Abstract: An aerobic bacteria sewage treatment apparatus for treating waste water mixed with activated sludge by circulating the mixed liquor about a clarification compartment placed in a main treatment tank from which the clarification compartment withdraws water at a quiescent zone and further separates out and filters solid matter, finally delivering a well clarified effluent withdrawn from the top of the clarification compartment, the apparatus having an auxiliary digester compartment operative to periodically receive a proportion of the contents of the main tank, which contents are treated and allowed a time to settle out solids, whereupon the clear water from the auxiliary compartment is returned to the main treatment tank and the solids are left to accumulate for further treatment and later removal, the transfer of said proportion of the mixed liquor from the main tank being accomplished by overflow resulting from a purge cycle during which the clarification compartment is back-flushed into the main treatment ta

Abstract: A filter system to follow a primary sewage treatment unit delivering substantially clarified effluent, the filter system having plural vertical filter columns nearly filled with filter aggregate and each column having a vertical stand pipe terminating near the bottom of the column and operative to introduce air to bubble up through the aggregate while the column is having water backflushed through it, and the filter system having a separate path by which backflushed water with the solids entrained therein is returned to the primary treatment unit during backflush purge cycles.

Abstract: An aerobic bacteria sewage treatment apparatus using compressed air to aerate activated sludge, and to cause it to circulate about a cylindrical clarification compartment placed in the apparatus in a way to provide a zone of relative quiescence in the flowing sewage from which the clarification compartment withdraws liquid and further separates solid matter therefrom, finally delivering a very well clarified effluent, the effluent pipe being placed in the clarification compartment such that heavier particles tend to sink away from it and lighter particles tend to rise above it, whereby the effluent is substantially free of solid matter.