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Decolourization of textile dye effluents


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Dye effluents impose hazardous effects on human beings as well as on environment. The present powerpoint deals with some of the decolourization techniques that can be adopted for treating wastewater containing toxic dyes and chemicals

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Decolourization of textile dye effluents

  1. 1. 1 Seminar on Decolourization of Textile Dye Effluents by Shameembanu A.Shameembanu A. ByadgiByadgi
  2. 2. 2 Water is the main component used in all type of industries Water used for different processes is not completely utilized & is discharged as wastewater Introduction
  3. 3. 3 Textile industry is one of the biggest consumer of potable water as well as chemicals used during textile processing stages Dyeing & finishing stages are the major producer of wastewater with complex characteristics The unused dyes & chemicals are discharged as dye effluents from various units Dyeing Bleaching Wet finishing Scourin gNeutralizing Desizing Mercerizing Printing Others Carbonizing Fueling 85% 62% 58% 52% 33% 21% 13% 10% 4% 2% 2%
  4. 4. Composition of textile dye effluents Parameters Permissible limit pH 6.5 – 8.5 Biochemical Oxygen Demand (mg/L) 100 – 300 Chemical Oxygen Demand (mg/L) 150 – 250 Total Suspended Solids (mg/L) 100 – 600 Total Dissolved Solids (mg/L) 500 – 2000 Chloride (mg/L) 250 – 1000 Total Nitrogen (mg/L) 70 – 100 4
  5. 5. 5 Dye effluents Plant species Aquatic animals Human beings Environmen t  Interrupt photosynthesis activity  Decreases soil quality  Affects plant growth  Increased level of danger to life of aquatic animals  Hazardous diseases  Carcinogenic  Increase aqueous toxicity, COD & BOD Effects of dye effluents
  6. 6. Textile wastewater is highly coloured Contain heavy metals that are complex compounds Cause high electrolyte and conductivity concentrations in the dye wastewater leading to acute and chronic toxicity problems Discolour water bodies and increase BOD of the contaminated water Carcinogenic, mutagenic and generally very harmful to the environment Need for dye effluent treatment 6
  7. 7. Decolourization techniques Physical treatment Chemical treatment Physico-chemical treatment Biological treatment 7
  8. 8. Physical Treatment ………removal of substances by use of naturally occurring forces, such as gravity, electrical attraction, and van der Waal forces, as well as by use of physical barriers Adsorption efficient in the removal of pollutants result of two mechanisms: adsorption & ion exchange influenced by many physico-chemical factors, e.g., sorbent surface area, particle size, pH, contact time 8 Methods
  9. 9. Activated carbon most commonly used method effective for adsorbing cationic, mordant & acid dyes, disperse, direct, vat, pigment and reactive dyes performance depends on the type of carbon used and the characteristics of wastewater Membrane filtration can clarify, concentrate and separates dye from effluent exhibit special features like resistance to temperature, adverse chemical environment and microbial attack 9
  10. 10. Investigation on the removal of direct red dye using Aspergillus niger and Aspergillus flavus under static and shaking conditions with modeling Mohan et. al., 2012 Tamil Nadu Objective: To investigate the potential of fungal cultures for decolourization of synthetic textile dyes 10
  11. 11. Decolourization of dyes Direct red dyes mixed in 100 ml synthetic water at different concentrations (50, 100 and 200 mg/L) Isolated organisms in the solution Incubate Static condition Shaker (37ºC and pH7) (150 rpm, 37ºC, pH 7) OD values measured at maximum absorbance values of each dye at 24th , 48th , 72nd and 96th hr Inoculate Methodology 11
  12. 12. % decolourization = OD value for control – OD value for sample OD value for Control Average decolourization = C x % D x 1000 100 x t C = initial concentration of dye (mg/l) % D = dye decolourization (%) t = time 12
  13. 13. Results and Discussion 13 Figure 1. Decolourization of Direct red by A.niger at static conditions Figure 2. Decolourization of Direct red by A.niger at 150 rpm
  14. 14. Figure 3. Decolourization of Direct red by A.flavus at static conditions Figure 4: Decolourization of Direct red by A.flavus at 150 rpm 14
  15. 15. Conclusion Isolated organisms, Aspergillus niger and Aspergillus flavus have the ability to decolorize the direct red dye Aspergillus niger decolourizes the dyes in static condition potentially where as A.flavus decolourizes at shaking growth condition The study brings out the ability of Aspergillus sp. to degrade direct dyes and reinforces the potential of these fungi for the decolourization of textile effluents 15
  16. 16. Chemical Treatment Chemicals are used in an array of processes to expedite disinfection Used alongside biological and physical cleaning processes to achieve various water standards 16
  17. 17. 17 Ozonation  A good oxidizing agent  The dosage applied is dependent on the total colour and residual COD to be removed Oxidative process  commonly used method for decolourization by chemical means  main oxidizing agent used is hydrogen peroxide  removes the dye effluent by oxidation in aromatic ring cleavage of the dye molecules Methods
  18. 18. Fenton reagent  suitable for the treatment of effluents which are resistant to biological treatment or poisonous to live biomass  Performance depends on good flock formation and settling quality 18 Photo chemical process  Degrades dye molecules into carbon dioxide and water by UV treatment  Degradation is caused by the production of high concentrations of hydroxyl radicals  The rate of removal is influenced by the intensity of UV radiation, pH, dye structure and the dye bath composition
  19. 19. Decolourization and removal of COD and BOD from raw and biotreated textile dye bath effluent through advanced oxidation processes (AOPS) Muhammad et. al., 2008 Lahore, Pakistan Objective: To study the effect of advanced oxidation processes (AOPs) on decolourization of raw and biotreated textile dye bath effluents 19
  20. 20. Methodology 20
  21. 21. Table 1. Characterization of raw and biotreated textile dye bath effluent 21 *Absorbance of colour at 465nm Parameters Raw Biotreated COD (mg/l) 750 154 A* (Colour) 1.8 1.2 BOD (mg/l) 261 76.2 pH (units) 12.1 8.4
  22. 22. Figure 5. Comparison of AOPs in terms of COD, color & BOD removal of raw textile effluent Results and Discussion 22
  23. 23. Figure 6. Biodegradability improvement of raw textile effluent 23
  24. 24. Figure 7. Comparison of AOPs in terms of (%) removal of COD, color & BOD of biotreated textile effluent 24
  25. 25. Figure 8. Biodegradability improvement of biotreated textile effluent 25
  26. 26. Conclusion The application of a combined method i.e., biotreatment and AOPs for treating dye bath effluent was advantageous The combined approach allowed better achievement of decolourization efficiency and reduced treatment costs Application of AOPs to biotreated textile effluent was more effective than raw effluent Ozonation process for raw textile effluent was better for decolourization than the AOPs applied 26
  27. 27. Decolourization of Textile dye waste waters by Hydrogen peroxide, UV and Sunlight Dinarvand, 2014 Iran Objective: To investigate the efficiency of decolourization of the azo dye with UV radiation in the presence of H2O2 27
  28. 28. Methodology 28 Figure 9. UV radiation constructed reactor box Ultraviolet radiation treatment Specifications 60 x 40 x 30 cm UV lamp of 30W Radiation wavelength 254nm Solar radiation treatment Quartz tubes with 3mL of wastewater Placed at 45º angle Exposed to sunshine (12pm – 4pm) Assessed for colour removal
  29. 29. Results and Discussion Figure 10. Decolourization by UV irradiation in the absence of H2O2 29
  30. 30. 30 Figure 11. Decolourization by UV irradiation in the presence of H2O2
  31. 31. 31 Figure 12. Decolourization by UV radiation at pH 7 with different concentrations of H2 O2
  32. 32. Optimum operating conditions of Solar light/H2 O2 In the presence of 0.143M H2 O2 solution, maximum of 97% decolourization at pH 4 and minimum of 40% decolourization at pH 10 was achieved after 90 minutes 32
  33. 33. 33 Conclusion  Decolourization percentage with UV radiation at 60 minutes in presence of 0.014M H2 O2 at 50°C temperature was 99.8  The presence of 0.143M of hydrogen peroxide caused maximum per cent decolourization (97%) in case of solar light/H2O2  It was suggested that the decolourization of dye DB-177 should be performed in the presence of ultraviolet radiation
  34. 34. 34 Physico-chemical Treatment
  35. 35. 35 Methods Sedimentation  Removal of floc by solid-liquid separation  Achieved by using low, medium and high rate settlers  The rate is determined by the speed at which water and sludge are separated Coagulation  Destabilization or neutralization of negative charges in the wastewater by addition of coagulant during rapid mixing and very short contact time  The quantity of coagulant applied depends on the quality of water  Commonly used coagulants are ferric chloride, ferric sulphate, aluminium sulphate, lime, etc
  36. 36. 36 Flocculation  Referred to formation of flocs and bridges  Previously formed flocs group together, increase in volume and density, later gets sedimented  Achieved by applying a gradient and contact time varying between 15 minutes and 3 hours
  37. 37. Removal of reactive yellow dye from aqueous solutions by using natural coagulant (Moringa oleifera) Veeramalini et. al., 2012 Chennai, India Objective: To examine the decolourization of the Reactive Yellow 145 dye by Moringa oleifera under static conditions 37
  38. 38. Methodology Preparation of coagulant 38
  39. 39. 39 Coagulation study (Jar test) 1000ml dye solution Add coagulant with rapid mixing at 100rpm for 2 min Slow mixing at 40rpm for 30 min Kept for sedimentation for 30 min Filtered using Whatman filter paper Analyzed for colour removal
  40. 40. Results and Discussion Figure 13: Effect of coagulant dose on the removal of colour 40
  41. 41. 41 Figure 14: Effect of contact time on decolourization
  42. 42. 42 Figure 15. Effect of pH on decolorization of Reactive yellow dye by M.oleifera
  43. 43. Conclusion  100mg Moringa oleifera gave approximately 95% COD reduction after10 minutes contact time while 500mg M.oleifera reduced colour by 90% at pH 10  100mg coagulant enhances efficient removal of COD and colour in the coagulation process 43
  44. 44. Decolourization and COD reduction efficiency of magnesium over iron based salt for the treatment of textile wastewater containing diazo and anthraquinone dyes Verma et. al., 2012 Odisha, India Objective: To investigate the effectiveness of MgCl2 & FeSO4 for decolourization and COD reduction 44
  45. 45. 45 Methodology Materials used Concentration (mg/L) Function Starch 1000 Sizing agent Acetic acid 200 Sizing agent Sucrose 600 Sizing agent Dyes 200 Colouring agent NaOH 500 Hydrolysing agent H2SO4 300 pH neutralization Na2CO3 500 Fixing agent NaCl 3000 Fixing agent Sodium lauryl sulphate 100 Scouring agent Table 2. Chemical constituents used for the preparation of synthetic textile wastewater
  46. 46. Optimum coagulant dosage: Determined by Jar test COD reduction: COD was analysed as per closed reflux colourimetric method Removal (%) = (Aut – At ) x 100 Aut Aut & At = absorbencies of untreated and treated wastewater samples 46
  47. 47. Results and Discussion Figure 16a. Colour removal (%) & COD reduction of textile wastewater containing RB5 (Reactive Black 5) 47
  48. 48. 48 Figure 16b. Colour removal (%) & COD reduction of textile wastewater containing CR (Congo Red)
  49. 49. 49 Figure 16c. Colour removal (%) & COD reduction of textile wastewater containing DB3 (Disperse Blue 3)
  50. 50. 50 Figure 16d. Colour removal (%) & COD reduction of textile wastewater containing RB5+CR
  51. 51. 51 Figure 16e. Colour removal (%) & COD reduction of textile wastewater containing CR+DB3
  52. 52. 52 Figure 16f. Colour removal (%) & COD reduction of textile wastewater containing RB5+DB3
  53. 53. 53 Figure 16g. Colour removal percentage for textile wastewater containing RB5+CR+DB3
  54. 54. Conclusion MgCl2 in combination with lime was superior over the other coagulants for decolourization & COD reduction More than 99% decolorization efficiency & 63% COD reduction efficiency was observed using MgCl2 /Lime as coagulants MgCl2 /Lime can be used as an efficient coagulant system for the treatment of textile wastewater 54
  55. 55. 55 Biological Treatment  Remove dissolved organics from effluent and thus reduce chemical and biological oxygen demands of the effluents  Achieved biologically wherein bacteria/fungi are used to convert the colloidal and dissolved carbonaceous organic matter into various gases
  56. 56. 56 Methods Aerobic Treatment  Dissolved oxygen is utilized by microorganism and finally wastes are converted into biomass and carbon dioxide  Organic matter is partially oxidized and some of the energy produced is used for generating new living cells under the formation of flocs  Bacteria and fungi have been most widely studied for their capability to remediate textile and dye wastewaters
  57. 57. 57 Anaerobic treatment  Involves an oxidation-reduction reaction with hydrogen rather than free molecular oxygen aerobic system  Dyes are degraded and converted into aromatic amines, later the produced aromatic amines are degraded by aerobic biodegradation
  58. 58. Evaluation of microbial systems for biotreatment of textile waste effluents in Nigeria: Biodecolourization and biodegradation of textile dye Agarry and Ajani, 2011 Nigeria Objective: To evaluate the remediation potential of isolated micro organisms to decolourize the dye and reduce the COD & BOD of textile effluents 58
  59. 59. Methodology Micro organisms Bacterial species Pseudomonas fluorescence Pseudomonas nigificans Pseudomonas gellucidium Fungal species Aspergillus niger Fusarium compacticum Proteus morganii 59 Batch microbial treatment Autoclaved mineral salt medium (0.8L) + 3L textile waste effluent in a bioreactor Add inoculum (200ml) aseptically to make 4L working solution Stir at room temperature with agitation speed of 300 rpm Ferment for 14 days Filter the solution through Whatman paper No. 1 & centrifuged for 10 minutes Analysis of decolourization, COD & BOD
  60. 60. 60 % decolourization = A – B x 100 A A = Initial absorbance B = Final absorbance Determination of COD & BOD COD – standard colourimetric method (APHA – AWWA, 1985) BOD – 5 day BOD test Determination of decolourization percentage
  61. 61. Results and Discussion Figure 17. Decolourization of textile waste effluents by isolated microbial species [A = P.flourescence, B = P.nigificans, C = P.gellucidium, D = A.niger, E = P.morganii, F = F.compacticum] 61 Order of percent dye decolourization A. niger > P. fluorescence > P. morganii > F. compacticum > P. nigificans > P. gellucidium
  62. 62. Figure 18. COD reduction of textile waste effluents by isolated microbial species [A = P.flourescence, B = P.nigificans, C = P.gellucidium, D = A.niger, E = P.morganii, F = F.compacticum] 62
  63. 63. 63 Figure 19. BOD reduction of textile waste effluents by isolated microbial species [A = P.flourescence, B = P.nigificans, C = P.gellucidium, D = A.niger, E = P.morganii, F = F.compacticum]
  64. 64. Figure 20. Effect of dye concentration on decolourization by binary mixed culture of P.fluorescence and A.niger 64
  65. 65. Conclusion Aspergillus niger, Pseudomonas fluorescence, Proteus morganii, Fusarium compacticum, Pseudomonas nigificans & Pseudomonas gellucidium have a significant potential for dye decolourization and degradation 65
  66. 66. Biological treatment of azo dyes and textile industry effluent by newly isolated White rot fungi Schizophyllum commune and Lenzites eximia Selvam and Shanmuga, 2012 Coimbatore Objective: To study the dye decolourization of azo dye and textile industry effluent treatment by White rot fungi in batch and continuous mode 66
  67. 67. Methodology 67 Decolourization of azo dyes C-limited medium containing congo red, methylorange & erichrome black-T (each 50µM) Spore suspension of S.commune & L.eximia Rotary shaker (120rpm) at 39ºC for 6 days Filtered through G3 sintered glass filter Decolourization of textile industry effluent C-limited medium containing textile dye effluent (950ml) 50ml of spore suspension (105 spore/ml) of S.commune & L.eximia Maintained at 39ºC for 6 days Analysed for colour removal Inoculate Inoculate Incubate
  68. 68. Results and Discussion Figure 21. Removal of Azo dyes from aqueous solution by Schizophyllum commune 68
  69. 69. Figure 22. Removal of Azo dyes from aqueous solution by Lenzites eximia 69
  70. 70. Figure 23. Colour removal of textile industry effluent by Schizophyllum commune Figure 24. Colour removal of textile industry effluent by Lenzites eximia 70
  71. 71. Conclusion Schizophyllum commune was more efficient than Lenzites eximia for the treatment of azo dyes and textile dye industry effluent in both batch mode and continuous mode The batch mode treatment of textile industry effluents by Schizophyllum commune was more efficient when compared to continuous mode 71
  72. 72. 72 Summary Conventional technologies to treat textile wastewater include combinations of biological, physical and chemical methods, but require high capital and operating costs Biological treatments can efficiently remove dyes from large volumes of wastewater at low cost Need of the day is to substitute hazardous chemicals by using environment friendly methods Best approach to reduce wastewater discharge is to manufacture eco- friendly products and to modify certain areas of textile processing in to avoid toxicity
  73. 73. 73 “Better handling of textile waste and their efficient disposal will surely be an appropriate step to maintain ecological balance on earth”