A continuous system for disinfecting waste water streams, such as sewage and streams containing organic matter and removing suspended solids therefrom is disclosed. A waste water stream is passed into an electrolytic cell open to the atmosphere and between a series of electrically charged parallel electrode plates. A controlled amount of electrolyte such as sodium chloride is added to the waste water stream before it passes through the electrolytic cell. During passage between the electrode plates a foam is generated which entrains suspended selected nutrient solids contained in the waste water stream, the foam removed by skimming and/or suction means. The treated water discharged from the electrolytic cell is filtered to remove additional non-nutrient suspended solids not entrained with the foam. A portion of the treated water from the electrolytic cell is recycled and reinjected into the influent stream. Control means are included to control residual chlorine in the effluent discharged from the electrolytic cell while maintaining high dissolved oxygen in the effluent.