Factors that affect the permeability of commercial hollow-fibre membranes in a submerged anaerobic MBR (HF-SAnMBR) system

► Membrane performance in SAnMBR treating urban wastewater was similar to aerobic MBRs. ► The main variables affecting K20 under sub/supra-critical conditions were tested. ► SGDm and BF are the physical variables that affect membrane performance most. ► No chemical cleaning was needed after two years operating sub-critically. ► K20 remained above 100 LMH bar−1 and RT below 1013 m−1.