Influence of C/N Ratios on Nitrification Performance in Membrane Aerated Biofilm Reactors

Membrane aerated biofilm reactor (MABR), as a wastewater biotreatment technology, is approaching maturity on the commercial scale. The gas-permeable membrane used in MABR allows the diffusion of oxygen into the attached biofilm, which directly leads to biological oxidation of pollutants in wastewater. This research aims to identify the capabilities of nitrification and oxygen transfer of ZeelungTM fibres used in MABR system. The impacts of various C/N ratios (in the range of 0.4-5.3) on membrane modules using 3 bench-scale reactors were investigated in this study throughout a 210 day-long experiment. This study demonstrated that the removal efficiencies of 92% for BOD, 99% for ammonia and 25% for TN while 16 g/m2/d of oxygen transfer ability could be accomplished in the chosen conditions. A dramatical reduction in the population of nitrifying bacteria with high C/N ratio in hybrid operation mode was identified through analyzing biofilm samples by the combination of FISH and CLSM methods.