From YourSITE.com
Refreshing cup of seawater
By USGS
Jun 13, 2005, 11:13
Thirsty? How 'bout a cool, refreshing cup of seawater?
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Most of the United States has, or can gain access to, ample supplies of fresh water for drinking purposes. But, fresh water can be in short supply in some parts of the country (and world). And, as the population continues to grow, shortages of fresh water will occur more often, if only in certain locations. In some areas, salt water (from the ocean, for instance) is being turned into freshwater for drinking. |
| A promising method to desalinate seawater is the "reverse osmosis" method. Right now, the high cost of desalinization has kept it from being used more often, as it can cost over $1,000 per acre-foot to desalinate seawater as compared to about $200 per acre-foot for water from normal supply sources. Desalinization technology is improving and costs are falling, though, and Tampa Bay, FL is currently desalinizing water at a cost of only $650 per acre foot. As both the demand for fresh water and technology increase, you can expect to see more desalinization occurring, especially in areas, such as California and the Middle East.
What do we mean by "saline water?" Water that is saline contains significant amounts (referred to as "concentrations") of dissolved salts. In this case, the concentration is the amount (by weight) of salt in water, as expressed in "parts per million" (ppm). If water has a concentration of 10,000 ppm of dissolved salts, then one percent (10,000 divided by 1,000,000) of the weight of the water comes from dissolved salts.
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Fresh water - Less than 1,000 ppm