Abstract: Disclosed herein is a system for chemically treating a waste water including a storage tank, a reaction tank, and a pump for transferring the waste water from the storage tank to the reaction tank. Conduits connecting the pump to the tank and control valves controlling the flow through the conduits are arranged so that, by coordinated actuation of the valves, the pump recirculates the waste water through the reaction tank to provide intermixing of the treatment chemicals and discharges the waste water from the reaction tank after treatment. The chemical reagents are introduced into the system on the suction of the pump so that gravity feed or separate pumping means is not required for the reagents. The tanks are preferably circular and mounted in a spaced relationship on a common base forming the bottoms thereof.