NOVELTY - An organic wastewater is biologically processed by supplying organic wastewater to biological treatment tank (2), biologically processing organic compound contained in wastewater, separating produced process liquid into solid and liquid, removing sludge as solid content, injecting one part of sludge by carrying out picking appearance to sludge disposal tank with aeration apparatus (8,30), controlling sludge injected quantity and amount of aeration, and supplying again sludge disposal liquid removed from sludge disposal tank to biological treatment tank.    USE - Biological processing of organic wastewater.    ADVANTAGE - The method simply and easily enforces sludge disposal method, and reduces environmental problem and great expense burden.    DETAILED DESCRIPTION - An organic wastewater is biologically processed by supplying organic wastewater to biological treatment tank (2), biologically processing organic compound contained in wastewater, separating produced process liquid into solid and liquid, removing sludge as solid content while discharging purified water phase out of system, injecting one part of sludge by carrying out picking appearance to sludge disposal tank with aeration apparatus (8,30), blowing in air from aeration apparatus at normal temperature, controlling sludge injected quantity and amount of aeration to less than or equal to 0.15, and supplying again sludge disposal liquid removed from sludge disposal tank to biological treatment tank. The value of biochemical oxygen demand (BOD)/mixed liquor volatile suspended solids (MLVSS) of solid-liquid mixture in sludge disposal tank which carried out sludge disposal by aerobic condition is less than or equal to 0.1. An INDEPENDENT CLAIM is included for a biological processing apparatus of organic wastewater.    DESCRIPTION OF DRAWING(S) - The drawing shows an explanatory view of the biological treatment facility of organic waste water.    Biological treatment tank (2)    Wastewater inflow line (4)    Flow volume adjustment tank (6)    Aeration apparatus (8,30)    Solid-liquid separation tank (10)