NOVELTY - Treating raw sewage and fats/oils/greases/waxes (FOG) waste involves introducing digesting sludge, at a temperature (preferably 98-104 degrees F) high enough to soften the waste, into a holding tank (5); introducing the waste of a volume into the holding tank; mixing the digesting sludge and the waste in the holding tank to form a conditioned feedstock; and transporting the conditioned feedstock to an anaerobic digester.    USE - For treating raw sewage and fats/oils/greases/waxes (FOG) waste (claimed).    ADVANTAGE - The method avoids problems of emulsified grease at the input or head end of the waste digestion cycles in a treatment plants. In this method sticky FOG is offloaded removing any adhering greases/oils/fats/waxes and particulate in the line thereby essentially eliminating possibilities of a clog-up during subsequent offloads; and affords servo control for optimizing both digestion processes in the digesters and steady-state methane production for electrical power generation inherent in the capacity to meter introduction of a highly bioreactive, flowable feedstock slurry from the reaction/holding tank into the continuously circulating warm, actively digesting sludge slipstream loop for introduction with sewage and/or other digestible wastes into anaerobic digester systems.    DETAILED DESCRIPTION - Treating raw sewage and fats/oils/greases/waxes (FOG) waste involves introducing digesting sludge, at a temperature (preferably 98-104 degrees F) high enough to soften the waste, into a holding tank (5); introducing the waste of a volume into the holding tank; mixing the digesting sludge and the waste in the holding tank to form a conditioned feedstock; and transporting the conditioned feedstock to an anaerobic digester. The digesting sludge is introduced from a slipstream loop (11) along which the digesting sludge moves from the secondary digester to the primary digester. The digesting sludge is introduced from a lower portion of a secondary digester in an arrangement including at least first and second digesters. The digesting sludge and waste mixing decreases particle size in the waste. The mixing is achieved using at least one mixing chopper pump (7). The method further involves allowing the introduced digesting sludge to react with the introduced waste to form the conditioned feedstock; injecting conditioned feedstock from the holding tank into slipstream loop at a point between the secondary and primary digesters to form a digesting sludge/conditioned feedstock mixture to transport the conditioned feedstock to the primary digester; and maintaining a set minimum volume of liquid in the holding tank by filling the holding tank to the predetermined minimum volume when the holding tank level drops to a predetermined low level.    DESCRIPTION OF DRAWING(S) - The figure shows a labeled diagram of the invented integrated cogeneration system for treating raw sewage, and polar fats/oils/greases/waxes (FOG) wastes.    Sludge circulation pump (1)    Hot water heat exchanger (2)    Holding tank (5)    Chopper pump (7)    Rock separator (8)    Sludge slipstream loop (11)