In MEE sequences of vessels are used. Here water is boiled in the vessels, each held at a lower pressure than the last, because the boiling temperature of the water decreases as pressure decreases the vapour boiled off in one vessel can be used to heat the next, and only the first vessel (at the highest pressure) requires an external source of heat. Effluent fed into MEE is of a kind which has very high TDS. Water recovery in this process is around 95%.
