SYSTEM AND METHOD FOR TREATING WASTEWATER AND RESULTING PRIMARY AND BIOLOGICAL SLUDGE

摘要

A method of treating primary sludge and activated sludge produced by a wastewater system is disclosed. A portion of the activated sludge is wasted to form biological sludge. The biological sludge is thermally hydrolyzed. The method entails cooling the thermally hydrolyzed biological sludge by mixing primary sludge with the thermally hydrolyzed biological sludge. Thereafter, the combined sludge is directed through a pasteurization process and then to an anaerobic digester which performs anaerobic digestion of the combined sludge.

主权项

1. A method of treating wastewater and resulting sludge comprising:
subjecting the wastewater to primary treatment and producing primary sludge; after subjecting the wastewater to primary treatment, subjecting the wastewater to biological treatment and producing biological sludge; directing the biological sludge to a thermal hydrolysis unit and subjecting the biological sludge to a thermal hydrolysis process and producing thermally hydrolyzed biological sludge; mixing the primary sludge and thermally hydrolyzed biological sludge in a pressurized structure at a pressure greater than atmospheric pressure to form a sludge mixture; cooling the thermally hydrolyzed biological sludge in the pressurized structure by transferring sensible heat from the thermally hydrolyzed biological sludge to the primary sludge; transferring the mixture of primary sludge and thermally hydrolyzed biological sludge from the pressurized structure to a pasteurization unit and subjecting the sludge mixture to a pasteurization process; and after pasteurizing the mixture of sludge, transferring the mixture of thermally hydrolyzed biological sludge and primary sludge from the pasteurization unit to an anaerobic digester and subjecting the mixture of sludge to anaerobic digestion.