ADEQUACY AND EFFICACY OF

TREATMENT PLANT TREATING

ELECTRONICS INDUSTRY WASTEWATER

Objective of the Study

To experimentally check the adequacy and efficacy of

various treatment processes involved in the treatment

plant by calculating the design parameters at different

points.

2

Scope of the Study

• This experimental study focuses on types of treatment processes used by the

Electronics Industry in treating the effluent wastewater.

• Study aims to suggest positive changes, if any, in the processes for attainingthe maximum efficiency.

• For the treatment of wastewater this facility has 2 treatment facilities-

a) Effluent Treatment Plant (ETP)

b) Sewerage Treatment Plant (STP)

Our experimental study has chosen the Effluent Treatment Plant.

• An effluent treatment plant of a reputed MNC in the field of electronics

manufacturing is chosen. This company is in electronics manufacturing field in

India since 90s.

3

Design Basis

The following characteristics have been considered in the design of ETP-

Treatment Plant Details

Sr. No. Parameter Inlet Outlet

1 Flow (m3/hr) 10 10

2 pH 7-8 7-8

3 Fe (ppm) 32.11 <3

4 Zn (ppm) 277.2 <5

5 Mn (ppm) 6.2 <2

6 Pb (ppm) 3 <0.1

7 Cu (ppm) 0.3 <3

4

5

Flow Diagram of the treatment Plant

C BUILDING

COLLECTION

TANK

SKIMMING

TANK

AERATION

TANKREACTION

TANK

PRIMARY

CLARIFIER

HOLDING

TANK

EQUALIZATION

TANK

MULTI GRADE

FILTER

pH

CORRECTION

TANK

SECONDARY

CLARIFIER

OUTLET

Sludge

6

Technical DataTechnical Data of the treatment plant is summarized below:

Sr. No. Description Size/Capacity Quantity Make

1 Collection cum oil removal tank 4.2m x 0.5m x 1.0m 1 No. RCC

2 Equalization tank 4.5m x 4.0m x 3.5m 1 No. RCC

3 pH tank 3.5m x 1.0m x 1.8m 1 No. RCC

4 Sludge sump 2.5m x 2.5m x 1.6m 1 No. RCC

5 Lime dosing tank 1.4m x 1.5m x 1.6m 2 No. RCC

6 Oil collection tank 1 m3 1 No. MS

7 Fume absorber - 1 No. MSRL

8 Sludge transfer Pumps 5 m3/ hour @10 MWC 2 No. CI

9 Reaction tank 2.0 m x 1.8m x 1.6m 1 No. RCC

10 Multi grade filter 1.0 dia x 23 m H.O.S 1 No. MS

11 Pipe oil skimmer 80 NB x 500 mm long 1 No. MSEP

12 High rate solids contact clarifier grade

mechanism

Suitable for 4.0 m dia 2 No. MSEP

13 Air compressor 0.25 m3 / hr 2 No. CI

14 Centrifuge 5 m3 / hr 1 No. CI

7

Effluent Treatment Plant

Way to Secondary Clarifier

Parameters Considered

8

Various Parameters calculated in this study are as follows:

• pH

• Conductivity

• Dissolved Oxygen

• Total Dissolved Solids

• Total Suspended Solids

• Mixed Liquor Suspended Solids

• Sludge Volume Index

• Biological Oxygen Demand

• Chemical Oxygen Demand

• Ammonical Nitrogen

• Phosphate

• Oil and Grease

• Heavy Metals

Materials and Methodology

9

Sampling and Sample Preservation-

• All the experiments were performed according to the standard procedure established

by the regulatory bodies.

• Instruments used in the experiments were from the reputed companies and comply

with the necessary standards.

• Grab sampling has been done at different points of the treatment plant-

a. Inlet

b. Equalization Tank

c. Secondary Clarifier

d. Outlet

• Sampling was also done at the aeration tank for calculating the design parameters.

• One litre new PVC bottles were used for all samples taken. Sample bottles were

securely sealed following sampling and stored securely.

• The wastewater sample preserved to about 4 degrees Celsius.

Experiments Performed:

10

Sr.

No.

Parameter Method Instrument/Material Used

1 pH Electrometric Method Hach Portable Meter

Package with pH Electrode

2 Electrical Conductivity Direct Conductivity Method Hach Portable Meter

Package with Conductivity

probe

3 Dissolved Oxygen Direct DO Probe Method Hach Portable Meter

Package with DO probe

4 Total Dissolved Solids Direct TDS Method Hach Portable Meter

Package with TDS probe

5 Total Suspended Solids Gravimetric Whatman Filter Paper

6 Mixed Liquor Suspended

Solids

Gravimetric Whatman Filter Paper

7 Sludge Volume Index Volumetric followed by

gravimetric

Graduated Beaker

11

Sr. No. Parameter Method Instrument

8 Biological Oxygen

Demand

Respirometric Method BOD Bottles,

Incubator

9 Chemical Oxygen

Demand

Closed Reflux Method COD Digester,

Spectrophotometer

10 Ammonical Nitrogen Nesslerisation Method Spectrophotometer

11 Phosphate Stannous Chloride Method Spectrophotometer

12 Oil and Grease Partition-gravimetric method Separating funnel, 1L

with TFE (Teflon)

stopcock

13 Heavy Metals Flame Analysis Atomic Absorption

Spectroscopy

Results and Discussions

12

Parameter Observed Value

Inlet Equalization Tank Secondary Clarifier Outlet

pH 8.89 7.34 7.27 6.82

EC (μS/cm) 1189 1120 554 383

DO (mg/L) 5.48 4.91 7.38 7.57

13

Parameter Observed ValueInlet Equalization Tank Secondary Clarifier Outlet

TDS (mg/L) 589 549 271 188

TSS (mg/L) 239 216 156 89

589

239

549

216

271

156188

89

0

100

200

300

400

500

600

700

TDS TSS

mg/

L

Parameters

Inlet

Equalization Tank

Secondary Clarifier

Outlet

1414

Parameter Observed ValueInlet Equalization Tank Secondary Clarifier Outlet

BOD (mg/L) 160.44 132.91 79.38 38.65

COD (mg/L) 267.33 201.05 148.68 72.31

160.44

267.33

132.91

201.05

79.38

148.68

38.65

72.31

0

50

100

150

200

250

300

BOD COD

mg/

L

Parameters

Inlet

Equalization Tank

Secondary Clarifier

Outlet

15

Parameter Observed ValueInlet Equalization Tank Secondary Clarifier Outlet

Ammonical Nitrogen(mg/L)

1.00 0.735 0.249 0.127

Phosphate (mg/L) 0.775 0.624 0.349 0.201

1

0.7750.7350.624

0.249 0.324

0.1270.201

0

0.2

0.4

0.6

0.8

1

1.2

Ammonical Nitrogen Phosphate

mg/

L

Parameters

Inlet

Equaliazation Tank

Secondary Clarifier

Outlet

16

Parameter Observed ValueInlet Outlet

Oil and Grease (mg/L) 7.289 1.251

Heavy Metals (ppm)

a. Arsenic Lead

b. Iron

c. Selenium

d. Chromium

e. Lead

0.423 0.264

3.074 0.417

Not Detected Not Detected

0.253 0.003

0.321 0.205

17

0.423

3.074

0.253 0.3210.2640.417

0.0030.205

0

0.5

1

1.5

2

2.5

3

3.5

Arsenic Iron Chromium Lead

pp

m

Heavy Metals

Inlet

Outlet

18

Design Parameters in the Aeration Tank

Sr. No. Parameter Resulting Value

1 Mixed Liquor Suspended Solids 3140 (mg/L)

2 Mixed Liquor Volatile Suspended Solids 2355 (mg/L)

3 Sludge Volume Index 128 (mg/L)

4 Yield Coefficient 0.492

5 Substrate Concentration 14.50 (mg/L)

6 Volume of the Aeration Tank 78 cubic mt.

Dissolved Oxygen level is also checked at the four corners of the aeration

tank and it is averaged as 4.19 mg/ L which is more than the minimum

level of DO required.

19

Sr. No Parameter Resulting Value

7 F/M ratio 0.101 kg BOD5

8 Detention Period 7.2 hrs.

9 Return Sludge Pumping 108 m3/day

20

REMOVAL EFFICIENCIES

Parameter Efficiency (%)

Overall BOD Removal Efficiency 75.90

COD Removal Efficiency 72.95

TSS Removal Efficiencya. Primary Clarifierb. Secondary Clarifier

62.7621.0936.43

TDS Removal Efficiency 68.08

Ammonical Nitrogen Removal Efficiency 87.30

Phosphate Removal Efficiency 74.19

Oil and Gas Removal Efficiency 82.85

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Comparison of effluent discharge quality with the standards prescribed:

38.65

72.31

30

250

0

50

100

150

200

250

300

BOD COD

Sta

nd

ard

(m

g/L

)

Parameters

Observed Values (Outlet)

CPCB Standard

BOD & COD

22

1.25

89

10

100

0

20

40

60

80

100

120

O&G TSS

Sta

nd

ard

(m

g/L

)

Parameters

Observed Value (Outlet)

CPCB Standard

Oil and Grease & TSS

23

0.127 0.2

50

4.40

10

20

30

40

50

60

Ammonical Nitrogen Phosphate

Sta

nd

ard

(m

g/L

)

Parameters

Observed Value (Outlet)

CPCB Standard

Ammonical Nitrogen & Phosphate

24

0.2640.417

0.205

0.003

0.2

4.4

0.1 0.1

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Arsenic Iron Lead Chromium

Sta

nd

ard

(m

g/L

)

Parameters

Observed Value (Outlet)

CPCB Standard

Heavy Metals

Conclusions from the Study

25

Results from the present study Adequacy and Efficacy of Treatment Plant

Treating Electronics Industry Wastewater has been discussed below-

• BOD and COD removal efficiency of the treatment plant found to be

75.09% and 72.95% respectively.

• Treatment plant is capable of removing oil and grease, ammonical

nitrogen and phosphate efficiently.

• pH at the Inlet is found to be more than the design basis. Therefore, a pH

correction unit should be installed.

• Suspended Solids removal efficiency at the Primary Clarifier is found to

be 21% and at the secondary clarifier it is 36%. Therefore, additional

requirements to be done for increasing the efficiency of the primary

clarifier which is quite below.

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• Treatment plant is efficient in removing heavy metals like Iron and

Chromium as the effluent values are below CPCB standards. But

plant is not efficiently removing heavy metals like Arsenic and Lead

(effluent values found above CPCB standards).

• Important design parameters of aeration tank MLSS and SVI are

found in the acceptable limit.

• Volume of the Aeration tank required for the suspended growth

process is less than the design volume of the tank.

• Plant is adequate in its processes in the removal of various harmful

objects but some necessary arrangements are to be done for making it

more efficient.

Recommendations

27

• In the concerned Effluent treatment plant volume of the aeration tank is

not adequate to meet the suspended growth process; therefore, its capacity

should be increased for better efficiency.

• Arsenic and lead content is beyond the acceptable limits which should be

further treated with tertiary treatment processes.

• There should also a policy to be formed for better management and

operation of the unit processes.

• There should be proper working of on-site testing lab which all available

instruments for proper monitoring.

• The impact of semiconductor, electronics and optoelectronic industries ondownstream perfluorinated chemical contamination in Taiwanese rivers by AngelaYu-Chen Lin, Sri Chandana Panchangam, Chao-Chun Lo (page 1 and 8)

• Pollution assessment and heavy metal determination by AAS in waste watercollected from Kushtia industrial zone in Bangladesh by Rafiquel Islam, Jannat AlFoisal, Hasanuzzaman, Musrat Rahman, Laisa Ahmed Lisa & Dipak Kumar Paul(page 1,4& 8)

• Physico-chemical Investigations of Semiconductor Industrial Wastewater by Y.C.Wong, V. Moganaragi and N.A. Atiqah (page 1,3,4&7)

• PERFORMANCE EVALUATION OF A COMMON EFFLUENT TREATMENTPLANT TREATING TEXTILE WASTEWATERS IN INDIA by Anju Singh, RichaGautam and Swagat Kishore Mishra (page 1,3&10)

• Performance evaluation of effluent treatment plant of dairy industry by DIPALI H.CHAIUDHARI* and R.M. DHOBLE (page 1,3,4 & 6)

References

28

29

• Managing and Monitoring Effluent Treatment Plants by Mohidus Samad

Khan, Jerry Knapp, Alexandra Clemett, Matthew Chadwick, Mahbub

Mahmood and Moinul Islam Sharif (page 5,6,7,14,10 & 12)

• Electronics Manufacturing Report by World Bank

• Detection of heavy metals (Pb, Sb, Al, As) through atomic absorption

spectroscopy from drinking water by Afrasiab Khan Tareen, Imrana Niaz

Sultan (page 1,3 & 4)

• Guide Manual: Water and Wastewater Analysis by CPCB

• Performance Status of Common Effluent Treatment Plants in India by CPCB

• http://nptel.ac.in/courses/105104102/Lecture%2025.html

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THANK YOU