Aerobic sewage treatment system

Abstract

An aerobic sewage treatment method and system includes a tank divided by a baffle into at least a treatment chamber and a settling chamber. A return flow pipe at the normal liquid level, from the settling chamber into the aerating chamber, has on its treatment chamber side a tee fitting aimed to the side of the treatment chamber, along the baffle separating it from the settling chamber. Floating particles near the settling chamber discharge thus flow back into the treatment chamber for further aeration and reduction. Flow through such return pipe is induced by a stream from the aerating unit directed against the surface of the turned end of the return pipe, whereby some of that flow moves along the pipe and draws a return flow into the aerating chamber. The stream for causing this return flow is obtained from the discharge of an improved aerating unit which discharges a few directed streams, as opposed to an annular stream of greater velocity but lesser total mass flow. This multiple stream flow is obtained by a unique deflector incorporated into the housing of the aerating unit, near its top and just above several circumferentially spaced discharge openings through the upper side wall of the housing. Rotational positioning of the unit within the treatment chamber locates the desired flow streams from these openings to interact with the return pipe from the settling chamber.