Impact of Alternating Reactor Functions on Aerobic Granular Sludge: Treatment Efficiency of Brewery Wastewater and Microbial Community

Brewery wastewater typically contains abundant refractory organic substances, that pose challenges, such as poor stability and low pollutant removal efficiency, when treated with conventional aerobic granular sludge (AGS). Hydrolytic acidification (HA) is an effective pretreatment approach that enhances the biological properties of wastewater. However, prolonged HA may lead to the disintegration of the AGS, thereby affecting its treatment efficacy. To address this issue, we propose an operational mode with alternating reactor functions, integrating HA with an SBR and alternately switching the functions of HA and SBR to maintain the stability of AGS and improve wastewater treatment efficiency. The experimental findings revealed that after the acclimation stage, the removal efficiencies of chemical oxygen demand, total nitrogen, NH4⁺-N, and PO₄³⁺-P in the experimental group reached 84.95%, 77.05%, 98.96%, and 79.38%, respectively, which were notably superior to those in the control group, which were 76.7%, 70.6%, 97.73%, and 78.61%, respectively. The results of the microbial community analysis suggest that the alternating operational mode facilitates the enrichment of functional microbial communities associated with pollutant removal, further augmenting the pollutant removal capacity. Our results offer a novel perspective for the application of AGS in the treatment of brewery wastewater and demonstrate that the alternating reactor function mode can effectively enhance treatment efficiency. Future research could further optimize the operating conditions and explore the application potential of the alternating operation of HA and SBR in the treatment of diverse types of wastewater.