NOVELTY - An apparatus for treating aqueous organic waste, comprises anaerobic digester (1) including a vessel, and at least one heating coil (13). The vessel includes a lower section (5) housing acidogenic microbes; an upper section (7) housing methanogenic microbes; and at least one waste circulation system (29) that retains aqueous organic waste in suspended state as the organic waste moves from the lower section to upper section. The acidogenic microbes convert organics in the organic waste to a mixture of organic acids. The methanogenic microbes convert mixture of organic acids to methane gas.    USE - As an apparatus for treating aqueous organic waste, to form a treated product containing a mixture of methane gas and water (claimed); useful for treating aqueous organic waste such as winery effluent, sewage and industrial grease trap waste.    ADVANTAGE - The apparatus converts the aqueous organic waste into the treated product, in less than or equal to 24 hours, unlike conventional anaerobic digestion systems that require a conversion time of 15-30 days. The apparatus can treat aqueous organic waste having biological oxygen demand (BOD) of 2000-80000 ppm; and provides treated product of high quality standard i.e. clean water with a BOD of 10 mg/l, which can be used for e.g. irrigation of vegetable crops. The apparatus eliminates or minimizes rafting/floating material at the gas/liquid or solid/liquid interface; and eliminates or minimizes the release of gas that gets trapped in a slime layer at the water/gas disengagement zone. Thus, the apparatus provides an even, continuous and thorough mixing of the digester contents, resulting in efficient temperature control throughout the digester; provides immediate and efficient contact of the aqueous organic waste with the microbial population; provides enhanced digestion of waste and improved gas production; and prevents raft and scum blockages. The maintenance of material having high specific gravity than the liquid phase of suspension, such as magnesium hydroxide, used for pH adjustment, is eliminated, as the material is prevented from collecting in the base of the digester to form a thick sludge barrier. Thus, magnesium hydroxide introduced into the digester, can used more efficiently.    DETAILED DESCRIPTION - An apparatus for treating aqueous organic waste, comprises an anaerobic digester (1) including a vessel, and at least one heating coil (13). The vessel includes a lower section (5) housing acidogenic microbes; an upper section (7) housing methanogenic microbes; and at least one waste circulation system (29) that retains aqueous organic waste in a suspended state as the organic waste moves from the lower section to the upper section. The acidogenic microbes convert organics in the organic waste into a mixture of organic acids. The methanogenic microbes convert mixture of organic acids into methane gas. The methane gas is collected from the upper section of vessel, and is used as a fuel source to heat the vessel contents. The heating coil is preferably located in the lower section of vessel. The waste circulating system is located in the lower section of the vessel, through which a fluidizing medium is introduced into the vessel. The fluidizing medium is a fluid recycled from the vessel, or a fresh aqueous organic waste. The fluidizing medium is intermittently injected into the lower section of vessel. The aqueous organic waste is preferably continuously introduced into the lower section of the vessel. The vessel is preferably operated in a continuous mode, and the residence time of the aqueous organic waste in the vessel is less than or equal to 24 hours. The vessel further comprises a mesh platform (9) on which a microbial population can grow. The platform allows passage of fluids like gas and water through it, while preventing passage of microbes such as bacteria, yeast or fungi. The apparatus optionally comprises an ozone tower and/or a filter unit.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of an apparatus for treating aqueous organic waste.    Anaerobic digester (1)    Lower section of vessel (5)    Upper section of vessel (7)    Mesh platform (9)    Heating coil (13)    Temperature probe (17)    Pipings (18, 25)    Overflow port (19)    Methane collection point (21)    Pump (23)    Waste circulation system. (29)