Water Desalination: Freshwater from the Sea

Did You Know? Ocean water contains about 35,000 parts per million of salt. Fresh water contains less than 1,000 parts per million. The first scientific paper on desalting was published by Arab chemists in the eighth century. Desalination/distillation is one of mankind's earliest forms of water treatment. 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. The largest inland desalination plant in the world, the El Paso-Fort Bliss desalination plant, has a design capacity of approximately 27.5 MGD (30,800 acre-feet). The average cost to produce 1 acre-foot of desalinated water from seawater ranges from approximately $800 to about $1,400. The size of each reverse osmosis membrane pore used in the desalination process is about 1/100,000th the size of one human hair.