Comparison Between Hybrid and Non-hybrid Membrane Aerated Biofilm Reactors in Treating Municipal Wastewater

Hybrid membrane aerated biofilm reactor process (HMABR) has been developed by integrating activated sludge process and membrane aerated biofilm reactor (MABR). It has shown promise by promoting simultaneous removal of organic matters and nitrogen pollutant efficiently due to the increased biomass content and improved mass transfer. Meanwhile, partial nitrification–denitritation in MABR could result in less oxygen consumption and carbon supply, lower CO2 emission, less sludge production, and smaller volume of bioreactors as compared to conventional nitrogen removal processes. Further, synergistic benefits might be achieved through combining partial nitrification–denitritation with HMABR. Three MABR parallel experimental systems equipped with Zeelung™ membrane fibers were continuously operated to treat synthetic wastewater for 230 days. Up to 14% and 11% of influent NH4+-N could be removed by nitritation–denitritation in HMABRs and MABRs, respectively. High organic loading coupled with insufficient gas scouring intensity accelerated the faster growth of heterotrophic bacteria in the MABRs than HMABRs, thereby, reducing nitrogen removal. Partial nitrification in both HMABRs and MABRs increased with the increase in ammonia loading and C/N ratio, while HMABRs demonstrated significantly better nutrient removal when high substrate loading rates were applied for MABRs.