An air diffuser for sewage treatment consisting of a <a href="https://www.khnwatertreatment.com/">rapid sand filters</a> basin shell, rubber plate, screw, and nut. An air diffuser for wastewater treatment consisting of a gas duct, a rubber disc, a movable tray, a disc body and a fixing ring. The structure of the present invention is cleverly designed, when aeration, the air blown out of the gas between the disc body and the movable pallet rotates and rises in a jet, due to the shear and