PURPOSE: To perform sewage treatment where the generation quantity of excess mud is suppressed and denitrification is promoted, by switching the water flow direction of the contact aeration tank for sewage treatment alternately at every fixed time.
CONSTITUTION: Contact filter material 9 such as conglomerate is filled in, for example, earth type contact aeration tank 6 forming a long filter bed flow path as the whole. The flow direction of sewage to this contact aeration tank 6 is changed alternately at every several months to cause sewage to pass through. Thus, density distribution of the microbe group living in filter material 9 in tank 6 is averaged, and sewage is treated effectively to cause the generation quantity of excess mud to approach zero and denitrify nitrogen components in sewage.
NIIMI MASANORI
NAKADE SHIYOUICHI
NIIMI MASAAKI
| JPS526810A | 1977-01-19 |