Enhancement of cleaning-in-place (CIP) of a reverse osmosis desalination process with air micro-nano bubbles

Concentration polarization (CP) is a major operational challenge for reverse osmosis (RO) desalination because it results in decreased permeate flux and increased transmembrane pressure (TMP). In this study, lab-scale and pilot-scale cross-flow filtration experiments were performed to evaluate the impact of air micro-nano bubbles (MNBs) on permeate flux, TMP and solute rejection. Results indicated that MNBs can increase permeate flux recovery up to 100%. Also, the permeate flux and solute rejection were increased up to 24.62% and 0.8%, respectively. These results are attributed to the disruption of the CP layer by MNBs. Furthermore, since this is a non-chemical, membrane cleaning in place (CIP) method, this does not contribute to environmental pollution, making it a more applicable cleaning method.