Control of Membrane Attached Biofilm (MAB) formation and accumulation is a key aspect in the operation of Extractive Membrane Bioreactors (EMBs). In this work, MAB control was attempted in a novel EMB configuration which presents two innovative aspects: the presence of a biphasic biomedium and a contained liquid membrane module. This reactor, where the benefits of high shear forces and the use of a biphasic biomedium are effectively combined, was operated without any biofilm formation or reduction in organic substrate flux over time.