THERMOPHILIC AEROBIC DIGESTION PROCESS FOR PRODUCING ANIMAL NUTRIENTS AND OTHER DIGESTED PRODUCTS

摘要

THERMOPHILIC AEROBIC DIGESTION PROCESSFOR PRODUCING ANIMAL NUTRIENTS AND OTHER DIGESTED PRODUCTSAbstract of the DisclosureAnimal waste matter, for example manure produced byhogs, sheep, cattle, chickens and humans is aerobically digestedat thermophilic digestion temperatures to produce single cell,proteinaceous material suitable for feeding to animals as part ofthe animals' nutritive diet. Animal waste matter is introducedinto a digesting zone that is sufficiently insulated to preventany substantial heat loss from the digesting material during thedigestion process. An oxygenating gas such as air is introducedinto the digesting material during all phases of the digestion.The digesting material is simultaneously vigorously agitated.The waste material is placed into the digester at ambient tempera-tures and is contacted with the oxygenating gas at a rate and isagitated at a level effective to cause thermogenic microbialdigestion of the materials present in the waste matter. Sincethe microbial digestion is thermogenic and because the digester isinsulated the temperature of the digestion waste material willrise from ambient to thermophilic digestion temperatures. There-after, the digesting mixture is continuously contacted with theoxygenating gas at a rate and is agitated at a level effective tomaintain the thermophilia digestion temperatures for a period ofat least four days.In a broader aspect of the present invention, lignocel-lulosic materials, such as woody plants, as well as biochemicallydegradable organic materials, such as sewage sludges, organicdomestic and industrial wastes and animal, vegetable and fruitprocessing plant wastes, are digested by the thermophilic micro-organisms present in the foregoing process. When the foregoing-1-process has reached thermophilic digestion temperatures, ligno-cellulosic material and biodegradable organic wastes can beplaced in the digester, preferably in chipped or finely dividedform. The lignin is digested out of the lignocellulosic complexin a period of about four days after placement in the digester,leaving free individual cellulosic cells that can be assimilatedby animals. Likewise, biodegradable materials are digested in asimilar amount of time. Alternatively, lignocellulosic materialor biodegradable material in the form of an aqueous slurry can beplaced in a digester with a small quantity of animal waste matteror a thermophilic bacterial culture extracted from the fecalmatter digestion process described above. Thereafter the slurryis agitated and aerated in accordance with the foregoing require-ments. The aqueous slurry will gradually rise to thermophilicdigestion temperatures and can be maintained at those temperaturesto substantially digest the lignin out of the lignocellulosiccomplex or to digest the biodegradable material, as the case maybe.-2-