Title of Invention

"AN IMPROVED COMPOSITION USEFUL FOR THE TREATMENT OF BLACK LIQUOR, AND PROCESS THEREOF FOR THE TREATMENT OF BLACK LIQUOR"

Abstract

ABSTRACT An improved composition useful for the treatment of black liquor, an effluent from pulp and paper industry and a process for treatment of black liquor The invention relates to an improved composition useful for the treatment of black liquor, an effluent from pulp and paper industry and a process for treatment of black liquor. The pulp and paper industry in India is one of the highly polluting industries. The industry uses on an average 250-300 m3 of fresh water per ton of paper produced and nearly 75% of which is discharged as effluent popularly known as black liquor. Thus it is obvious that the proper treatment of pulp and paper industry effluent (Black Liquor) is quite necessary. This invention related to an improved composition useful for the treatment of black liquor, an effluent from pulp and paper industry and the use there of in such treatment. The novelty of the process lies in the use of flocculating agent, comprising salt from Group I elements, transition metal and natural earth. The process of the present invention removes COD. TDS and color simultaneously from black liquor at ambient temperature, thus saving energy cost, the operation does not involve any use of mineral acid thus, avoiding corrosion problems.

Full Text

This invention related to an improved composition useful for the treatment of black liquor, and process therof for treatment of black liquor. More particularly the invention is related to an improved method for the reduction of Chemical Oxygen Demand (COD), Total Dissolved Solids (TDS) and color from the effluents of pulp and paper industry. Despite developments in technologies, the pulp and paper industry particularly in India is seen as smock-stack industry lacking glamorous hitech approach. It is one of the highly polluting industries and the pollutants are released through liquid, solid and gaseous discharges. The industry in other parts of the world has made tremendous progress by adapting total recycling concept, resource conservation and effective environmental management. Paper industries in countries like India and China face problems continuously in the area of environmental management particularly because of low scale of operation, various and mixed raw materials inputs and lack of adequate modernization. The industry uses on an average 250-300m of fresh water per ton of paper produced and nearly 75% of which is discharged as effluent popularly known as black liquor. It contains organic and inorganic pollutants imparting high COD, BOD and dark color. If such untreated wastewater is allowed to accumulate, the decomposition of organic materials it contains can lead to production of malodourous gases. Moreover wastewater contains numerous toxic substances, which affect the aquatic flora and fauna, resulting in loss of productivity of natural waters and deterioration of water quality to such an extent that the water becomes unusable. Thus it is obvious that the proper treatment of pulp and paper industry effluent (Black Liquor) is quite necessary. The paper and board industries generally use bamboo, straws, bagasse, rags, waste papers and other agricultural residues as raw materials, therefore volume and characteristics of wastewater known as black liquor, differ from industry to industry. Black liquor mainly contains 3 -6% of lignin originated from the bark of the plant, which is not easily biodegradable, along with other organic and inorganic impurities. The dark color of the black liquor is mainly due to presence of polyphenolic bodies like coniferyl, sinapyl and p- coumaryl alcohols produced during partial degradation of lignin. The pulp & paper industry uses large amounts of water, which is recycled, and reused resulting in temperature rise and dissolution of more solids in water enhancing problems e.g. corrosion, slime and other deposits. In order to conform to environmental quality guidelines a number of primary and secondary treatment systems such as clarifiers, aerated lagoons, trickling filters, biomethanation and other biological systems are installed. All these treatments reduce reasonably good amount of COD and BOD but not color toxicity and inorganic impurities. Ultra filtration has also been tried and found futile to remove TDS as well as color completely. Due to stringent environmental norms, such partially treated effluents of industries are not allowed to be mixed in the natural stream. In the prior art the following methods are used to remove COD, BOD, TDS and color of Black Liquor. Several methods hitherto used are described in brief herein below: Color removal from a waste effluent by combined use of Fe(II), lime and bone charcoal. Shen, X.; Bousher, A.; Edyvean, R. G. J. (Dep. Chem. Eng., Univ. Leeds, Leeds LS2 9JT, UK). IChemE Res. Event-Eur. Conf. Young Res, Chem. Eng., 1st, Volume 1, 469- 71. Inst. Chem. Eng.: Rugby, UK. (English) 1995. CODEN: 61OUA9. DOCUMENT TYPE: Conference CA Section: 60 (Waste Treatment and Disposal) Section crossreference^): 45, 49, CA 123:122024 A study was conducted by Shen et al to remove color from a chem. manufg. effluent. The effluent contained high levels of sol. org. compds. The effluent was intensely black; the high soly. of colored constituents made common coagulation or adsorption techniques unsuitable for color removal. Results showed that a combination of FeC12:4H2O (as a reducing agent), lime, and bone charcoal removed 97% of the color. Removal of COD and nitrogen from wastewater. Ishida, Koji; Iwabe, Hideki; Minami, Hirokazu; Kamisaka, Taichi (Kubota Kk, Japan). Jpn. Kokai Tokkyo Koho JP 07214092 A2 15 Aug 1995 Heisei, 4 pp. (Japan). CODEN: JKXXAF. CLASS: ICM: C02F009-00. ICS: C02F009-00; B01D019-00; C02F001-20; C02F001-58; C02F001-70; C02F001-78; C02F003-28. APPLICATION: JP 94-10157 1 Feb 1994. DOCUMENT TYPE: Patent CA Section: 60 (Waste Treatment and Disposal), CA 123:349361 The title process includes oxidizing COD-contg. wastewater by contacting with O3 in an O3 contactor, blowing N2 into the oxidn.-treated water in a dissolved 02-removing tank to remove completely dissolved O2, and biol. treating in an anaerobic filtration bed under anaerobic condition. 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, ML, 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. Removal of carboxylic acids from wastewaters using polyaluminum chlorohydrate. Brown, William M.; Trevino, Maria (Baker Hughes, Inc., USA). U.S. US 5395536 A 7 Mar 1995, 5 pp. (United States of America). CODEN: USXXAM. CLASS: ICM: C02F001-56. NCL: 210727000. APPLICATION: US 93-57879 7 May 1993. DOCUMENT TYPE: Patent CA Section: 60 (Waste Treatment and Disposal), CA 123:40265 After or during initial contact of the wastewater with the compn. comprising polyaluminum chlorohydrate and a cationic poly electrolyte, an org. liq. may optionally be added after which sepn. into an aq. phase and an org. phase occurs whereby the org. acids are removed in the org. phase which was reported by Brown & Trevino. The preferred polyaluminum chlorohydrate is aluminum chlorohydrate, and the preferred cationic polyelectrolyte is a high mol. wt. poly(di-Me diallyl)ammonium chloride. Treatment of kraft bleaching effluents by lignin-degrading fungi. I. Decolorization of kraft bleaching effluents by the lignin-degrading fungus IZU-154. Lee, Seon Ho; Kondo, Ryuichiro; Sakai, Kokki; Nishida, Tomoaki; Takahara, Yoshimasa (Fac. Agric., Kyushu Univ., Fukuoka 812, Japan). Mokuzai Gakkaishi, 39(4), 470-8 (English) 1993. CODEN: MKZGA7. ISSN: 0021-4795. DOCUMENT TYPE: Journal CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products) Section crossreference^): 60, CA 119:273687 Three white-rot fungi (IZU-154, Phanerochaete chrysosporium Burds and Coriolus versicoloy (L. ex Fr.) Quel.) were tested by Lee et al for their abilities to decolorize kraft bleaching effluents from the 1st alk. extn. stage. The fungus IZU-154 exhibited the effective decolorization of not only hardwood but also softwood kraft pulp bleaching effluent. For the softwood bleach plant effluent contg. 10,000 color units (CU) , treatment with IZU-154 in the presence of a small amt. of glucose (0.5%) resulted in 78% and 89% redn. of the color after one- and two-day incubation, resp. On the other hand, when the effluent was treated under the same conditions, only 32% and 36% of the decolorization with C versicolor and 49% and 72% of the decolonization with P. chrysosporium were obsd. within one- and two-day incubations, resfectively. In comparison with 53% and 78% of color redns. achieved by IZU-154 with the softwood bleach plant effluent including glucose, addn. of glucono-d-lactone to the effluent showed remarkable decolorizations of 83% and 94% within 12- and 24-h incubations. resp. Furthermore, the color of the effluent was effectively removed by the addn. of acetic acid as an additive. Therefore, a greater color redn. by IZU-154 can be expected for a possible biotechnol. application. Biological decolorization of paper mill wastewater. Nghiem, Nhuan P. (Nalco Chemical Co., USA). U.S. US 5407577 A 18 Apr 1995, 10 pp. (United States of America). CODEN: USXXAM. CLASS: ICM: C02F003-34. NCL: 210606000. APPLICATION: US 93-80933 22 Jun 1993. DOCUMENT TYPE: Patent CA Section: 60 (Waste Treatment and Disposal) Section cross-reference(s): 43, CA 123:92323 Nghiem, has investigated a process for removing color from a pulp and paper wastewater includes treating the wastewater with an enzyme, which is capable of oxidizing at least a portion of the color forming components of the wastewater, followed by treatment with a tannin-degrading microorganism capable of degrading at least a portion of the oxidized color-forming components. Molecular adsorption on porous styrene-divinylbenzene copolymers. II. Froelich, Peter; Schwachula, Gerhard; Sarodnik, Eberhard (Sekt. Chem., Martin-Luther- Univ., Halle, Fed. Rep. Ger.). Plaste Kautsch., 27(10), 557-9 (German) 1980. CODEN: PLKAAM. ISSN: 0048-4350. DOCUMENT TYPE: Journal CA Section: 36 (Plastics Manufacture and Processing) Section cross-reference(s): 66, CA 94:31432 Froelich et al have observed that the sorption-desorption properties of humic acids, colored substances in molasses, and the antibiotic Turimycin [39405-35-1] on anion exchangers and porous divinylbenzene-styrene copolymer [9003-70-7] (or terpolymers with acrylic compds.) indicate that polymeric adsorbents can be used to advantage in removing organophilic substances from polar solvents. Wastewater treatment. Sakurai, Shigeru (Taisei Road Construction Co., Ltd., Japan). Jpn. Kokai Tokkyo Koho JP 54051250 21 Apr 1979 Showa, 3 pp. (Japanese). (Japan). CODEN: JKXXAF. CLASS: 1C: C02C005-12; C02C005-04. APPLICATION: JP 77-117659 30 Sep 1977. DOCUMENT TYPE: Patent CA Section: 60 (Sewage and Wastes) Section crossreference^): 44, CA 91:78574 Sakurai et al have described a following method, H202 is added to wastewater, then the pH is adjusted to £4, and the wastewater is electrolyzed with an Fe anode to oxidize sol. pollutants. The insol. pollutants are flocculated by adjusting the pH to 6.0-8.5. Thus, molasses manuf. wastewater contg. 125 ppm COD was mixed with 0.5 mL 35% H2O2 soln./L, then the pH was adjusted to 2.9, and the wastewater was electrolyzed 20 min at 4.5-6.8 V with aeration. The treated wastewater was treated with NaOH to pH 8, then with polymer coagulant. The treated wastewater contained 8.0 ppm COD. Separation of organic acids from kraft black liquors using membranes. Bowe, John (United States Dept. of-6-725 720. (English). (United States of America). CODEN: XAXXAV. APPLICATION Agriculture, USA). U. S. Pat. Appl. US 725720 AO 20 Dec 1985, 19 pp. Avail. NTIS Order No. PAT-APPL: US 85-725720 22 Apr 1985. DOCUMENT TYPE: Patent CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products), CA 104:151147 A method was described by Bowe to recover low mol. wt. aliph. org. acids from kraft black liquor by ultracentrifugation (UC) of liquor followed by electrodialysis (E) of UC permeate, treating deionate from E with acid to ppt. lignin and electrolytic H2O-splitting of resulting soln. Research on the decolonization of melanoidin by microorganisms. Part III. Detection of lactic acid and amino acids from melanoidin decolorized by enzymes of Coriolus versicolor Ps4a. Ohmomo, Sadahiro; Aoshima, Ikuko; Tozawa, Yukiko; Ueda, Kiyomoto (Inst. Appl. Biochem., Univ. Tsukuba, Sakura 305, Japan). Agric. Biol. Chem., 49(9), 2767-8 (English) 1985. CODEN: ABCHA6. ISSN: 0002-1369. DOCUMENT TYPE: Journal CA Section: 10 (Microbial Biochemistry), CA 103:175323 Ohmomo, et al have studied decolorization of melanoidin, a dark brown pigment in molasses wastewater, by enzymes from C. versicolor which produced lactic acid and various amino acids, such as, glycine, valine, glutamate, leucine, serine, etc. The amt. of lactic acid was equiv. to 10.5% of the C in melanoidin, whereas the amts. of amino acids were equiv. to 4-6% of the N in melanoidin. Treatment of molasses wastewater with the decolorizing enzymes reduced the color d. and at the same time some useful org. acids were produced. Kraft overload recovery Beaupre, Marc F.; Cambron, Emile A.; Cambron, Emily T. (Can. ). U.S. US 4470876 A 11 Sep 1984,5 pp. (English). (United States of America). CODEN: USXXAM. CLASS: 1C: D21C011-12. NCL: 162016000. APPLICATION: US 82-400960 22 Jul 1982. DOCUMENT TYPE: Patent CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products), C A 101:194014 Beaupre, has described a process, in which a portion of black liquor (BL) is coned, to at least 40%, cooled to 5-50°, acidified with H2SO4 contg. Na2SO4, from C1O2 prepn., to pH 4.5, heated to -60° to sep. lignin [9005-53-2], neutralized with NaOH, treated with the 1st portion of BL and burned in furnace to recover inorgs., was described for augmenting the recovery capacity of kraft system. Recovery of inorganic compounds from kraft pulping black liquors. (Domtar, Inc., Can.). Jpn. Kokai Tokkyo Koho JP 58036292 A2 3 Mar 1983 Showa, 5 pp. (Japanese). (Japan). CODEN: JKXXAF. CLASS: 1C: D2ICO 11-04. APPLICATION: JP 82-128830 23 Jul 1982. PRIORITY: CA 81-382387 23 Jul 1981. DOCUMENT TYPE: Patent CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products), CA 99:89814 Na compds. from kraft pulping black liquors are recovered by first acidifying the cooled liquor with acids contg. H2SO4 to pH filtering the liquor, and finally cooling the filtrate to form crystd. Na2SO4 for recycling. Thus, kraft pulping black liquor (solids -50%) was cooled to -40°, acidified with H2S04 to pH -3.5, heated at -60°, filtered, and cooled to -0° to give recyclable Na2SO4. Recovery of solids from black liquors. Caperos Sierra, Alberto (Institute Nacional de Investigaciones Agrarias, Spain). Span. ES 2006964 A6 16 May 1989, 4 pp. (Spain) CODEN: SPXXAD. CLASS: ICM: D21C009-00. ICS: D21C011-00. APPLICATION: ES 88-1697 27 May 1988. DOCUMENT TYPE: Patent CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products) Section cross-reference(s): 60, CA 114:26042 Caperos et al have studied that solids in black liquors are recovered as ppt. by mixing 1 part black liquor with 0.1-1.0 part reactive pptg. agents and sepg. the ppt. Thus, 1000 cm3 black liquor of E. globulus was mixed with 1000 cm3 satd. soln. of CaC12 in EtOH to form ppt., which was sepd. with a centrifuge and washed with a 1:1 EtOH-water mixt. to give ppt. 134, org. components 105, lignin 53, and pentosans 8 g, with 85% yield. Research on the decolorization of melanoidin by microorganisms. Part X. Continuous decolorization of molasses waste water using immobilized Lactobacillus hilgardii cells. Ohmomo, Sadahiro; Yoshikawa, Hiroshi; Nozaki, Kazuhiko; Nakajima, Tomoyoshi; Daengsubha, Wiwut; Nakamura, Isei (Inst. Appl. Biochem., Univ. Tsukuba, Tsukuba 305, Japan). Agric. Biol. Chem., 52(10), 2437-41 (English) 1988. CODEN: ABCHA6. ISSN: 0002-1369. DOCUMENT TYPE: Journal CA Section: 60 (Waste Treatment and Disposal) Section cross-reference(s): 16, CA 109:236219 The continuous decolorization of molasses wastewater (MWW) by immobilized cells of Lactobacillus hilgardii W-NS was studied by Ohmomo et al. The immobilized cells showed the maximal decolorization efficiency in the presence of 1% glucose with a medium pH of 5.0 at 45°. On successive decolorization of MWW with recycling of the immobilized cells, 90% of the maximal decolonization yield was maintained for 1 mo when 0.05% peptone was added to MWW. In contrast, on continuous decolorization in a column type reactor, a sufficient decolorization yield could not be maintained, the decolorization yield dropped to half the maximal level during operation for 5 days. Removal of lignin from alkaline waste pulping liquors. Ishikawa, Hisao; Koide, Kazuo (Oji Paper Co., Ltd., Japan). Jpn. Kokai Tokkyo Koho JP 62090389 A2 24 Apr 1987 Showa, 7 pp. (Japan) CODEN: JKXXAF. CLASS: ICM: D21C011-04. ICS: C02F001-44. APPLICATION. JP 85-226870 14 Oct 1985. DOCUMENT TYPE: Patent CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products), CA 107:79808 Ishikawa & Koide, have reported the title removal to involve colloidizing the sol. lignin, followed by ultrafiltration. Thus, beech chips were cooked at effective alkali 14%, sulfidity 25%, liquor ratio 4, and 165°. The resulting black liquor was filtered, adjusted pH to 11, 10, and 9 with CO2, and ultrafiltered to give delignification 89%, 94%, and 97%, resp. Radiation degradation of molasses pigment The fading color and product. Sawai, Teruko; Sekiguchi, Masayuki; Tanabe, Hiroko; Sawai, Takeshi (Tokyo Metrop. Isot. Res. Cent., Setagaya 158, Japan). Tokyo-toritsu Aisotopu Sogo Kenkyusho Kenkyu Hokoku, 10, 1-9 (Japanese) 1993. CODEN: TASHEK. ISSN: 0289-6893. DOCUMENT TYPE: Journal CA Section: 60 (Waste Treatment and Disposal), CA 121:16954 Decolorization of wastewater treatment plant effluent contg. molasses pigment by gamma irradn. was studied by Sawai et al. The COD decreased and the dark brown color of the 12 effluent faded away with increasing radiation dosage. The high mol. wt. components of molasses pigment were degraded to lower mol. wt. substances and were decompd. finally to carbon dioxide. Org. acids, such as formic, acetic, oxalic, citric, and succinic acid were formed as intermediates. The radiation treatment was enhanced by the addn. of H202 Treatment of black pulping liquor by coacervation and precipitation. Zhang, Muen (Peop. Rep. China). Faming Zhuanli Shenqing Gongkai Shuomingshu CN 1057079 A 18 Dec 1991, 5 pp. (People's Republic of China). CODEN: CNXXEV. CLASS: ICM: D21C011-04. APPLICATION: CN 90-104181 5 Jun 1990. DOCUMENT TYPE: Patent CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products) Section cross-reference(s): 60, CA 117:173646 Black pulping liquor is treated by adding solid CaC12 or aq. soln. contg. CaC12 (2-5 g/100 mL) to black pulping liquor, coagulating, and pptg. to remove lignin and recover dild. NaOH soln which was reported by Zhang. Thus, 17.5 g lignin and 6 g/L NaOH aq. soln. were recovered by adding 3 g CaC12 in 100 ml sulfate black liquor (from prepn. of pine pulp), pptg., and filtration. Decolorization and polysaccharide production from molasses waste water by fungus D-l. Thananonniwat, Direk; Jatikavanich, Suchada; Sihanonth, Prakitsin (Fac. Sci., Chulalongkorn Univ., Bangkok 10330, Thailand). Microb. Util. Renewable Resour, Volume Date 1990, 7, 457-64 (English) 1991. CODEN: MURRE6. DOCUMENT TYPE: Journal CA Section: 60 (Waste Treatment and Disposal) Section crossreference^): 10, 16, 44, CA 117:55118 Thananonniwat et al have screened of 380 fungal strains isolated from Thai soil, fungal strain D-1 to decolorize molasses wastewater and produce polysaccharides at the same time. Conditions such as environmental factors and medium compn. that affected growth, decolorization efficiency, and polysaccharide prodn. were studied. Molasses wastewater supplemented with 2.5% glucose and 0.1% yeast ext., with the initial pH adjusted to 5.0, agitated on rotary shaker at 200 rpm, and incubated at 30° gave the max. growth rate of-0.6257 g dried mycellal wt. per 100 mL of medium, max. decolorization activity of-97%, max. polysaccharide prodn. of-0.355 g, and the max. dried matter wt. per 100 mL of medium. Treatment of molasses wastewater by ozonization and biological treatment. Ichikawa, Hiroyasu, Taira, Naohide; Wada, Shinji; Tatsumi, Kenji (Hydrospheric Environmental Protection Department, National Institute Resources and Environment, Tsukuba 305, Japan). Mizu Kankyo Gakkaishi, 19(12), 1004-1008 (Japanese) 1996 Nippon Mizu Kankyo Gakkai CODEN: MKGAEY. ISSN: 0916-8958. DOCUMENT TYPE: Journal CA Section. 60 (Waste Treatment and Disposal) Section crossreference^): 16, CA 126:135031 A soln. of molasses wastewater, pretreated by activated sludge, was ozonated and then completely decolorized by ozone by Ichikawa et al. Total org. C (TOC) could be reduced only to -50% during a period of 60 min ozonization. The ozonated soln., after being mixed with activated sludge culture, was incubated for 10 days at 25°, and biodegradability was then assessed by dissolved org. C (DOC) redn. DOC of the nonozonated soln. could hardly be reduced even after 10 days incubation, indicating biodegradability. For the ozonated soln. of pretreated molasses wastewater, a DOC removal of 70% was achieved and DOC in the soln. was greatly improved the biodegradability of refractory org. compounds. A soln. of molasses wastewater was ozonated directly. Ozone decolorized -90% of the molasses wastewater but TOC was reduced to only -8%. Biodegradability of ozonated molasses wastewater was improved. An improved process for the treatment of black liquor waste from paper mills In our copending application no. 796/Del/97, we have described a process for treatment of black liquor which comprises separation of lignin from black liquor waste of paper mills using flocculant consisting of salts from Group -IA, preferably sulphated of aluminum, alkali metal salts from Group-HA preferably calcium chloride, transition metals preferably iron and earth such as dolomite or bentonite. The lime is added to attain the pH at 10-12 and then mixture of above flocculant is added. The lignin along with other organic and inorganic impurities gets precipitated and pH of the treated effluent is highly alkaline. The treated effluent is passed over bed of ion exchange resins to obtain a clear colourless effluent. In the above mentioned patent application the lime is used and even the flocculating mixture contains alum. Because of the use of lime the pH of the treated effluent ranges from 10-12. This requires initial as well as final pH adjustment to neutral value before disposing to natural streams. This also generates large quantity of sludge imparting solid waste disposal problem. The present invention attempts to remove this drawback wherein the use of lime and alum is totally eliminated because of which there is no problem of pH adjustment by adding additional chemicals and the sludge removal. The novelty of the present invention therefore lies in treating the effluent with out any dilution, avoiding the use of lime necessitating the initial and final pH adjustments which require the use of scarce resources like water, environmental friendly deletion of use of lime and sludge disposal problem which could have cause further environmental damage. In the hitherto known processes main drawbacks are use of acidic media, which involves corrosion problems, filtration problems due to colloidal nature of the particles and incomplete removal of organic, inorganic matter as well as colour (mainly due to the presence of lignin and mellanoidins) of the effluent water. There is continued interest on development of new improved process for removal of color and other organic & inorganic impurities produced during the manufacturing process of paper and pulp. 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. The main objective of the present invention is therefore to provide an improved composition for the treatment of black liquor an effluent from paper and pulp industry. Another objective is to provide an improved process using the said composition for treatment of black liquor. Still another object is to provide a process eliminating the use of lime and alum resulting in environmentally friendly process for such treatment of black liquor. Yet another object is to provide a process which reduces/ eliminates use of scarce natural resources like water for dilution of the black liquor before treatment. The process of the present invention removes COD, TDS and color simultaneously from black liquor an effluent from pulp and paper industry at 20 to 40°C temperature, thus saving energy cost, the operation does not involve any use of mineral acid thus, avoidingcorrosion problems. The novelty of the process lies in the use of flocculating agent, comprising salt from Group I elements, transition metal and natural earth. Accordingly, the present invention provides an improved composition for treatment of black liquor effluent generated from paper and pulp industry, which comprises an Inorganic Ferrous salt selected from sulfate, chloride, nitrate preferably ferrous sulphate in the range of 40 to 50 wt%, an Inorganic alkaline metal salt such as chlorides, carbonates, nitrates, sulphates of the metals of Group-II A, exemplified by sodium carbonate, potassium carbonate, lithium carbonate preferably sodium carbonate in the range of 18 to 50 wt%, and optionally a solidifying agent such as natural earths, sand, fullers earth, dolomite, bentonite preferably dolomite in the range of 0 to 42 wt%. The present invention also provides the process thereof using the composition provided hereinabove for treatment of effluents from paper and pulp industry and which comprise mixing the effluent from paper and pulp industry with the composition initially under agitation for a period of 1-10 minutes at ambient temperature, allowing to settle for a further period of 30-120 minutes, to obtain the treated black liquor in the supernatant. In an embodiment of the present invention the concentration of the composition with black liquor may range from 0.8:1 to 1.25:1. In one of the features of the present invention, treatment was done at original pH of the black liquor and thereby avoiding pH adjustment of the final treated effluent before disposal, wherein when calcium carbonate and chloride is used, as a flocculating agent pH adjustment is mandatory before and after the treatment. Also handling of calcium carbonate and chloride at large scale operations is problematic. In the features of the present invention all the operations of the treatment were carried out at ambient temperature without any use of mineral acid. In the feature of the present invention after the treatment of the Black liquor, significant reduction of color, TDS and COD was observed. In the features of the present invention it was observed that use of sodium carbonate as a flocculating agent is advantageous cost-wise, compared to other carbonates like lithium, potassium and calcium. The sludge volume and its dry weight is comparably less when sodium carbonate is used instead of calcium carbonate and chloride as a flocculating agent. Sodium carbonate (washing soda) is a non-phosphate water softener and boost cleaning power of plain water. Therefore use of washing soda as flocculent in effluent treatment is non-hazardous as well as non-toxic in nature. Although the process provided by the present invention for the treatment of black liquor from paper and pulp industry using the composition as above mentioned is useful for most of the paper industries the concentration of the composition used for the treatment may vary depending upon the initial characteristics of. the black liquor particularly the COD level which should be preferably below 3000 ppm. If COD exceeds 3000 ppm, higher dosage of the composition is required to obtain better results. 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 -1 500 ml Black Liquor generated from pulp and paper industry (COD - 1412 ppm and IDS 2320 ppm of pH- 9.7) was taken in 1000 ml beaker to which flocculent comprising of mixture of ferrous sulphate, washing soda and dolomite (550mg) in 25:10:20 proportion was added and mixed thoroughly and poured in a 500 ml measuring cylinder and allowed to settle for 30 minutes at ambient temperature. The supernatant thus obtained was analyzed for its COD, TDS and color reduction using spectrophotometer at 580 nm. The treated sample of the Black Liquor showed COD as 471 ppm, TDS 1710 ppm and color reduction was found to be 90%. Example -2 500 ml Black Liquor generated from pulp and paper industry (COD - 1412 ppm and TDS 2320 ppm of pH- 9.7) was taken in 1000 ml beaker to which flocculent comprising of mixture of ferrous sulphate, washing soda and bentonite (400mg) in 20:10:10 proportion was added and mixed thoroughly and poured in a 500 ml measuring cylinder and allowed to settle for 30 minutes at ambient temperature. The supernatant thus obtained was analyzed for its COD, TDS and color reduction using spectrophotometer at 580 nm. The treated sample of the Black Liquor showed COD as 392 ppm, TDS 1620 ppm and color reduction was found to be 92%. Example -3 100 ml Black Liquor generated from pulp and paper industry (COD - 1412 ppm and IDS 2320 ppm of pH- 9.7) was taken in 250 ml beaker to which flocculent comprising of mixture of ferrous sulphate, potassium carbonate and dolomite (lOOmg) in 40:20:40 proportion was added and mixed thoroughly and poured in a 100 ml measuring cylinder and allowed to settle for 30 minutes at ambient temperature. The supernatant thus obtained was analyzed for its COD, TDS and color reduction using spectrophotometer at 580 nm. The treated sample of the Black Liquor showed COD 425 ppm, TDS 990 ppm and color reduction was found to be 90%. Example ~4 100 ml Black Liquor generated from pulp and paper industry (COD - 1412 ppm and TDS 2320 ppm of pH- 9.7) was taken in 250 ml beaker to which flocculent comprising of mixture of ferrous sulphate, lithium carbonate and dolomite (lOOmg) in 40:20:40 proportion was added and mixed thoroughly and poured in a 100 ml measuring cylinder and allowed to settle for 30 minutes at ambient temperature. The supernatant thus obtained was analyzed for its COD, TDS and color reduction using spectrophotometer at 580 nm. The treated sample of the Black Liquor showed COD 465 ppm, TDS 1640 ppm and color reduction was found to be 92%. Example -5 50 ml Black Liquor generated from pulp and paper industry (COD - 1412 ppm and IDS 2320 ppm of pH- 9.7) was taken in 100 ml beaker to which flocculent comprising of mixture of ferrous sulphate, sodium carbonate (50mg) in 25:25 proportion was added and mixed thoroughly and poured in a 50 ml measuring cylinder and allowed to settle for 30 minutes at ambient temperature. The supernatant thus obtained was analyzed for its COD, IDS and color reduction using spectrophotometer at 580 nm. The treated sample of the Black Liquor showed COD as 500 ppm, TDS 1230 ppm and color reduction was found to be 88%. Advantages of the invention: The present process of treating black liquor an effluent from paper and pulp industry has following advantages; 1. It reduces COD, TDS and color simultaneously at ambient temperature. 2. Treatment is done without dilution of the original effluent thereby solving the problem of water scarcity. 3. There is no requirement for initial and final pH adjustment. 4. The operation does not involve any use of mineral acid thus, avoiding corrosion problems. 5 The sludge generated during the treatment process is very less, easy to dispose and may be used as bio-composite. 6. 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, cost-effective as well as eco-friendly. 7. The overall process is cost-effective. We Claim : 1. An improved composition for treatment of black liquor effluent generated from paper and pulp industry, which comprises an Inorganic Ferrous salt selected from sulfate, chloride, nitrate preferably ferrous sulphate in the range of 40 to 50 wt%, an Inorganic alkaline metal salt such as chlorides, carbonates, nitrates, sulphates of the metals of Group-II A, exemplified by sodium carbonate, potassium carbonate, lithium carbonate preferably sodium carbonate in the range of 18 to 50 wt%, and optionally a solidifying agent such as natural earths, sand, fullers earth, dolomite, bentonite preferably dolomite in the range of 0 to 42 wt%. 2. A process for treatment of black liquor effluent from paper and pulp industry using a composition as claimed in claim 1, comprising steps of: mixing the effluent from paper and pulp industry with the composition as claime in claim 1 initially under agitation for a period of 1-10 minutes at ambient temperature, allowing the solution to settle for a further period of 30-120 minutes and , obtaining the treated black liquor in the supernatant. 3. A process as claimed in claim 2, wherein the concentration of the composition with black liquor may range from 0.8:1 to 1.25:1. 4. An improved composition useful for the treatment of black liquor, and process therof for treatment of black liquor substantially as herein described with reference to the examples.

Documents:

217-DEL-2003-Abstract-(14-11-2008).pdf

217-del-2003-abstract.pdf

217-DEL-2003-Claims-(14-11-2008).pdf

217-DEL-2003-Claims-(15-12-2008).pdf

217-del-2003-claims.pdf

217-del-2003-complete specification (granted).pdf

217-DEL-2003-Correspondence-Others-(10-12-2008).pdf

217-DEL-2003-Correspondence-Others-(14-11-2008).pdf

217-DEL-2003-Correspondence-Others-(15-12-2008).pdf

217-del-2003-correspondence-others.pdf

217-del-2003-correspondence-po.pdf

217-DEL-2003-Description (Complete)-(14-11-2008).pdf

217-DEL-2003-Description (Complete)-(15-12-2008).pdf

217-del-2003-description (complete).pdf

217-del-2003-form-1.pdf

217-del-2003-form-18.pdf

217-DEL-2003-Form-2-(14-11-2008).pdf

217-del-2003-form-2.pdf

217-DEL-2003-Form-3-(14-11-2008).pdf

217-del-2003-form-3.pdf