Abstract: A method of dewatering an aqueous suspension by concurrently subjecting the aqueous suspension to the action of a sonic or ultrasonic field and an electrical field so as to remove the water from the suspension. The suspension is moved into a dewatering chamber between opposing electrodes one of which is permeable to water. The sonic or ultrasonic field is then applied to the suspension concurrently with the electrical field, at a frequency and amplitude adapted to cause water to separate from the suspension particles. The concurrently applied electrical field between the electrodes causes the particles to migrate away from the permeable electrode and water to migrate toward the permeable electrode. Water is then removed through the permeable electrode. The method requires less energy to remove a unit of water, has a faster rate of water removal and achieves a lower moisture content than if only an electrical field or acoustical field were used separately or in sequence.