NOVELTY - A detector (13) senses water level of a storage tank (10) that receives disposed waste containing organic sludge. A control unit operates an air lift pipe (11) and a blower (12) to transfer precipitate and treated water for further processing chambers, so as to adjust water level in storage tank to specified level. The tank is set capable to balance water level displacement during operation of disposer. DETAILED DESCRIPTION - A solid-liquid separator (20) separates solid particle from the contents of storage tank and supplies to the composting unit (30). A water treatment tank (40) purifies the treated water from storage tank. A precipitator (50) precipitates the treated water from the water treatment tank and a pipe (51) returns the precipitated sludge to the storage tank. The load of water treatment tank is controlled, based on the detected water level of the storage tank. An aeration pipe (41) is provided for the aeration of water in treatment tank. Amount of precipitated sludge transferred to storage tank from precipitator and aeration degree of water treatment tank are reduced, when water level in storage tank is below a predetermined level. The water level detector is of electrode type that detects the water level from the change in electricity, between the electrodes installed in the storage tank. A control unit impresses a voltage or inverses the polarity of voltage impressed, between the electrodes only during the detection of water level in the storage tank.    USE -   For waste water treatment plant and to process disposed waste containing organic sludge.    ADVANTAGE -   The overflow of disposed water and wastes is prevented reliably, since the water level in storage tank is adjusted suitably by the operation of air lift pump and blower. The state of microorganism in water treatment tank is kept constant by uniform control of load of water treatment tank based on detected water level in disposed waste storage tank and hence the degradation of organic substance is performed efficiently. The drying of raw water in storage tank when disposed wastes are not supplied to the storage tank, is prevented. Prevents corrosion of electrodes and reduces elution amount between electrodes since voltage impressed between electrodes is adjusted suitably and by carrying out inversion of polarity of impressed voltage periodically. Electrical charging time is reduced sharply. DESCRIPTION OF DRAWING(S) - The figure shows organic refuse processing system. (10) Storage tank; (11) Air lift pipe; (12) Blower; (13) Water level detector; (20) Solid-liquid