cleaner production
Content
APPCB INFORMATION BULLETIN
PUBLICATION 104 DECEMBER 1998
OPPORTUNITIES FOR WASTE MINIMISATION IN TEXTILE PROCESSING INDUSTRIES
BACKGROUND Step 3: DYEING In Andhra Pradesh there are about 50 textile units processing 10 lakh meters per day of Grey cloth. Most of the units are located in and around Hyderabad and processing synthetic grey cloth (polyester). The textile processing industry is high water consuming industry generating large volumes of waste water. These industries are facing serious problems in discharging their treated effluents as they are land locked with no final disposal point. A.P.Pollution Control Board has attempted to solve this problem through waste minimisation programme. A.P.Pollution Control Board has conducted Waste Audits in Vivek Textile Mills (p) Ltd., Mahendra Textile Industries ltd., Kothur and M/s Vijay Anand Textile Mills (p) Ltd, Kattedan to identify the options of waste reduction.From the Audits conducted it was witnessed that there is a potential for significant financial benefit as well as reduction in effluent disposal problem.This bulletin highlights the potential for waste minimisation in the textile processing industries. PROCESS DESCRIPTION Processing of synthetic grey cloth involves mainly the following sequence of operations. Step 1: SCOURING Grey cloth in the required batch is fed into a jet dyeing machine charged with water,Sodium hydrosulphite and caustic. The cloth to water ratio for the U jet machine is 1:3 and for long jet 1:7.Scouring is carried to remove the oil and other impurities present in the cloth. Step 2: NEUTRALISATION Neutralisation of the fabric is carried A.P.POLLUTION CONTROL BOARD, HYDERABADout using Hydrochloric acid and oxalic acid. Step 8: WASHING During washing, thickener and other additives are removed. Washing is carried out in a series of open tanks by feeding the cloth manually. Step 9:FINISHING The final finishing of the fabric is carried out in the stenter. Finishing chemicals such as silicone, softener and body agents are used to obtain fineness. For the cotton blended material (Usually 10% of the total production) Step 1 to Step 5 is repeated in the jiggers to process the cotton fibre. Chemicals such as acetic acid, levelling agent, water softener and dyes are used. This process is carried out at high temperature and pressure. Step 4: RINSING Rinsing is carried out to further neutralise the cloth and to remove the traces of chemicals and impurities. Step 5: DRYING AND WIDTH SETTING Drying and width setting of the fabric is carried out at 0 a temperature of 200 C in the stenter. The purpose is to fix the width of the cloth before sending it for printing. Step 6: PRINTING Printing of the cloth is carried out on flat bed printing machines by application of colours according to predetermined designs. Step 7: AGEING The fabric is sent to the ager after printing to ensure colour fixation. Ageing is carried out under high pressure and temperature using dry steam.
WATER BALANCE FOR A TYPICAL SYNTHETIC TEXTILE PROCESSING INDUSTRY OF CAPACITY 100 TPA. Grey cloth 100 T
Water - 2000 Kl
A1 -400 Kl
DYEING
Floor & Eqpt. Wash - 120 Kl Water - 3500 Kl Steam 1150 Kl A2 - 730 Kl Steam – 1940 Kl B O I L E R Water-3500 Kl Floor & Eqpt. Wash - 350 Kl Steam 305 Kl A3 -265Kl L1 - 2870 Kl
PRINTING & AGEING
L2 - 5060 Kl
FINISHING
Water 205 Kl Boiler blow down (L4) – 105 Kl L3 – 245 Kl
Note: A - Air Emissions L - Waste water
Product - 100 T
The figures of water consumption and waste water generation shown above for a typical textile processing plant of 100 TPA are prior to the implementation of the various waste reduction options identified. The waste audits have indicated that 50% of the waste water can be reduced by implementing waste reduction options.
A.P.POLLUTION CONTROL BOARD, HYDERABAD
WATER BALANCE FOR A TYPICAL SYNTHETIC TEXTILE PROCESSING INDUSTRY OF CAPACITY 100 TPA. Grey cloth 100 T
A1 -400 Kl
Water - 2000 Kl
DYEING
Floor & Eqpt. Wash - 120 Kl Water - 3500 Kl Steam 1150 Kl A2 - 730 Kl B O I L E R Steam – 1940 Kl Water-3500 Kl Floor & Eqpt. Wash - 350 Kl Steam 305 Kl A3 -265Kl L1 - 2870 Kl
PRINTING & AGEING
L2 - 5060 Kl
FINISHING
Water 205 Kl Boiler blow down (L4) – 105 Kl L3 – 245 Kl
Note: A - Air Emissions L - Waste water
Product - 100 T
The figures of water consumption and waste water generation shown above for a typical textile processing plant of 100 TPA are prior to the implementation of the various waste reduction options identified. The waste audits have indicated that 50% of the waste water can be reduced by implementing waste reduction options.
A.P.POLLUTION CONTROL BOARD, HYDERABAD
WASTE REDUCTION OPTIONS
Improved house keeping and work practices
Raw material change Recycling Equipment modification
Various approaches that can be adopted for minimisation of waste are Equipment modification, Improved house keeping and work practices, recycling of waste water and raw material change.
EQUIPMENT MODIFICATION
IMPROVED HOUSE KEEPING AND WORK PRACTICES • • • • • • • • • Arrest gaps in stenter walls and doors to reduce energy losses. Control moisture content in stenter exhaust by controlling the flow of air and speed of the stenter. Cover all jiggers to minimise loss of energy Arrest leaks in the steam line and provide proper insulation Take measures to avoid spillages in dyeing and washing sections. Segregate scour bath and dye bath effluents and treat separately. Isolate wet operations namely dyeing, washing, screen washing from the printing and stenter area. Plan production schedule to optimise batch size Clean dye containers with high pressure low volume wash techniques to minimise water consumption Optimise batch size Plan dyeing schedule starting from lighter shades to darker shades to reduce washings. Avoid approximation in measuring chemicals & dyes Reduce rejects by maintaining proper records and avoid repetition of same mistakes.
• • • • •
•
Install meters to maintain correct liquor ratio in jet dyeing machine, preferably electronic ones. Replace long jet machines with U-jet low liquor ratio machines. Install doctor blade in the printing machine to wipe off excess print paste Introduce vacuum slitters before stenter to reduce excess moisture and minimise energy consumption. Introduce squeezers before and after every wash tank in the washing section to minimize the use of chemicals and water. Automise color preparation to reduce dye wastage
RECYCLING OF WASTE WATER • • • • • • Recover steam condensate and reuse as boiler feed water to save energy and reduce waste water. Reuse rinse water after scouring and dyeing in the subsequent scour bath and dye bath preparation Reuse scour bath water after removing oil. Avoid contamination of cooling water by minimising the leakages in heat exchangers and recycle the water. Recycle the treated waste water for blanket and screen washings. Use treated effluent for first wash of dye containers in colour room.
• • • •
RAW MATERIAL CHANGE • Use Grey cloth with less than 3% oil content.
A.P.POLLUTION CONTROL BOARD, HYDERABAD.
FINANCIAL BENEFITS
Implementation of waste minimisation programme needs management commitment and support and would lead to significant financial gains. The expected savings from implementing the waste reduction options are : Sl.No OPTIONS SAVINGS
per annum In Rupees
1 2. 3. 4. 5.
Install electronic water meters to maintain correct liquor ratio in jet dyeing machine. Reuse second rinse bath for dye bath preparation in jet dyeing machine. Reuse scour bath in the successive scour bath after removing oil Reuse Cooling water by maintaining the heat exchanger without any leaks. Reuse steam condensate as boiler feed water to reduce water consumption and minimise energy requirements. Install squeezers in between washing tanks to avoid carryover of water along with fabric Reuse the treated effluent for blanket washing and screen washing by installing water recirculation system. Install doctor blade in the printing machine to wipe off excess print paste and reuse it for black colour preparation.
50,000 15,000 60,000 35,000 30,000
6. 7.
1,35,000 50,000
8.
45,000
References:
• Guidelines for preparing waste Assesments EPA Victoria #277 October 1994 Waste Minimisation: Assessments and Opportunities for industry EPA Vic #351 July 1993 UNEP textile guidelines
For further information and assistance Contact :
Mr. P. Vishwanatham or Mr.S.S.S.Murali. CLEANER PRODUCTION CELL, A.P.POLLUTION CONTROL BOARD, II FLOOR, HUDA COMPLEX, MAITRIVANAM,S.R.NAGAR POST, HYDERABAD – 38.
Phone: 3734043, 3731120, 3732132, 3731126 Fax: 040 293261
•
•
A.P.POLLUTION CONTROL BOARD, HYDERABAD
PUBLICATION 104 DECEMBER 1998
OPPORTUNITIES FOR WASTE MINIMISATION IN TEXTILE PROCESSING INDUSTRIES
BACKGROUND Step 3: DYEING In Andhra Pradesh there are about 50 textile units processing 10 lakh meters per day of Grey cloth. Most of the units are located in and around Hyderabad and processing synthetic grey cloth (polyester). The textile processing industry is high water consuming industry generating large volumes of waste water. These industries are facing serious problems in discharging their treated effluents as they are land locked with no final disposal point. A.P.Pollution Control Board has attempted to solve this problem through waste minimisation programme. A.P.Pollution Control Board has conducted Waste Audits in Vivek Textile Mills (p) Ltd., Mahendra Textile Industries ltd., Kothur and M/s Vijay Anand Textile Mills (p) Ltd, Kattedan to identify the options of waste reduction.From the Audits conducted it was witnessed that there is a potential for significant financial benefit as well as reduction in effluent disposal problem.This bulletin highlights the potential for waste minimisation in the textile processing industries. PROCESS DESCRIPTION Processing of synthetic grey cloth involves mainly the following sequence of operations. Step 1: SCOURING Grey cloth in the required batch is fed into a jet dyeing machine charged with water,Sodium hydrosulphite and caustic. The cloth to water ratio for the U jet machine is 1:3 and for long jet 1:7.Scouring is carried to remove the oil and other impurities present in the cloth. Step 2: NEUTRALISATION Neutralisation of the fabric is carried A.P.POLLUTION CONTROL BOARD, HYDERABADout using Hydrochloric acid and oxalic acid. Step 8: WASHING During washing, thickener and other additives are removed. Washing is carried out in a series of open tanks by feeding the cloth manually. Step 9:FINISHING The final finishing of the fabric is carried out in the stenter. Finishing chemicals such as silicone, softener and body agents are used to obtain fineness. For the cotton blended material (Usually 10% of the total production) Step 1 to Step 5 is repeated in the jiggers to process the cotton fibre. Chemicals such as acetic acid, levelling agent, water softener and dyes are used. This process is carried out at high temperature and pressure. Step 4: RINSING Rinsing is carried out to further neutralise the cloth and to remove the traces of chemicals and impurities. Step 5: DRYING AND WIDTH SETTING Drying and width setting of the fabric is carried out at 0 a temperature of 200 C in the stenter. The purpose is to fix the width of the cloth before sending it for printing. Step 6: PRINTING Printing of the cloth is carried out on flat bed printing machines by application of colours according to predetermined designs. Step 7: AGEING The fabric is sent to the ager after printing to ensure colour fixation. Ageing is carried out under high pressure and temperature using dry steam.
WATER BALANCE FOR A TYPICAL SYNTHETIC TEXTILE PROCESSING INDUSTRY OF CAPACITY 100 TPA. Grey cloth 100 T
Water - 2000 Kl
A1 -400 Kl
DYEING
Floor & Eqpt. Wash - 120 Kl Water - 3500 Kl Steam 1150 Kl A2 - 730 Kl Steam – 1940 Kl B O I L E R Water-3500 Kl Floor & Eqpt. Wash - 350 Kl Steam 305 Kl A3 -265Kl L1 - 2870 Kl
PRINTING & AGEING
L2 - 5060 Kl
FINISHING
Water 205 Kl Boiler blow down (L4) – 105 Kl L3 – 245 Kl
Note: A - Air Emissions L - Waste water
Product - 100 T
The figures of water consumption and waste water generation shown above for a typical textile processing plant of 100 TPA are prior to the implementation of the various waste reduction options identified. The waste audits have indicated that 50% of the waste water can be reduced by implementing waste reduction options.
A.P.POLLUTION CONTROL BOARD, HYDERABAD
WATER BALANCE FOR A TYPICAL SYNTHETIC TEXTILE PROCESSING INDUSTRY OF CAPACITY 100 TPA. Grey cloth 100 T
A1 -400 Kl
Water - 2000 Kl
DYEING
Floor & Eqpt. Wash - 120 Kl Water - 3500 Kl Steam 1150 Kl A2 - 730 Kl B O I L E R Steam – 1940 Kl Water-3500 Kl Floor & Eqpt. Wash - 350 Kl Steam 305 Kl A3 -265Kl L1 - 2870 Kl
PRINTING & AGEING
L2 - 5060 Kl
FINISHING
Water 205 Kl Boiler blow down (L4) – 105 Kl L3 – 245 Kl
Note: A - Air Emissions L - Waste water
Product - 100 T
The figures of water consumption and waste water generation shown above for a typical textile processing plant of 100 TPA are prior to the implementation of the various waste reduction options identified. The waste audits have indicated that 50% of the waste water can be reduced by implementing waste reduction options.
A.P.POLLUTION CONTROL BOARD, HYDERABAD
WASTE REDUCTION OPTIONS
Improved house keeping and work practices
Raw material change Recycling Equipment modification
Various approaches that can be adopted for minimisation of waste are Equipment modification, Improved house keeping and work practices, recycling of waste water and raw material change.
EQUIPMENT MODIFICATION
IMPROVED HOUSE KEEPING AND WORK PRACTICES • • • • • • • • • Arrest gaps in stenter walls and doors to reduce energy losses. Control moisture content in stenter exhaust by controlling the flow of air and speed of the stenter. Cover all jiggers to minimise loss of energy Arrest leaks in the steam line and provide proper insulation Take measures to avoid spillages in dyeing and washing sections. Segregate scour bath and dye bath effluents and treat separately. Isolate wet operations namely dyeing, washing, screen washing from the printing and stenter area. Plan production schedule to optimise batch size Clean dye containers with high pressure low volume wash techniques to minimise water consumption Optimise batch size Plan dyeing schedule starting from lighter shades to darker shades to reduce washings. Avoid approximation in measuring chemicals & dyes Reduce rejects by maintaining proper records and avoid repetition of same mistakes.
• • • • •
•
Install meters to maintain correct liquor ratio in jet dyeing machine, preferably electronic ones. Replace long jet machines with U-jet low liquor ratio machines. Install doctor blade in the printing machine to wipe off excess print paste Introduce vacuum slitters before stenter to reduce excess moisture and minimise energy consumption. Introduce squeezers before and after every wash tank in the washing section to minimize the use of chemicals and water. Automise color preparation to reduce dye wastage
RECYCLING OF WASTE WATER • • • • • • Recover steam condensate and reuse as boiler feed water to save energy and reduce waste water. Reuse rinse water after scouring and dyeing in the subsequent scour bath and dye bath preparation Reuse scour bath water after removing oil. Avoid contamination of cooling water by minimising the leakages in heat exchangers and recycle the water. Recycle the treated waste water for blanket and screen washings. Use treated effluent for first wash of dye containers in colour room.
• • • •
RAW MATERIAL CHANGE • Use Grey cloth with less than 3% oil content.
A.P.POLLUTION CONTROL BOARD, HYDERABAD.
FINANCIAL BENEFITS
Implementation of waste minimisation programme needs management commitment and support and would lead to significant financial gains. The expected savings from implementing the waste reduction options are : Sl.No OPTIONS SAVINGS
per annum In Rupees
1 2. 3. 4. 5.
Install electronic water meters to maintain correct liquor ratio in jet dyeing machine. Reuse second rinse bath for dye bath preparation in jet dyeing machine. Reuse scour bath in the successive scour bath after removing oil Reuse Cooling water by maintaining the heat exchanger without any leaks. Reuse steam condensate as boiler feed water to reduce water consumption and minimise energy requirements. Install squeezers in between washing tanks to avoid carryover of water along with fabric Reuse the treated effluent for blanket washing and screen washing by installing water recirculation system. Install doctor blade in the printing machine to wipe off excess print paste and reuse it for black colour preparation.
50,000 15,000 60,000 35,000 30,000
6. 7.
1,35,000 50,000
8.
45,000
References:
• Guidelines for preparing waste Assesments EPA Victoria #277 October 1994 Waste Minimisation: Assessments and Opportunities for industry EPA Vic #351 July 1993 UNEP textile guidelines
For further information and assistance Contact :
Mr. P. Vishwanatham or Mr.S.S.S.Murali. CLEANER PRODUCTION CELL, A.P.POLLUTION CONTROL BOARD, II FLOOR, HUDA COMPLEX, MAITRIVANAM,S.R.NAGAR POST, HYDERABAD – 38.
Phone: 3734043, 3731120, 3732132, 3731126 Fax: 040 293261
•
•
A.P.POLLUTION CONTROL BOARD, HYDERABAD
