JPS57177392A - Disposal of night soil - Google Patents

Abstract

PURPOSE: To perform efficient purification, while suppressing the generation of a bulking phenomenon, by mixing night soil with circulating night soil from a reaction vessel in a mixing vessel only, holding the mixture under a highly concentrated condition for a proper period, and then feeding the mixture into the reaction vessel.

CONSTITUTION: In a mixing vessel 4, night soil and circulating night soil fed through a pumping passage 7 are let flow through a zigzag passage R defined by partition plates 8, and agitated and mixed by gas from spargers 9. These night soils are further mixed with their supply to a decomposing vessel 3, and ammoniac nitrogen in the mixture is nitrified by the action of active sludge in a nitrifying vessel 5. Thereafter, the mixture is fed into a denitrifying vessel 10, where the mixture is subjected to reducing treatment, and then into an aerating vessel 11, where the biological oxygen demand of the mixture is sufficiently lowered by oxygen-contg. gas from a passage 12. The purified water is then fed into a precipitating vessel 13 to separate the active sludge, and excess sludge is treated by a post-treating means 15. The resultant effluent is post-treated, e.g. disinfected, and then drained.

COPYRIGHT: (C)1982,JPO&Japio