Insulator-based dielectrophoresis for fouling suppression in submerged membranes bioreactors: Impact of insulators shape and dimensions

Abstract

The application of insulator-based dielectrophoresis (iDEP) has the potential to enhance membrane fouling suppression in submerged membrane bioreactors without extra energy consumption. In this study, the effect of the insulators shapes and sizes within the interidigitated electrodes (IDE) configuration was investigated for a better dielectrophoresis (DEP) force with a better membrane fouling suppression. Three circular insulators CS 1, CS 1.5 and CS 2 with diameters of 1 mm, 1.5 mm and 2 mm, respectively, were tested. A 2 mm side square section insulator SS 2 was also examined. The numerical simulation results show that the DEP force extension is greater with a similar diameter as the excited electrodes (2 mm in this study) when using circular insulators. The use of square section insulator (SS 2) increases the overall electric field gradient squared (?|E|2) by 16% compared to the 2 mm circular insulator (CS 2). The square section insulator also extends the dielectrophoresis (DEP) force field more uniformly across the membrane surface while generating sufficient force to move the suspended solids away from the membrane. The experimental investigation verified the theoretical simulation prediction and demonstrated that SS 2 membrane modules provide longer membrane service time by maintaining a normalized permeate flux of 55% more than the circular section membrane modules, with a maximum intensification factor of 14 at a 220 V voltage and 50 Hz with a transmembrane pressure of 0.1 bar.