Optimization of Aeration Strategies in Moving Bed Biofilm Reactor for Hospital Wastewater Treatment

The growing complexity of hospital wastewater presents significant challenges for traditional treatment methods, highlighting the need for innovative and energy-efficient alternatives. This study investigated the effect of different aeration strategies on the biological removal efficiency of carbon and nitrogen in a laboratory-scale moving bed biofilm reactor (MBBR). The system was operated under three aeration conditions: continuous aeration and two intermittent aeration regimes. The results show that intermittent aeration enhanced nitrogen removal through simultaneous nitrification-denitrification (SND) while maintaining high organic matter degradation efficiency. In Phase I (continuous aeration), carbon removal efficiency reached 87.4%, whereas total nitrogen removal remained below 20% due to the absence of anoxic conditions. In contrast, intermittent aeration in Phases II and III significantly improved nitrogen removal to 82.5% and 87.8%, respectively, while achieving comparable carbon removal rates. The most effective operational mode involved a 40-min aeration period followed by 20 min without aeration, facilitating denitrification and minimizing energy consumption. Furthermore, the system maintained stable biofilm development, with mixed liquor suspended solids (MLSS) concentrations ranging from 1.9 to 3.3 g/L. Despite the low MLSS concentration, the system consistently exhibited high treatment performance, underscoring the robustness of biofilm-based processes in MBBR systems. These findings highlight the potential of optimized aeration strategies in MBBR systems to enhance treatment efficiency while reducing operational costs. This study provides valuable guidance for designing sustainable hospital wastewater treatment systems that meet stringent regulatory standards.