Orbital wastewater treatment system with combined surface aerator and submerged impeller

摘要

An improved wastewater aeration and mixed liquor pumping arrangement for an orbital-type actuated sludge purification method includes the addition of a radial flow impeller on a shaft extension below the normal surface aerator. Both the combined radial flow impeller and surface aerator are positioned with respect to an end of a partition wall forming the flow channels of the orbital system such that both the impeller and the aerator pump the mixed liquor in the same direction, so that the mixed liquor is moved at a sufficient velocity through and around the various channels and returned. The radial flow impeller is positioned adjacent to the bottom of the orbital channel and enhances the propulsion of the mixed liquor along the bottom of the channel thus permitting deeper channels with attendant concrete and land area savings in constructing the system. The system may be operated at various wastewater levels so that when oxygenation levels are high or oxygenation needs are low, the level is lowered by a weir so that only the lower radial impeller functions to propel the mixed liquor. Auxiliary compressed or aspirated air may also be inputted through the lower radial impeller.