Patent ID: 7708885

Claim:
A method for digesting a waste stream in an anaerobic solids digestion apparatus comprising: (a) feeding a waste stream comprising anaerobically biodegradable solids to a digester; (b) digesting the anaerobically biodegradable solids in the waste stream with anaerobic bacteria in the digester to reduce the biodegradable solids by an amount, thereby producing a mixed liquor and a biogas, wherein the biogas is a product of anaerobic digestion; (c) introducing at least a portion of the mixed liquor to the digester through a shearing device that comprises a nozzle having a nozzle gas inlet; and (d) mixing the mixed liquor with the remaining anaerobically biodegradable solids in the digester, wherein the method further comprises removing a portion of the biogas from the digester and introducing the portion of the biogas into the nozzle gas inlet, and the biodegradable solids are sheared to achieve a sludge retention time (SRT) of less than 20 days.