The MBBR process has the advantages of both traditional fluidized bed and biological contact oxidation method, and is a new and efficient sewage treatment method, which relies on the aeration and water flow in the aeration tank to make the carrier in a fluidized state, and then forms suspended activated sludge and attached biofilm, which makes the moving bed biofilm use the entire reactor space, give full play to the advantages of both the attached phase and the suspended phase organism, and make it develop its strengths and avoid weaknesses, and complement each other. Unlike conventional fillers, suspended fillers are known as "mobile biofilms" because they are in frequent and repeated contact with sewage.