 4 100

at 27 C) (51-62)

4. Suspended Solids 119 25 122 17 84 15 100

(68-100)

5. Total Dissolved 11,4813320 9562 1426 6268 319 2100

Solids (5890-6840)

6. Chlorides as Cl 3911 2182 6433 606 5567 388 1000

(5100-6200)

7. Phenolic 1.50 1.01 1.58 0.36 0.30 0.07 1

Compound (0.18-0.40)

8. Ammonical 26 10 27 5 13 2 50

Nitrogen as N (10-16)

9. Hexavalent 0.06 0.05 0.08 0.01 0.06 0.01 0.1

Chromium (0.04-0.08)

10. Nickel 0.26 0.18 0.15 0.27 0.13 0.02 1

(0.11-0.16)

11. Oil and Grease 5.58 2.94 8.03 1.22 2.70 0.41 10

(2.2-3.4)

Value in parenthesis gives range

All values except pH are expressed as mg/l

S. D. = Standard deviation

Table 2. Design criteria Adopted for CETP

Sr. No. Name of Unit Number Capacity in liters

1. Collection tank 2 6,75,000

2. Lime dosing tank 2 5,000

3. Ferrous Sulphate tank 2 5,000

4. Polyelectrolyte dosing tank 2 5,000

5. Flocculating chamber 1 36,000

6. Primary clarifier 1 1,00,000

7. Aeration tank 2 11,00,000

8. Secondary clarifier 1 1,00,000

9. Treated water tank 2 62,500


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1. pH of primary treated waste water (6.9-

8.2) from equalization tank ( 7.2 7.9)

and treated waste water (7.1 7.5) from

CETP was fall within the GPCB limit of

6.5 to 8.5.2. Mean COD value of treated water from

CETP is 262 mg/l (in a range of 247 to

284 mg/l), which is almost in agreement

with GPCB limit of 250 mg/l.

3. The mean value of BOD is 56 mg/l for

treated water (in the range of 51 to 62

mg/l), which is below the GPCB

permissible limit of 100 mg/l.

4. Mean value of SS is 84 mg/l (with a

range of 68 to 108 mg/l), which is below

the GPCB permissible limit of 100 mg/l.

5. Mean value of ammonical nitrogen is 13

mg/l (with a range of 10 to 16 mg/l),

which is below the GPCB limit of 50 mgl.

6. Mean value of phenolic compound is

0.30 mg/l (with a range of 0.18 to 0.40

mg/l), which is below the GPCB

permissible limit of 1 mg/l.

7. Mean value of Hexavalent chromium

(0.06 mg/l) and Nickel (0.13 mg/.) are

below the permissible limit of GPCB.

8. Mean value of oil and grease content of

treated wastewater is 2.7 mg/l with a

range of 2.2 to 3.4 mg/l, which is below

the GPCB permissible limit of 10 mg/l.

9. Mean value of TDS is 6268 mg/l and

chloride is 5567 mg/l, which are muchhigher than the GPCB permissible limit

of 2100 and 1000 mg/l for TDS and

chloride respectively. This is due to very

high TDS of borewell water, which is

used by most of the industries.

CONCLUSION

Treated waste water from CETP

reduces the mean level of BOD, more than

93% and COD reduction was 90%, reduction

of TDS and SS was 45 and 30% respectively.

Mean reduction of phenolic compound, nickel,oil and grease up to 50%.Thus it is seen that

CETP is quite effective in treating the effluent

water of about 30 industries combined and the

quality of effluent water meets the requirement

of GPCB and can be safely discharged in

sewage. If every industry sets up its own plant

for effluent treatment was much more costly.

The recurring cost of CETP and workload of

GPCB monitoring the effluent water quality is

also sufficiently reduced.

Fig. 1. Flow Diagram of CETP.


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Acknowledgement: The authors are

thankful to CETP ,Sachin and Department of

Chemistry, Veer Narmad South Gujarat

University,Surat for providing laboratory

facilities.REFERENCES

1. Burangey A. S. and Sharma V., Dye

industry effluent. Environ. Update, 4, 23-

24 (1997).

2. Khanna S. K. and Das M. J. Sci. Ind.

Res., 50, 965-974 (1991).

3. Sarkar S. and Gupta G.,Indian J. Environ

Hlth, 45(1),73-82 (2003).

4. Standard Methods for Examination of

water and waste water, APHA, AWWA,

WPCF, U. S. A., 20th

Ed. (1998).5. Rao K.L., Journal IAEM, 32,23-27

(2005).

6. Rajamani S., Suthathrarajan R.,

Ravindranath E. and Baghavan,

K.V., Jo ur na l IA EM, 22 ,175-178

(1995).

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