Optimal Operation and Effect Research of Enhanced Denitrification AAO Process for Treating Rural Domestic Sewage

Abstract

In view of the low concentration of organic matter in rural domestic sewage and the lack of carbon source in the biochemical denitrification process, resulting in excessive total nitrogen in the effluent, the traditional AAO process was improved to enhance the system's biochemical denitrification capacity. Through engineering demonstration, an improved process based on enhanced denitrification AAO process was constructed and applied to a village in Zhejiang Province. This process can ensure the complete separation of mixed liquid denitrification and sludge denitrification. While ensuring the denitrification efficiency, it can further reduce nitrate entering the anaerobic zone, so as to ensure a stable denitrification and phosphorus removal effect. The removal rates of the system for COD, NH3-N, TN, TP and SS are 95.6%, 99.5%, 75.1%, 97.6%, 91.6% respectively, in line with Zhejiang Province's "Water Pollution Discharge Requirements for Rural Domestic Sewage Centralized Treatment Facilities" (DB33 973-2021) Table 1 Level 1 Standard. In addition, the system energy consumption is 0.28 kwh/m³, which meets the requirements of low energy consumption system. This case can provide technical reference for the technical selection of rural domestic sewage treatment in my country.