Simulations of particle trajectories in a crossflow membrane filtration process coupled with ac dielectrophoresis (DEP) are presented. Analytic and numerical approaches for evaluating the dielectrophoretic forces on a colloidal particle traversing an array of parallel microelectrodes, numerical estimates of the velocity field near the membranes accounting for the intermittence in wall suction, as well as particle trajectory analysis in presence of dielectrophoretic and hydrodynamic forces are presented. The results indicate that fouling of membranes can be prevented in an entirely physical manner by utilizing the repulsive dielectrophoretic forces acting on the suspended particles. Furthermore, placing an array of parallel microelectrodes on the membrane alters the flow field near the membrane, which additionally aids in preventing the particles from depositing on the membrane. © 2005 Elsevier B.V. All rights reserved.