A pilot-scale staged anaerobic fluidized membrane bioreactor (SAF-MBR) was operated continuously for
485 days, without chemical cleaning of membranes, treating primary-settled domestic wastewater with
wastewater temperature between 8 and 30 C and total hydraulic retention time (HRT) between 4.6 and
6.8 h. Average chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) removals averaged
81% and 85%, respectively, during the first winter at 8–15 C before full acclimation had occurred.
However, subsequently when fully acclimated, summer and winter COD removals of 94% and 90% and
BOD5 removals of 98% and 90%, respectively, were obtained with average effluent COD never higher than
23 mg/L nor BOD5 higher than 9 mg/L. Operational energy requirement of 0.23 kW h/m3 could be met
with primary and secondary methane production, and could be reduced further through hydraulic
change. Biosolids production in all seasons averaged 0.051 g volatile suspended solids per g COD
removed.