NOVELTY - Sewage treatment comprising separating a waste stream into a primary sludge and a water effluent, anaerobically digesting the primary sludge and dewatering the digested primary sludge to convert the primary sludge to a Class A biosolid without subjecting the primary sludge to a hydrothermal process, aerobically digesting the water effluent, separating the digested effluent, and treating waste activated sludge by hydrothermal process, is new.    USE - For sewage treatment, e.g. wastewater treatment.    ADVANTAGE - The method employs mechanical, thermal, and chemical integration to generate an exceptional quality (EQ) Class A biosolid at low capital and operating costs. It allows for increased operating temperatures and retention times in an anaerobic digester without undesirable increases in capital or operating costs. It strips nitrogen from a waste activated sludge, and recovers the nitrogen in the form of an ammonia-water solution or an ammonium salt, without the need for a separate hydrothermal process. It provides for enhanced performance of bacteria in the aerobic/anoxic digester. It offers enhanced biological nitrogen removal and biological phosphorus removal in the aerobic/anoxic digester. It reduces or eliminates fouling and clogging problems encountered in processing sludges in a hydrothermal process.    DETAILED DESCRIPTION - Sewage treatment comprising:    (a) separating a waste stream into a primary sludge and a water effluent;    (b) anaerobically digesting the primary sludge and dewatering the digested primary sludge to convert the primary sludge to a Class A biosolid without subjecting the primary sludge to a hydrothermal process;    (c) aerobically digesting the water effluent;    (d) separating the digested effluent to provide a waste activated sludge; and    (e) treating waste activated sludge by hydrothermal process without subjecting the waste activated sludge to anaerobic digestion.    DESCRIPTION OF DRAWING(S) - The drawing is a flow chart showing a waste treatment system.