| 摘要 |
1531591 Bacteria used in sewage treatment GENERAL ENVIRONMENTAL SCIENCE CORP 10 Feb 1976 [21 Feb 1975] 5130/76 Heading C1C [Also in Division C6] An aqueous suspension of bacteria rendered dormant, useful in the treatment of waste waters and sewage, is prepared by a method involving (a) growing bacteria under aerobic conditions in a sterilized aqueous medium by adding thereto at least one species of Pseudomonas bacteria which is capable of enzymatically reducing nitrate to nitrogen and at least one species of Rhodopseudomonas bacteria capable of photosynthetically forming red pigment; (b) dissolving in the bacteriacontaining medium a sodium or potassium sulphide (or mixture thereof) in an amount, usually in the range 0.07 to 0À3 grams per litre, sufficient to render the bacteria dormant but capable of being reactivated without a significant percentage being destroyed; and (c) exposing the sulphide-containing medium to light, under anaerobic conditions, for a period of time sufficient to cause photosynthetic red pigment to develop in the Rhodopseudomonas bacteria. Step (c) is continued for a period of substantially 24 hours under fluorescent lighting. In the treatment of sewage by the mixed culture, ammonia is converted to gaseous nitrogen via nitrate and concomitantly with the nitrate reduction, sulphur is converted to sulphate and acetate to gaseous carbon dioxide. Noxious odours are thereby eliminated. A preferred mixed culture includes six species of bacteria viz. one Bacillus (Gram positive, spore-forming, rods), one Rhodopseudomonas (photosynthetic, non-sulphur purple, Gram negative, non spore-forming, rods), and four Pseudomonas (Gram negative, non spore-forming, rods) at least one of which is capable of reducing nitrate to nitrogen or nitrous oxide gases. The mixed culture can be used in the treatment of waste waters and sewage generally, many specific applications being mentioned, including grease traps and waste from restaurants and slaughterhouses.
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