The primary desalination technologies are Reverse Osmosis, Multi Effects and Mechanical Vapor Compression.

Reverse Osmosis Desalination (RO)

RO has been in use commercially around the world for more than 50 years. It can treat a wide variety of water types, from recycled sewage to seawater. RO pushes feed water (for instance, sea water) through a salt-removing filter. After this occurs, two liquids remain. One is drinkable, the other heavily saline. Reverse osmosis is used widely for municipal desalination (for instance, in Perth and, soon, Sydney). It is also commonly used for tourist resorts and cruise ships. RO is also used to create industrial feed water supplies of various quality, and to create water that can be used for various cooling and boiler feed needs in power generation. The benefits of RO are its rapidly-falling costs.

Multi Effect Desalination (MED)

MED puts feed water through a series of evaporation stages to separate drinking water from salt. Each stage is generally called an "effect" In each effect, water is evaporated through applying heat and pressure. The vapor water is then recondensed into water and re-evaporated until the required water quality is reached. The benefits of MED include its flexibility, its relatively low maintenance needs and its low energy consumption.

Mechanical vapor compression is the most efficient of the distillation processes because it continuously recycles thermal energy and avoids the large number of stages or effects that adds complexity to traditional MED designs. With MVC, heat initially evaporates the feed water and a specialised compressor regains much of the heat during the recondensation process and recycles it back into the initial evaporation process. The benefits of MVC are its very low energy needs.


Containerized desalination plant