Patent ID: 8329455

Claim:
An apparatus for decomposition of organic matter into biogas and compost, the apparatus comprising: a waste processing tank into which solid organic waste is loaded and in which hydrolysis and composting takes place at separate times, with composting of the solid organic waste taking place during a separate stage after hydrolysis is completed, wherein the waste processing tank comprises a drain at or near its base, the drain allowing flow of percolation liquid out of the waste processing tank during the hydrolysis stage, the drain also serving as a vent through which air flows into and/or out of the solid organic waste in the waste processing tank during the composting stage; a spraying system configured to spray percolate liquid onto the solid organic waste in the waste processing tank during the hydrolysis stage, wherein the percolate liquid comprises fatty acids leached from the solid organic waste and wherein the percolate liquid is recycled from the base of the waste processing tank during the hydrolysis stage; and a biogas reactor tank into which the percolate liquid from the waste processing tank is pumped for generation of biogas under anaerobic conditions during a gasification stage, wherein the drain comprises a dual-purpose drain assembly for transport of the percolation liquid from the waste processing tank during the hydrolysis stage and for ventilation of the waste processing tank during the composting stage, the drain assembly comprising: a channel disposed below the processing tank; one or more rails through which a plurality of conduits are drilled, wherein each of the conduits has (i) a first end facing the waste processing tank containing the solid organic waste being processed and (ii) a second end facing the channel through which the percolation liquid flows out of the waste processing tank during the hydrolysis stage and through which air flows into the waste processing tank during the composting stage, wherein the first end has a width or diameter smaller than the second end; and a removable plate supported by the one or more rails, the plate covering the channel to prevent the solid organic waste in the waste processing tank from entering the channel.