1. Distillation 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. The above diagram and information is courtesy of Delaware: The Encyclopedia of Desalination and Water Resources. Distillation in lab link Next page: Does the U.S.A. have any desalination plants?

2. There are more than 7,500 desalination plants around the world providing freshwater from salt and brackish water alike. This number continues to grow as researchers work to improve the process, both in terms of cost effectiveness and energy efficiency. The largest number in Saudi Arabia. # of Desalination Plants in the United States Last updated Mar 30, 2010 12:00PM 191 California TexasFlorida 33 120 38

3. Maintaining a Fresh Water Supply Most submarines have a distillation apparatus that can take in seawater and produce fresh water. The distillation plant heats the seawater to water vapor, which removes the salts, and then cools the water vapor into a collecting tank of fresh water. This water is used mainly for cooling electronic equipment (such as computers and navigation equipment) and for supporting the crew (for example, drinking, cooking and personal hygiene).