AEROBIC FILTER BED TANK OR SEWAGE SEPTIC TANK HAVING AIR DIFFUSING PIPE FOR WASHING ARRANGED THERETO AT ECCENTRIC POSITION

摘要

PROBLEM TO BE SOLVED: To provide an aerobic filter bed tank or sewage septic tank capable of discharging SS together with washing waste water without stagnating SS in the vicinity of the bottom surface of the tank and keeping stable capacity. SOLUTION: In an aerobic filter bed tank C wherein a biological reaction bed (upper filter bed) 1 and a filter bed (lower filter bed) 2 are arranged and a ring-shaped air diffusing pipe 4b for washing is arranged to the lower part of the filter bed 2 and a washing waste water withdrawing port 5a is formed at the lower part of the tank, the air difficing pipe 4b for washing is eccentrically arranged so that the center (P2) of the air diffusing pipe is positioned on the side of the washing waste water withdrawing port 5a from the center (P1) of the bottom surface of the filter bed 2.