Characteristics And Biological Nutrient Removal Of Process Combining Muitistage A/O With Biofilm

In South, nitrogen and phosphorus removal efficiency is lower due to insufficient carbon source and low temperature in winter. Development and application of new process and technology is essential for nitrogen and phosphorus removal. This paper investigated process combining muitistage A/O with biofilm using low carbon municipal wastewater. By operating parameters’ optimization and consortiums with nutrient and phosphorus removal capability to increase the effluent performance of TN and TP. At last, the dynamic succession of bacterial community was analyzed before and after bioaugmentation using pyrosequencing.Two consortiums with aerobic denitrification and denitrifying phosphorus capability respectively have been successfully domesticated and enriched. In low temperature, using these two consortiums, the specific removal rates of TN and TP reached 84.21% and 83.15%. Domesticating these consortiums using sewage water, the specific removal rates of TN and TP reached 37.83% and 37.92% under 10% bacterial agent dose.Combining with wastewater treatment and pilot process, we operated A2/O-A/O process. By comparing the different operating parameters, the optimal condition is HRT =10 h, inflow distribution ratio=3: 1 and Sludge recycle ratio=100%. The optimal effluent performance of NH4+-N, TN and total TP were 0.50 mg/L, 9 mg/L and 0.60 mg/L, increasing 19.74%, 6.06% and 14.27% respectively.In winter, the nitrogen and phosphorus removal efficiency is lower. In order to strengthen the effluent, added aerobic denitrification and denitrifying phosphorus consortiums to the pilot process. The optimal effluent performance of COD, NH4+-N, TN and total TP were 20 mg/L, 1 mg/L, 10 mg/L and 0.40 mg/L, increasing 8.25%, 3.71%, 23.18% and 20.28% respectively combining with wastewater treatment.The microbial community structure was analyzed before and after bioaugmentation using pyrosequencing. After debugging and optimization, the abundance of bacteria with feature of removing nitrogen and phosphorus was increased, including Nitrosomonadaceae_uncultured, Nitrospirae, Aeromonas and Accumulibacter. After bioaugmentation, the change of microbial community structure is apparent. The abundance of Pseudomonas with feature of aerobic denitrification and denitrifying phosphorus capability was increased, which strengthen the effluent in winter.