Abstract: A sewage treatment system is divided into two stages with a collection system dispersed therebetween. The first stage includes anoxic treatment units producing an anaerobic effluent which is moved through the vacuum tight collection system to the second stage of treatment including an oxidation unit producing an aerobic effluent containing nitrates, dissolved oxygen and activated sludge. The two liquids are mixed in a chamber and are subjected to treatment before discharge for producing a highly treated effluent from which a major part of the nutrients have been removed.

Abstract: A sewage disposal system in which sewage is permitted to accumulate to a desired level in a sump or receptacle, following which it is evacuated from the receptacle through a discharge conduit, by means of a partial vacuum transmitted through the conduit from a central collection point. Disposed in the discharge conduit is a normally closed flow valve, the control of which is by means of a control valve. Negative pressure transmitted through the discharge conduit is utilized both for opening the flow valve and for maintaining it and the control valve opened until the sump is evacuated, at which time atmospheric pressure entering the discharge conduit from the sump acts upon the control valve to close the latter, which in turn shuts off the flow valve. Triggering of the flow valve to commence the evacuation operation may be performed either manually or automatically by means responsive to the rising liquid level within the sump.