Aerobic/anaerobic sludge digestion process

摘要

A process for digestion of sludge comprises introducing the sludge and aeration feed gas to a first digestion zone, oxygenating the sludge therein at a temperature of from 35 to 75 DEG C to form partially stabilized sludge and then anaerobically digesting the partially stabilized sludge in a covered second digestion zone at a temperature of from 25 to 60 DEG C to form further stabilized sludge and methane gas.