Abstract: A modular sewage treatment plant is disclosed using a vessel adapted to contain the standard three phases of a sewage treatment, aeration, settling and clarification. The vessel of this invention uses an inverted, centrally located funnel section to received raw sewage to be treated at the upper opening, and to inject air, counter-currently, at a 180 degree angle to the descending sewage. The aerated sewage leaves the bottom of the aeration section and solids enter a settling section therebelow whereas water to be clarified rises around the outer surface of the funnel shaped aeration section. A hopper shaped bottom in the settling section is provided to facilitated solids removal and a weir system is provided on the upper surface of the clarification section to serve as a scum remover for the clarified water.