Textile effulent treatment, Waste water treatment

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Textile effulent treatment, Waste water treatment

  1. 1. MADE BY: SYEDA AELYA SHAH ROLL# 36
  2. 2. REASONS OF TEXTILE EFFLUENT  Wet processing of textiles involves, in addition to extensive amounts of water and dyes, a number of inorganic and organic chemicals aid in the dyeing process to impart the desired properties to dyed textile products.  Natural impurities such as waxes, proteins and pigment.  Other impurities used in processing such as spinning oils, sizing chemicals and oil stains present in cotton textiles, are removed during desizing, scouring and bleaching operations.  This results in an effluent of poor quality, which is high in BOD and COD load.
  3. 3. WHY WASTE WATER NEEDS TO BE TREATED?  Out of various activities in textile industry, chemical processing contributes about 70% of pollution.  Due to the nature of various chemical processing of textiles, large volumes of waste water with numerous pollutants are discharged.  These streams of water affect the aquatic eco-system in number of ways such as depleting the dissolved oxygen content or settlement of suspended substances in anaerobic condition, a special attention needs to be paid.
  4. 4. DIFFERENT TYPE OF WASTE GENERATED  Appearance  Ph  Color  Heavy Metal  Suspended Solid  Total Dissolved Solid  Chemical Oxygen Demand (COD)  Bio Chemical Oxygen Demand (BOD)  Oil & Grease  Surfactant
  5. 5. NATURE OF WASTE GENERATED AT EACH STEP High COD
  6. 6. LEVEL OF TREATMENT Preliminary PRIMARY SECONDARY TERTIARY
  7. 7. Preliminary Treatment It involves removal of large solids such as rags, sticks, grit and grease that may result in damage to equipment or operational problems (Physical treatment)
  8. 8. PRIMARY TREATMENT It involves removal of floating and settable materials, i.e. suspended solids and organic matter (Physical and Chemical);
  9. 9. SECONDARY TREATMENT It involves removal of biodegradable organic matter and suspended solids (Biological and Chemically)
  10. 10. TERTIARY TREATMENT It involves removal of residual suspended solids / dissolved solids (Physical, Chemical and Biological)
  11. 11. SCREENING  Coarse suspended matters such as rags, pieces of fabric, fibres, yarns and lint are removed.  Bar screens and mechanically cleaned fine screens remove most of the fibres
  12. 12. EQUALIZATION  Effluent streams are collected into ‘sump pit’.  Sometimes mixed effluents are stirred by rotating agitators or by blowing compressed air from below.  The pit has a conical bottom for enhancing the settling of solid particles EQUALIZATION TANK
  13. 13. SEDIMENTATION  This process is particularly useful for treatment of wastes containing high percentage of settable solids or when the waste is subjected to combined treatment with sewage.  The sedimentation tanks are designed to enable smaller and lighter particles to settle under gravity.  The settled sludge is removed from the sedimentation tanks by mechanical scrapping into hoppers and pumping it out subsequently. SEDIMENTATION TANK
  14. 14. NEUTRALIZATION  Normally, pH values of cotton finishing effluents are on the alkaline side. Hence, pH value of equalized effluent should be adjusted.  Use of dilute sulphuric acid and boiler flue gas rich in carbon dioxide are not uncommon.  Since most of the secondary biological treatments are effective in the pH 5 to 9, neutralization step is an important process to facilitate.
  15. 15. Chemical coagulation and Mechanical flocculation Finely divided suspended solids and colloidal particles cannot be efficiently removed by simple sedimentation by gravity. In such cases, mechanical flocculation or chemical coagulation is employed.
  16. 16. Chemical coagulation  It is a controlled process, which forms a floc (flocculent precipitate) and results in obtaining a clear effluent free from matter in suspension or in the colloidal state.  The degree of clarification obtained also depends on the quantity of chemicals used. In this method,  80-90% of the TSS  40-70% of BOD, 5days,  30-60% of the COD and  80-90% of the bacteria can be removed.  Most commonly used chemicals for chemical coagulation are alum, ferric chloride, ferric sulphate, ferrous sulphate and lime.
  17. 17. Mechanical flocculation  In mechanical flocculation, the textile waste water is passed through a tank under gentle stirring; the finely divided suspended solids coalesce into larger particles and settle out.  Specialized equipment such as clari-flocculator is also available, wherein flocculation chamber is a part of a sedimentation tank.
  18. 18. Result After Primary Treatment INLET EFFULENT PARAMETER AFTER PRIMARY TREATMENT PH 9.0-10.0 8.0-9.0 TSS 500-1500 mg/lit 250-750 mg/lit (50%) decrease COD 1500-3000 mg/lit 600-1200 mg/lit (60%) decrease BOD 200-400 mg/lit 50-100 mg/lit (25%) decrease
  19. 19. THANK -YOU

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