Title of Invention	"AN IMPROVED PROCESS FOR THE REDUCTION OF CHEMICAL OXYGEN DEMAND (COD), TOTAL DISSOLVED SOLIDS (TDS) AND COLOR FROM THE EFFLUENT OF COTTON LINTER PROCESSING INDUSTRY"
Abstract	This invention relates to an improved process fro the reduction of Chemical Oxygen Demand (COD), Total Dissolved Solids (TDS) and color from the effluent of cotton linter processing industry. Process steps are: mixing the effluent characterized in that with a flocculating agent for a period of 1-10 minutes at a temperature ranging from 20 to 40°C, allowing the effluent to settle fro a period ranging from 30-120 minutes to obtain the desired treated effluent.

Title of Invention

"AN IMPROVED PROCESS FOR THE REDUCTION OF CHEMICAL OXYGEN DEMAND (COD), TOTAL DISSOLVED SOLIDS (TDS) AND COLOR FROM THE EFFLUENT OF COTTON LINTER PROCESSING INDUSTRY"

Abstract

This invention relates to an improved process fro the reduction of Chemical Oxygen Demand (COD), Total Dissolved Solids (TDS) and color from the effluent of cotton linter processing industry. Process steps are: mixing the effluent characterized in that with a flocculating agent for a period of 1-10 minutes at a temperature ranging from 20 to 40°C, allowing the effluent to settle fro a period ranging from 30-120 minutes to obtain the desired treated effluent.

Full Text	This invention relates to an improved process for the reduction of Chemical Oxygen Demand (COD), Total Dissolved Solids (TDS) and color from the effluent of cotton linter processing industry. According to literature COD, TDS and color of effluents from cotton linter processing industry may be attributed to the presence of lignin, hemicellulose, monosaccharides, amino acids, proteins, straight chain compounds like furfural and phenolics from the raw material like different varieties of cotton e.g. Gossypium hirsutum, G. arborium, G. herbaceum, G. thurberi, G. raimondi, G. tricuspidatum etc. which are generally used for making pulp for production of alpha cellulose. The presence of above mentioned impurities can affect pulp properties like color, strength of fiber etc. The raw material of the said process is the cotton linter, which are small fibers left out after removing the staple fiber from the seed coat. The cotton linters contain about 70-75% of alpha cellulose, 25 - 30% are the other impurities such as hemicellulose, fatty matter, proteins, pectins, amino acids, charred sugars, wax, lignin & other organic & inorganic impurities. Thus processed alpha cellulose is used as a starting material in the manufacture of nitrocellulose, an explosive used in defense. The cellulosic manmade fibers have acquired leading position in certain applications like clothing, home textiles, polyesters, bed linen, viscose rayons. Cellulose finds applications in the following areas such as films, cellophane, sausage casings, artificial kidneys, gums, thickeners, foods and Pharmaceuticals, cosmetics & a derivative of cellulose viz. cellulose acetate in reverse osmosis. The cotton linter pulp is digested with dilute alkali under pressure to obtain high quality pulp of alpha cellulose, and during this treatment the impurities are leached out in the Black Liquor imparting deep color, high COD & TDS. The alkali digested pulp is washed thoroughly and the effluent thus generated is known as Black Wash water having high COD & TDS also color. The digested linters are further treated with bleaching agent and the discharge of this process is known as Wash Water which mainly contains carbonyl and carboxylic groups . Until past 2-3 decades or so large amount of colored effluents containing waxes, pectins, aminoacids, proteins, fatty matter, charred sugars, hemicellulose, lignin and other organics imparting high COD, TDS and color were discarded into natural stream and waterways as dilute aqueous solutions which is not tolerated now. In order to conform to environmental quality guidelines a number of primary and secondary treatment systems are installed. The treatment systems comprise clarifiers to remove 85 wt.% of suspended solids, aerated lagoons, trickling filters, modified biological systems to remove most of the solids and toxicity with reduction of COD but, very little removal of color & TDS. Ultrafiltration has also been tried and found futile to remove TDS as well as color completely. In the prior art following methods are used to treat wastewater generated from processing plant of cotton linter. A few methods hitherto practiced are described in brief herein below: Controlled enzyme biodegradation of organic natural fibers and method for releasing contaminants. Wyatt, Caryl Heintz; Wyatt, Bobby Gene; Carr, Deborah L. (USA). PCT Int. Appl. WO 9613601 Al 9 May 1996,57 pp. DESIGNATED STATES: W: CA; RW: AT, BE, CH, DE, DK, ES, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE. (World Intellectual Property Organization). CODEN: PIXXD2. CLASS: ICM: C12P013-04. ICS: C12S003-00; B09B003-00; C08B001-00. APPLICATION: WO 94-US12438 27 Oct 1994. DOCUMENT TYPE: Patent CA Section: 60 (Waste Treatment and Disposal) Section cross-reference(s): 51, CA 125:66433 Wyatt et al. observed that aqueous medium enzyme compns. are provided which are suitable for degrading natural fibers inclusive of cellulose-based and protein-based fibers resulting in release of adsorbed, absorbed and/or entrained petroleum products and radioactive contaminants. A method is presented for releasing petroleum and hydrocarbon products sorbed onto or entrained by natural fibers in an aq. medium through the use of enzymes to degrade the natural fiber sorbents utilized for oil spill cleanup, the method provides an opportunity for achieving responsible sepn. of oil from oil spill sorbent materials. A method is also presented for prepg. cellulosic linter fibers by controlled enzyme biodegrdn. of cellulosic fibers by mixing the cellulosic fibers in an aq. medium with cellulases to degrade the natural fibers under controlled conditions for a sufficient period of shorten the cellulosic fiber source materials to linter lengths. The aq. medium enzyme compns. are also suitable for degrading protein-based fibers in an aq. medium enzyme compn. resulting in the prodn. of protein food supplements of the various amino acids which constitute the protein-based fibers. A kinetic investigation of concentrated acid hydrolysis of cotton linters and municipal solid waste. Zhu, Haiquan (Mississippi State Univ., Mississippi State, MS, USA). 328 pp. Avail. Univ. Microfilms Int., Order No. DA9616490 From: Diss. Abstr. Int., B 1996, 57(2), 1270 (English) 1995. DOCUMENT TYPE: Dissertation CA Section: 60 (Waste Treatment and Disposal) Section cross-reference(s): 40,48, CA 125:66294 Abstract Unavailable Bleaching of cotton linters with hydrogen peroxide and ultraviolet light. Abbot, John; Ault, Katie (Chem. Dep., Univ. Tasmania, Hobart 7000, Australia). Appita J., 46(5), 341-8 (English) 1993. CODEN: APJOES. DOCUMENT TYPE: Journal CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products), CA 121:159579 Abbot et al have studied Bleaching of cotton linters pulps with alk. H2O2 at 65°. Addn. of commonly used stabilizers, such as magnesium salts, DTPA, and silicate, did not enhance the bleaching response. However, the presence of low concns. of certain transition metals, esp. Cu and Co, can enhance peroxide bleaching of cotton linters. This effect was correlated with the generation of hydroxyl radicals. The cotton pulp could also be effectively bleached at low pulp concns. by exposure to UV radiation, both in the presence and absence of alk. peroxide. The obsd. bleaching characteristics of cotton linters showed greater similarity to delignification of kraft pulps than to conventional peroxide bleaching of mech. pulps. Environmental pollution control in cotton textile industry. Upadhyay, Rajeev; Pandey, G. N. (U.P. Pollut. Control Board, Bareilly 243 122, Ire.). J. Ind. Pollut. Control, 7(2), 67-75 (English) 1991. CODEN: JIPCE4. ISSN: 0970-2083. DOCUMENT TYPE: Journal; General Review CA Section: 60 (Waste Treatment and Disposal) Section cross-reference(s): 40, CA 117:96574 Upadhyay et al have written a review, with 12 refs., on environmental aspects of the cotton textile industry in India, including manufg. processes and sources of effluent, including sizing, desizing, kiering, bleaching, mercerization, and dyeing; vols. of effluents; characteristics of effluents from different sections; water pollution; and pollution control, including good housekeeping, process control, redn. in chem. usage, recovery and reuse of chems., flow or vol. redn., process chem. substitution, and chem. and biol. treatment of waste-waters. Use of polyelectrolytes in the treatment of cotton textile waste. Sihorwala, T. A.; Reddy, K. G. (Dep. Civ. Eng., Shri G. S. Inst. Technol. Sci., Indore 452 003, India). Indian J. Environ. Prot., 9(7), 513-15 (English) 1989. CODEN: IJEPDH. ISSN: 0253-7141. DOCUMENT TYPE: Journal CA Section: 60 (Waste Treatment and Disposal) Section cross-reference(s): 40, CA 113:157985 Sihorwala et al have reported that the textile plant under study discharges its waste through 2 channels (channel-1 and channel-2). Channel-1 gets its waste from desizing, mercerizing and kiering sections whereas channel-2 gets its waste from dyeing, printing and finishing sections. The treatability of waste by coagulation was studied sep. and also by combining the 2 channel wastes in a ratio of 1:1. Channel-1 waste was less amenable to coagulation than channel-2 waste and the combined waste was intermediately amenable to coagulation treatment. The coagulants tested were alum, FeC13 and Catfloc-T, and APH-35. Catfloc-T is effective in removal of color, COD, and total solids from cotton textile waste. It is effective at pH >10.0. The removal also occurred with anionic polyelectrolyte but to a less extent. Catfloc-T is more economic than alum and FeC13 as this did not involve the redn. of pH as required in the case of alum and FeC13. Analysis of the quality of treated cotton industry wastewaters and their reuse. Przybinski, Jerzy (Inst. Inz. Ladowej, Sanit. Politech. Lodzkiej, Lodz, Pol.). Przegl. Wlok., 41(8), 309-11 (Polish) 1987. CODEN: PRZWAZ. ISSN: 0033-2410. DOCUMENT TYPE: Journal; General Review CA Section: 60 (Waste Treatment and Disposal) Section cross-reference(s): 40, 61, CA 108:26512 A review with 9 refs. on the cotton industry waste-waters includes compn. of raw and treated effluents, treatment methods, and quality requirements for recycled water. Reactor design principle and pilot tests for the treatment of cotton slurry black liquor by wet air oxidation. Gao, Feng; Lu, Bo; Shen, Dagang (Dep. Chem. Eng., Zhejiang Univ., Hangzhou, Peop. Rep. China). Huaxue Fanying Gongcheng Yu Gongyi, 4(3), 81-8 (Chinese) 1988. CODEN: HFGGEU. DOCUMENT TYPE: Journal CA Section: 60 (Waste Treatment and Disposal) Section cross-reference(s): 40,49, CA 110:159816 Gao Feng et al have studied the mass transfer and reaction kinetics of the wet air oxidn. process for the treatment of cotton slurry black liquor. The bubbling loop reactor with single cap was used as a pilot reactor. The oxidn.-alkalization-recycling process results in a COD removal of 42 - 48%, color redn. >95%, and overall soda recovery >90% under the conditions of 5.4-5.9 MPa, 240 - 250°, and 0.7 h residence time. The recovery of caustic soda from caustic effluents. Simpson, A. E.; Buckley, C. A. (Dep. Chem. Eng., Univ. Natal, Durban 4001, S. Afr.). ChemSA, 14(3), 76-8, 80 (English) 1988. CODEN: CHEMDU. ISSN: 0379-4687. DOCUMENT TYPE: Journal CA Section: 49 (Industrial Inorganic Chemicals) Section cross-reference(s): 40, 72, CA 110:26144 Simpson et al have reported that NaOH is recovered from cotton fiber scouring effluents by neutralization with C12 or CO2 (the latter is preferred), cross-flow microfiltration, charged-membrane ultrafiltration, and electrolysis in a cell with a Nafion 324 membrane. The COD and Ca and Mg contents were decreased by 90, 70, and 70% in the CO2 neutralization stage. The current efficiency of NaOH electrowinning was 80% and energy consumption 4000 kWh/ton 100% NaOH. The recovered NaOH and the depleted brine soln. with total solid content 500 mg/L are suitable for reuse. Studies of the optimization of biological and advanced treatment of textile industry wastewater together with domestic sewage. Boehnke, B. (Inst. Siedlungswasserwirtsch., Rhein.-Westf. Tech. Hochsch., Aachen, Fed. Rep. Ger.). Gewaesserschutz, Wasser, Abwasser, 97, 391 pp. (German) 1987. CODEN: GWABDO. ISSN: 0342-6068. DOCUMENT TYPE: Journal CA Section: 60 (Waste Treatment and Disposal) Section cross-reference(s): 40, CA 107:160784 Boehnke has observed that complete or nearly complete decolorization of cotton dyeing wastewater is only possible with advanced physico-chem., post-activated sludge treatment. Dual media filtration and activated C filtration following A-B activated-sludge, 2-stage treatment can give completely decolorized effluents. Partial decolorization is obtainable with post-pptn. and dual media filtration after the biol. step. Desorption and regeneration of dye colors from low-cost materials. McKay, G.; Ramprasad, G.; Mowli, Pratapa (Dep. Chem. Eng., Queen's Univ. Belfast, Belfast BT9 SDL, UK). Water Res., 21(3), 375-7 (English) 1987. CODEN: WATRAG. ISSN: 0043-1354. DOCUMENT TYPE: Journal CA Section: 60 (Waste Treatment and Disposal) Section cross-reference(s): 41, CA 107:27887 McKay et al have used low cost materials such as bentonite clay, among the 6 low-cost sorbents studied for the removal of 8 selected dyes, and shown that it could sorb all dyes with the exception of the acid dyes. The regeneration of clay is not possible in the sorption of dyes, since strong chem. bonding occurs between it and the sorbed dyes. Rice husk, bark, cotton waste, and hair could sorb only the red and blue basic dyes and a combination of ion-exchange and chem. bonding occurs in the sorption process. Pulp bleaching and the environment. Assessing the potential impacts of pulping and bleaching operations on the aquatic environment. Owens, J. William; Lehtinen, Karl-Johan (Procter and Gamble Company, Cincinnati, OH, USA). Pulp Bleaching, 767-798. Edited by: Dence, Carlton W.; Reeve, Douglas W. TAPPI Press: Atlanta, Ga. (English) 1996. CODEN: 63CKAZ. DOCUMENT TYPE: Conference; General Review CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products), CA 125:145373 A review with 114 refs. on the potential impacts of pulping and bleaching operations on the aquatic environment is presented. Topics discussed are chem. and phys. characterization of effluents and receiving environments, biol. characterizations of effluents and receiving environments, and expected trends and future research needs. A glossary of 18 tech. terms from the field of aquatic environmental pollution is added. Effect of pretreatment on the enzymic hydrolysis of cellulose-containing wastes of cotton manufacture. Yuldashev, B. T.; Rakhimov, M. M.; Rabinovich, M. L. (Tashkent State Univ., Tashkent, Uzbekistan). Prikl. Biokhim. Mikrobiol, 28(3), 443-8 (Russian) 1992. CODEN: PBMIAK. ISSN: 0555-1099. DOCUMENT TYPE: Journal CA Section: 60 (Waste Treatment and Disposal) Section cross-reference(s): 40, 70, CA 117:257471 Yuldashev et al have studied the hydrolysis of cellulose-contg. cotton manuf. wastes by cellulolytic enzymes from Trichoderma viride and Aspergillus foetidus. Saccharification was In hitherto known processes main drawbacks are the use of acidic media which results into corrosion problems, use of enzymes which is economically not feasible, use of hydrogen peroxide and ultraviolet rays which are hazardous during handling. The main objective of the present invention is to provide an improved process for the reduction of Chemical Oxygen Demand (COD), Total Dissolved Solids (TDS) and color from the effluent of cotton linter processing industry which obviate the drawbacks as detailed above. There is continued interest on development of new improved process for removal of color and other organic & inorganic impurities produced during the pulping process of cotton linter. It is a well known fact that organics, inorganics as well as color in such type of effluents are not easily biodegradable and hence, have disposal problems in the natural environment. Accordingly, the present invention provides an improved process for the reduction of chemical oxygen demand (COD), total dissolved solids (IDS) and color from the effluent of cotton linter processing industry which comprises; mixing the effluent characterized in that with a flocculating agent for a period of 1-10 minutes at a temperature ranging from 20 to 40°C, allowing the effluent to settle fro a period ranging from 30-120 minutes to obtain the desired treated effluent. In an embodiment of the present invention the effluent used for the treatment is selected from whe Black liquor, Black wash water and the mixture thereof along with wash water in black liquor: black wash water: wash water ratio of 8-9 : 95-110: 180-195. In an another embodiment the flocculating agent used is a mixture of three components wherein the first component being a sulphate, chloride, nitrate of transition metals preferably sulphate of iron and sulphate, chloride, nitrate of Group III metals preferably sulphate of aluminum and the second component being oxide of alkali or alkaline earth metals, of Group I or II such as sodium, potassium, magnesium, calcium, preferably an oxide of calcium and the third component being natural earth namely fullers earth, bentonite, dolomite, sand, garden soil, preferably dolomite and bentonite. In yet another embodiment the flocculating agent used is comprising a mixture of sulphate of aluminum & iron and the mixture of natural earths such as dolomite and bentonite and an oxide of alkali or alkaline earth metal in the ratio of 35-45: 45-55: 4-6 : 4-6 : 190-210. In still another embodiment the mixing time of flocculation agent with the effluent is preferably 2 minutes. In the feature of the present invention after the flocculation treatment of the individual Black liquor as well as Black wash water sample and mixture of black liquor, black wash water and wash water, significant reduction of color, and COD was observed for all the three effluent samples tested. The process of the present invention reduces COD, color and to some extent TDS simultaneously at 20 to 40°C temperature from cotton linter processing effluent, thus saving energy cost, the operation does not involve any use of mineral acid, thus avoiding corrosion problems. The novelty of the process lies in the use of flocculating agent comprising of a mixture of transition metal salts and the oxide of alkaline earth metal and a mixture of natural earths. The process of the present invention is described herein bellow with reference to the examples which are illustrative only and should not be construed to the limit of scope of the present invention in any manner. Example -1 200 ml Black Liquor generated from the cotton linter processing plant was diluted with tap water to 1 lit. ( COD - 1 l,936ppm and TDS 25,770ppm of pH- 10.0) was taken in 2 Lit. beaker to which flocculent comprising of mixture of aluminum sulphate, ferrous sulphate, dolomite and bentonite (200mg) in 40:50:5:5 proportion and calcium oxide 20g was added and mixed thoroughly and poured in a 1 Lit. measuring cylinder for 30 minutes at ambient temperature. The supernate thus obtained was analyzed for it's COD, IDS, BOD and color reduction using spectrophotometer at 480 nm after adjusting the pH of the sample to ~ 8. The treated sample of the Black Liquor showed COD as 1818 ppm, TDS 4160 ppm and color reduction was found to be 88%. Example- 2 200 ml Black wash water ( COD -849ppm and TDS 840ppm of pH- 8.8) generated from the cotton linter processing plant was diluted with tap water to 1 lit. and was taken in a 2 Lit. beaker to which flocculent comprising of mixture of aluminum sulphate, ferrous sulphate, dolomite and bentonite (200mg) in 40:50:5:5 proportion and calcium oxide 400mg was added and mixed thoroughly and poured in a 1 Lit. measuring cylinder for 30 minutes at ambient temperature. The supernate thus obtained was analyzed for it's COD, TDS, BOD and color reduction using spectrophotometer at 480 nm after adjusting the pH of the sample to ~ 8. The treated sample of the Black Liquor showed COD as 80 ppm, TDS 440 ppm and color reduction was found to be 35%. Example -3 1000 ml of the mixture of the effluent containing 30ml of Black Liquor, 334ml of Black wash water and 636ml of Wash water generated from the cotton linter processing plant having COD -513 ppm and TDS 2310 ppm of pH- 7.2, was taken in a 2 Lit. beaker to which flocculent comprising of mixture of aluminum sulphate, ferrous sulphate, dolomite and bentonite (l.Og) in 40:50:5:5 proportion and calcium oxide 2.0g was added and mixed thoroughly and poured in a 1 Lit. measuring cylinder for 30 minutes at ambient temperature. The supernate thus obtained was analyzed for it's COD, TDS, BOD and color reduction using spectrophotometer at 480 nm after adjusting the pH of the sample to ~ 8. The treated sample of the Black Liquor showed COD as 102.7 ppm, TDS 2370 ppm and color reduction was found to be 95%. Example - 4 100 m3 of the mixture of the effluent containing 3m3 of Black Liquor, 33.4m3 of Black wash water and 63.6m3 of Wash water generated from the cotton linter processing plant having COD - 727 ppm and TDS 2310ppm of pH- 7.2 was taken in 210m3 capacity rectangular setteling tank to which flocculent comprising of mixture of aluminum sulphate, ferrous sulphate, dolomite and bentonite (100kg) in 40:50:5:5 proportion and calcium oxide 200kg was added and mixed thoroughly with a movable floating mixer and allowed to settle at ambient temperature. The supernate thus obtained was analyzed for it's COD, TDS, BOD and color reduction using spectrophotometer at 480 nm after adjusting the pH of the sample to ~ 8. The treated sample of the Black Liquor showed COD as 241 ppm, TDS 2390 ppm and color reduction was found to be 95%. Advantages of the invention : The present process has following advantages such as it reduces COD, TDS and color simultaneously at ambient temperature from cotton linter pulp effluents, thus saving energy cost, the operation does not involve any use of mineral acid thus, avoiding corrosion problems , thus the process is eco-friendly. The process does not involve any hazardous chemicals like hydrogen peroxide and expensive reactants like enzymes for the treatment. Thus the process is easy to operate as well as cost effective. We Claim: 1. An improved process for the reduction of chemical oxygen demand (COD), total dissolved solids (TDS) and color from the effluent of cotton linter processing industry which comprises; mixing the effluent characterized in that with a flocculating agent for a period of 1-10 minutes at a temperature ranging from 20 to 40°C, allowing the effluent to settle fro a period ranging from 30-120 minutes to obtain the desired treated effluent. 2. An improved process as claimed in claim 1, effluent used for the treatment is selected from when Black liquor, Black wash water and the mixture thereof along with wash water in a black liquor: black wash water: wash water proportion of 8-9: 95-110: 180- 195. 3. An improved process as claimed in claims 1 and 2, wherein the flocculating agent used is a mixture of three components wherein the first component being a sulphate, chloride, nitrate of transition metals preferably sulphate of iron and sulphate, chloride, nitrate of Group III metals preferably sulphate of aluminum and the second component being oxide of alkali or alkaline earth metals, of Group I or II such as sodium, potassium, magnesium, calcium, preferably an oxide of calcium and the third component being natural earth namely fullers earth, bentonite, dolomite, sand, garden soil, preferably dolomite and bentonite. 4. An improved process as claimed in claims 1-3 wherein the flocculating agent used is comprising a mixture of sulphate of aluminum & iron and the mixture of natural earths such as dolomite and bentonite and an oxide of alkali or alkaline earth metal in the ratio of 35-45 : 45-55 : 4-6 : 4-6 : 190-210. 5. An improved process as claimed in Claims 1-4, wherein the mixing time of the flocculation agent is preferably 2 minutes. 6. An improved process for the reduction of chemical oxygen demand (COD), total dissolved solids (TDS) and color from the effluent of cotton linter processing industry substantially as herein described with reference to the examples 1 to 4.

Full Text

This invention relates to an improved process for the reduction of Chemical Oxygen Demand (COD), Total Dissolved Solids (TDS) and color from the effluent of cotton linter processing industry.
According to literature COD, TDS and color of effluents from cotton linter processing industry may be attributed to the presence of lignin, hemicellulose, monosaccharides, amino acids, proteins, straight chain compounds like furfural and phenolics from the raw material like different varieties of cotton e.g. Gossypium hirsutum, G. arborium, G. herbaceum, G. thurberi, G. raimondi, G. tricuspidatum etc. which are generally used for making pulp for production of alpha cellulose. The presence of above mentioned impurities can affect pulp properties like color, strength of fiber etc. The raw material of the said process is the cotton linter, which are small fibers left out after removing the staple fiber from the seed coat. The cotton linters contain about 70-75% of alpha cellulose, 25 - 30% are the other impurities such as hemicellulose, fatty matter, proteins, pectins, amino acids, charred sugars, wax, lignin & other organic & inorganic impurities. Thus processed alpha cellulose is used as a starting material in the manufacture of nitrocellulose, an explosive used in defense. The cellulosic manmade fibers have acquired leading position in certain applications like clothing, home textiles, polyesters, bed linen, viscose rayons. Cellulose finds applications in the following areas such as films, cellophane, sausage casings, artificial kidneys, gums, thickeners, foods and Pharmaceuticals, cosmetics & a derivative of cellulose viz. cellulose acetate in reverse osmosis. The cotton linter pulp is digested with dilute alkali under pressure to obtain high quality pulp of alpha cellulose, and during this treatment the impurities are leached out in
the Black Liquor imparting deep color, high COD & TDS. The alkali digested pulp is
washed thoroughly and the effluent thus generated is known as Black Wash water
having high COD & TDS also color. The digested linters are further treated with
bleaching agent and the discharge of this process is known as Wash Water which mainly
contains carbonyl and carboxylic groups .
Until past 2-3 decades or so large amount of colored effluents containing waxes, pectins,
aminoacids, proteins, fatty matter, charred sugars, hemicellulose, lignin and other
organics imparting high COD, TDS and color were discarded into natural stream and
waterways as dilute aqueous solutions which is not tolerated now.
In order to conform to environmental quality guidelines a number of primary and
secondary treatment systems are installed. The treatment systems comprise clarifiers to
remove 85 wt.% of suspended solids, aerated lagoons, trickling filters, modified
biological systems to remove most of the solids and toxicity with reduction of COD but,
very little removal of color & TDS. Ultrafiltration has also been tried and found futile to
remove TDS as well as color completely.
In the prior art following methods are used to treat wastewater generated from processing
plant of cotton linter. A few methods hitherto practiced are described in brief herein
below:
Controlled enzyme biodegradation of organic natural fibers and method for
releasing contaminants.
Wyatt, Caryl Heintz; Wyatt, Bobby Gene; Carr, Deborah L. (USA). PCT Int. Appl. WO
9613601 Al 9 May 1996,57 pp. DESIGNATED STATES: W: CA; RW: AT, BE, CH,
DE, DK, ES, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE. (World Intellectual Property
Organization). CODEN: PIXXD2. CLASS: ICM: C12P013-04. ICS: C12S003-00; B09B003-00; C08B001-00. APPLICATION: WO 94-US12438 27 Oct 1994. DOCUMENT TYPE: Patent CA Section: 60 (Waste Treatment and Disposal) Section cross-reference(s): 51, CA 125:66433
Wyatt et al. observed that aqueous medium enzyme compns. are provided which are suitable for degrading natural fibers inclusive of cellulose-based and protein-based fibers resulting in release of adsorbed, absorbed and/or entrained petroleum products and radioactive contaminants. A method is presented for releasing petroleum and hydrocarbon products sorbed onto or entrained by natural fibers in an aq. medium through the use of enzymes to degrade the natural fiber sorbents utilized for oil spill cleanup, the method provides an opportunity for achieving responsible sepn. of oil from oil spill sorbent materials. A method is also presented for prepg. cellulosic linter fibers by controlled enzyme biodegrdn. of cellulosic fibers by mixing the cellulosic fibers in an aq. medium with cellulases to degrade the natural fibers under controlled conditions for a sufficient period of shorten the cellulosic fiber source materials to linter lengths. The aq. medium enzyme compns. are also suitable for degrading protein-based fibers in an aq. medium enzyme compn. resulting in the prodn. of protein food supplements of the various amino acids which constitute the protein-based fibers.
A kinetic investigation of concentrated acid hydrolysis of cotton linters and municipal solid waste.
Zhu, Haiquan (Mississippi State Univ., Mississippi State, MS, USA). 328 pp. Avail. Univ. Microfilms Int., Order No. DA9616490 From: Diss. Abstr. Int., B 1996, 57(2),
1270 (English) 1995. DOCUMENT TYPE: Dissertation CA Section: 60 (Waste
Treatment and Disposal) Section cross-reference(s): 40,48, CA 125:66294
Abstract Unavailable
Bleaching of cotton linters with hydrogen peroxide and ultraviolet light.
Abbot, John; Ault, Katie (Chem. Dep., Univ. Tasmania, Hobart 7000, Australia). Appita
J., 46(5), 341-8 (English) 1993. CODEN: APJOES. DOCUMENT TYPE: Journal CA
Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products), CA 121:159579
Abbot et al have studied Bleaching of cotton linters pulps with alk. H2O2 at 65°. Addn.
of commonly used stabilizers, such as magnesium salts, DTPA, and silicate, did not
enhance the bleaching response. However, the presence of low concns. of certain
transition metals, esp. Cu and Co, can enhance peroxide bleaching of cotton linters. This
effect was correlated with the generation of hydroxyl radicals. The cotton pulp could
also be effectively bleached at low pulp concns. by exposure to UV radiation, both in the
presence and absence of alk. peroxide. The obsd. bleaching characteristics of cotton
linters showed greater similarity to delignification of kraft pulps than to conventional
peroxide bleaching of mech. pulps.
Environmental pollution control in cotton textile industry.
Upadhyay, Rajeev; Pandey, G. N. (U.P. Pollut. Control Board, Bareilly 243 122, Ire.). J.
Ind. Pollut. Control, 7(2), 67-75 (English) 1991. CODEN: JIPCE4. ISSN: 0970-2083.
DOCUMENT TYPE: Journal; General Review CA Section: 60 (Waste Treatment and
Disposal) Section cross-reference(s): 40, CA 117:96574
Upadhyay et al have written a review, with 12 refs., on environmental aspects of the
cotton textile industry in India, including manufg. processes and sources of effluent,
including sizing, desizing, kiering, bleaching, mercerization, and dyeing; vols. of effluents; characteristics of effluents from different sections; water pollution; and pollution control, including good housekeeping, process control, redn. in chem. usage, recovery and reuse of chems., flow or vol. redn., process chem. substitution, and chem. and biol. treatment of waste-waters.
Use of polyelectrolytes in the treatment of cotton textile waste. Sihorwala, T. A.; Reddy, K. G. (Dep. Civ. Eng., Shri G. S. Inst. Technol. Sci., Indore 452 003, India). Indian J. Environ. Prot., 9(7), 513-15 (English) 1989. CODEN: IJEPDH. ISSN: 0253-7141. DOCUMENT TYPE: Journal CA Section: 60 (Waste Treatment and Disposal) Section cross-reference(s): 40, CA 113:157985
Sihorwala et al have reported that the textile plant under study discharges its waste through 2 channels (channel-1 and channel-2). Channel-1 gets its waste from desizing, mercerizing and kiering sections whereas channel-2 gets its waste from dyeing, printing and finishing sections. The treatability of waste by coagulation was studied sep. and also by combining the 2 channel wastes in a ratio of 1:1. Channel-1 waste was less amenable to coagulation than channel-2 waste and the combined waste was intermediately amenable to coagulation treatment. The coagulants tested were alum, FeC13 and Catfloc-T, and APH-35. Catfloc-T is effective in removal of color, COD, and total solids from cotton textile waste. It is effective at pH >10.0. The removal also occurred with anionic polyelectrolyte but to a less extent. Catfloc-T is more economic than alum and FeC13 as this did not involve the redn. of pH as required in the case of alum and FeC13.
Analysis of the quality of treated cotton industry wastewaters and their reuse.
Przybinski, Jerzy (Inst. Inz. Ladowej, Sanit. Politech. Lodzkiej, Lodz, Pol.). Przegl.
Wlok., 41(8), 309-11 (Polish) 1987. CODEN: PRZWAZ. ISSN: 0033-2410.
DOCUMENT TYPE: Journal; General Review CA Section: 60 (Waste Treatment and
Disposal) Section cross-reference(s): 40, 61, CA 108:26512
A review with 9 refs. on the cotton industry waste-waters includes compn. of raw and
treated effluents, treatment methods, and quality requirements for recycled water.
Reactor design principle and pilot tests for the treatment of cotton slurry black
liquor by wet air oxidation.
Gao, Feng; Lu, Bo; Shen, Dagang (Dep. Chem. Eng., Zhejiang Univ., Hangzhou, Peop.
Rep. China). Huaxue Fanying Gongcheng Yu Gongyi, 4(3), 81-8 (Chinese) 1988.
CODEN: HFGGEU. DOCUMENT TYPE: Journal CA Section: 60 (Waste Treatment
and Disposal) Section cross-reference(s): 40,49, CA 110:159816
Gao Feng et al have studied the mass transfer and reaction kinetics of the wet air oxidn.
process for the treatment of cotton slurry black liquor. The bubbling loop reactor with
single cap was used as a pilot reactor. The oxidn.-alkalization-recycling process results
in a COD removal of 42 - 48%, color redn. >95%, and overall soda recovery >90% under
the conditions of 5.4-5.9 MPa, 240 - 250°, and 0.7 h residence time.
The recovery of caustic soda from caustic effluents.
Simpson, A. E.; Buckley, C. A. (Dep. Chem. Eng., Univ. Natal, Durban 4001, S. Afr.).
ChemSA, 14(3), 76-8, 80 (English) 1988. CODEN: CHEMDU. ISSN: 0379-4687.
DOCUMENT TYPE: Journal CA Section: 49 (Industrial Inorganic Chemicals) Section
cross-reference(s): 40, 72, CA 110:26144
Simpson et al have reported that NaOH is recovered from cotton fiber scouring effluents by neutralization with C12 or CO2 (the latter is preferred), cross-flow microfiltration, charged-membrane ultrafiltration, and electrolysis in a cell with a Nafion 324 membrane. The COD and Ca and Mg contents were decreased by 90, 70, and 70% in the CO2 neutralization stage. The current efficiency of NaOH electrowinning was 80% and energy consumption 4000 kWh/ton 100% NaOH. The recovered NaOH and the depleted brine soln. with total solid content 500 mg/L are suitable for reuse. Studies of the optimization of biological and advanced treatment of textile industry wastewater together with domestic sewage.
Boehnke, B. (Inst. Siedlungswasserwirtsch., Rhein.-Westf. Tech. Hochsch., Aachen, Fed. Rep. Ger.). Gewaesserschutz, Wasser, Abwasser, 97, 391 pp. (German) 1987. CODEN: GWABDO. ISSN: 0342-6068. DOCUMENT TYPE: Journal CA Section: 60 (Waste Treatment and Disposal) Section cross-reference(s): 40, CA 107:160784 Boehnke has observed that complete or nearly complete decolorization of cotton dyeing wastewater is only possible with advanced physico-chem., post-activated sludge treatment. Dual media filtration and activated C filtration following A-B activated-sludge, 2-stage treatment can give completely decolorized effluents. Partial decolorization is obtainable with post-pptn. and dual media filtration after the biol. step. Desorption and regeneration of dye colors from low-cost materials. McKay, G.; Ramprasad, G.; Mowli, Pratapa (Dep. Chem. Eng., Queen's Univ. Belfast, Belfast BT9 SDL, UK). Water Res., 21(3), 375-7 (English) 1987. CODEN: WATRAG. ISSN: 0043-1354. DOCUMENT TYPE: Journal CA Section: 60 (Waste Treatment and Disposal) Section cross-reference(s): 41, CA 107:27887
McKay et al have used low cost materials such as bentonite clay, among the 6 low-cost
sorbents studied for the removal of 8 selected dyes, and shown that it could sorb all dyes
with the exception of the acid dyes. The regeneration of clay is not possible in the
sorption of dyes, since strong chem. bonding occurs between it and the sorbed dyes. Rice
husk, bark, cotton waste, and hair could sorb only the red and blue basic dyes and a
combination of ion-exchange and chem. bonding occurs in the sorption process.
Pulp bleaching and the environment. Assessing the potential impacts of pulping and
bleaching operations on the aquatic environment.
Owens, J. William; Lehtinen, Karl-Johan (Procter and Gamble Company, Cincinnati,
OH, USA). Pulp Bleaching, 767-798. Edited by: Dence, Carlton W.; Reeve, Douglas W.
TAPPI Press: Atlanta, Ga. (English) 1996. CODEN: 63CKAZ. DOCUMENT TYPE:
Conference; General Review CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood
Products), CA 125:145373
A review with 114 refs. on the potential impacts of pulping and bleaching operations on
the aquatic environment is presented. Topics discussed are chem. and phys.
characterization of effluents and receiving environments, biol. characterizations of
effluents and receiving environments, and expected trends and future research needs. A
glossary of 18 tech. terms from the field of aquatic environmental pollution is added.
Effect of pretreatment on the enzymic hydrolysis of cellulose-containing wastes of
cotton manufacture.
Yuldashev, B. T.; Rakhimov, M. M.; Rabinovich, M. L. (Tashkent State Univ., Tashkent,
Uzbekistan). Prikl. Biokhim. Mikrobiol, 28(3), 443-8 (Russian) 1992. CODEN:
PBMIAK. ISSN: 0555-1099. DOCUMENT TYPE: Journal CA Section: 60 (Waste Treatment and Disposal) Section cross-reference(s): 40, 70, CA 117:257471 Yuldashev et al have studied the hydrolysis of cellulose-contg. cotton manuf. wastes by cellulolytic enzymes from Trichoderma viride and Aspergillus foetidus. Saccharification was In hitherto known processes main drawbacks are the use of acidic media which results into corrosion problems, use of enzymes which is economically not feasible, use of hydrogen peroxide and ultraviolet rays which are hazardous during handling.
The main objective of the present invention is to provide an improved process for the reduction of Chemical Oxygen Demand (COD), Total Dissolved Solids (TDS) and color from the effluent of cotton linter processing industry which obviate the drawbacks as detailed above.
There is continued interest on development of new improved process for removal of color and other organic & inorganic impurities produced during the pulping process of cotton linter. It is a well known fact that organics, inorganics as well as color in such type of effluents are not easily biodegradable and hence, have disposal problems in the natural environment.
Accordingly, the present invention provides an improved process for the reduction of chemical oxygen demand (COD), total dissolved solids (IDS) and color from the effluent of cotton linter processing industry which comprises; mixing the effluent characterized in that with a flocculating agent for a period of 1-10 minutes at a temperature ranging from 20 to 40°C, allowing the effluent to settle fro a period ranging from 30-120 minutes to obtain the desired treated effluent.
In an embodiment of the present invention the effluent used for the treatment is selected from whe Black liquor, Black wash water and the mixture thereof along with wash water in black liquor: black wash water: wash water ratio of 8-9 : 95-110: 180-195.
In an another embodiment the flocculating agent used is a mixture of three components wherein the first component being a sulphate, chloride, nitrate of transition metals preferably sulphate of iron and sulphate, chloride, nitrate of Group III metals preferably sulphate of aluminum and the second component being oxide of alkali or alkaline earth metals, of Group I or II such as sodium, potassium, magnesium, calcium, preferably an oxide of calcium and the third component being natural earth namely fullers earth, bentonite, dolomite, sand, garden soil, preferably dolomite and bentonite.
In yet another embodiment the flocculating agent used is comprising a mixture of sulphate of aluminum & iron and the mixture of natural earths such as dolomite and bentonite and an oxide of alkali or alkaline earth metal in the ratio of 35-45: 45-55: 4-6 : 4-6 : 190-210.
In still another embodiment the mixing time of flocculation agent with the effluent is preferably 2 minutes.
In the feature of the present invention after the flocculation treatment of the individual Black liquor as well as Black wash water sample and mixture of black liquor, black wash water and wash water, significant reduction of color, and COD was observed for all the three effluent samples tested.
The process of the present invention reduces COD, color and to some extent TDS simultaneously at 20 to 40°C temperature from cotton linter processing effluent, thus saving energy cost, the operation does not involve any use of mineral acid, thus avoiding corrosion problems. The novelty of the process lies in the use of flocculating agent comprising of a mixture of transition metal salts and the oxide of alkaline earth metal and a mixture of natural earths.
The process of the present invention is described herein bellow with reference to the examples which are illustrative only and should not be construed to the limit of scope of the present invention in any manner.
Example -1
200 ml Black Liquor generated from the cotton linter processing plant was diluted with tap water to 1 lit. ( COD - 1 l,936ppm and TDS 25,770ppm of pH- 10.0) was taken in 2 Lit. beaker to which flocculent comprising of mixture of aluminum sulphate, ferrous sulphate, dolomite and bentonite (200mg) in 40:50:5:5 proportion and calcium oxide 20g
was added and mixed thoroughly and poured in a 1 Lit. measuring cylinder for 30 minutes at ambient temperature. The supernate thus obtained was analyzed for it's COD, IDS, BOD and color reduction using spectrophotometer at 480 nm after adjusting the pH of the sample to ~ 8. The treated sample of the Black Liquor showed COD as 1818 ppm, TDS 4160 ppm and color reduction was found to be 88%.
Example- 2
200 ml Black wash water ( COD -849ppm and TDS 840ppm of pH- 8.8) generated from the cotton linter processing plant was diluted with tap water to 1 lit. and was taken in a 2 Lit. beaker to which flocculent comprising of mixture of aluminum sulphate, ferrous sulphate, dolomite and bentonite (200mg) in 40:50:5:5 proportion and calcium oxide 400mg was added and mixed thoroughly and poured in a 1 Lit. measuring cylinder for 30 minutes at ambient temperature. The supernate thus obtained was analyzed for it's COD, TDS, BOD and color reduction using spectrophotometer at 480 nm after adjusting the pH of the sample to ~ 8. The treated sample of the Black Liquor showed COD as 80 ppm, TDS 440 ppm and color reduction was found to be 35%.
Example -3
1000 ml of the mixture of the effluent containing 30ml of Black Liquor, 334ml of Black wash water and 636ml of Wash water generated from the cotton linter processing plant having COD -513 ppm and TDS 2310 ppm of pH- 7.2, was taken in a 2 Lit. beaker to which flocculent comprising of mixture of aluminum sulphate, ferrous sulphate, dolomite and bentonite (l.Og) in 40:50:5:5 proportion and calcium oxide 2.0g was added and mixed thoroughly and poured in a 1 Lit. measuring cylinder for 30 minutes at ambient temperature. The supernate thus obtained was analyzed for it's COD, TDS, BOD and
color reduction using spectrophotometer at 480 nm after adjusting the pH of the sample to ~ 8. The treated sample of the Black Liquor showed COD as 102.7 ppm, TDS 2370 ppm and color reduction was found to be 95%.
Example - 4
100 m3 of the mixture of the effluent containing 3m3 of Black Liquor, 33.4m3 of Black wash water and 63.6m3 of Wash water generated from the cotton linter processing plant having COD - 727 ppm and TDS 2310ppm of pH- 7.2 was taken in 210m3 capacity rectangular setteling tank to which flocculent comprising of mixture of aluminum sulphate, ferrous sulphate, dolomite and bentonite (100kg) in 40:50:5:5 proportion and calcium oxide 200kg was added and mixed thoroughly with a movable floating mixer and allowed to settle at ambient temperature. The supernate thus obtained was analyzed for it's COD, TDS, BOD and color reduction using spectrophotometer at 480 nm after adjusting the pH of the sample to ~ 8. The treated sample of the Black Liquor showed COD as 241 ppm, TDS 2390 ppm and color reduction was found to be 95%. Advantages of the invention :
The present process has following advantages such as it reduces COD, TDS and color simultaneously at ambient temperature from cotton linter pulp effluents, thus saving energy cost, the operation does not involve any use of mineral acid thus, avoiding corrosion problems , thus the process is eco-friendly. The process does not involve any hazardous chemicals like hydrogen peroxide and expensive reactants like enzymes for the treatment. Thus the process is easy to operate as well as cost effective.

We Claim:
1. An improved process for the reduction of chemical oxygen demand (COD), total
dissolved solids (TDS) and color from the effluent of cotton linter processing industry
which comprises; mixing the effluent characterized in that with a flocculating agent for a
period of 1-10 minutes at a temperature ranging from 20 to 40°C, allowing the effluent to
settle fro a period ranging from 30-120 minutes to obtain the desired treated effluent.
2. An improved process as claimed in claim 1, effluent used for the treatment is selected
from when Black liquor, Black wash water and the mixture thereof along with wash
water in a black liquor: black wash water: wash water proportion of 8-9: 95-110: 180-
195.
3. An improved process as claimed in claims 1 and 2, wherein the flocculating agent used is
a mixture of three components wherein the first component being a sulphate, chloride,
nitrate of transition metals preferably sulphate of iron and sulphate, chloride, nitrate of
Group III metals preferably sulphate of aluminum and the second component being
oxide of alkali or alkaline earth metals, of Group I or II such as sodium, potassium,
magnesium, calcium, preferably an oxide of calcium and the third component being
natural earth namely fullers earth, bentonite, dolomite, sand, garden soil, preferably
dolomite and bentonite.
4. An improved process as claimed in claims 1-3 wherein the flocculating agent used is
comprising a mixture of sulphate of aluminum & iron and the mixture of natural earths
such as dolomite and bentonite and an oxide of alkali or alkaline earth metal in the ratio
of 35-45 : 45-55 : 4-6 : 4-6 : 190-210.
5. An improved process as claimed in Claims 1-4, wherein the mixing time of the
flocculation agent is preferably 2 minutes.
6. An improved process for the reduction of chemical oxygen demand (COD), total
dissolved solids (TDS) and color from the effluent of cotton linter processing industry
substantially as herein described with reference to the examples 1 to 4.

Documents:

105-del-2001-abstract.pdf

105-del-2001-claims.pdf

105-del-2001-correspondence-others.pdf

105-del-2001-correspondence-po.pdf

105-del-2001-description (complete).pdf

105-del-2001-form-1.pdf

105-del-2001-form-19.pdf

105-del-2001-form-2.pdf

105-del-2001-form-3.pdf

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Patent Number

215566

Indian Patent Application Number

0105/DEL/2001

PG Journal Number

11/2008

Publication Date

14-Mar-2008

Grant Date

27-Feb-2008

Date of Filing

31-Jan-2001

Name of Patentee

COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI- 110 001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	PRAMOD PRABHAKAR MOGHE	NATIONAL CHEMICAL LABORATORY, PUNE 411008, MAHARASHTRA, INDIA.
2	ASHWINI VINAYAK POL	NATIONAL CHEMICAL LABORATORY, PUNE 411008, MAHARASHTRA, INDIA
3	VINITA VINAY PANCHANADIKAR	NATIONAL CHEMICAL LABORATORY, PUNE 411008, MAHARASHTRA, INDIA
4	PRAKASH KONDIBA BAHIRAT	NATIONAL CHEMICAL LABORATORY, PUNE 411008, MAHARASHTRA, INDIA

PCT International Classification Number

CO2F 1/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA