An experimental rig has been developed to study the effects of electric and acoustic fields on constant pressure filtration. The filter is designed with the medium support acting as a cathode, and with a variable height anode located in the feed suspension inducing an electric field normal to the filter medium. A flat plate ultrasonic transducer attached to the side of the filter applied ultrasonic energy tangentially to the medium. Electric and acoustic fields, suspension characteristics and process parameters can all be varied independently. Experimental results demonstrate that acoustic fields have little or no effect on the dewatering of suspensions of concentrations higher than 1% by volume. Changes in the conductivity induced by ultrasonic irradiation are pH dependent and may affect the suspension such that application of an electrical field is enhanced. Electric fields enhance filtration rates but form filter cakes with higher porosities. The power consumed by the ultrasonic field is large; the power consumed by the electric field is much smaller and is more effective at improving filtration characteristics.