| 摘要 |
Disclosed is a method that eliminates a decrease in activity of an activated sludge-processing microorganism group, raises processing efficiency by greatly increasing the processing ability thereof, and reduces the amount of excess sludge. The wastewater processing method is characterized by performing a first sludge-returning step (Va) (a step wherein, in a first excess sludge tank or sludge retention tank (12a) equipped with an aerator/agitator, aerated/agitated sludge is returned to a processing tank, batch tank, or anaerobic tank; and/or a step wherein, in a second excess sludge tank or concentrated sludge retention tank (13a) equipped with an aerator/agitator, aerated/agitated sludge is returned to the processing tank, batch tank, or anaerobic tank) when activated sludge-processing raw water (1a), and by activated sludge processing while maintaining the number of bacilli in the processing tank, batch tank, or anaerobic tank to which said sludge has been returned at 2.0×10-22.5×10 cfu/mL. |
