Ozone Chemically-Enhanced Backwashes For Ceramic Membrane Fouling Control in Cyanobacteria-Laden Surface Water Applications

Membrane fouling in surface waters impacted by cyanobacteria is poorly controlled and results in high operating costs. A possible solution is the chemically-enhanced backwash (CEB). This research investigates the potential of using an ozone CEB to control the fouling caused by Microcystis aeruginosa in surface water on a ceramic ultrafiltration membrane. Batch ozonation and dead-end, continuous flow, experiments were conducted with ozone doses between 0 and 19 mg O3/mg carbon on the membrane. In the batch tests, ozone reacted more rapidly with the surface water than with cyanobacteria. The opposite was observed during a CEB, highlighting the contribution of the hydraulic force on CEB performance since ozone likely weakens the compressible cake layer formed by cyanobacteria on the membrane surface. Overall, all ozone CEBs were capable of recovering over 80% of the membrane's specific flux whereas only 66% overall was recovered without the use of ozone.