Enhancing the anoxic/oxic process for treating hypersaline amide wastewater using a synthetic bacterial agent to regulate core bacterial interactions

Targeted enhancement of biological salt-tolerance, biodegradation performances, and functional microbial interactions by introducing new bacterial agent is crucial for constructing saline wastewater treatment bioreactor. Herein, we demonstrated the efficient removal of acetoacetanilide (AAA, an amide compound) simulated and real wastewater, microbial responses upon hypersaline (1–5 % salinity) stress using a halotolerant synthetic bacterial agent enhanced anoxic/oxic process. The results indicated that the bacterial agent significantly enhanced the removal efficiency (90.15 %) of AAA (1 % salinity, 1500 mg/L) with a hydraulic retention time of 49.40 h. Notably, the bacterial agent led to fivefold increase of NH₃-N compared to the control group, remarkably facilitating the ammonification of AAA (5 % salinity) wastewater. Furthermore, it promoted positive interactions among oxic sludge communities and expanded the niche width of core bacteria. This study highlights the enhanced performance of bacterial agent by regulating the core bacterial interactions, presenting a sustainable bioaugmentation approach for hypersaline organic wastewater treatment.