NOVELTY - A treatment tank (2) having a stirrer (3) which stirs the refuse and refuse disposal material (6) filled in the tank, is new. An overflow hole (13) for overflow of processing residue (6') which is not decomposed by microorganisms in the tank, is provided at the upper end of a side face of the tank, and is opened/closed by a shielding board (15). A receptacle (14) which receives the overflown residue is provided below the tank.    USE - For performing decomposition of organic refuse and refuse disposal material, using microorganisms.    ADVANTAGE - Since the overflow hole is normally closed during the operation of the tank, and is opened only during ejection of the residue, prevents the outflow of heat and moisture content from the tank, hence reduces the heat loss in the tank. Eliminates the need to operate the heater for a longer period, for heating the refuse in the tank. Since moist air does not contact the outer surface of the receptacle, the formation of dew at the outer surface is prevented.    DETAILED DESCRIPTION - A treatment tank (2) having a stirrer (3) which stirs the refuse and refuse disposal material (6) filled in the tank, is new. An overflow hole (13) for overflow of processing residue (6') which is not decomposed by microorganisms in the tank, is provided at the upper end of a side face of the tank, and is opened/closed by a shielding board (15). A receptacle (14) which receives the overflown residue is provided below the tank. The shielding board whose upper end is hinged to the casing (1) of the processing apparatus, opens, co-operating with the operation of the stirring blades of the rotary stirrer, which eject the residue from the tank.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of the organic refuse processing apparatus. (Drawing contains non-English language text).    Tank (2)    Stirrer (3)    Refuse disposal material (6)    Processing residue (6')    Overflow hole (13)    Receptacle (14)    Shielding board (15).