Title of Invention | A PROCESS FOR MICROBIAL REMOVAL OF PHOSPHORUS |
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Abstract | A process for removal of phosphorus from LD Slag using microorganisms was invented. The solubilisation of phosphorus from LD Slag into the liquid medium takes place at room temperature, atmospheric pressure and simple phosphorus solubilising medium supplemented with glucose with natural isolated soil microorganisms. Up to 70% phosphorus removal after 12 days was possible using this particular microorganism. |
Full Text | MICROBIAL REMOVAL OF PHOSPHORUS FROM LD SLAG The present invention relates to an unique process for the removal of phosphorus from LD Slag using soil microorganisms. The present invention relates to an important process for the removal of phosphorus from the LD slag generating from steel manufacturing industry. The invention particularly deals with the removal of phosphorus from LD slag using microbial technology. LD Slag is a bi-product of iron and steel industry which comes from the refining of Pig iron using the LD converter process. Chemical analysis of LD slag has indicated that it is a good substitute for limestone due to its high value of CaO. LD slag has got high fluxing capacity ( basicity >3.0 ) and can be charged in the blast furnace due to easy melt and better utilization of Calcium value. However due to high content of Phosphorus and Sulphur in the slag, its recycle in sinter-mix has been restricted. LD slag which was put into regular use in blast furnace at Bhilai Steel Plant was discontinued due to wide fluctuation in raw material component as well as Phosphorus and Sulphur. The application of LD slag is in agriculture, concrete, plastering and environmental technology industries. It is also used for the base and sub-base layer of roads. Few applications relating to the recovery of metal values reducing at high temperature has also been studied. However the recycling of LD slag in blast furnace or sintering plant is limited due to high Phosphorus content. A wide variety of microorganisms are known today which can solubilise phosphorus from its insoluble form present in nature, thus exhibiting their role in phosphorus cycle in ecosystem (Bhattacharya P., Jain R.K., 2000, Fert.News, 45:45-52 ). Several strains of bacterial and fungal species have been reported and investigated in detail for phosphorus solubilising capabilities (Singh C.P., Mishra M.M., Kapoor K.K., 1982, Rev.Ecol.Biol.Sci., 19:17-25; Kukcey R.M.N., 1983, Can.J.Soil.Sci., 63:671-678;Singh C.P., Pareek R.P., SinghT.A., 1984, Cur.Sci., 53:1212-1213). Microbial solubilisation of insoluble phosphate is by the action of either phosphatase enzyme or production of organic acids (Ghosh R., Banik A.K., 1998, J.Surf.Sci.Technol, 14:286-298; Michoustine E.N., 1972, Rev.Ecol.Biol.Sol.T., 9:521-528). These phosphorus solubilising microbes have been utilized as biofertilizers, in bioremediation for removal of phosphates from water, wastes and sludge. The bioconversion occur at ambient temperature and is more selective to phosphate extraction than the conventional physico-chemical processes. The increased selectivity of attack may reduce the solubilization of other components present in the slag. The process uses easily available carbohydrate (glucose) as the source of energy/ proton source (Ghosh R., Banik A.K., 1998, J.Surf.Sci.Technol, 14:286-298; Kole S.C, Ghosh T., 1999, Indian.Biol, 31:14-18) as opposed to the wet acid processes that uses concentrated sulphuric acid. The main objective of the present invention is the removal of phosphorus from LD Slag using soil microorganisms. Another objective of the present invention is to carry out the the leaching operation at moderate temperature. Yet another objective of the present invention is that the process does not use corrosive chemicals. Yet another objective of the present invention is that the end product phosphorus removed in the solution as byproduct can be used as fertilizer. Yet another objective of the present invention is that the process neither requires sophisticated instrumentation nor skilled manpower. Yet another objective of the present invention is that the process is economical. Yet another objective of the present invention is that the reuse of phosphorus-less LD Slag (otherwise waste) in sintering process enhances resource utilization. Yet another objective of the present invention is that the process utilizes naturally occurring soil microorganism thus not hazardous to human being. The above mentioned property of solubilisation of phosphorus by microorganisms has been utilized for removal of phosphorus from LD slag. The major steps in the process are (a.) Isolation of phosphorus solubilising microorganisms from nature. (b.) Adaptation of the microorganisms to LD slag. (c.) Leaching of Phosphorus from LD slag by microorganisms. Accordingly, the present invention provides a unique process for microbial removal of phosphorus using natural soil microorganisms, which comprises a. preparing phosphorus solubilising medium adding about 10% overnight grown Frateuria aurentia bacteria culture and adding about 20% LD Slag, b. adding glucose as supplement for growth and metabolite production, c. shaking continually for 4 to 15 days, filtering and washing the residue with water and analysis for phosphorous content In an embodiment of the present invention the Frateuria aurentia bacteria has the following chararteristics : a. Gram native, motile aerobic, rods. b. Growth temperature, 30V to 40°C, c. pH-5 to ll, d. Citrate utilization: Positive e. Starch hydrolysis : negative f Catalase: Positive g. Gelatine liquification: Negative h. Indole Test: Negative i. Growth on Macconkey agar: Positive j. Able to utihse dextrose, fructose, galactose, inositol, lactose, maltose, manitol, raffinose, sorfitol, sucrose, xylose, as carbon source. In another embodiment of the present invention the naturally occurring isolated In another embodiment of the present invention the process was carried out at room temperature ranging between 20 to 45°C. In yet another embodiment of the present invention phosphorus solubilising medium was used for leaching. In still another embodiment of the present invention the phosphorous removal by the said process is about 70%. In still another embodiment of the present invention the sterilized phosphorus solubihsing medium containing 0.5 g 1- (NH4)2S04, 0.5 g -1 MgS04, 0.2 g 1-1 NaCl, of commercial grade is used. In still another embodiment of the present invention thee LD slag pulp density may be 20%. In still another embodiment of the present invention the 1 -10 g 1 -1 glucose was used as carbon and energy source. In still another embodiment of the present invention the 10% (v/v) bacterial inoculum contains 3 x 10 8 cfu / ml. In still another embodiment of the present invention the LD slag having particle size - 150 microns was used. The process of this invention is illustrated by example, which should not be construed to limit the scope of this invention. Example-1: 90 ml of phosphorus solubihsing medium containing 1.0 g glucose and 20g of LD slag were sterilized by autoclaving in 250ml Erlenmeyer flask. Two experimental flask were inoculated with 10 ml of active bacterial culture containing 3x10^ cfu / ml. Both inoculated and un-inoculated control flask were incubated at 33° C on a rotary shaker (150 rpm). One flask after 6 days & another flask after 12 days and control were filtered separately and the residue were washed thoroughly with distilled water. The residue was dried and analyzed for phosphorus. After 6 days the phosphorus removal was 15%) and after 12 days the phosphorus removal was 70%). Example-2 : 90 ml of phosphorus solubihsing medium and 20g of LD slag were sterilized by autoclaving in 250 ml Erlenmeyer flask. Two experimental flask one supplemented with 0.lg sterile glucose and another flask supplemented with Ig sterile glucose (in water solution) were inoculated with 10 ml of active bacterial culture containing 3 x 10 8 cfu / ml. The inoculated and un-inoculated control flask were incubated at 33 C on a rotary shaker (150 rpm). All the flasks were harvested after 12 days, filtered separately and residue washed thoroughly with distilled water. The residue was dried and analyzed for phosphorus. After 12 days, the phosphorus removal was 30 % with 0.1 %glucose supplement and about 70% with 1% glucose supplement. The main advantages of the present invention are: a. The leaching operation is carried out at moderate temperature. b. The process does not use corrosive chemicals. c. The end product phosphorus removed in the solution as byproduct can be used as fertilizer. d. The process neither requires sophisticated instrumentation nor skilled manpower. e. The process is economical. f. Reuse of phosphorus-less LD Slag (otherwise waste) in sintering process enhances resource utilization. g. As LD Slag will be used again thereby overcoming waste disposal problem thus reducing environmental pollution. h. The process utilizes naturally occurring soil microorganism thus not hazardous to human being. We claim: 1. A process for the microbial removal of phosphorus, which comprises: [a] inoculating a phosphorus solubilizing medium comprising 0.5g/l (NH4)2S04/ 0.5g/l MgS04 and 0.2g/l NaCI with 10% [v/v] of an overnight grown culture of Frateuria aurentia and adding 20% LD slag; [b] adding 1 to 10 g/l glucose as supplement to the medium of step [a] for growth and metabolite production; [c] incubating the medium of step [c] at a temperature in the range of 20 to 45 degree C for 4 to 15 days followed by filtering and washing the residue with water and analyzing for phosphorus content. 2. A process as claimed in claim 1, wherein the phosphorus removal is up to 70%. 3. A process as claimed in claim 1, wherein the LD slag pulp density is 20%. 4. A process as claimed in claim 1, wherein the LD slag having particle size of 150 microns is used. 5. A process as claimed in claim 1, wherein 10% bacterial inoculum contains 3X108 cfu/ml. 6. A process for the microbial removal of phosphorus substantially as herein described with reference to the foregoing examples. |
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474-del-2004-Claims-(30-12-2009).pdf
474-del-2004-Correspondence-Others-(30-12-2009).pdf
474-del-2004-correspondence-others.pdf
474-del-2004-correspondence-po.pdf
474-del-2004-description (complete).pdf
474-del-2004-Form-1-(30-12-2009).pdf
474-del-2004-Form-2-(30-12-2009).pdf
474-del-2004-Form-3-(30-12-2009).pdf
Patent Number | 238615 | ||||||||||||||||||
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Indian Patent Application Number | 474/DEL/2004 | ||||||||||||||||||
PG Journal Number | 8/2010 | ||||||||||||||||||
Publication Date | 19-Feb-2010 | ||||||||||||||||||
Grant Date | 11-Feb-2010 | ||||||||||||||||||
Date of Filing | 16-Mar-2004 | ||||||||||||||||||
Name of Patentee | COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH | ||||||||||||||||||
Applicant Address | RAFI MARG, NEW DELHI-110001, INDIA | ||||||||||||||||||
Inventors:
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PCT International Classification Number | C02F3/34 | ||||||||||||||||||
PCT International Application Number | N/A | ||||||||||||||||||
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