Patent ID: 6454944
Filing Date: 2002-09-24
Classification: C02F,C12M,Y02E,Y02W

Abstract:
A process for converting biodegradable organic material into a product gas which leaves substantially no waste comprising:a. introducing a metered stream of slurry comprising a mixture of non-contaminated water and a non-toxic biodegradable feedstock containing at least 10 percent biodegradable solids, of which at least 95 percent of the solids will convert to gas, into a completely mixed thermophilic anaerobic digester at a thermophilic reaction temperature, said digester having an active, producing microbial anaerobic digestion population comprising hydrolysis fermentation organisms and methanogenic organisms suspended in fluids, said biodegradable feedstock being selected from the group of glucose, beet sugar, sugar beet molasses, sugar beet syrup, sugar beet juice, sugar cane molasses, cane sugar, sugar cane syrup, sugar cane juice, corn syrup, cereal grains, oat flour, rice flour, corn flour, wheat flour, potato juice, potato pulp, sorghum and combinations thereof; b. generating biogas by anaerobically digesting said mixture in said thermophilic anaerobic digester at a thermophilic reaction temperature; c. withdrawing said biogas from a headspace of said thermophilic digester; d. transferring a portion of said mixture from said thermophilic digester into a completely mixed methanogenic digester at a mesophilic reaction temperature, said digester having an active, producing microbial anaerobic digestion population comprising hydrolysis fermentation organisms and methanogenic organisms suspended in fluids; e. generating biogas by anaerobically digesting said mixture in said methanogenic anaerobic digester at a mesophilic reaction temperature; f. withdrawing said biogas from a headspace of said methanogenic digester; and g. using said biogas.