Development and Application of a novel anaerobic/aerobic/anoxic process in municipal wastewater treatment utilizing intracellular carbon sources

Municipal wastewater treatment plants (WWTPs) face a significant challenge in controlling treatment costs while meeting increasingly stringent wastewater discharge standards. To address this challenge, A novel anaerobic/anoxic/aerobic (AOA) process has been proposed. In this study, long-term nutrient removal and microbial community variations were investigated in the AOA systems of different scales, including three laboratory-scale systems, one pilot-scale and one full-scale systems. In the AOA system, nitrogen removal exceeded 50% was carried out in the post-anoxic zone via endogenous denitrification driven by intracellular carbon sources. The synergistic effect of denitrifying bacteria (DNB), anaerobic ammonium oxidation (anammox) bacteria, and fermentative bacteria (FB) enhanced nitrogen removal. Advanced nutrient removal was successfully achieved in the AOA process under different environments and influent quality. Under a low influent carbon-nitrogen ratio, the effluent total nitrogen (TN) concentration was 3.6-8.7 mg/L, with a TN removal efficiency of 71-95%. Total phosphorus (TP) concentration in effluent of 0.2-0.3 mg/L was also achieved. Moreover, compared to the widely used anaerobic/aerobic/anoxic (AAO) process, the AOA process reduced 60% of energy consumption by aeration and recirculation. In conclusion, the AOA process has the potential for practical implementation and provides an economical and efficient nutrient removal process for municipal wastewater treatment.