NOVELTY - An anaerobic digester (12) comprises a reaction chamber (22); an inlet pipe (24) for the supply of organic waste into the reaction chamber; an effluent outlet (26) for supplying an effluent from the anaerobic digester to an aerobic digester; a waste gas outlet (28) for mixed waste biogas produced in the reaction chamber to flow out of the reaction chamber; two or more biogas discharge mixing devices (32) provided in the reaction chamber; and a pumping apparatus (29a) for supplying mixed biogas to the biogas discharge mixing devices.    USE - Anaerobic digester for an organic microbial waste treatment apparatus for treating organic waste. (Claimed)    ADVANTAGE - The anaerobic digester has greatly improved mixing, thus resulting in the minimization of dead spaces and a more homogeneous liquid. The anaerobic digester has improved efficiency, and prevents or limits the build up of solids on interior surfaces.    DETAILED DESCRIPTION - An anaerobic digester (12) comprises:    (1) a reaction chamber (22);    (2) an inlet pipe (24) for the supply of organic waste into the reaction chamber;    (3) an effluent outlet (26) for supplying an effluent from the anaerobic digester to an aerobic digester;    (4) a waste gas outlet (28) for mixed waste biogas produced in the reaction chamber to flow out of the reaction chamber;    (5) two or more biogas discharge mixing devices provided in the reaction chamber; and    (6) a pumping apparatus (29a) for supplying mixed biogas to the biogas discharge mixing devices.    The or each biogas discharge mixing device has discharge outlets for the discharge of mixed biogas into the organic waste in the reaction chamber. The first discharge outlets of at least one of the mixing devices are oriented to direct the mixed biogas into the organic waste for mixing the waste. The second discharge outlets of the other mixing device are oriented to direct the mixed biogas at one or more interior surfaces of the reaction chamber for scouring the or each interior surface. A computer control is provided in the anaerobic digester for sequencing and timing operation of the biogas discharge mixing devices. The computer control includes a dynamic statistical feedback control of the anaerobic digester based on carbon- and/or hydrogen- and/or fatty acids- and/or methane-fluctuation in the reaction chamber, and/or microbial response; an access unit for local and remote operator access; and a manual override for operating the biogas discharge mixing devices. An INDEPENDENT CLAIM is included for an organic microbial waste treatment apparatus (10) for treating organic waste, comprising the anaerobic digester; an aerobic digester (14); and a feed pump (18).    DESCRIPTION OF DRAWING(S) - The drawing is a schematic view of the organic microbial waste treatment apparatus.    Organic microbial waste treatment apparatus (10)    Anaerobic digester (12)    Aerobic digester (14)    Feed pump (18)    Reaction chamber (22)    Inlet pipe (24)    Effluent outlet (26)    Waste gas outlet (28)    Pumping apparatus (29a)    Biogas discharge mixing devices (32)