Comprehensive review of different types of water desalination

Desalination of saline and seawater is one of the best ways to provide fresh water. This article provides an overview of different types of water desalination processes, with introduction of advantages, disadvantages and various techniques to increase their efficiency. The results of this study suggest that for saline waters with salts greater than 1.2% mass fraction, it is more economical to use reverse osmosis devices instead of electro-dialysis process. Furthermore, the resistance of electro-dialysis membranes is much higher than of reverse osmosis membranes. Multiple-effect distillation (MED) is the most important thermal process that can produce a large amount of fresh water. The vapor-compression (VC) method does not require an external heating source and is exerted by electricity, therefore, the method is suitable for populated areas that have access to electricity. Low energy consumption in the freezing method is the most important advantage of that in comparison to other methods. Because, most areas in need of fresh water have high solar irradiations, so solar water desalination is the best way to provide the required water. Passive solar desalinations are devices that do not require a variety of energy and pumping systems and work with the least peripheral equipment, therefore, are cost-effective than solar active desalinations. The advantage of a stepped-solar still is that by placing a small basin with phase change material at the bottom of the absorber plate, it is possible to use the benefits of a single basin solar still at all period of day and night.