Chapter - 6 Treatment for Recycling of Segregated Wastewater Generated from Dyes, Dye Intermediates and Textile Dyeing and Printing Industries of

Transcription

1 Chapter - 6 Treatment for Recycling of Segregated Wastewater Generated from Dyes, Dye Intermediates and Textile Dyeing and Printing Industries of Sachin Industrial Area

2 6.1 Introduction Sachin industrial area is having two major types of industrial units; one of them is textile dyeing and printing industries, while another is dyes and dye intermediate manufacturing industries.sachin Industrial area has two different common effluent treatment plants (CETPs) for the treatment and disposal of these two types of industrial units. While visiting the industrial estate, it was observed that both these CETPs are sharing common wall, it means that they are located adjacent to each other, so it was decided that, if both the CETPs are in same industrial estate and located adjacent to each other and still they are treating different kind of effluent. The CETP for textile wastewater treatment is having capacity of 50MLD while the CETP for dyes and dye intermediate industry is having capacity of 0.5 MLD. Considering the capacity and location of both of the CETP and their member industries they caters, it was decided that wastewater from the selected industries mixed in a pre-calculated ratio (based on wastewater generation from individual industry) and give various wastewater treatment. As described in Chapter 4, an attempt was made to combine and provide primary treatment of wastewater generated from dyes and dye intermediate manufacturing industries. As concluded from findings of Chapter 4and Chapter 5; Stream -3, Stream -4 and Stream -5 can be mixed with each other but wastewater. Stream -1 may have contamination due to other products manufactured by same industry, so it was decided to provide evaporation treatment to this stream. It is evident from the findings in Chapter -5 that during stream wise segregation wastewater characteristics were almost identical during a whole year. Considering above facts, following were decided: a) Wastewater Stream -1 was decided to be subjected to evaporation because, considering its high COD and TDS value, this stream cannot be mixed with mixture of Streams 3,4 & 5; if it is mixed with Stream 3, 4 & 5, it will increase TDS level significantly and ultimately create difficulties in activated sludge process and recycling; it cannot be mixed with wastewaterstream-2 either, else it will result in reduction of acidity and this will inhibit the reaction to produce ferrous sulphate, therefore, It was decided that process effluent generated from Stream-1 of dye intermediates manufacturing unit needs to be treated with distillation / evaporation system. 184

3 b) Wastewater stream of Stream -2, can be used to produce ferrous sulphate by addition of Iron. For this the wastewater needs to be checked for ph and acidity only. c) Mix Stream -3, Stream -4 and Stream -5 and give primary treatment followed by secondary treatment with activated sludge process and tertiary treatment with Fenton reagent. This wastewater than passed through lab scale sand and carbon filters and then analyzed. As concluded in Chapter -5 and above section 6.1, it was decided to mix Stream -3, Stream -4 and Stream -5 and give primary, secondary and tertiary treatment. The resulting treated wastewater will be checked for its various uses in industrial level. 6.2 Material And Method Source Of Sampling For Identified Wastewater Streams From Dyes, Dye Intermediates And Textile Dyeing And Printing Industries. As described in Chapter -5, Table 5.2.2, industry wise effluent stream segregation, samples were collected from dyes, dye intermediates and textile dyeing and printing industries during year 2012 and characterized for various parameters. Details of characterization and various treatments given to segregated streams and results obtained during the treatments are described in Section Analysis Of Stream -2 For Acidity Parameter For preparation of ferrous sulfate from acidic wastewater, acidity is the most important parameter. Therefore, while providing treatment to Stream -2, only ph and acidity were selected as major parameter. Method of analysis for acidity is described below: i) Acidity: Acidity of water is its quantitative capacity to react with a strong base to a designated ph 1,2. It may be defined as equivalent concentration of hydrogen ions in mg/lit. The equation in its simplest form is as follows. H + + NaOH H 2 O + Na + Procedure: - Determine the ph of water. - If ph is less than 3.7, add 3 to 4 drops of methyl orange in an aliquot sample and titrate against 0.02 N NaOH solution till faint orange colour persist. - In another flask add phenolphthalein as an indicator (ph 8.3) and titrate against 0.02N NaOH solution till pink colour persists. 185

4 Calculation : Acidity at ph 3.7 as mg/lit CaCO 3 = A x N x V Acidity at ph 8.3 as mg/lit CaCO 3 = B x N x V Where, A = Volume in ml of std. NaOH used to titrate to ph 3.7 N = Normality of std. NaOH solution. V = Volume in ml of sample taken for test. B = Volume in ml of std. NaOH used to titrate to ph 8.3 Note: We have considered Acidity at ph value 8.3 for our experiments. Generally, Acidity is represented in % instead of mg/l. Acidity value from mg/l to % can be converted by dividing acidity value mg/l by Result and Discussion Characterization Of Wastewater Samples Collected From Different Streams Of Dyes, Dye Intermediates And Textile Dyeing And Printing Industries Wastewater samples for all streams (i.e. Stream 1 to 5) were collected during year 2012 and initial characteristics were determined. The characteristics of untreated wastewater streams are mentioned in Section Characteristics Of Untreated Wastewater Samples Of Different Streams Table describes characteristics of wastewater Stream -1 and Stream -2. Stream-2 was decided to be used in preparation of ferrous sulfate slurry as Stream -2 is highly acidic and having high TDS value. It is also evident from Chapter -5, Table that Stream -2 was not containing other pollutants such as heavy metals (i.e. Chromium, Nickel), Ammoniacal Nitrogen, Phenol etc. during various sampling and analysis done for the same stream. Table describes characteristics of wastewater Stream -3, 4 and

5 Table Characterization Of Wastewater Sample Collected From Stream-1 And Stream -2 Date of preparation of combined wastewater Date of Analysis No. Parameters Unit Stream -1 Stream ph ph Unit Acidity % NA 37% 3. Chemical Oxygen Demand mg/l NA 4. Biochemical Oxygen mg/l 8240 NA Demand 5. Total Dissolved Solids mg/l NA 6. Total Suspended Solids mg/l 340 NA 7. Chloride mg/l NA 8. Ammonical Nitrogen mg/l 180 NA 9. Phenolic Compounds mg/l 20.4 NA 10. Hexavalent Chromium mg/l 0.25 NA 11. Total Chromium mg/l 1.98 NA 12. Nickel mg/l ND NA 13 Oil & Grease mg/l 87 NA Note: ND = Parameter analyzed but Not Detected, NA = Parameter not analyzed. 187

6 Table Characterization Of Wastewater Samples Collected From Stream 3, Stream -4 And Stream 5 Date of preparation of combined wastewater Date of Analysis No. Parameters Unit Dyeing and Utility Dyes stream printing stream (Stream -3) stream (Stream -4) (Stream -5) 1. ph ph Unit Chemical Oxygen Demand mg/l Biochemical Oxygen mg/l Demand Total Dissolved Solids mg/l Total Suspended Solids mg/l Chloride mg/l Ammonical Nitrogen mg/l Phenolic Compounds mg/l Hexavalent Chromium mg/l 0.09 ND Total Chromium mg/l Nickel mg/l ND ND Oil & Grease mg/l Note: ND = Parameter analyzed but Not Detected, 188

7 6.3.3 Treatment For Recycling Of Wastewater Stream 1 Generated From The Industries. As described in Chapter -5, Table 5.2.2, Stream -1 is generated from Industries 1 to 5, whereas Industry -6 is not generating Stream -1. All industries are not generating equal quantity of Stream -1 therefore; Table describes the quantity of wastewater Stream -1 collected from each industry to prepare 10L of representing combined wastewater of Stream-1 for selected industries. Table Quantity Of Stream -1 Wastewater Collected From Each Industry To Make 10L Combined Wastewater Stream Sr. no. Industry Stream -1 Sampled Quantity (L) 1 Industry Industry Industry Industry Industry Industry -6 0 Total 10 As shown in Table 6.3.1, the wastewater of Stream -1 is acidic in nature and also as evident from COD and BOD values it also contains dissolved organic material. Therefore, it was decided that this effluent stream needs to be evaporated, this will separate dissolved organic matter from wastewater stream and the condensate water obtained during evaporation can be recycled back to the member industries. The following method was used to evaporate wastewater Stream L of wastewater sample was taken in laboratory scale distillation flask of 1L capacity. Water condenser was attached with this distillation flask. The distillation flask was heated with caution and condensate water was collected in previously washed and dried beaker of 1 L capacity. The distillation flask was heated till complete evaporation of the residue. The 189

8 condensate water thus collected was measured for its volume. The distillation flask was cooled and little amount of distilled water was added to dissolve solid residue remained in the flask. This distilled water was transferred into previously weighed beaker. This beaker was put on water bath to facilitate evaporation of distilled water. After complete evaporation the glass beaker was weighed again. The amount of solid residue obtained was noted. The data of this experiment is provided in Table Table Quantity Of Condensate Water And Solid Residue Generated From Evaporation Of Stream -1wastewater No. Particulars Unit Amount 1 Quantity of wastewater Liter 0.5 (Stream -1) 2 Quantity of solid waste Gram remaining 3 Final quantity of wastewater stream (i.e. condensate water recovery) Liter 0.45 As shown in above Table 6.3.4, during this treatment, condensate water which had ph of 6.74and TDS 10 mg/l was obtained. This condensate water is having high purity and can be used in critical operations of manufacturing process. After distillation /evaporation, the solid material generated can be reused by sale to Cement industries or disposed off to the TSDF site Treatment For Recycling Of Wastewater Stream -2 Generated From The Industries As described in Chapter -5, Table 5.2.2, Stream -2 is generated from Industry 1,2 and 4 to 6, where Industry -3 is not generating Stream -2. All industries are not generating equal quantity of stream -2 therefore; Table describes the quantity of wastewater Stream -2 collected from each industry to prepare 10L of representing combined wastewater of Stream-2 for selected industries. 190

9 Table Quantity Of Stream -2 Collected From Each Industry To Make 10L Combined Wastewater Stream Sr. no. Industry Stream -2 Sampled Quantity (L) 1 Industry Industry Industry Industry Industry Industry -6 2 Total 10 The wastewater Stream -2 is highly acidic in nature and considering the manufacturing process; it is containing mainly sulfuric acid. As mentioned in Table 6.3.1, ph of the wastewater is 1.15 (highly acidic) and Acidity is 37%. This wastewater was converted into ferrous sulphate by addition of waste powdered iron scrap. The ferrous sulphate slurry thus produced was utilized for treatment of combined wastewater stream of textile dyeing and printing (i.e. combined wastewater stream of Stream -3, Stream -4 and Stream -5). The following method was used to estimate iron powder requirement and ferrous sulphate recovery. In2 L of this wastewater iron scrap (powder) was added in 1 gm portions, gradually. The wastewater was constantly stirred during addition. When the added powder dissolved completely, another 1 gm portion was added. This process was continued till the wastewater became saturated with iron powder. The wastewater was filtered and unreacted iron powder was removed. The lab scale experiment was done on wastewater having 37% acidity, however, data collected from industry suggested that at industry level the acidity of Stream -2 will vary from 20% to 37%. Therefore, for estimation of industry level, data presented in Table are estimated based on three acidity levels 37%, 25% and 20%. 191

10 Table Quantity Of Iron Scrap Required To Produce Ferrous Sulphate From Wastewater Stream -2 Part A : Lab Scale Experiment No. Particulars Unit Amount 1 Quantity of wastewater (stream -2) having 37% acidity Liter Quantity of Iron Scrap consumed Gram Final quantity of wastewater stream (i.e. ferrous sulphate slurry) Liter Part B : Estimation for entire quantity of stream -2 generated No. Particulars Unit Estimations (I) (II) (III) 1 Acidity % Quantity of wastewater (Stream -2) KL/day Quantity of Iron Scrap required MT/day Final quantity of wastewater stream (i.e. ferrous sulphate slurry) KL/day This slurry can be directly used to provide primary as well as tertiary treatment to the mixed Stream 3, 4 & 5. or can be diluted as per requirement of the treatment process. 192

11 6.3.5 Treatment For Recycling Of Effluent Generated From The Dyes Industries, The Utility Wastewater From Dyes, Dye Intermediates Manufacturing Industries And Wastewater From Textile Dyeing And Printing Industries During visit to the CETP of textile industries, the normal operation was studied. The CETP authority has established a dosing pattern through their extensive experience and various treatability studies. As shown in Table 6.3.7, Stream 3, 4 and 5 were mixed as per their wastewater contribution ratio. The mixed stream is containing textile wastewater as a main contributing stream therefore it was decided to adopt the same treatment pattern for our treatment. Table Quantity OfStream -3,4 And 5 Collected From Each Industry To Make 10L Combined Wastewater Stream Sr. Stream -3 Stream -4 Stream -5 Industry no. Sampled Quantity (ml) Sampled Quantity (ml) Sampled Quantity (ml) 1 Industry Industry Industry Industry Industry Industry Industry Industry Industry Industry Industry Industry Industry Industry Industry Industry Industry Industry Industry Industry Total ml Total 10 L 193

12 Part -1 Primary Treatment 2.5 L of this mix wastewater was taken in a 5L capacity large bucket which was provided with a tap of air to facilitate constant mixing of the wastewater. 10 % solution of hydrated lime was added into this bucket until ph of the solution was raised to 9.5. The wastewater was allowed to react with hydrated lime solution for 10 minutes. After 10 minutes, the ferrous sulfate slurry (i.e. the slurry obtained in section 6.3.4) was added till the ph of the solution come down in neutral range. Then the wastewater was allowed to react again for 10 minutes. Then wastewater was filtered and filtered wastewater was analyzed for various parameters. The entire filtrate was preserved at lower temperature and was used to provide further treatment. The results of primary treated combined wastewater stream 3,4 and 5 are tabulated in Table Table Details Of The Primary Treatment Given To The Mixed Wastewater Stream Date of preparation of combined wastewater NA Date of primary treatment No. Parameters Unit NA Date of Analysis Untreated mixed wastewater Primary treated wastewater % Removal after primary treatment 1. ph ph Unit NA 2. Chemical Oxygen Demand mg/l Biochemical Oxygen mg/l Demand 4. Total Dissolved Solids mg/l Total Suspended Solids mg/l Chloride mg/l Ammoniacal Nitrogen mg/l Phenolic Compounds mg/l Hexavalent Chromium mg/l Total Chromium mg/l Nickel mg/l ND ND NA 12. Oil & Grease mg/l NOTE: ND = Parameter analyzed but Not Detected., NA = Not Applicable 194

13 Part -2 Secondary Treatment To study effect of activated sludge process on primary treated wastewater, a lab scale secondary treatment setup was established in a 1L plastic beaker. From the aeration tank of textile CETP, activated sludge having concentration of 3240 mg/l of suspended solids, was collected. A tap of air with small diffuser system was provided to maintain dissolved oxygen level in the system. The activated sludge was taken from textile CETP because primary treated wastewater is also having textile dyeing and printing wastewater as main contributing stream. On next day, the sludge was settled and the liquid part was discarded than 2L of primary treated wastewater was kept in separating funnel and added in to beaker containing activated sludge. This addition was kept slow so that 2L of primary treated wastewater take about 1 day to complete the addition. Overflow of the reactor was collected in another 2L plastic flask and filtered with the use of filter paper on next day. The filtered water was analyzed for its characteristics. The results are described in Table

14 Table 6.3.9Characteristic Of Primary Treated Mix Wastewater Stream After Primary And Secondary Treatment Date of preparation of combined wastewater NA NA Date of primary treatment NA NA Date of secondary treatment NA NA No. Parameters Unit Date of tertiary treatment NA NA NA Date of Analysis Untreated mixed wastewater Primary treated wastewater Secondary treated wastewater % Removal after secondary treatment 1. ph ph Unit NA 2. Chemical Oxygen Demand mg/l Biochemical Oxygen Demand mg/l Total Dissolved Solids mg/l Total Suspended Solids mg/l Chloride mg/l Ammoniacal Nitrogen mg/l Phenolic Compounds mg/l Hexavalent Chromium mg/l Total Chromium mg/l Nickel mg/l ND ND ND NA 12. Oil & Grease mg/l NOTE: ND = Parameter was analyzed but Not Detected. NA = Not Applicable 196

15 Part -3Tertiary Treatment The tertiary treatment is also known as polishing treatment. The wastewater after secondary treatment (as mentioned in above Table is already complying with most of the discharge parameter. But it was decided to provide further treatment to the treated wastewater so that the quality of treated wastewater can be further improved. For this, the secondary treated wastewater was reacted with 5% solution of ferrous sulphate slurry to bring the ph to 4.0 and 30 % solution of hydrogen peroxide was added to the solution. Then 10% lime solution was added to bring ph to 7.0. The wastewater was filtered and passed through lab scale sand and carbon filter. The filtrate was analyzed. The results are provided in Table

16 Table Characteristic Of Secondary Treated Mix Wastewater Stream After Tertiary Treatment Date of preparation of combined wastewater NA NA NA Date of primary treatment NA NA NA Date of secondary treatment NA NA NA Date of tertiary treatment NA NA NA Date of Analysis No. Parameters Unit Untreated mixed wastewater Primary treated wastewater Secondary treated wastewater Tertiary treated wastewater % Removal after tertiary treatment 1. ph ph Unit NA 2. Chemical Oxygen Demand mg/l Biochemical Oxygen Demand mg/l Total Dissolved Solids mg/l Total Suspended Solids mg/l Chloride mg/l Ammoniacal Nitrogen mg/l Phenolic Compounds mg/l Hexavalent Chromium mg/l ND NA 10. Total Chromium mg/l Nickel mg/l ND ND ND ND NA 12. Oil & Grease mg/l NOTE: ND = Parameter was analyzed but Not Detected. N.A. = Not Applicable 198

17 Characteristics of, untreated mixed wastewater Stream -3, Stream -4 and Stream -5 and after each treatment stages, can be summarized in following Table , while removal efficiency in %, for the selected parameters is provided in Table During these treatments, chemicals were used for providing primary and tertiary treatment to the mixed wastewater streams, the lab scale consumption as well as estimated quantity for entire quantity of wastewater stream is provided in Table Table Characteristic Of Mixed WastewaterStream - 3,4 & 5; Untreated, After Primary, Secondary And Tertiary Treatment No. Parameters Unit Mixed Wastewater Stream -3, 4 and 5 Untreated Primary Secondary Tertiary treated treated treated GPCB norms for discharge in rivers, creeks 5.5 to ph ph Unit 2. Chemical mg/l Oxygen Demand 3. Biochemical mg/l Oxygen Demand 4. Total Dissolved mg/l Solids 5. Total Suspended mg/l Solids 6. Chloride mg/l Ammoniacal mg/l Nitrogen 8. Phenolic mg/l Compounds 9. Hexavalent mg/l ND Chromium 10. Total Chromium mg/l Nickel mg/l ND ND ND ND Oil & Grease mg/l Note: ND = Parameters analyzed but Not Detected 199

18 Table % Removal Observed During Treatment Of Mixed Stream 3,4 & 5 % Removal No.` Parameters After After After Primary Secondary Tertiary treatment treatment treatment 1. ph NA NA NA 2. Chemical Oxygen Demand Biochemical Oxygen Demand Total Dissolved Solids Total Suspended Solids Chloride Ammoniacal Nitrogen Phenolic Compounds Hexavalent Chromium NA 10. Total Chromium Nickel NA NA NA 12. Oil & Grease Note: NA =Not applicable Figure and Figure are showing comparison of analysis results for selected parameters with GPCB norms, while Figure is showing % reduction achieved in each parameter after primary, secondary and tertiary treatment given to mixed wastewater stream.. 200

19 Mixed waste water (Stream 3,4 &5) Chemical Oxygen Demand, mg/l Biochemical Oxygen Demand, mg/l Total Dissolved Solids, mg/l Total Suspended Solids, mg/l Chloride, mg/l Ammonical Nitrogen, mg/l Primary treated mixed wastewater (stream 3, 4 & 5) Secondary treated wastewater (stream 3, 4 & 5) Tertiary treated wastewater (stream 3, 4 & 5) GPCB Discharge Norms for Rivers, Creek etc Figure Graphical Representation Showing Analysis Data With GPCB Norms (Part -1) 201

20 Mixed waste water (Stream 3,4 &5) Primary treated mixed wastewater (stream 3, 4 & 5) Secondary treated wastewater (stream 3, 4 & 5) ND ND ND ND ND Phenolic Compounds, mg/l Hexavalent Chromium, mg/l Total Chromium, mg/l Nickel, mg/l Oil and Grease, mg/l Figure Graphical Representation Showing Analysis Data With GPCB Norms (Part -2) Tertiary treated wastewater (stream 3, 4 & 5) GPCB Discharge Norms for Rivers, Creek etc 202

21 After Primary treatment After Secondary treatment After Tertiary treatment Chemical Oxygen Demand Biochemical Oxygen Demand Total Dissolved Solids Total Suspended Solids Chloride Ammonical Nitrogen Phenolic Compounds NA Hexavalent Chromium Total Chromium NA NA NA Nickel Oil and Grease Figure Percentage Removal Achieved After Primary, Secondary And Tertiary Treatment Given To Mixed Wastewater Stream 203

22 As shown, in the Table , that the treated combined wastewater is suitable for discharging the wastewater as per statutory limits. Table and Figure shows comparison of removal efficiency in percentage (%) for each parameter for primary, secondary and tertiary treatment of mixed wastewater stream 3, 4 & 5. % removal in COD values ranges from to 65.04%, maximum % removal of % was obtained during secondary treatment. % removal in BOD values ranges from to 85.25%, maximum % removal of % was obtained during secondary treatment. % removal in TDS values ranges from 5.31 to %, maximum % removal of % was obtained during primary treatment. % removal in TSS values ranges from to %, maximum % removal of % was obtained during primary treatment. % removal in Chloride values ranges from to %, maximum % removal of % was obtained during primary treatment. % removal in Ammoniacal nitrogen values ranges from to %, maximum % removal of % was obtained during secondary treatment. % removal in Phenolic compounds values ranges from to %, maximum % removal of % was obtained during tertiary treatment. Hexavalent chromium was not detected after tertiary treatment however; maximum % removal of % was obtained during primary treatment. % removal in Total chromium values ranges from to %, maximum % removal of % was obtained during primary treatment. % removal in Oil and Grease values ranges from to %, maximum % removal of % was obtained during secondary treatment. The characteristics of treated wastewater were compared with water quality requirement mentioned in the established standards 3 and shown in Table As per this standards, the quality of treated wastewater, obtained after treatment of combined Stream -3, 4 and 5, is acceptable for use for washing off stages after scouring, bleaching, dyeing /printing and finishing. About 50-70% of total water consumption consists of such water needs.in addition to this, this treated wastewater can be used for washing down equipment, screen washing in print works and general wash down of print paste containers and floors.about % of total water consumption consists of such waster needs. THIS CONCLUDES THAT ABOUT 60 TO 90% OF FRESH WATER CONSUMPTION CAN BE REPLACED BY RECYCLING OF THE TREATED WASTEWATER TO THE TEXTILE DYEING AND PRINTING UNITS. 204

23 Table Comparison Of The Quality Of Treated Wastewater With Recommended Water Quality Suitable For Washing Off Processes No. Parameters Unit Tertiary treated Maximum waste water Recommended level 1. ph ph Unit Chemical Oxygen Demand mg/l Biochemical Oxygen Demand mg/l 28 NA 4. Total Dissolved Solids mg/l 1960 NA 5. Total Suspended Solids mg/l 7 NA 6. Chloride mg/l Ammoniacal Nitrogen mg/l 5 NA 8. Phenolic Compounds mg/l 0.24 NA 9. Hexavalent Chromium mg/l ND NA 10. Total Chromium mg/l Nickel mg/l ND NA 12. Oil & Grease mg/l 1.05 NA Note: ND = Parameters analyzed but Not Detected NA = Not Applicable Table Details On Chemical Consumed And Sludge Generation For Treatment Of Mix Streams 3,4& 5 Part A Lab Scale Experiment No. Treatment Stage Chemical Dosing Sludge generation 1. Primary treatment Lime Ferrous 210 mg/l 480 mg/l 810 mg/l 2. Tertiary Treatment Ferrous 110 mg/l Lime 50 mg/l Hydrogen Peroxide 2.5 ml/l 174 mg/l Part BEstimation for entire quantity of stream -3,4 and 5 Quantity No. Treatment Stage Chemical required Lime 1.6 MT/day 1. Primary treatment Ferrous 3.8 MT/day Sludge generation 6.5 MT/day Ferrous 0.3 MT/day 2. Tertiary Treatment Lime 0.9 MT/day 1.3 MT/day Hydrogen Peroxide 19.8 kl/day Note: The estimation for entire quantity of stream 3, 4 & 5 is based on total flow of 7928 kl/day. Table shows the consumption of treatment chemicals and sludge generation during 205

24 lab scale treatment and as well as estimation of chemical consumption and sludge generation for entire wastewater quantity of stream 3, 4 and 5 (i.e kl/day). Recovery and Reuse Options: 1. The FeSO4 solution will be charged in a form of 5% slurry, which is estimated to be 46.7 KL/day. 2. The concentrated FeSO 4 slurry generated from Stream -2, is estimated to be 55 % of FeSO 4 solution and estimated generation is about 44 KL/day,which can be diluted to 5% and used in treatment process. 3. Studies show the potential of textile ETP sludge as an alternative raw material in Cement industry, as fuel in Captive power plant 4-7. A cement plant located nearby Tirupur is already consuming 50 TPD of ETP sludge as an alternative raw material mixed with limestone. The sludge generated during treatment of combined stream -3, 4 and 5 can be used as a raw material by Cement industries, 4. It is also established by researchers that the use of Textile ETP sludge up to a maximum of 30% substitution for cement, may be possible in the manufacture of non-structural building materials. The use of Textile ETP sludge in these applications could serve as an alternative solution to disposal. 8 Therefore, the sludge generated during treatment of entire mixed wastewater was sent to external laboratory to obtain the characteristics of the sludge generated during lab scale treatment of combined wastewater Stream 3, 4 & 5. Table shows the comparison between characteristics of sludge recommended for recycling as alternate raw material in cement industries with the characteristics of sludge obtained during wastewater treatment of combined Stream 3,4 &5. Table Comparison of sludge characteristics with typical characteristics of textile ETP sludge used as alternate raw material. Characteristics of sludge Typical characteristics of Sr. Parameter obtained during combined Textile ETP sludge used as No. treatment of Stream 3,4 & 5 alternate raw material 1 Lime (CaO) 20.8 % 4.6 to 44.1 % 2. Moisture 22.5% 20 to 36% 3. MnO 18.7 % 1 to 990 ppm 4. Cr 2 O ppm 0.1 to 390 ppm 5. NiO 0.1 ppm 0 to 540 ppm 6. Chloride 0.42% 0.09 to 0.91 % It is evident from Table that the sludge obtained during treatment of combined wastewater Stream 3,4& 5 can be reused as alternative raw material in cement industries. 206

25 6.4 Conclusion Quality Of Treated Wastewater Stream -1 As mentioned in section 6.3.3, the condensate wastewater is distilled water which was having ph of 7.0 and all other parameters were below detection level. This water can be considered as distilled water and can be used as distilled water Quality Of Treated Wastewater Stream-2 As mentioned in Section 6.3.4, the wastewater after treatment is ferrous sulphate slurry which can be used as treatment chemical. So there is no wastewater generated after the treatment Quality And Quantity Of Recycled Effluent Generated From The Dyes Industries, The Utility Wastewater From Dyes And Dye Intermediates And Wastewater From Textile Dyeing And Printing Industries. As mentioned in section 6.3.5, Table the tertiary treated wastewater can be reused in textile industry itself for various non-critical process like grey cloth initial washing, floor washing and also it can be used in dyeing and printing section also. From above results following conclusion can be made 1) Segregation of effluent has facilitated effective treatment to the industrial area of Sachin GIDC. 2) The highly acidic wastewater stream was converted in to ferrous sulphate slurry which was used as a treatment chemical. So the neutralizing of this stream was completely eliminated. Therefore, sludge generation was drastically reduced. 3) Segregation and mixing of similar type of effluent from various industrieshas provided better wastewater management in the selected industry. And the treated wastewater is suitable for recycling back to the industry for non- critical applications such as first washing of grey cloth, floor washing etc. 4) Sludge generated during the treatment can be reused by Cement industry as alternate raw material, as well as reused as alternative to cement in the manufacturing of non-structural building materials. 207

26 Figure is showing present treatment scheme at Sachin GIDC however considering above conclusions the changes in treatment scheme for Sachin GIDC is suggested as shown in Figure and Figure Wastewater of textile dyeing and printing industries Wastewater of Dyes, Dye intermediate manufacturing industries Primary treatment at member unit Treatment at CETP Disposal High amount of sludge from industries and Disposal of treated wastewater Sludge and treated wastewater disposal results in, Land Contamination Ground water Contamination Surface water contamination Transportation cost of sludge to the disposal site is very high No Recovery No Reuse Figure Present Treatment Scenario At GIDC Sachin 208

27 Segregation of wastewater based on product group (Dyes intermdediate industries) Stream -1 Stream -2 Stream -4 Evaporation Check for Acidity Mixed with Steam -3 & 4 Condensate Water REUSE Evaporation Residue Reuse Acidity is higher or equal to 60% Sold as Spent Acid RECOVERY Acidity is less than 60% Add Iron Scrap Slurry of Ferrous sulphate To be used in physico chemical treatment REUSE *Note: Further treatment of Stream- 4 is shown in Figure Figure Proposed Treatment Scheme (Plant Layout): Wastewater Stream Segregation, Treatment And Recycle (PART -1) 209

28 Remaining Streams Dyes Industry (Stream -3) Utilizes (Wastewater Stream -4) Textile dyeing and Printing Industry (Wastewater Stream -5) Combine stream -3, 4 & 5 Primary Treatment with Lime solution and Ferrous sulfate slurry prepared from stream -2 Secondary treatment (Activated Sludge process) Sludge Reuse Tertiary Treatment with Fanton's Reagent with Hydrogen Peroxide and Ferrous sulfate slurry prepared from stream -2 Carbon and Sand Filtration Sludge Reuse Treated water Reused by member industry Figure Proposed Treatment Scheme (Plant Layout): Wastewater Stream Segregation, Treatment And Recycle (PART -2) 210

29 This treatment scheme can be financially beneficial to the industries as well as the CETP as little modification is required at member industries level and at CETP level, and the implementation of this scheme can generate revenue by means of sale of Ferrous sulfate, spent acid and recycling of wastewater, recovery and reuse of sludge. 211

30 References 1. Indian Standard, Methods Of Sampling And Test (Physical And Chemical) For Water And Wastewater, IS-3025, Part-22Acidity(1986). 2. APHA, AWWA, WEF. Standard methods for the examination of water and Wastewater, Washington, USA, 22(2012) 3. Sustainable water use in chemical, paper, textile and food Industries, Water quality demands in paper, chemical, food and textile companies, European Union s 7 th Framework Programme 226 (2010) 4. S.P.Gautam, R.K.Jain, B.N.Mohapatra, S.M. Joshiand R.M. Gupta, Energy recovery from solid waste in cement rotary kiln and its environmental impact. J. of Solid Waste Technol.Manag.Philadelphia, USA. 24, (2009). 5. P. Stehlik, Efficient waste processing and waste to Energy: Challenge for the future. Clean Technologies and Environmental Policy.11(1), 7-9(2008).. 6. S.P. Gautam,, P. S.Bundela,R.K.Jain,V.Padmanabhan, Co-Incineration Of Textile ETP Sludge In Captive Power HouseBoilerRecent Research in Science and Technology, 3(4), (2011). 7. Action plan for enhancing the use of alternate fuels and raw materials in the Indian cement industry, Institute for Industrial Productivity, New Delhi. 26 (2013). 8. J. Balasubramanian, P.C. Sabumon, John U. Lazar, R. Ilangovan; Reuse of textile effluent treatment plant sludge in building materials, Waste Management 26, (2006) 212

31 SUMMARY Chapter -1 Chapter -1 describes the introduction about the present study, it also describes various treatment methods in detail. Various chemical and biological wastewater treatment are discussed with their significance. Literature review for treatment of dyes and textile wastewater is presented in the Chapter -1. Chapter -2 As the Present study is taken up, on the dyes manufacturing units, dye intermediates manufacturing units. Basic information on production, water consumption, wastewater generation from dyes, dye intermediates manufacturing industries and detailed study of manufacturing process is provided in this chapter.initially a study was carried out, to identify initial details of industries like their production capacity, source of water, water consumption, and presentwastewater treatment and disposal scheme. In this study, it was found that the present wastewater treatment scheme is resulting in the generation of high volume of sludge. Industries were facing problems in disposal of this sludge. After that, manufacturing process was studied in detail and sources of wastewater generation at various stages of manufacturing process were identified. This study was carried out to identify wastewater streams which are having similar characteristics, so that wastewater having similar characteristics can be segregated and mixed, and can be treated effectively. It was found that wastewater was mixed by the industries from all the wastewater sources at one place, which makes it difficult to establish effectiveness inwastewater treatment. Chapter -3 For the present study 10 numbers of textile dyeing and printing industries were selected. Out of them 6 industries were involved in only dyeing of textile fiber while remaining 4 industries are involved in dyeing and printing of textile fiber. Details regarding type of industry whether industry is carrying out dyeing only or dyeing and printing both is mentioned inthis chapter. General details on water consumption, source of raw water, water balance, raw materials, wastewater generation, effluent treatment plant, disposal of treated wastewater are presented in this chapter. The i

32 chapter concludes that, if streams having similar characteristics with wastewater of textile dyeing and printing industries are found than wastewater from dye intermediates and dyes manufacturing industries can be mixed with it. Chapter -4 In this chapter, details regarding primary treatment of dyes and dye intermediate manufacturing industries is provided Because, after studying the characteristics of wastewater generated from all 20 industries it was decided to prepare combined wastewater from dyes and dye intermediate manufacturing industry as the wastewater from industry 1 to 10 has showed similar characteristics and also decided that primary treatment to this combined wastewater to be given so as to bring its characteristics nearer to match with the characteristics of textile dyeing and printing industries. If this is possible than, a uniform treatment methodology can be established for entire industrial area. It was observed that waste water generated from dye intermediates manufacturing industries is having very low ph and high value of COD, TDS and other parameters. Wastewater was collected during 3 times a year from equalization tank of dyes and dye intermediate industries and mixed in a pre-calculated ratio. 1L of this combined and equalized wastewater was given primary treatment with 10% solution of hydrated lime and 5% solution of Ferrous Sulphate. ph of wastewater was raised to 11 to 12 with lime solution and neutralized to bring 7 to 8 ph value with Ferrous Sulphate solution. This treatment generates chemical sludge which was filtered by a filter cloth and kept in an oven for drying at 70 o C for 24 hours. After drying this sludge was collected and weighed. The treated wastewater was analyzed for the same parameters as of untreated wastewater. The volume of sludge generated was found in the range of 482 to 502 mg/l. Chapter -5 After studying manufacturing process of dye intermediates, manufactured at industrial unit of Sachin GIDC, it was found that four stages are involved in the process of dye intermediate manufacturing these are: 1) Sulphonation, 2) Drawing 3) Filtration and 4) Centrifuge. The wastewater generated is from 1) Filtration and 2) Centrifuge. The manufacturing process also indicated that during manufacturing of all products involves sulphonation but Schaeffer s Acid, G Salt and Amino G Salt products requires either ammonia liquor or caustic flakes during isolation stages, so the ii

33 wastewater generated from filtration and centrifuge stage is mild acidic streams (designated as Stream -1), while K Acid, Sulfo Tobias Acid and Aniline 2:5 Di Sulfonic acid are isolated by pouring reaction mass on Ice bath, therefore the wastewater stream from these products is resulting in highly acidic stream at the centrifuge stage (designated as Stream -2). Therefore it was decided to collect wastewater streams generated from each product, regardless to manufacture at same industry or not. This chapter shows that, Wastewater samples of Stream-1 and Stream -2 were collected from Filtration stage and Centrifuge stages from the plant based on product manufactured from all industries and then it was mixed stream wise, based on ratio identified from manufacturing capacity and wastewater quantity of each industry. This chapter also describes the manufacturing process of dyes produced by industrial unit. It was found that the dyes manufactured are Azo dyes and which is produced by coupling of dye intermediates so, wastewater was generated from filtration / centrifuge stages of dye manufacturing process, which is indicated as Stream -3. However, from all industries (dyes intermediate, dyes manufacturing industries, textile dyeing and printing industries) wastewater is also generated from utilities like boiler, cooling tower and while washing of reactors, spillages etc., this stream was collected from each industries and was mixed based on ratio identified from manufacturing capacity and wastewater quantity of each industry, which is indicated as Stream-4. From textile dyeing and printing industry samples were collected from main wastewater collected tank where wastewater from entire manufacturing plant is received, this stream is indicated as Stream -5.Therefore, the identified streams can be summaries as below: Stream -1 Wastewater sample collected from filtration and centrifuge stage from dye intermediate manufacturing industries which manufacture either of Schaeffer s Acid, G Salt, Amino G Salt. Stream -2 Wastewater sample collected from filtration and centrifuge stage from dye iii

34 intermediate manufacturing industries which manufacture either of K Acid, Sulfo Tobias Acid, Aniline 2:5 Di Sulfonic acid. Stream -3 Wastewater samples collected from filtration and centrifuge stage from dyes manufacturing industries. Stream -4 Wastewater samples collected from boiler, cooling and washing streams from dyes and dye intermediate manufacturing industries Stream -5 Wastewater samples collected from textile dyeing and printing industries. Chapter -6 It was observed that during stream wise segregation wastewater characteristics were almost identical during a whole year, as the streams for segregation was identified after studying the products manufactured by each selected industries.the manufacturing process of each product and the possible characteristics of the wastewater generated from each industry were also studied.the wastewater of Stream -1 is acidic in nature and also as evident from COD and BOD values it also contains dissolved organic material. Therefore, it was decided that this wastewater stream needs to be evaporated, this will separate dissolved organic matter and the condensate water can be recycled back. During this treatment, distilled water will be generated which is having high purity and can be used in critical operations of manufacturing process. After distillation /evaporation, the solid material generated can be reused or disposed off to TSDF site. This chapter shows that, wastewater stream -2, can be used to produce ferrous sulphate by addition of Iron. For this the wastewater needs to be checked for ph and acidity only.this slurry can be directly used to provide primary as well as tertiary treatment to the mixed stream a) above. It is also described that, the Stream -3, Stream -4 and stream -5 were combined and primary treatment followed by secondary treatment with activated sludge process and tertiary treatment with Fenton reagent were given to the mixed combined wastewater, this wastewater than passed through lab scale sand and carbon filter and then was analyzed. iv

35 Comparison of removal efficiency in percentage (%) for each parameter for primary, secondary and tertiary treatment of mixed wastewater stream 3, 4 & 5 is provided below. % removal in COD values ranges from to 65.04%, maximum % removal of % was obtained during secondary treatment. % removal in BOD values ranges from to 85.25%, maximum % removal of % was obtained during secondary treatment. % removal in TDS values ranges from 5.31 to %, maximum % removal of % was obtained during primary treatment. % removal in TSS values ranges from to %, maximum % removal of % was obtained during primary treatment. % removal in Chloride values ranges from to %, maximum % removal of % was obtained during primary treatment. % removal in Ammoniacal nitrogen values ranges from to %, maximum % removal of % was obtained during secondary treatment. % removal in Phenolic compounds values ranges from to %, maximum % removal of % was obtained during tertiary treatment. Hexavalent chromium was not detected after tertiary treatment however; maximum % removal of % was obtained during primary treatment. % removal in Total chromium values ranges from to %, maximum % removal of % was obtained during primary treatment. % removal in Oil and Grease values ranges from to %, maximum % removal of % was obtained during secondary treatment. Based on above study the Treatment Scheme was suggested, the study also confirms that it is possible to recycle wastewater and the treated wastewater can be reused for different manufacturing stages, which ultimately reduces the wastewater discharges and ultimately helps to conserve precious fresh water resources. Process wastewater of stream -2 of dye intermediates manufacturing units can be collected and analyzed for its acidity, based on acidity the entire wastewater can be sold as Spent acid to end users. If the acidity is lower, then the wastewater can be treated with waste iron to produce ferrous sulphate which can be used as wastewater treatment chemicals and resulting wastewater can be treated along with either Stream-1 wastewater for evaporation. During this recycling process due to implementation of segregation, by-products like Ferrous sulfate, Spent acid were recovered, which are potential sources of income for such centralized facility.sludge v

36 generated during the treatment can be reused by Cement industry as alternate raw material, as well as reused as alternative to cement in the manufacturing of non-structural building materials. Entire utility wastewater (i.e. Wastewater generated from boiler, cooling tower) generated from dye intermediate manufacturing industry can be mixed with textile dyeing and printing industry wastewater and dyes manufacturing industrywastewater and can be treated in conventional CETP, which is operational at Sachin industrial area. For this purpose process modification, i.e.installation of tertiary treatment units is suggested at present CETP of Sachin industrial area. vi