Research on the Application of Heterotrophic Nitrification-Aerobic Denitrification Bacteria in Membrane Bioreactor (MBR)

The inoculation of heterotrophic nitrification-aerobic denitrification bacteria (HN-AD) in MBR facilitates the simultaneous nitrification and denitrification process. However, many HN-AD will be lost during operation. Therefore, this study compares the application results of enhancing MBR with a self-designed biological amplifier coupled with HN-AD against the performance of conventional MBR. Post-enhancement, the MBR achieved removal efficiency of 96.7% for NH 4 + -N (100 mg/L), 96.4% for COD(400 mg/L) in synthetic wastewater, with a 33% increase in the removal efficiency of TN(100 mg/L). Before enhancement, the dominant denitrifying genus of MBR was Thauera, with the highest abundance of 56.1%. After enhancement, the dominant bacterial in the MBR were Alcaligenes (48.4%) and Thauera (15.2%). In addition, the abundance of denitrification genes (nirK, norB, nosZ) increased in the enhanced MBR, which contributed to an improved TN removal efficiency. The use of biological amplifier effectively solved the problem of HN-AD loss in sewage treatment.