Patent ID: 7771601

Claim:
A process for treating a sludge of biological solids comprising: mixing the sludge with an oxide-containing chemical and a pozzolanic material, said oxide-containing chemical selected from the group consisting of calcium oxide, potassium oxide, potassium hydroxide, sodium hydroxide and iron oxide; reacting the mixture in a reaction chamber so as to elevate a temperature of the sludge to between 40° C. and 140° C.; pressurizing the mixture in said reaction chamber to a pressure of greater than 14.7 p.s.i.a.; splitting the reacted and pressurized mixture into a recycle stream and a sterilized sludge stream; passing said recycle stream to said reaction chamber so as to increase a solids content and a temperature of the mixed sludge in said reaction chamber; and flashing said sterilized sludge stream across a resisting orifice into a flashing chamber so as to cause a liquid component to be evaporated, said flashing chamber having a pressure of less than 14.7 p.s.i.a, the discharging producing a pathogen-free and vector-free sludge product.