Abstract: A method of separating water from an aqueous emulsion using a minimum of energy includes heating the aqueous emulsion in a sump, conveying concentrated emulsion from the sump to a heat exchanger so as to pass therethrough back to the sump, circulating water vapor and non-condensable gases from the sump through a compressor to raise its temperature and passing the heated water vapor and non-condensable gases through the heat exchanger to condense and heat the concentrated emulsion therein and evaporate water therefrom, a thermostat filled with water and water vapor, together with first and second pressure switches respectively communicating with the sump and the external atmosphere and the heat exchanger and the external atmosphere, maintaining a temperature differential between 0.5.degree. and 3.degree. C. between the aqueous emulsion in the sump and the temperature of the compressed water vapor and noncondensable gases.