Abstract: An apparatus for treating water in which water is delivered under pressure to a closed tank in the form of a spray or fog. An aerator in the bottom of the tank draws atmospheric air from outside of the tank and creates laterally directed air jets for violently stirring up and oxidizing the water. Gases are exhausted from the tank at the top. A series of baffles surround the aerator against which the jets impinge and provide for hydraulic streams. Float valves control the amount of water maintained within the tank. Treated water is drawn from the tank through a pipe extending to the lower portion.