Quorum sensing signaling molecules enhance the treatment performance of the HN-AD bacteria-Chlorella symbiotic system in MABR

To enhance the stability of membrane aerated biofilm reactor (MABR) and accelerate the formation of biofilm, this study introduced a symbiotic system composed of heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria and Chlorella into the MABR, and compared it with a control system inoculated with HN-AD bacteria and activated sludge. The effects of adding 0.8 μM exogenous C8-HSL on biofilm formation and the efficiency of nitrogen and phosphorus removal were investigated by comparing systems with and without the signaling molecule. Results showed that 0.8 μM C8-HSL enhanced the removal efficiencies of ammonia nitrogen, total nitrogen (TN), and total phosphorus (TP) by 25.17 %, 36.22 %, and 38.74 %, respectively, and increased extracellular polymeric substances (EPS) production by 68.62 %. High-throughput sequencing identified Desulfomicrobium and Aliidiomarina as the dominant microorganisms involved in nitrogen and phosphorus removal. The nirB gene played a key role in the denitrification process, and phoBR gene was essential for phosphorus removal. This study provides theoretical support for the application of quorum sensing in MABR systems, offering a novel strategy to improve the efficiency and stability of high ammonia wastewater treatment.