Waste min

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Waste min

  1. 1. WASTE MINIMISATION - FEW CASE STUDIES Dr. R.B. CHAVAN PROFESSOR, DEPARTMENT OF TEXTILE TECHNOLOGY, INDIAN INSTITUTE OF TECHNOLOGY, HAUZ KHAS, NEW DELHI - 110016 INDIA
  2. 2. WASTE MINIMISATION TECHNIQUES <ul><li>WATER CONSERVATION </li></ul><ul><li>OPTIMISATION OF CHEMICAL USAGE </li></ul><ul><li>PROCESS INNOVATIONS </li></ul><ul><li>SUBSTITUTION OF NON-ECOFRIENDLY CHEMICALS </li></ul>
  3. 3. AVERAGE WATER CONSUMPTION IN TEXTILE CHEMICAL PROCESSING <ul><li>FIBRE WATER CONSUMPTION </li></ul><ul><li> (l/kg) </li></ul><ul><li>COTTON 50 - 200 </li></ul><ul><li>WOOL 75 - 300 </li></ul><ul><li>SYNTHETIC FIBRES 10 - 100 </li></ul>
  4. 4. WATER CONSUMPTION <ul><li>POSSIBILITIES TO ACHIEVE 25% CONSERVATION IN SOME CASES </li></ul><ul><li>REDUCE TOTAL EFFLUENT VOLUME </li></ul><ul><li>TOTAL POLLUTION LOAD </li></ul>
  5. 5. <ul><li>WASTE MINIMISATION THROUGH PROCESS OPTIMISATION </li></ul><ul><li>SIZING AGENT </li></ul><ul><li>STARCH MOST COMMON SIZING AGENT </li></ul><ul><li>HIGH BOD </li></ul><ul><li>CONTRIBUTE ~ 50% BOD LOAD </li></ul><ul><li>DEGRADATION DURING DESIZING </li></ul><ul><li>RECOVERY NOT POSSIBLE </li></ul><ul><li>MEASURE </li></ul><ul><li>REPLACE STARCH BY PVA </li></ul><ul><li>RECOVER PVA </li></ul><ul><li>LESS EFFLUENT LOADING </li></ul><ul><li>COST SAVING </li></ul><ul><li>APPLICATION NOT SUITABLE FOR SMALL AND MEDIUM MILLS </li></ul><ul><li>PVA COST IS HIGH </li></ul><ul><li>EXPENSIVE PVA RECOVERY SYSTEM (ULTRA FILTRATION ) </li></ul>
  6. 6. <ul><li>MODIFICATION OF DESIZING PROCESS </li></ul><ul><li>HYDROLYTIC DESIZING </li></ul><ul><li>ENZYME OR ACID DESIZING </li></ul><ul><li>DEGRADATION PRODUCTS CONTRIBUTE TO BOD </li></ul><ul><li>OXIDATIVE DESIZING </li></ul><ul><li>HYDROGEN PEROXIDE </li></ul><ul><li>PERSULPHATE </li></ul><ul><li>DEGRADATION PRODUCTS </li></ul><ul><li>CARBON DIOXIDE </li></ul><ul><li>WATER </li></ul><ul><li>FREE FROM EFFLUENT LOAD </li></ul><ul><li>PROBLEMS </li></ul><ul><li>FORMATION OF OXY-CELLULOSE </li></ul><ul><li>PRECAUTION </li></ul><ul><li>CONTROL OVER CHEMICAL CONCENTRAION, TIME AND TEMPERATURE </li></ul>
  7. 7. <ul><li>USE OF NEW ENZYMES </li></ul><ul><li>NEW ENZYMES DEVELOPED FOR HOME LAUNDRING MARKET DEGRADE STARCH TO ETHANOL </li></ul>
  8. 8. <ul><li>TRANSFER PRINTING </li></ul><ul><li>CONVENTIONAL PRINTING (SEQUENCE) </li></ul><ul><li>PREPARATION OF COLOUR PASTE </li></ul><ul><li>PRINTING </li></ul><ul><li>DRYING </li></ul><ul><li>FIXATION </li></ul><ul><li>WASHING </li></ul><ul><li>EFFLUENT LOAD </li></ul><ul><li>DISCHARGE OF UNUSED PRINT PASTE </li></ul><ul><li>WASHING OF DESIGN SCREENS AND PRINT BLANKET </li></ul><ul><li>WASHING OF PRINTED FABRIC </li></ul>
  9. 9. <ul><li>TRNSFER PRINTING </li></ul><ul><li>SEQUENCE </li></ul><ul><li>PRINT PAPER </li></ul><ul><li>DRY </li></ul><ul><li>TRANSFER OF DESIGN ON FABRIC </li></ul><ul><li>NO WASHING OPERATION AT TEXTILE MILL </li></ul><ul><li>DRY PROCESS </li></ul><ul><li>SUITABLE FOR POLYESTER ONLY </li></ul>
  10. 10. <ul><li>WASTE MINIMISATION THROUGH ADVANCED DYEING </li></ul><ul><li>TWO WAYS TO SOLVE POLLUTION PROBLEM </li></ul><ul><li>EFFLUENT TREATMENT </li></ul><ul><li>REDUCING WASTE GENERATION AT SOURCE </li></ul><ul><li>WAYS TO MINIMISE DYE WASTE </li></ul><ul><li>LOWER LIQUOR RATIO </li></ul><ul><li>PROCESS OPTIMISATION AND INNOVATIONS </li></ul><ul><li>SUBSTITUTION OF OFFENDING DYES AND CHEMICALS </li></ul>
  11. 11. <ul><li>LOWER LIQUOR RATIOS </li></ul><ul><li>THIS APPROACH HELPS IN </li></ul><ul><li>REDUCTION IN TOTAL EFFLUENT VOLUME </li></ul><ul><li>REDUCTION IN THE QUANTITY OF CHEMICALS USED WHERE CHEMICAL CONCENTRATION EXPRESSED IN g/l </li></ul><ul><li>REDUCTION IN POLLUTION LOAD </li></ul><ul><li>EXAMPLE </li></ul><ul><li>DYEING OF COTTON WITH VAT OR REACTIVE DYE </li></ul><ul><li>CHANGE OF LIQUOR RATIO FROM 10 : 1 TO 5 : 1 </li></ul><ul><li>DECREASE IN POLLUTION LOAD ~ 40% </li></ul>
  12. 12. <ul><li>PROCESS INNOVATION </li></ul><ul><li>VERY IMPORTANT STEP TOWARDS WASTE MINIMISATION </li></ul><ul><li>CLOSE INTERACTION BETWEEN PROCESSORS, DYESTUFF MANUFACTURERS AND MACHINERY MANUFACTURERS IS ESSENTIAL </li></ul>
  13. 13. <ul><li>CASE STUDY </li></ul><ul><li>DYEING OF COTTON WITH LOW SALT REACTIVE DYES </li></ul><ul><li>SALT REQUIRMENT </li></ul><ul><li>CONVENTIONAL REACTIVE DYES 30 - 80 g/l </li></ul><ul><li>LOW SALT REACTIVE DYES 20 g/l </li></ul>
  14. 14. <ul><li>EFFECT OF HIGH SALT CONCENTRATION ON ENVIRONMENT </li></ul><ul><li>REMOVAL OF ONLY SMALL QUANTITY OF SALT DURING EFFLUENT TREATMENT </li></ul><ul><li>MAJOR QUANTITY OF SALT REMAINS IN EFFLUENT WATER </li></ul><ul><li>RIVERS AND LAKES POLLUTED BY HIGH INFLUX OF DYE EFFLUENTS CONTAINING HIGH SALT CONCENTRATION </li></ul><ul><li>FRESH WATER ORGANISMS CAN SUFFER TOXIC EFFECT </li></ul><ul><li>IN REGIONS WITH SCARCE FRESH WATER RESOURSES, SUCH WASTE WATER HAS TO BE USED FOR IRRIGATION </li></ul><ul><li>HOWEVER, IF THE SALT </li></ul><ul><li>CONCENTRATION IS TOO HIGH SOIL MAY BECOME OVER LOADED WITH SALT AND THE LAND MAY BECOME INFERTILE AND ULTIMATELY HAVE TO BE ABONDONED </li></ul>
  15. 15. <ul><li>APPROACHES TO SOLVE PROBLEM OF SALT LOAD </li></ul><ul><li>DYEING AT LOWEST POSSIBLE LIQUOR RATIO </li></ul><ul><li>USING DYE CLASSES OTHER THAN REACTIVE e.g. VAT REQUIRING LOW SALT CONCENTRATION FOR DYEING </li></ul><ul><li>USING REACTIVE DYES GIVING HIGH EXHAUSTION AND FIXATION AT LOW SALT CONCENTRATION </li></ul>
  16. 16. <ul><li>LOW SALT REACTIVE DYES </li></ul><ul><li>BI-REACTIVES </li></ul><ul><li>MEDIUM REACTIVITY </li></ul><ul><li>STABLE DYE FIBRE BOND </li></ul><ul><li>TWO CHROMOPHORES CONTRIBUTE TO HIGH AFFINITY AND HIGH COLOUR STRENGTH </li></ul><ul><li>HIGH EXHAUSTION AND FIXATION AT LOW SALT CONCENTRATION </li></ul>
  17. 17. <ul><li>THE SALT REQUIREMENT IS REDUCED TO 1/4th COMPARED TO CONVENTIONAL REACTIVE DYES </li></ul><ul><li>RINSING STEP AFTER DYE FIXATION IS MUCH FASTER AND LESS WATER IS NEEDED </li></ul><ul><li>LOW SALT DYES GIVE HIGHER FIXATION THAN CONVENTIONAL DYES </li></ul><ul><li>THIS LEADS TO LOWER DYE CONCENTRATION IN THE EFFLUENT </li></ul>
  18. 18. <ul><li>LOW SALT DYES ARE AN EXAMPLE OF ECOLOGICAL PRODUCT DESIGN THAT CONTRIBUTES TO A SAFER AND HEALTHIER ENVIRONMENT </li></ul><ul><li>THEY ADDRESS SOME URGENT ENVIRONMENTAL PROBLEMS SIMPLY BY NOT CREATING THEM IN THE FIRST PLACE </li></ul>
  19. 19. SUBSTITUTION OF OFFENDING DYES AND CHEMICALS <ul><li>SUBSTITUTION OF DYES </li></ul><ul><li>AVOID USING DYES WHICH FALL UNDER THE PREVIEW OF GERMAN REGULATIONS </li></ul><ul><li>SUBSTITUTES ARE AVAILABLE FOR MOST SUCH PRODUCTS </li></ul><ul><li>LEADING DYESTUFF MANUFACTURERS CERTIFY FOR THE ECO-FRIENDLINESS OF THEIR PRODUCTS </li></ul>
  20. 20. SUBSTITUTION OF CHEMICALS IN DYEING <ul><li>ACETIC ACID IS USED IN LARGE QUANTITIES FOR DYEING OF POLYESTER, WOOL, SILK, NYLON AND ACRYLIC </li></ul><ul><li>IT CONTRIBUTES MORE THAN 15% OF COD, BOD LOAD IN EFFLUENT </li></ul><ul><li>REPLACEMENT BY FORMIC ACID SIGNIFICANTLY LOWERS COD AND BOD LOAD </li></ul><ul><li>BOMBAY TEXTILE RESEARCH ASSOCIATION HAS DEVELOPED A BUFFER SYSTEM WHICH IS FREE FROM DRAW BACKS OF ACETIC ACID AND EFFECTIVELY MAINTAINS THE DYEBATH pH </li></ul>
  21. 21. SUBSTITUTION OF SODIUM HYDROSULPHITE IN VAT DYEING <ul><li>UNIVERSELY USED REDUCING AGENT FOR REDUCTION OF VAT DYES </li></ul><ul><li>DECOMPOSITION OF SODIUM HYDROSULPHITE IN EFFLUENT LEADS TO FORMATION OF SEVERAL BY PRODUCTS SUCH AS SODIUM SULPHATE, SODIUM BISULPHITE, SODIUM THIOSULPHATE, SODIUM SULPHIDE etc. THESE CONTRIBUTE TO POLLUTION LOAD </li></ul><ul><li>AN ECO-FRIENDLY PRODUCT BASED ON Fe (II) COMPLEX HAS BEEN DEVELOPED AT IIT DELHI </li></ul>
  22. 22. <ul><li>SUBSTITUTION OF SODIUM SULPHIDE BY GLUCOSE IN SULPHUR DYEING </li></ul><ul><li>SULPHUR DYES ARE INSOLUBLE IN WATER </li></ul><ul><li>FOR SOLUBILISATION USE OF SODIUM SULPHIDE AND SODA ASH ARE NECESSARY </li></ul><ul><li>SULPHUR BLACK MOST WIDELY USED </li></ul><ul><li>AFTER DYEING TOXIC SODIUM SULPHIDE GOES IN TO EFFLUENT UNDER ACIDIC CONDITIONS SODIUM SULPHIDE DECOMPOSES LIBERATING HYDROGEN SULPHIDE WHICH HAS SMELL OF ROTTEN EGGS </li></ul><ul><li>SULPHUR COMPOUNDS ARE TOXIC TO FISH </li></ul><ul><li>IT IS THEREFORE NECESSARY TO REPLACE SODIUM SULPHIDE IN SULPHUR DYEING </li></ul>
  23. 23. <ul><li>CASE STUDY </li></ul><ul><li>CENTURY TEXTILE MILL MUMBAI HAS IDENTIFIED AN ECO - FRIENDLY REDUCING AGENT “HYDROL” AS A SUBSTITUTE OF SODIUM SULPHIDE IN SULPHURE DYEING </li></ul><ul><li>HYDROL IS A BY-PRODUCT IN (IN LIQUID FORM) OF MAIZE STARCH INDUSTRY </li></ul><ul><li>HYDROL CONTAINS REDUCING SUGAR WHICH UNDER ALKALINE CONDITIONS (NaOH) ACT AS REDUCING AGENT AT DYEING TEMPERATURS ( 80 - 85 O C ) </li></ul><ul><li>HYDROL IS COST EFFECTIVE ENVIRONMENT FRIENDLY SUBSTITUTE OF SODIUM SULPHIDE </li></ul><ul><li>THE RESULTS OF THIS SUBSTITUTION ON EFFLUENT PLANT WERE ENCOURAGING </li></ul>
  24. 24. <ul><li>NOT ONLY SULPHIDE IN THE EFFLUENT WAS REDUCED BUT IHE AERATION SYSTEM WORKED BETTER IMPROVING SETTLING CHARACTERISTICS OF THE EFFLUENT </li></ul><ul><li>THE FOUL SMELL ASSOCIATED WITH SODIUM SULPHIDE IS ELIMINATED </li></ul><ul><li>AT PRESENT 3500 kg OF COTTON IS BEING DYED EVERY DAY IN THIS WAY </li></ul><ul><li>NO CAPITAL EXPENDITURE IS INVOLVED IN THIS SUBSTITUTION </li></ul>
  25. 25. <ul><li>STUDY AT IIT DELHI </li></ul><ul><li>A PROJECT IS IN PROGRESS AT DEPT. OF TEXTILE TECHNOLOGY, IIT , DELHI , FOR THE IN HOUSE PREPARATION OF REDUCING SUGAR BY THE HYDROLYSIS OF CARBOHYDRATE BASED PRODUCTS AND ITS USE FOR DYEING OF COTTON WITH SULPHUR DYES </li></ul>
  26. 26. <ul><li>CASE STUDY </li></ul><ul><li>POLLUTION CONTROL IN WET PROCESSING (RADHA KANHAIYA PROCESSORS, ICHALKARANJI) </li></ul><ul><li>ICHALKARANJI- INDUSTRIAL TOWN IN MAHARASHTRA STATE </li></ul><ul><li>POWER LOOMS 65000 </li></ul><ul><li>SMALL PROCESSING UNITS 25 </li></ul><ul><li>HAND PROCESSING UNITS 15 </li></ul><ul><li>SPINNING MILLS 20 </li></ul><ul><li>DYE HOUSE EFFLUENT DISPOSAL WITHOUT TREATMENT INTO PUBLIC SEWER OR INTO RIVER CAUSING SERIOUS PROBLEM FOR IRRIGATION AND THREAT TO ENVIRONMENT </li></ul><ul><li>SOME PROCESSORS TRIED TO TREAT EFFLUENT HOWEVER THE TREATMENT WAS INADEQUATE AND EFFLUENT NOT CONFIRMING TO THE NORMS OF POLLUTION CONTROL BOARD </li></ul>
  27. 27. <ul><li>A STUDY WAS CONDUCTED AT TEXTILE ENGINEERING INSTITUTE, ICHALKARANJI AND EFFLUENT PLANT WAS SET UP AT A PROCESS HOUSE TO DEAL WITH THE EFFLUENT WATER DISPOSAL </li></ul><ul><li>TOTAL PRODUCTION 40,000 m / day </li></ul><ul><li>FABRICS PROCESSED </li></ul><ul><li>POLYESTER, POLYESTER / COTTON AND POLYESTER / VISCOSE BLENDS </li></ul><ul><li>PROCESSES CARRIED OUT </li></ul><ul><li>DESIZING </li></ul><ul><li>SCOURING </li></ul><ul><li>MERCERISATION </li></ul><ul><li>BLEACHING </li></ul><ul><li>DYEING </li></ul><ul><li>FINISHING </li></ul><ul><li>EFFLUENT GENERATED 2,25,000 lit / day </li></ul>
  28. 28. <ul><li>CHARACTERISTICS OF COMBINED EFFLUENT </li></ul><ul><li> BEFORE AFTER </li></ul><ul><li> mg/l mg/l </li></ul><ul><li>1. pH 10 - 11 9 - 10 </li></ul><ul><li>2. T.D.S. 3200 - 3700 2000 - 2050 </li></ul><ul><li>3. S.S. 650 - 900 350 - 575 </li></ul><ul><li>4. B.O.D. 270 - 325 150 - 190 </li></ul><ul><li>5. C.O.D. 1200 - 1700 700 - 915 </li></ul><ul><li>6. CHLORIDES 750 - 950 300 - 450 </li></ul><ul><li>7. SULPHATE 500 - 950 500 - 650 </li></ul><ul><li>8. OILS & GREASES 15 - 17 9 - 11 </li></ul>
  29. 29. <ul><li>EFFLUENTS GENERATED IN VARIOUS DEPARTMENTS PER DAY </li></ul><ul><li>BLEACHING AND FINISHING 1,10,000 lit </li></ul><ul><li>DYEING 95,000 lit </li></ul><ul><li>DOMESTIC AND SANITORY 20,000 lit </li></ul><ul><li>TOTAL EFFLUENT 2,25,000 lit </li></ul>
  30. 30. <ul><li>MEASURES TAKEN </li></ul><ul><li>REDUCTION IN WASTE VOLUME </li></ul><ul><li>REDUCTION IN CONCENTRATION OF DYES, CHEMICALS USED </li></ul><ul><li>REDUCTION IN WASTE CONCENTRATION THROUGH RECOVERY AND REUSE </li></ul><ul><li>REDUCTION IN WASTE CONCENTRATION BY CHEMICAL SUBSTITUTION </li></ul><ul><li>REDUCTION IN WASTE CONCENTRATION BY PROCESS MODIFICATION </li></ul><ul><li>DESIGNING OF SUITABLE EFFLUENT TREATMENT PLANT </li></ul>
  31. 31. <ul><li>REDUCTION IN WASTE VOLUME </li></ul><ul><li>MEASURES </li></ul><ul><li>LEAKAGE OF WATER THROUGH PIPES, TAPS AND VALVES WAS STOPED BY REPLACING CORRODED PIPES AND TAPS </li></ul><ul><li>NUMBER OF WASHING DURING BLEACHING OF POLYESTER / COTTON ON JUMBO JIGGER WERE REDUCED FROM 3 TO 2 </li></ul><ul><li>THE FINAL WASH WATER AFTER BLEACHING WAS UTILISED FOR GIVING FIRST WASH TO THE NEXT FABRIC LOT </li></ul><ul><li>COUNTER CURRENT SYSTEM OF WASHING WAS EMPLOYED ON MERCERISATION RANGE FOR EFFICIENT REMOVAL OF CAUSTIC SODA FROM FABRIC </li></ul><ul><li>M:L IN JET DYEING WAS BROUGHT DOWN FROM 1:10 TO 1:8 </li></ul><ul><li>IN THIS WAY A REDUCTION OF 20 - 30% IN VOLUME OF WASTE WATER </li></ul>
  32. 32. <ul><li>REDUCTION IN CONCENTRATION OF DYES, CHEMICALS AND AUXILIARIES </li></ul><ul><li>MEASURES </li></ul><ul><li>INTRODUCTION OF COMPUTRE COLOUR MATCHING SYSTEM HELPED TO USE OPTIMUM DYEING RECEIPS </li></ul><ul><li>REDUCTION IN SALT CONCENTRATION BY 5 - 10 % </li></ul><ul><li>NEW FINISH FORMULATIONS WHERE IN OPTIMUM FINISHING CHEMICALS, AUXILIARIES WERE USED </li></ul>
  33. 33. <ul><li>REDUCTION IN WASTE CONCENTRATION </li></ul><ul><li>MEASURES </li></ul><ul><li>CAUSTIC RECOVERY FROM MERCERISING MACHINE ENHANCED FROM 60 % TO 80 % BY EFFICIENT WASHING OPERATION </li></ul><ul><li>LEFT OVER FINISHING FORMULATIONS WERE REUSED INSTEAD OF DISCHARGING INTO THE DRAIN </li></ul><ul><li>IN THE CARBONISING PROCESS FOR THE DISSOLUTION OF CELLULOSIC COMPONENT IN POLYESTRE BLEND, SULPHURIC ACID WAS REUSED AFTER REMOVING THE SOLID IMPURITIES BY FILTRATION </li></ul><ul><li>SOME PART OF THIS ACID WAS USED FOR LOWERING THE pH OF COMBINED EFFLUENT </li></ul>
  34. 34. <ul><li>REDUCTION IN </li></ul><ul><li>WASTE CONCENTRATION </li></ul><ul><li>BY CHEMICAL SUBSTITUTION </li></ul><ul><li>MEASURES </li></ul><ul><li>USE OF MINERAL ACID (0 BOD) IN PLACE OF ACETIC ACID (60 %) </li></ul><ul><li>USE OF DETERGENT HAVING LOW BOD IN PLACE OF SOAP (HIGH BOD) </li></ul>
  35. 35. <ul><li>EFFECT OF THE MEASURES TAKEN </li></ul><ul><li>REDUCTION IN TOTAL EFFLUENT VOLUME FROM 2,25,000 lit /day TO 2,00,000 lit / day </li></ul><ul><li>REDUCTION IN POLLUTION LOAD BY 40 - 45 % </li></ul>
  36. 36. <ul><li>EFFLUENT TREATMENT </li></ul><ul><li>SINCE THE DISPOSAL WAS NOT IN TO THE MUNICIPAL SEWERAGE BUT DIRECTLY IN TO STREAM, PRIMARY TREATMENT FOLLOWED BY SECONDARY TREATMRNTS BECAME ESSENTIAL </li></ul><ul><li>FOLLOWING OPERATIONS WERE ADOPTED </li></ul><ul><li>SCREENING </li></ul><ul><li>EQUALISATION </li></ul><ul><li>ACID DOSING </li></ul><ul><li>COAGUALATION </li></ul><ul><li>SEDIMENTATION </li></ul><ul><li>ACTIVATED SLUDGE PROCESS </li></ul><ul><li>SECONDARY SETTLING </li></ul><ul><li>FILTRATION </li></ul><ul><li>ACTIVATED CARBON TREATMENT </li></ul>
  37. 37. <ul><li>SCREENING </li></ul><ul><li>REMOVAL OF </li></ul><ul><li>COARSE FLOATING MATTER LIKE FIBRES AND LINTERS </li></ul><ul><li>HEAVY AND READILY SETTELABLE GRIT AND DIRT </li></ul><ul><li>EQUALISATION </li></ul><ul><li>MIXING OF EFFLUENT FROM VARIOUS DRAINS AND ITS EQUALISATION FOR ~8 HOURS </li></ul><ul><li>TAKE CARE OF WIDE VARIATIONS AND PREVENTION OF SHOCK LOADS </li></ul><ul><li>HELP IN SELF NEUTRALISATION OF ACIDIC AND ALKALINE STREAMS </li></ul>
  38. 38. <ul><li>ACID DOSING </li></ul><ul><li>pH CORRECTION FOR IMPROVING THE EFFICIENCY OF SUBSEQUENT TREATMENT </li></ul><ul><li>EFFLUENT pH BROUGHT DOWN FROM 9 - 10 TO 8 BY ADDING SULPHURIC ACID FROM THE CARBONISATION PROCESS </li></ul><ul><li>CONTROL OF SULPHURIC ACID ADDITION BY pH MEASURMENT </li></ul><ul><li>CHEMICAL COAGULATION </li></ul><ul><li>CARRIED OUT IN FLASH MIXER </li></ul><ul><li>ADDITION OF REQUIRED QUANTITIES OF ALUM AND POLYELECTROLITE </li></ul><ul><li>EFFECTIVELY REMOVED COLOUR AND SUSPENDED MATTER LIKE STARCH etc. </li></ul><ul><li>REDUCTION IN BOD TO AN EXTENT OF 70 - 75 % </li></ul>
  39. 39. <ul><li>SEDIMENTATION </li></ul><ul><li>CARRIED OUT IN SUITABLY DESIGNED PLATE SAPERATOR </li></ul><ul><li>THE FLOCULATED SOLID GOT SETTLED AT THE BOTTOM FORMING A SLUDGE </li></ul><ul><li>REMOVAL OF THE CLEAR SUPERNATENT LIQUID FROM THE TOP </li></ul><ul><li>REMOVAL OF SEDIMENTED SOLIDS AFTER 4 - 6 HOURS WITH THE HELP OF MUD PUMP AND TRANSFERING THE SLUDGE TO THE DRYING BEDS </li></ul><ul><li>ACTIVATED SLUDGE PROCESS / AERATION </li></ul><ul><li>THE MIXING OF SUPERNATENT LIQUOR WITH ACTIVATED SLUDGE IN A BIG TANK </li></ul><ul><li>AERATION FOR 8 HOURS </li></ul>
  40. 40. <ul><li>SECONDARY SETTLING </li></ul><ul><li>FLOW OF LIQUOR CONTAINING ACTIVATED SLUDGE INTO SETTLING TANK </li></ul><ul><li>SLUDGE SEPERATION AND ITS RECYCLING TO AERATION TANK </li></ul><ul><li>CLEAR SUPERNATENT LIQUOR </li></ul><ul><li>FILTRATION </li></ul><ul><li>REMOVAL OF SUSPENDED AND PRECIPITETED PARTICALS WITH THE HELP OF FILTER BED COMPRISING OF GRAVEL AND SAND OF VARIOUS SIZES </li></ul><ul><li>ACTIVATED CARBON TREATMENT </li></ul><ul><li>REMOVAL OF COLOUR, ODOUR AND CHLORINE </li></ul><ul><li>CLEAR WATER SUITABLE FOR DISCHARGE IN TO RIVER </li></ul>
  41. 41. <ul><li>CHARACTERISTICS OF EFFLUENT AFTER ACTIVATED CARBON TREATMENT </li></ul><ul><li> A B </li></ul><ul><li>1. pH 6 - 9 7 - 7.5 </li></ul><ul><li>2. Temperature 40 O C 30 - 35 O C </li></ul><ul><li>3. T.D.S.(mg/l) 2100 1950 - 2100 </li></ul><ul><li>4. S.S. (mg/l) 100 20 - 25 </li></ul><ul><li>5. BOD (mg/l) 30 25 - 35 </li></ul><ul><li>6. COD (mg/l) 250 175 - 200 </li></ul><ul><li>7. Chloride (as Cl mg/l) 600 250 - 425 </li></ul><ul><li>8. Sulphate(as SO4 mg/l) 1000 300 - 500 </li></ul><ul><li>9. Oils and Greases (mg/l) 10 6 - 8 </li></ul><ul><li>10. Total resudial Chlorine 1 0.3 - 0.5 </li></ul><ul><li>Bio assay test 90 % survival in 96 hours </li></ul><ul><li>A: TOLERANCE LIMITS FOR DISCHARGE IN TO </li></ul><ul><li>INLAND SURFACE WATER </li></ul><ul><li>B: TREATED EFFLUENT </li></ul>
  42. 42. <ul><li>THE TREATED EFFLUENT WAS FOUND TO BE SUITABLE FOR DIRECT DISCHARGE IN TO RIVER </li></ul><ul><li>COST </li></ul><ul><li>TREATMENT PLANT </li></ul><ul><li>FOR 2,00,000 lit /day Rs. 3,00,000 </li></ul><ul><li>RUNNING EXPENSES Rs. 18,000/month </li></ul>

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