NOVELTY - The apparatus (1) has bypass line (L3) connected to aerobic reactor (4) to supply raw water. The pH sensor (11) measures water quality parameter showing the advancing condition of nitrification reaction of water. The input keyboard (13) sets threshold value of water quality parameter for reference, so as to determine quality of treated water. The measured value of water quality parameter is contrasted with threshold value. The aerobic reactor is controlled to directly supply small or whole quantity of raw water by bypass line, when measured value is deviated from threshold value.    USE - Apparatus for processing organic wastewater such as sewage e.g. domestic sewage or city sewage, agricultural colony wastewater, and industrial or foodstuff factory wastewater.    ADVANTAGE - The organic wastewater can be processed effectively at low cost without inhibiting the reaction in anaerobic processing reactor. The strong ammonia nitrogen of the toxicity can be oxidized by the action of nitric bacteria and nitrifying bacteria on the aerobic conditions through nitrification reaction. The oxidized reaction can be eventually disassembled even into weak nitrate of toxicity. The organic loading applied to the aerobic reactor can be raised, thus the advancing of nitrification reaction can be suppressed and the fall of pH of the treated water can be prevented. Hence the stable water treatment performance can be obtained. The denitrifying reaction can be stimulated easily within anaerobic reactor. The nitrogen concentration of treated water can be reduced. Since the oxygen supply can be again carried out in the lower portion of redistribution apparatus, the activity of the aerobic microorganisms of lower-stage portion can be increased. The process performance of the pollutant material can be improved. The power cost of the pump can be reduced.    DESCRIPTION OF DRAWING(S) - The drawing shows a structure block diagram of the organic wastewater processing apparatus. (Drawing includes non-English language text)    Organic wastewater processing apparatus (1)    Aerobic reactor (4)    PH sensor (11)    Input keyboard (13)    Bypass line (L3)