Mechanical dewatering through filtration can be problematic for materials that form compressible filter cakes and that have high specific surface areas. For this reason, dewatering is expected to be a major process challenge in the development of biorefineries aimed at producing materials with these characteristics. This study investigates the use of electrofiltration to dewater one such cellulosic material: a mechanically-modified microcrystalline cellulose. The local filtration properties were investigated during dead-end electrofiltration. The electric field was shown to decrease filter cake growth, which thereby decreased the filtration resistance. The application of an electric field during filtration was shown to improve the filtration rate of the microcrystalline cellulose to a greater extent than could be achieved by making changes to the pH of the suspension. The influence of ohmic heating and electrolysis reactions at the electrodes were considered and the influence of electroosmosis and electrophoresis on the filtration operation was described by an electrofiltration model.