Authors:Péter Bor, József Csanádi, Gábor Veréb, Sándor Beszédes, Zita Šereš, Zsuzsanna László, Cecilia Hodúr and Szabolcs Kertész
To meet the requirements defined by environmental protection regulations effective wastewater treatment is required to process effluents before discharging them into sewers or living waters. While membrane separation offers a quite advantageous method to reduce the organic load of wastewaters, membrane fouling is still limiting its application in wastewater treatment.
In this study, the possibility of membrane fouling reduction by increased shear rates on the surface of the membrane was investigated. 7 and 10 kDa MWCO ultrafiltration and 240 Da nanofiltration membranes were studied, with the use of a laboratory mode Vibratory Shear Enhanced Processing. This work mostly focused on studying the effects of module vibration and recirculation feed flow rate on permeate flux, specific energy demand and membrane rejections. Using the same operation parameters, vibration and non-vibration mode experiments were carried out with high and low recirculation flow rate to have a deeper understanding of the shear rate effects. It can be concluded that higher shear rate had a positive effect on the process: increased shear rate resulted in higher flux, higher overall rejection values, as well as a significantly decreased specific energy demand. By calculating and comparing the shear rates in experiments with different operating parameters, both vibration and nonvibration mode, both low and high recirculation flow rate, we have reached the conclusion that vibration causes a significantly higher shear rate increase than setting the recirculation flow rate high.