Nitrification Comparison between Synthetic Wastewater and Secondary Effluent Using Membrane-Aerated Biofilm Reactor (MABR) Process

Abstract

Two pilot-scale membrane aerated biofilm reactors (MABR) were operated for over 530 days to compare the nitrification in both synthetic wastewater and secondary effluent, and to examine the impacts of hydrodynamic shear caused by adjusting effluent recirculation on ammonia removal. The results showed that secondary effluent had enhanced the nitrifying biofilm formation and/or detention. The ammonia removal efficiencies up to 0.262±0.024 and 0.252±0.023 kgN/m 3 /d were achieved for synthetic wastewater and secondary effluent, respectively. An optimum fluid mixing existed so that the balance between biofilm detachment and substrate mass transfer can be maintained for maximum oxidation capacity. Furthermore, the optimum mixing conditions were found to be dependent of influent composition. Further evaluation shows that low mixing intensity is a good strategy for the initiation of nitrifying biofilm in MABR, especially for the treatment of wastewater of no organic carbon.