The new type of vortex concave aerator (aeration head) injects "microbubbles" directly into untreated sewage through a diffuser impeller. Under the joint action of coagulants and flocculants, suspended solids undergo physical and chemical flocculation, forming large suspended solids flocs. Under the buoyancy of the bubble group, the "flocs" float to the liquid surface to form floating slag, which is separated from the water by a scraper; No need to clean the nozzle, there will be no blockage.