An apparatus and method for applying electric fields at specific amplitudes, gradients, and frequencies for separating oil and water from emulsions thereof, are described. Significant reduction of water concentration in stable water-in-crude oil emulsions having high (>65%) as well as low (<3%) water-cuts has been demonstrated. The apparatus does not require pre-heating of the emulsions or addition of chemicals thereto, and can be stand-alone or functionally integrated with other processes, such as mechanical or gravitational separation technologies. The apparatus may be adapted to small-volume and narrow-space environments, such as pipes.
STATEMENT REGARDING FEDERAL RIGHTS
 This invention was made with government support under Contract No. DE-AC52-06NA25396 awarded by the U.S. Department of Energy. The government has certain rights in the invention.