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CP Audit in a 

Visu/Kumar 

Textile Industry 

Prof. C. Visvanathan, UEEM Program 

Dr. S. Kumar, Energy Program 

School of Environment, Resources and Development 

Asian Institute of Technology 

1

CP Audit in a Textile Industry 

ZEBRA Industry Co., Ltd.: Medium size factory in Samutprakarn 

Products: Knitted fabrics, dyed cloth and yarns 

Two main sections: Knitting and dyeing 

Office and 

Residence 

Visu/Kumar 

Municipal 

Workshop 

Yarn 

Dyeing 

Section 

Knitting Section 

Boiler 

Office 

LAB Dyeing 

Finishing 

Section 

Gate 

1 

2 

3 

4 

WW to 

Klong 

5 

6 

7 

1. Setting pond 

2. Aerated pond 2 

3. Aerated pond 1 

4. Equalization pond 

5. Oxidation pond 3 



2

Step 1: Define the Objectives and Scope of Auditing 

Objectives: 

Visu/Kumar 

• Upgrade and modify the existing treatment processes, to 

obtain higher removal efficiency of COD and color 

• Adopt a long term economically viable Cleaner Production 

approach, which essentially focuses into the possibility of waste 

prevention and reduction at the production stage, rather than 

concentrating on the end of the line pollution control 

• Investigate energy conservation measures 

Scope: 

What should be the scope of the study?? 

• Focus mainly on the dyeing and finishing section 

3

Step 2: Formation of Audit Team 

Name Designation 

Dr. C. Visvanathan Professor, Environmental Engineering Program, 

Visu/Kumar 

Audit Team Advisor 

Dr. Kumar Associate professor, Energy program 

Mr. Ramon C. de Mesa 

Ms. Mendeluz B. 

Mr. T. Pichitchai Plant Manager 

Mrs. N.T.Lien Ha Research Associate 

Mr. D.Q. Tuan Research Associate 

Ms. Yamuana Alles Dye Master 

Mr. Ashish Arora Plant Engineer 

Mr. T. Visuth Plant Engineer 

4

Step 3: Plant Walk Through: Understanding the Dyeing Process 

Visu/Kumar 

Start plant walkthrough 

After plant walkthrough, what can you observe? 

Observations: 

• Leaks/overflow in the production area 

• Bad Housekeeping at dye kitchen 

• 

• Bad insulation(steam pipes) 

• Bad smell from WWTP/Products plant 

• 

Higher emission from the boiler 

Layout problems 

•Both boilers working; no metering of steam 

•Flue gas measurement not continuous 

What Else…?? 

5

Step 4: Listing of Unit Operations 

Cloth Dyeing Section 

Visu/Kumar 

Bleaching 

Scouring 

Washing 

Filling 

Dyeing 

Washing 

Filling 

Fixing 

Drying 

What else?? 

6

Visu/Kumar 

H 2 O, L:R = 10:1 

NaOH, 1%W/W 

H 2 O 2 , 2% 

Detergent, 0.8% 

Sequestering, 1% 

OBA (Optical Brightening Agent), 0.3% 

H 2 O, 60 c 

Formic acid, 0.2% 

H 2 O 98 0 C, L:R = 10:1 

NaCl, 6.5% 

Formic acid 0.5% 

Dyestuff: disperse 0.012% 

Amonium sulphate 0.65% 

Dispersing Agent 1.0% 

Batch Operation 

H 2 O 40 0 C 

H 2 O 40 0 C 

H 2 O 40 0 C 

H 2 O 40 0 C 

H 2 O 60 0 C 

Fixing Agent 0.15% 

H 2 O L:R = 1:1 

PVAC 10% 

Softener 1% 

(non-ionic) 

H 2 O 60 0 C, L:R = 10:1 

Soaping Agent 0.15% 

Step 5: Process Flow Diagram 

Gray Cloth 

Bleaching/Scouring Fluorescent whitening 

Washing 1 

Washing 2 

Filling 1 

Cloth Dyeing 

Washing 3 

Washing 4 

Filling 2 

Fixing 

Drying 

Resin Finishing Flores whitening 

Drying 

Curing 

Rolling up Plainting Down 

What else 

is missing 

7

Step 6: Machine Layout of the Dyeing-Finishing Section 

R: Rapid Winch 

W: Washing Machine 

Visu/Kumar 

Finishing 

Finishing 

Drier 2 

Finishing 

Finishing 

Dryer1 

HT: High Temperature Winch 

: Sampling Site 

: Wastewater channels 

: Wastewater sump 

Screen 

Printing 

To Equalization Pond 

Samp. Site 4 

Sump 

Samp. Site 3 

WS3 WS2 WS1 

RW6 

RW5 

RW8 

RW7 

RW1 

RW9 

RW4 

RW3 

RW2 

HT3 HT2 HT1 

Samp. 

Site 3 

Samp. Site 3 

To Oxidation Pond 

8

Step 7: Review the WWTP 

To Klong 

Visu/Kumar 

Activated 

Carbon 

Sand filter 

Settling pond 

(400 m 2 ) 

Aerated pond 2 

(400 m 2 ) 

Aerated pond 1 

(400 m 2 ) 

Wetland 

Oxidation pond 1 (3000 m 2 ) 



Equalization 

Pond (400 m 2 ) 

Wastewater from Stentor 

Schematic Diagram of the Wastewater Treatment Plant 

Wastewater from sampling site 1 

9

Step 8: Material Consumption for the Cloth and Yarn Dyeing Sections 

Material Recorded 

Cloth (dry, kg/d) 12,000 

Yarn (dry, kg/d) 2,000 

Fresh Water (m 3 /d) 565 

Dyestuff (kg/d) 2.25 

Auxiliary Chemicals (kg/d) 3,068 

-NaOH 120 

-H2O2 240 

-Detergent 88 

- Sequestering Agent 120 

- NaCl 980 

-Formic acid 84 

- Ammonium sulphate(AMS) 66 

- Soaping Agent 30.4 

-Fixing Agent 219.2 

- Polyvinylacetate(PVAC) 1,200 

-Softener 120 

- Steam 142,000 

Visu/Kumar 

What is 

missing 

10

Step 9: 

Ground water Treated water 

softening) 

Visu/Kumar 

Domestic use 

Industrial use 

Boiler 

Yarn Dyeing section 

Cloth Dyeing section 

Knitting 

11

Step 10: Benchmarking (Comparison of wastewater generation) 

Visu/Kumar 

Type of 

processes 

Scouring, 

Bleaching, 

Dyeing and 

Washing 

Electricity 

Consumption 

Type of 

product 

Cotton Yarn 0.15 

UNIDO 

m 3 /Kg 

0.3-12.6 

MWh/ton 

Energy Consumption…???? …. > ….. 42% % 

Measured 

m 3 /Kg 

0.05 

18 MWh/ton 

Or you can use COD as another indicator (kg/ton) 

12

R: Rapid Winch 

W: Washing Machine 

Visu/Kumar 

Stenter 1 

Stenter 2 

Drier 2 

Stenter 3 

Stenter 4 

Dryer1 

HT: High Temperature Winch 

: Sampling Site 

: Wastewater channels 

: Wastewater sump 

To Equalization Pond 

Screen 

Printing 

Samp. Site 4 

Sump 

Samp. Site 3 

WS3 WS2 WS1 

RW6 

RW5 

RW8 

RW7 

RW1 

RW9 

RW4 

RW3 

RW2 

HT3 HT2 HT1 

Step 11: Sampling plan 

Samp. 

Site 3 

Samp. Site 3 

To Oxidation Pond 

13

Step 12: Overall Water Consumption Record 

Section 

Visu/Kumar 

Fresh 

water in 

To ETP Recycled Loss 

Domestic 30 30 0 

Boilers 142 N/A- 0 

Yarn 

Dyeing 

Cloth 

Dyeing 

Other 

(knitting) 

80 80 0 

485 29 0 

10 N/A 0 

Cooling 28 N/A 

Total 775 539 0 

Output: Wastewater = 539 m3 (This value was measured at the WWTP) 

Mass Balance:?? (775 -539) / (775) * 100 = 30.45% 

OK 

or not 

0 

142 

0 

56 

- 

228 

14

Step 13: Overall Water Consumption Record 

Visu/Kumar 

INPUT 

Boiler (142 m3) 

18% 

Knitting 

(10 m3) 

1% 

Domestic Usage 

(30 m3) 

4% 

Water Supply 

(775 m 3 /day) 

Yarn Dyeing 

(80 m3) 10% 

Cooling (28 m3) 

4% 

Cloth Dyeing 

(485m3) 

63% 

15

Step 14: Cloth Dyeing Wastewater 485 m 3 

Stentor WW 

6% 

Visu/Kumar 

Losses 

12% 

Fixing & 

Washing 

57% 

Bleaching 

12% 

Dyeing 

13% 

16

Step 15: Material Balance: Sector Level 

Total Input: 485 m 3 

Output 

Visu/Kumar 

Section m 3 /d 

Bleaching : 60 

Dyeing : 64 

Fixing and Washing : 274 

Stentor : 30 

TOTAL : 429 

Percentage deficit : (485 ….?? -429) / 485 * 100 % : 11.5 % < 20% 

Difference = 56 m 3 : due to evaporation losses / pick up on the cloth. 

OK 

17

Step 16: Unit Level Material Balance 

Percent Loss: 

Visu/Kumar 

Tie Compound COLOR : ADMI 

1 ADMI : 1 mg/L Dye 

Input: 

(At dyeing unit) 

Jet Dyeing : 2,040 g/d 

Dyeing 

Outputs: 

Washing 3 : 325 g/d 

Washing 4 : 275 g/d 

Fixing : 25 g/d 

Cloth : 1,400 g/d 

TOTAL : 2,025 g/d 

..?? (2040-02025)/(2040)*100 = 0.75 % How Excellent is it..? 

Total Waste 

(% Fixing of Dye) = 68% 

Industry Norms : ≥ 75% 

Which Item is not efficient..? Washing 3 

18

Step 17: Current Level of Water Reuse - Recycling 

Step 18: Quantifying the Process Outputs 

Major: 

Visu/Kumar 

Cloth Dry : 12,000 kg/d 

Wastewater : 539 m 3 /d 

Solid waste (including sludge) : 820 kg/d 

19

Step 19: 

Thousands 

16 

14 

12 

10 

8 

6 

4 

2 

0 

Visu/Kumar 

13.6 

3.5 

4 

W.W. x 0.1m3 COD Color x 0.5 ADMI BOD 

1.9 

1.5 

0.8 0.8 0.8 

1 

0.8 0.8 

0.8 0.8 

0.5 

0.7 

0.4 

0.5 

0.25 

0 0 0 0.05 0 0 

Bleaching Neutralizing Dyeing Washing 1 Fixing Washing 2 Stentor 

0.3 

7.3 

1 

PVAC 

3 

20

Step 20: Pollution Load per day on ETP 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

Visu/Kumar 

7 

Flow 

COD Load 

BOD Load 

1 1 

20 

2 2 

80 

96 

95 

8 

18 18 

Domestic Yarn Dyeing Cloth Dyeing Stenter 

21

Step 21: COD / BOD Removal Efficiency of the ETP 

Units Flowrate (m COD Removal BOD Removal 

Efficiency 

In Out Loss In Out Efficiency in out 

3 /d) 

(mg/L) 

(%) 

Visu/Kumar 

(mg/L) 

Filters 250 250 0 190 185 2.6 36 28 22.2 

Settling Pond 254 250 4 235 190 20.4 52 36 31.9 

Aerated Pond 2 258 254 4 271 235 14.6 122 52 58.0 

Aerated Pond 1 262 258 4 900 271 70.3 381 122 31.5 

Wetland Pond 539 262 277 2650 900 83.5 1174 381 84.2 

Equalization Pond 30 30 0 5800 1240 78.6 2628 338 87.1 

Total 289 

Loss in Pond: 277 m 3 /d 

How Much ??? 

Why? 

(%) 

22

Step 22: Performance of Current ETP 

Filters 

Out 250 m 3 

COD 190 

Out 250 m 3 

COD 190 

Visu/Kumar 

Setting 

Pond 

Wetland Area 

Loss due to infiltration and 

evaporation 277 m 3 (51.3%) 

20.4% COD 

31.9% BOD 

Out 254 m 3 

COD 235 

14.6% COD 

58.0% BOD 

Aerated Pond 

2 with 4 

aerators 

Loss 45.8% 

Out 258 m 3 

COD 271 

70.3% COD 

Aerated 

Pond 1 

83.5% COD 

84.2% BOD 

31.5% BOD 

Out 30 m 3 

78.6% COD 

87.1% BOD 

COD 1240 

Equalization 

Pond 

Input 539 m 3 

COD 2650 mg/L 

Out 262 m 3 

COD 900 

In 30 m 3 

COD 5800 

23

Step 23: Major Sources of Wastewater 

Visu/Kumar 

Bleaching / dyeing and finishing stage 

Wash water + Steam condensate 

Wastewater and COD Load on ETP 

24

R = Rapid Winch 

W = Washing Machine 

HT = High Temperature Winch 

CTP = Chemical Treatment Plant 

Visu/Kumar 

Sampling site 

Wastewater sump 

HT3 HT2 HT1 

Samp. 

Site 3 

RW3 

Less-polluted Wastewater channels 

Polluted Wastewater Channel 

RW4 

RW2 

RW5 

RW1 

RW7 

RW6 

RW8 

WS3 WS2 WS1 

RW9 

Sump 

1 

2 

3 

CTP 

Step 24: Proposed Layout of Segregated Effluent Channels and 

Modification of the Current ETP. 

4 

25

Step 25: 

Visu/Kumar 

Total dye Purchased : 2.25 

Total Dye Used : 2.04 

Difference in handling : ..??? % 

9.33% 

House keeping Records 

26

Option 1: Polyvinylacetate (PVAC) 

Visu/Kumar 

Used for resin finishing after dyeing process 

Daily consumption = 1200 kg/d (PVAC) 

Organic compound = compound volatile 

Expensive = 500 Baht / kg 

High BOD Load 

Smell in the drying chamber (OHS) 

Most of the ‘PVAC’ which is not attached to the cloth is removed 

at the drying chamber. 

Moisture content : at the finishing : 95% 

at the drying : 7.5% 

10% PVAC Add a vacuum evaporator 

27

Option 2: Steam Condensate 

Visu/Kumar 

Currently discharged as a Waste water at a 

temperature of 75 0 C, 

Measured volume = 120 m 3 / d 

Condensate Recovery System 

28

Fabric 

Visu/Kumar 

Boiler 

Underground cooling 

water storage 

Fresh boiler water IN 

Heat Exchanger 

Condensate discharge 

Fresh Cooling water IN 

Finishing Dip 

Drying chamber 

Fresh finishing 

chemicals 

29

Fabric 

Boiler 

Underground cooling 

water storage 

Visu/Kumar 

Boiler water 

makeup 

Heat Exchanger 

Condensate recovery unit 

Fresh Cooling water IN 

Finishing Dip 

EVAC suction system 

Drying chamber 

Fresh finishing 

chemicals 

30

Option 3: Recovery of Kerosene used in Textile Printing 

Brief Description : 

Kerosene is used as print paste thickener: 

Visu/Kumar 

120-140 c : recovery chamber 

Loss of Kerosene at Different Stages of Printing 

78% 

1% 

4% 

12% 

5% 

Before entry into Drier 

On Blankets, Screen & 

Drained waste 

On Curing machine 

Remains on fabric 

Atmospheric release from 

Drier 

Number of Trials 10 

Total kerosene used for preparation of print paste 1870 litres 

Quantity of kerosene evaporated at Dryer 1402 l itres 

Kerosene vapour recovered thro’ plant 1100 litres 

Percentage of kerosene recovery from printing Dryer 78.5% 

Percentage of Kerosene recovered based on total 

consumption 

58.8% 

31

Visu/Kumar 

Boiler is a very common heat exchange equipment 

Analyze the data 

→ Air used → 

Theoretical- Input 

Actual- Output 

→ Excess → Temp↓ 

Other Capacity 

(Blower) 

→ Efficiency 

Important (2 Phase) 

32

Visu/Kumar 

3 Pass Coal Fire Boiler 

Steam Out 

Fire Tube Steam Boiler 

Steam Out 

Smoke Stack 

Smoke Stack 

Water In 

Water Tube Steam Boiler 

33

Visu/Kumar 

Plant Walkthrough: Boiler Data 

1. Flue gas % (O 2 ) = 8.2% 

Temperature = 310 0 C 

2. Fuel = 750 kg/h 

(C = 85.9%, H = 11.8%, S = 2%,…. ) 

3. Oil Heater = 8 kW 

Oil Pump = 1 kW 

4. Fan = 30 kW 

5. Pumps = 1 kW 

6. Water Feed = 10 m 3 / h 

7. Blow Down = 0.6 m 3 / h 

8. Steam Pressure = 10 bar 

Temperature = 180 0 C 

9. Convection & Radiation Loss = 50,000 kJ/h 

34

Boiler is a very common heat exchange equipment. 

Visu/Kumar 

35

Visu/Kumar 

Boiler Analysis: Combustion 

A. Calculation of Theoretical Air requirement: 

Required data (Fuel constituents): 

C - 85.9% H - 11.8% S - 2% 

H 2 O - 0.3% Ash - 0.008% 

Chemical equations 

C + O 2 CO 2 

S + O 2 SO 2 

2H 2 + O 2 2H 2 O 

(2) (1) 

1 mole of air = 0.21 moles of O 2 + 0.79 moles of N 2 

∴ 1 mole of O 2 = 0.79/0.21 = 3.76 mole of N 2 

36

Visu/Kumar 

Calculation of Theoretical Air Requirement…….. 

Constituents % wt Moles Moles of O 2 

(for 100 Kg of fuel) (%wt/MW) required . 

C (12) 85.9 7.16 7.16 

H (2) 11.8 5.9 2.95 

S (32) 2 0.063 0.063 

For complete combustion, we require O 2 for this fuel, 

Mole of O 2 = .. 7.16 + 2.95 + 0.06 = 10.17 

??? 

∴ Theoretical Air req. = (MW)O 2*(Mole)O 2 + (3.76) * (Mole)O 2 * (MW)N 2 

A/F.. ??? 

= (32) (10.17) + (3.76) (10.17) 28 

= 1396 kg air/100 kg of fuel 

= 13.96 (kg of air/kg of fuel) 

37

Visu/Kumar 

B. Calculation of Actual Air Fuel Ratio: 

Kumar.. Check here the Water molecule in the calculation… 

Required data (Flue gas constituents) 

CO2 = 7.16 moles 

SO2 = 0.063 ,, 

N2 = (10.17) (3.76) = 38.2 (theoretical) 

O2 = x (Oxygen in flue gas - measured) 

= 3.76 x 

N 2 

∴ Total mole = 7.16 + 0.063 + 38.2 + x + 3.76 x 

= 45.46 + 4.76 x 

x 8.2 

∴ O 2 ratio in flue gas = --------------------- = ------- 

(45.46 + 4.76 x ) 100 

38

Visu/Kumar 

Calculation of Actual Air Fuel Ratio……. 

372.72 + 39.03 x = 100 x 

∴ x = 6.11 mole of O 2 

∴ Actual O 2 10.17 + 6.11 = 16.28 

∴ Actual air (kg) = (16.28) (32) + (16.28) (3.76) (28) 

= 2235.9 (kg of air/100kg of fuel) 

∴ Actual A/F = 22.35 kg of air/kg of fuel 

39

Visu/Kumar 

Flue Gas Analysis 

% O 2 in flue gas 8.2 % (measured) 

Summary 

• Theoretical Air/Fuel ratio = 13.9 (kg of air/kg of fuel) 

• Actual Air/Fuel ratio = 22.35 

Actual - Theoretical 

∴ Excess air = --------------------------- x 100 = 60% (very high) 

Theoretical 

Indicates improvements to be made in the control of air supply (for 

oil, excess air = approx 20%) 

How do you do this? Air flow control?… Valves? Fans? Blower? 

40

Visu/Kumar 

Fuel 

Air 

Water 

Electricity 

Boiler Energy Balance 

Radiation and 

convection losses 

Flue gas 

Steam 

Other losses 

Blow down 

41

A. Energy in Fuel: 

Visu/Kumar 

Boiler Energy Balance: Energy Input 

= Higher heating value of fuel oil 

= 39.7 MJ / kg of fuel 

= 39,700 kJ / kg of fuel 

B. Shaft work: (Electricity Inputs) 

(All in kJ / kg of fuel) 

Oil Heater = 8 kW * 3600/750 = 38.4 kJ / kg 

Pumps = 1 kW * 3600/750 = 4.8 kJ / kg 

Fan + Pumps = 46 kW * 3600/750 =220.8 kJ / kg 

TOTAL =264.0 kJ / kg 

Total Energy Input = 39,700 kJ / kg + 264 kJ / kg 


Energy in air is neglected ( = ambient temperature) 

42

Visu/Kumar 

h feed water 

h steam 

Enthalpy Value (From Table) : 

h water at steam 

= 217 kJ / kg 

= 2278.2 kJ / kg 

= 763 kJ / kg 

43

Visu/Kumar 

Energy Output 

Useful Output = Energy in Steam - Energy in Feed Water 

(Steam) = m w (h s -h f ) 

= 10 * 1000 (2278.2 - 217.7) / m fuel 

= 27,473 kJ / kg 

Energy lost in flue gas = m C P (T 2 -T 1 ) 

C P of air / flue gas = 1 kJ / (kg 0 K) 

m = 23 kg of air / kg of fuel 

= 23 * 1 * (310 - 30) 


44

Energy lost in blow down = m b (h b -h f ) 

= 0.6 *1000 (……. 763 - …….) 217 / 750 

Blow down value = ….… 437 kJ / kg 

Radiation and convection losses = 750,000 / m fuel 

= 750,000 / 750 

= 1,000 kJ / kg 

Energy in H 2 (lost as water vapor) = A (S + L+V) 

Visu/Kumar 

A = Water formed (kg) 

Wt of H2 = 0.118 kg /kg of fuel (data) 

A = (0.118*9) = 1.062 kg/kg of fuel 

2H 2 + O 2 = 2 H 2O 

4 + 32 = 36 

1 + 8 = 9 

45

Visu/Kumar 

S = Sensible heat of water (due to raise in temp) 

= C P (T 2 -T 1 ) 

= 4.18 (100 - 30) 

= 292.6 kJ / kg of water 

L = Latent heat of water at atmospheric condition 

= 2200 kJ / kg 

V = Sensible hot of water vapor 

= 2.18 (310 – 100) = 457.8 

Energy Loss = (1.062) (292.6 + 220)+457.8 

= 3000 kJ / kg of fuel 

Other losses = moisture in air + moisture in water 

46

Visu/Kumar 

Boiler Energy Balance Summary 

( In kJ / kg of fuel) 

Energy in = Fuel (39,700) 

= Other ( 264) 

Output = Steam (27,473) 

= Flue gas ( 6,440) 

= Blow down ( 437) 

= Hydrogen ( 3,000) 

= Radiation & 

Convection ( 1,000) 

Unaccounted --> Assumption in calculation 

Unaccounted losses ≈ 4.0 % 

Efficiency = 27,473 / 39,964 = 68.7 % 

39,964 

38,350 

1,614 

47

Option 4: Saving from Controlling Excess Air at Boiler. 

From specifications, optimum excess air air for fuel oil = 20% 

0.20 = 

Weight of excess air 

Weight of theoretical air 

Visu/Kumar 

Weight of excess air = 0.2 * 13.96 = 2.792 kg 

Weight of O 2 in excess air = 2.792 * 0.232 

= 0.65 kg 

Weight of N 2 in excess air = 2.14 kg 

Energy loss in flue gas at “correct+excess air condition” 

= m C P (T 2 -T 1 ) 

= (13.96 + 2.79) (1.02) (310 - 30) 

= 4,784 kJ / kg of fuel (1) 

48

Visu/Kumar 

But Energy loss in flue gas at 60% excess air, 

i. e., actual is 6,440 kJ/kg of fuel (2) 

Energy saving = 6,440 - 4,784 


Fuel consumption = 750 kg/h 

Energy saving / h = 1,656 * 750 

= 1,242,000 kJ/h 

49

Option 5: Heat loss through leaks away from Boiler 

• Steam pressure = 10 bar 

• Hole size = approximately 8 mm 

• From figure, heat lost for a 8 mm (0.25 inch) hole at a 

pressure of 10 bar (145 psi) can be got 

• Energy lost from steam (per year) = 3,000,000 Btu = 

3,165,300 kJ ( 1 Btu = 1.0551 kJ) 

• At 60% boiler efficiency, energy supplied by fuel = 5,275,500 

kJ (133 kg -> 150 litres of fuel) 

• Cost : Minimal (Good housekeeping) 

Visu/Kumar 

This is for only ONE leak! 

3165300 

0.6= 

x× 

3970 

X = 133 kg 

50

Annual heat loss (10 3 Btu / yr) 

Visu/Kumar 

4000 

3000 

2000 

1000 

0 

0.025 0.05 0.1 

600 psig 

400 psig 

Hole Size (in.) 

200 psig 

0.25 

100 psig 

Heat losses from steam leaks 

50 psig 

20 psig 

0.50 0.75 1.0 

51

Option 5: Heat Loss from Exposed Pipes (uninsulated) 

Visu/Kumar 

• Steam pressure = 10 bar 

• Exposed pipe length (one stretch) = approximately 5 m 

• Steam pipe diameter = 25 cm 

• From figure, heat lost for a 25 cm (10 inch) 

uninsulated pipe at a pressure of 10 bar (145 psi) can 

be got 


3,165,300 kJ ( 1 Btu = 1.0551 kJ) for 33 m 


479,590 kJ for 5 m 

• At 60% boiler efficiency, energy supplied by fuel = 

799,318 kJ (20 kg -> 23 litres of fuel) 

• Cost : Minimal (Good housekeeping) 

52

Heat loss per 100 ft of bare steam line (10 3 Btu / yr) 

5000 

4000 

3000 

2000 

1000 

Visu/Kumar 

0 

12 in. line 

10 in. line 

8 in. line 

0 100 200 300 400 500 600 

Operating steam pressure (psig) 

Heat losses from uninsulated pipes 

6 in. line 

4 in. line 

3 in. line 

2 in. line 

11/2 in. line 

1 in. line 

1/2 in. line 

53

Cost Calculation 

Water Reuse:condensate recovery 

Present effluent treatment cost = 10,200 B/month = 340 B/day 

Wastewater output = 539 m 3 /day 

Therefore cost per m 3 of wastewater = 0.6 B 

Saving due to reduction of wastewater treatment: 120 m 3 /day x 0.6 B/m 3 = 72 B/day 

Visu/Kumar 

Cost of raw water in the factory = 1.8 B/m 3 (Pumping) 

Saving due to water reuse: 120 m 3 /day x 1.8 B/m 3 = 216 B/day 

Net saving: 648 B/day = 194,400 B/year (300 working day) 

Investment: 100,000 B (reported by the factory management) 

Cost of Deionized water for Boiler = 3 B/m 3 

Saving = 3 * 120 = 360 B /d 

Cost of Fuel = 3%, 5 B /Liter 

Fuel consumption = 150,000 L/month 

Saving due to fuel reduction =?? = 150,000*3/100*12 m/y * 5 = 270,000 B 

Total Saving:?? 194,400 + 270,000 = 464,400 B 

1,000,000 B 

Payback Period : = 2.15 Years 

464,400 B/year 

54

Long-term Waste Reduction Options 

Stream Segregation 

30% of the effluents of the dyeing process could be 

separated in the form of a polluted stream 

Visu/Kumar 

60 m 3 from the bleaching stage and 64 m 3 from the 

dyeing process 

Length of channel to be built = 144 m 

Cost/m of channel = approx. 400 B/m (including labor) 

Total cost = 57 000 B 

If a reinforced concrete pipe is used instead of a channel, then 

cost/m of pipe = 200 B/m 

Total cost = 28 800 B 

55

Effluent Treatment Plant Modification: 

modification with the ETP such as adding a filter wall 

between aerated ponds 2 and 3 

Total cost of the treatment operation has decreased 

to 10,000 B/month from an original 20,000 B/month. 

Further modification of the ETP by segregation of the 

wastewater streams and using an optimum dosage of Alum 

will further reduce the treatment cost and simultaneously 

will increase its performance. 

Visu/Kumar 

56

Obvious Waste Reduction Measures 

Water Reuse: 

Condensate recycled back to boiler. 

Cooling water collected in a storage tank, and is used as non-process washing 

water. Saving of 120 m 3 of raw water per day. 

Dyeing Process: 

washing steps can be reduced to one washing each without considerably affecting 

the quality of dyeing. 

Assuming that four batches are dyed per day at 100% machine capacity, the 

reduction in raw water consumption will be 96 m 3 per day. 

Washing Practice: 

Floor and equipment washdown operations can still be improved by using hot 

water taken from the storage tank (collected cooling water) with the use of 

spray guns. 

Improving present drainage system: 

Visu/Kumar 

The drainage system can be improved by cleaning and removing all the current 

blocking objectes at site 5 and 6, inside the dyeing section and along the long 

channel leading to the wetland area. 

57

Long-term Waste Reduction Options 

Visu/Kumar 

Stream Segregation 

Innovation of Dyeing Process 

Heat Energy Conservation 

1. Improving boiler efficiency 

2. Reducing Heat Loss through leaks 

Effluent Treatment Plant Modifications 

1. treatment using Ferrous Sulfate 

2. treatment using Ferrous Sulfate and Lime 

3. treatment using Alum 

Combined Wastewater Treatment 

Colored Wastewater Treatment After Segregation 

Sludge Characteristics 

Treatment Train for Polluted Waste Stream 

Treatment Train for the Less-Polluted Stream 

58

Major Concerns of the Present Waste Water 

Treatment Plant: 

Visu/Kumar 

1. Groundwater Contamination - Wetlands ??? 

2. Aerators in Pond 1 & 2 

3. Addition of alum in pond 2 what for? 

4. Surface aeration in settling tank, what for ? 

5. Frequent regeneration of activated carbon. 

59

Option Evaluation by Weighted Sum Method 

Criteria Weight 

Option Rating (R) 

#1 Option #2 Option #3 Option #4 Option #5 Option 

R R*W R R*W R R*W R R*W R R*W 

Reduction in treatment/disposal costs 8 7 7 5 2 2 

Reduction of Input material costs 4 8 6 8 4 4 

Extent of current use in Industry 5 8 8 7 7 7 

Effect on Product quality (no effect=10) 10 9 9 2 8 8 

Low capital cost 5 2 5 4 7 8 

Low O and M cost 5 5 6 5 8 8 

Short Implementation period 8 3 5 3 7 8 

Ease of Implementation 7 3 6 5 7 8 

Reduction in Energy Bills 9 5 9 5 10 10 

Improvement in OHS 7 10 3 10 2 2 

Final 

Evaluation 

Sum of Weighted Ratings Σ (W*R) 

Option Ranking 

Feasibility Analysis Scheduled for (Date)






Reduction in treatment/disposal costs 8 7 56 7 56 5 40 2 16 2 16 

Reduction of Input material costs 4 8 32 6 24 8 32 4 16 4 16 

Extent of current use in Industry 5 8 40 8 40 7 35 7 35 7 35 

Effect on Product quality (no effect=10) 10 9 90 9 90 2 20 8 80 8 80 

Low capital cost 5 2 10 5 25 4 20 7 35 8 40 

Low O and M cost 5 5 25 6 30 5 25 8 40 8 40 

Short Implementation period 8 3 24 5 40 3 24 7 56 8 64 

Ease of Implementation 7 3 21 6 42 5 35 7 49 8 56 

Reduction in Energy Bills 9 5 45 9 81 5 45 10 90 10 90 

Improvement in OHS 7 10 70 3 21 10 70 2 14 2 14 

Final 

Evaluation 

Sum of Weighted Ratings Σ (W*R) 413 449 346 431 451 

Option Ranking 







Reduction in treatment/disposal costs 8 7 56 7 56 5 40 2 16 2 16 

Reduction of Input material costs 4 8 32 6 24 8 32 4 16 4 16 

Extent of current use in Industry 5 8 40 8 40 7 35 7 35 7 35 

Effect on Product quality (no effect=10) 10 9 90 9 90 2 20 8 80 8 80 

Low capital cost 5 2 10 5 25 4 20 7 35 8 40 

Low O and M cost 5 5 25 6 30 5 25 8 40 8 40 

Short Implementation period 8 3 24 5 40 3 24 7 56 8 64 

Ease of Implementation 7 3 21 6 42 5 35 7 49 8 56 

Reduction in Energy Bills 9 5 45 9 81 5 45 10 90 10 90 

Improvement in OHS 7 10 70 3 21 10 70 2 14 2 14 

Final 

Evaluation 

Sum of Weighted Ratings Σ (W*R) 413 449 346 431 451 

Option Ranking 4 2 5 3 1 


Audit Report 

Table of Contents 

Introduction.................................................................................................................................. 

I. Background ...................................................................................................................... 

1.1 Objective ..................................................................................................................... 

II. Planning and Organization 2 

2.1 Study Objectives.......................................................................................................... 

2.2 Formation of the Audit Team .................................................................................... 

2.3 Audit Approach........................................................................................................... 

III. Assessment Preparation Phase ........................................................................................ 

3.1 Plant's manufacturing process ................................................................................... 

3.1.1 Cloth dyeing section..................................................................................... 

3.1.2 Yarn dyeing section...................................................................................... 

3.2 Material consumption and wastewater generation.................................................... 

3.2.1 Raw material consumption.......................................................................... 

3.2.2 Water usage.................................................................................................. 

3.2.3 Wastewater characteristics .......................................................................... 

3.3 Performance of the current effluent treatment plant ................................................. 

3.3.1 Description................................................................................................... 

3.3.2 Assessment of the effluent treatment plant................................................. 

IV. Assessment Phase - Proposed reduction options............................................................ 

4.1 Obvious waste reduction measures............................................................................ 

4.2 Long term waste reduction options ........................................................................... 

4.3 Major concerns of the present effluent treatment plant ............................................ 

V. Feasibility Analysis Phase: Techno-economical Evaluation .......................................... 

Conclusions ...................................................................................................................... 

References 

Appendix A: Data Analysis 

B: Sequence of material handling observed during a one-batch period 

C: Detailed time schedule of the audit team 

D: Water use values taken from literature 

E: Flow rate measurement device 

F: Segregated flow channel dimensions 

G: Wastewater treatment 

Visu/Kumar 

Total no. of pages: 30 

63

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