Sub-critical filtration conditions of commercial hollow-fibre membranes in a submerged anaerobic MBR (HF-SAnMBR) system: The effect of gas sparging intensity

Abstract

A submerged anaerobic MBR demonstration plant with two commercial hollow-fibre ultrafiltration systems (PURON®, Koch Membrane Systems, PUR-PSH31) was operated using municipal wastewater at high levels of mixed liquor total solids (MLTS) (above 22gL -1). A modified flux-step method was applied to assess the critical flux (J C) at different gas sparging intensities. The results showed a linear dependency between J C and the specific gas demand per unit of membrane area (SGD m). J C ranged from 12 to 19LMH at SGD m values of between 0.17 and 0.5Nm 3h -1m -2, which are quite low in comparison to aerobic MBR. Long-term trials showed that the membranes operated steadily at fluxes close to the estimated J C, which validates the J C obtained by this method. After operating the membrane for almost 2years at sub-critical levels, no irreversible fouling problems were detected, and therefore, no chemical cleaning was conducted. © 2012 Elsevier Ltd.