A novel rotating HF membrane to control fouling on anaerobic membrane bioreactors treating wastewater

• A novel shear-enhanced membrane configuration.
• Significant improvement of flux during ultrafiltration of anaerobic suspensions.
• Fouling mitigation during dynamic filtration of concentrated and viscous suspensions.
• Application of rotational speed-step method.
• Promising operation for ultrafiltration of complex and viscous suspensions.

A novel rotating hollow fibre membrane (R-HFM) was assessed for filtering suspensions from a pilot Anaerobic Membrane Bioreactor (AnMBR) at lab-scale during short-term trials. The effectiveness of this shear-enhanced filtration in fouling mitigation has been compared to conventional gas-sparging configuration at different permeate fluxes. A higher level of fouling prevention was obtained for the rotating HF membrane than for the gas-sparging application (93–96% versus 41–44%, respectively). For viscous and concentrated suspensions, high values of rotational speeds w were required to achieve greater effectiveness in fouling limitation, which in the present study ranged from 81% to 99%. Based upon a rotational speed step method, the effect of w on residual fouling removal was analysed. Moreover, a reduced difference between fouling rates for decreasing and growing phases, which is related to the residual fouling phenomena, was reported for w values higher than 160 rpm.