Patent ID: 7329340

Claim:
A concentrated wastewater biosludge treatment system, comprising: a) a continuous flow, multistage, aerobic, exothermic oxygenation zone comprising; two or more gas-liquid contacting stages, each stage containing a separate liquid phase, an enclosed separate gas headspace above the liquid phase, and a gas-liquid contacting device, and the gaseous headspace being in fluid communication with the liquid phase for heat and mass transfer between said phases and said headspace; a feed liquid stage in communication with a serial liquid flow path through the entire multistage system; a feed gas headspace in communication with other gas headspaces in the multistage system according to a predetermined sequence, and having a countercurrent gas flow path through a portion of the flow path with respect to the serial liquid flow path; a gas feed to the multistage system containing at least 20 volume percent oxygen enriched gas; and b) a thermophilic treatment zone comprising an anaerobic digester downstream of said aerobic oxygenation zone.