Simple and effective corrugation of PVDF membranes for enhanced MBR performance

• Corrugated membranes were prepared for MBR by modifying the phase inversion process.
• Corrugations increased both membrane effective surface area and mean pore size.
• Corrugated membranes had higher critical flux in MBR than the flat membrane.
• Corrugated membranes had better filterability in lab-scale MBR test.
• Improved filterability is likely due to higher surface area.

Membrane fouling control in membrane bioreactors (MBRs) can be achieved by improving membrane properties. In this study, corrugated flat sheet polyvinylidenefluoride (PVDF) membranes were fabricated, characterized and tested in a lab-scale MBR for improved filterability and fouling resistance. A simple imprinting step was successfully developed and applied as part of the membrane preparation procedure, via phase inversion, to form corrugations on the membrane surface. The corrugation consisted of valleys-and-hills topography, which increased membrane effective surface area (AE) by ~50%. It also increased the membrane mean pore size (PS) as a result of changes in formation mechanism. Both higher AE and larger PS increased membrane permeability to about 5–6 times compared to the non-corrugated membrane, prepared under similar conditions. Surface corrugations reduced membrane fouling propensity as observed from the flux-stepping test and a lab-scale MBR operation, without affecting permeate quality.