Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process...
Patent
1991-06-06
1994-05-24
Naff, David M.
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
210601, 4352525, 4352625, 435313, 435315, 435818, 435832, C12P 100, C12N 120, C02F 100, C12M 104
Patent
active
053148061
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a method and system for the biological treatment of oxalates in general, and relates particularly to a method and system for substantially disposing of oxalate produced as an industrial by-product using a micro-organism as the biological agent. More particularly, though not exclusively, the invention is directed to a method and system for biological disposal of oxalate produced as a by-product of the Bayer refinery process using an oxalophilic micro-organism.
Although the present invention will be described with particular reference to the biological disposal of sodium oxalate, it will be understood that the invention is not limited to a method and system for biologically disposing of this particular oxalate. The method and system of the invention has wider applications where the reduction, removal or destruction of oxalates such as, for example, potassium oxalate, calcium oxalate or ammonium oxalate is required, as part of an industrial process or due to the problems they cause as pollutants or contaminants.
The present invention has particular application in the context of alumina refineries in which sodium oxalate is produced as a by-product of the refinery process.
DISCUSSION OF BACKGROUND ART
Sodium oxalate is a by-product of the Bayer refinery process used for producing aluminium hydroxide and alumina from bauxite. In the Bayer process, sodium oxalate is removed from sodium aluminate liquor, following or during aluminium hydroxide precipitation, by feeding the sodium aluminate liquor or liquor enriched in sodium oxalate to a crystalliser containing seed crystals of sodium oxalate. These seed crystals induce precipitation of further sodium oxalate. Sodium oxalate is normally removed by thickening and/or filtering the sodium oxalate slurry. Sodium oxalate is an environmentally hazardous compound and must be disposed of carefully. Typically the filtered sodium oxalate is reduced to solid cake form and must be transported to another site for disposal by combustion or other means.
Another method currently employed for the disposal of sodium oxalate from the Bayer process involves chemical treatment of the oxalate with lime. However, one of the products of this chemical treatment is calcium oxalate which is equally difficult to dispose of in an environmentally acceptable manner.
Australian Patent Application No. 39465/89 in the name of ALCAN INTERNATIONAL LTD describes a method for the biodegradation of oxalate in solution which has been removed from a Bayer processing system. Micro-organisms for degrading oxalates are maintained in a bio-reactor. Preparatory to introducing the oxalate-containing composition to the bio-reactor the pH of the oxalate-containing solution is adjusted to be compatible with the micro-organisms in the medium. In the Alcan method the pH of the solution is adjusted to the neutral range by the addition of a suitable acid, such as sulphuric acid. In addition, it may also be necessary to adjust the concentration of Na.sup.+ ions in the solution to a level which can be tolerated by the micro-organism developed to digest the oxalates. The micro-organisms employed were isolated from the soil of the rhizospheres of the oxalate producing plants Dieffenbachia picta and Rheum rhaponticum (Rhubarb), and it was believed that the prominent micro-organism which is capable of degrading oxalates is a Pseudomonas or Pseudomonas-like organism.
A significant disadvantage of the Alcan method of biodegradation of oxalate is the step of pretreatment of the oxalate-containing solution to adjust the pH to the neutral range and to reduce the sodium concentration to a level compatible with the micro-organisms. This pretreatment is necessary because the micro-organisms employed require an aqueous solution with pH in the neutral range and sodium concentration below a level of approximately 8000 mg/L. A further disadvantage is the need for an extended period of pre-stressing the microbial culture by exposure to varying concentrations of oxalates to en
REFERENCES:
patent: 4203841 (1980-05-01), Shimizu et al.
Derwent WPI/L Online Abstract Accession No. 66-41270F, JP, B. 44-28476 (Ashai Chemical Industries, Co. Ltd.).
Derwent WPI/L Online Abstract Accession No. 87-332947, SU, A, 686463 (Moscow Lomonosov Univ.) Apr. 30, 1987.
Derwent Abstract Accession No. 88-097051/14, Class D15, SU, A, 1331889 (As Belo Microbiolog.) Aug. 23, 1987.
AU, A, 39465/89 (Alcan International Ltd), Feb. 15, 1990.
Patent Abstracts of Japan, M-77, p. 1368, JP, A, 52-19468 (Suntory K K) Feb. 14, 1977.
Patent Abstracts of Japan, C-311, p. 166, JP, A, 60-122099 (Fuji Denki Sougou Kenkyusho K K) Jun. 29, 1985.
Database WPIL, Accession No. 88-097051 [14], Derwent Publications Ltd., London, GB; & SU-A-331 889 (Kovalenko et al.).
Dilworth Michael J.
Morton Robert A.
Wienecke Barbara
Naff David M.
Worsley Alumina Pty. Limited
LandOfFree
Biological degradation of sodium oxalate with bacillus agal N91/ does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Biological degradation of sodium oxalate with bacillus agal N91/, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Biological degradation of sodium oxalate with bacillus agal N91/ will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1972270