Interesting case about desalination

Desalination/Distillation is one of mankind's earliest forms of water treatment, and it is still a popular treatment solution throughout the world today. In ancient times, many civilizations used this process on their ships to convert sea water into drinking water. Today, desalination plants are used to convert sea water to drinking water on ships and in many arid regions of the world, and to treat water in other areas that is fouled by natural and unnatural contaminants. Distillation is perhaps the one water treatment technology that most completely reduces the widest range of drinking water contaminants.In nature, this basic process is responsible for the hydrologic cycle. The sun causes water to evaporate from surface sources such as lakes, oceans, and streams. The water vapor eventually comes in contact with cooler air, where it re-condenses to form dew or rain. This process can be imitated artificially, and more rapidly than in nature, using alternative sources of heating and cooling.

Brackish Water Desalination

Brackish water, containing minerals and salts typically less than 5,000 ppm total dissolved solids (TDS), can be economically treated with today's reverse osmosis (RO) and electrodialysis reversal (EDR) systems. Effective mineral and salt removal converts previously unusable waters to high-purity resources for drinking, irrigation or industrial process uses. The traditional process used in these operations is vacuum distillation—essentially the boiling of water at less than atmospheric pressure and thus a much lower temperature than normal. This is because the boiling of a liquid occurs when the vapor pressure equals the ambient pressure and vapor pressure increases with temperature. Thus, because of the reduced temperature, energy is saved. A leading distillation method is multi-stage flash distillation accounting for 85% of production worldwide in 2004