Waste oxidation process

Claim 1

IN A PROCESS FOR TREATING RAW SEWAGE SLUDGE OR NIGHT SOIL BY WET AIR OXIDATION AT A TEMPERATURE BETWEEN 150* AND 375*C. AND A PRESSURE BETWEEN 150 AND 4,000 PSIG SO THAT A REDUCTION OF BETWEEN 30 AND 70 PERCENT IN CHEMICAL OXYGEN DEMAND IS OBTAINED, SEPARATING THE GASEOUS, LIQUID AND SOLID PHASES FROM SAID OXIDATION, AND BIOLOGICALLY OXIDIZING THE LIQUID PHASE IN AN AERATION CONTACT TANK CONTAINING A BIOMASS SUITABLE TO EFFECT BIOLOGICAL OXIDATION OF THE ORGANIC SOLUTES PRESENT IN SAID LIQUID PHASE; THE IMPROVEMENT WHICH COMPRISES MAINTAINING POWDERED ACTIVATED CARBON IN THE AERATION CONTACT TANK IN AN AMOUNT SUFFICIENT TO ENHANCE THE BIOOXIDATION AND SUBSTANTIALLY REDUCE THE ODOR AND COLOR OF SAID LIQUID PHASE, CARRYING OUT THE BIOLOGICAL OXIDATION UNTIL EXCESS BIOMASS BUILDS UP AND THE ACTIVATED CARBON BECOMES SPENT, TRANSFERRING A MIXTURE OF THE EXCESS BIOMASS AND SPENT CARBON TO A WET OXIDATION REACTOR, AND OXIDIZING SAID MIXTURE UNDER CONDITIONS SIMILAR TO THOSE USED FOR WET AIR OXIDATION OF THE RAW SEWAGE SLUDGE OR NIGHT SOIL SO AS TO REGENERATE THE POWDERED ACTIVATED CARBON FOR FURTHER USE IN THE BIOLOGICAL OXIDATION STEP AND AT THE SAME TIME DISPOSING OF THE EXCESS BIOMASS.