Sonochemical control of fouling formation in membrane ultrafiltration of wastewater: Effect of ultrasonic frequency

Water scarcity is an increasing world-wide concern due to the rapid growth of population along with industrialization and urbanization. Membrane ultrafiltration represents a promising and sustainable technology for handling this problem through water reuse. However, fouling is still a significant drawback that limits the expansion of membrane filtration use. Recent studies have shown that ultrasound provides an alternative technology for membrane fouling control able to enhance the effluent water quality in an environmentally benign manner. Nevertheless, the ultrasonic parameters affecting the efficiency of the US-enhanced cleaning are not completely well known. In this work results from an experimental study of ultrasonically assisted ultrafiltration, varying ultrasonic frequencies, are presented. The performances of sonochemical oxidation, membrane ultrafiltration and their combination were evaluated on wastewater samples. Results show that ultrasonic field can drastically reduce membrane fouling. It was found that lower frequency (35 kHz) slows down the fouling formation, but, on the other hand, higher frequency (130 kHz) improves the organic matter removal. © 2014 Elsevier Ltd.