Abstract: An activated sludge treatment method and apparatus for the processing of sewage and other wastewater wherein a screening system is employed in combination with an aeration basin and a secondary clarifier. The screening device here employed is positioned to receive all or a part of the flow from the aeration basin for the removal of solids from this flow. The screened effluent is then directed to the secondary clarifier for the settling of remaining particles. The concentrate may be returned to the aeration basin as activated sludge or removed from the system as a means for controlling the amount of solids in the treatment system. The screening device includes a rotating screen structure having a distribution system located within the screen structure for distributing effluent from the aeration basin to the inner surfaces of the screens. Effluent passing through the screens is collected and directed to the secondary clarifier.