LAUSR

Abstract Anaerobic–Anoxic–Oxic (AAO) process is widely used in municipal wastewater treatment plants because of its simple structure, rich experience in engineering design, easy operation control and simultaneous nitrogen and phosphorus removal. The energy consumed in the aeration process occupies more than 50% of the total energy consumption of the sewage treatment plant, and reducing aeration is one of the major ways to reduce energy consumption. With the nitrification effect, the sewage treatment equipment controlled the dissolved oxygen (do) concentration in the aeration tank to 2 mg/L or more. The result shows that even nitrification can achieve complete nitrification. In a low oxygen state, the sewage treatment plant is reduced in energy consumption The degradation of pollutants in AAO process under different DO concentration was studied in a pilot-scale test. At the same time, the effects of temperature and carbon source on nitrogen removal in the system at low DO concentration were investigated, and the microflora structure was analyzed, in order to provide a reliable theoretical basis for the actual wastewater treatment plant to achieve stable and efficient nitrification at low DO concentration and save energy consumption.