Patent ID: 7556737

Claim:
A method for producing a gas which is a member selected from methane, hydrogen and combinations thereof using two-phase anaerobic digestion of solid organic material, said method comprising: (a) incubating a first hydrolysis mixture in a first hydrolysis phase vessel for a first period of incubation, said first hydrolysis mixture comprising said solid organic material and an aqueous liquid, under anaerobic conditions, said first hydrolysis phase vessel comprising therein a hydrolytic bacterial culture for which said solid organic material is a substrate; further, incubating a second hydrolysis mixture in a second hydrolysis phase vessel for a fourth period of incubation, said second hydrolysis mixture comprising said solid organic material and an aqueous liquid, under anaerobic conditions, said second hydrolysis phase vessel comprising therein a hydrolytic bacterial culture for which said solid organic material is a substrate; (b) after said first period of incubation, transferring a portion of said aqueous liquid of said first mixture residing in said first hydrolysis phase vessel to a buffer tank, forming a buffer tank mixture; (c) transferring a portion of said buffer tank mixture to a gasification reactor comprising a methanogenic bacterial culture therein for which said volatile fatty acid is a substrate, forming a biogasification mixture; (d) incubating said biogasification mixture for a second incubation period during which gas which is a member selected from methane, hydrogen and mixtures thereof is generated; and (e) transferring a portion of said biogasification mixture into said first hydrolysis phase vessel for a third incubation period.