Abstract
•Membrane aerators were added to anaerobic fluidized bed membrane bioreactor.•Simultaneous nitrogen and organic removal was achieved.•Dissolved methane was avoided and an anoxic environment was maintained.•Nitrogen was removed by nitrification and denitrification but not anammox.•Membrane fouling was well controlled, as indicated by low transmembrane pressures.
Dissolved methane and a lack of nutrient removal are two concerns for treatment of wastewater using anaerobic fluidized bed membrane bioreactors (AFMBRs). Membrane aerators were integrated into an AFMBR to form an aeration membrane fluidized bed membrane bioreactor (AeMFMBR) capable of simultaneous removal of organic matter and ammonia without production of dissolved methane. Good effluent quality was obtained with no detectable suspended solids, 93±5% of chemical oxygen demand (COD) removal to 14±11mg/L, and 74±8% of total ammonia (TA) removal to 12±3mg-N/L for domestic wastewater (COD of 193±23mg/L and TA of 49±5mg-N/L) treatment. Nitrate and nitrite concentrations were always low (<1mg-N/L) during continuous flow treatment. Membrane fouling was well controlled by fluidization of the granular activated carbon (GAC) particles (transmembrane pressures maintained <3kPa). Analysis of the microbial communities suggested that nitrogen removal was due to nitrification and denitrification based on the presence of microorganisms associated with these processes.