The influence of hydrodynamic cavitation on cleaning of hollow fiber membranes used for ultrafiltration

Abstract

Two identical hollow fibre membranes used for ultrafiltration as prefiltration stage of water drinking treatment were tested for assessing the efficiency of cleaning, by using hydrodynamic cavitation. Each membrane with outside-in permeate flow direction, and the same molecular weight cut-off (0.097 m) was placed vertically inside glass cylinders. One hollow fiber membrane was subjected tohydrodynamic cavitation and cavitation during backlfushing. For the other membrane no treatment was provided for comparison reason. The results highlighted that by using the procedure of simple cavitation a 16% increase of permeate flow were reported. In the case of cavitation during backflushing the increase of permeate flux was 24%. For the case study, cavitation during backflushing were most effective procedure then simple hydrodynamic cavitation or backflushing. Hydrodynamic cavitation could be used during the filtering process, without stopping the process and without using permeate water for cleaning. Still, internal fouling are not addressed. Hydrodynamic cavitation during backflushing is more effective for both external and internal fouling, preserving the mechanical integrity of the membrane.