To treat sewage without using a filter, in a miniaturized sewage treating structure of a rainwater permeating basin.
This rainwater permeating basin is composed of a pretreatment water tank 3 for temporarily storing dirty rainwater introduced from a rainwater inlet conduit 2, a water leakage structure 4 constituted so as to gradually leak water outward from the inside of the pretreatment water tank 3, an after-treatment water tank 5 for receiving the rainwater outputted from the water leakage structure 4, and a trap structure 6 for draining the rainwater gathered in the after-treatment water tank 5 to the outside of the after-treatment water tank 5 while meandering in the vertical direction. The rainwater permeating basin promotes to separate a heavy pollutant and a light pollutant included in the rainwater by sudden stop action by arranging a sudden stop structure 7 for suddenly stopping a flow of the rainwater introduced from the rainwater inlet conduit 2.
MATSUMOTO YASUHIRO
Takao Hamano
Morita Tetsuji
Teruichi Hirai