Engineering a macro-corrugated composite membrane with superior anti-biofouling property for extractive membrane bioreactor

The extractive membrane bioreactor (EMBR) is a prospective method for detoxifying high salinity organic wastewater by integrating a membrane extractive process with a bioreactor. However, uncontrolled biofilm adhesion on the hydrophobic membrane surface could significantly increase its organic transfer resistance. In this work, a novel strategy was proposed to alleviate membrane biofouling by constructing a corrugated topology on the hydrophobic composite extractive membrane. The phenol mass transfer coefficient and anti-biofouling performance of the corrugated composite membrane were evaluated in both side-stream and submerged EMBR configurations. Anti-biofouling assessments of the corrugated composite membrane were conducted in both parallel and vertical orientations. Computational fluid dynamics (CFD) simulations were employed to model the surface fluid behaviours of the membrane. The results revealed that the hydrophobic composite membrane with a corrugated pattern in both orientations exhibited a significantly lower biofouling tendency compared to the flat membrane without any pattern. Following a 14-day continuous submerged EMBR operation, the phenol mass transfer coefficients were only slightly reduced to 90% and 92% of their initial values in parallel and vertical orientations, respectively. The superior anti-biofouling property of the membrane can be attributed to the faster surface flow rate with an enhanced shear force in the parallel mode, effectively removing microorganisms attached to the membrane surface. In the vertical mode, vortices formed in the bottom of the valleys reduce foulant deposition through mixing and scouring. Furthermore, the corrugated topology of hydrophobic composite membrane makes it more challenging for microorganism colonies to attach and form stable biofilms on the membrane surface.