A new rotating hollow-fibre module has been designed in order to reduce membrane fouling in submerged anaerobic membrane bioreactors. Filtration performance under different permeate flux conditions was evaluated on a short-term pilot-scale basis. Results were compared with those obtained with a conventional gas-sparging module operating at similar specific energy demand. The experimental assessment of critical flux showed a 17–20% improvement with the membrane rotation. This technique not only reduced the fouling rate but also removed the fouling cake previously formed at the membrane. In sub-critical flux conditions, module rotation substantially extended cleaning-free filtration. It also permitted stable operation at a moderate supra-critical flux (16 L/h m2), enhancing backwashing efficiency and providing high net permeate fluxes (11.7–12.3 L/h m2)
