Ultrafiltration by hollow fibres has shown to be an efficient process for drinking water production. A new process, based on air sparging inside hollow fibres throughout the filtering period is proposed. The generated gas/liquid two-phase now inside fibres showed a high efficiency to enhance the stabilised permeate nux, by preventing particle deposition. In some operating conditions, the stabilised permeate flux was more than doubled thanks to the two-phase flow. This paper points out the effects of this process on the membrane productivity and more particularly on energy consumption. Moreover to understand phenomena involved in this flux enhancement, a link is demonstrated between hydrodynamic parameters, such as wall shear stresses, and the stabilised permeate flux.