a multistage separator for oilfield emulsions is disclosed . the separator utilizes a mechanical inclined plate separator constructed of electrically nonconductive materials disposed downstream of an electrostatic separation section . electrostatic charges imparted to the flowing emulsion by the electrostatic section migrate to the mechanical portion and establish a surface charge on the inclined plates thereof . this surface charge results in enhanced coalescence of the aqueous and nonaqueous dispersions present in the emulsion .