Microstructured spacers for submerged membrane filtration systems

We introduce a new type of membrane spacer design, based on the geometry of static mixers, for application in submerged membrane filtration. In particular we demonstrate the potential of the spacers to reduce air sparging and energy consumption. New operational modes are proposed and discussed critically. Critical flux measurements are performed with and without spacer at various process parameters such as spacer/channel height, air sparging rate and bubble size. The most relevant energy reducing parameters of submerged systems are determined with the Design of Experiments (DoE) methodology. Using the new spacers, the critical flux can be increased by 100%. Furthermore, fouling monitored by the trans-membrane pressure change can be significantly reduced by a factor of 7.5 when combined with elevated cross-flow velocities.