Thirsty? How ’bout a cool, refreshing cup of seawater?

No, don’t take us literally! Humans cannot drink saline water. But, saline water can be made into freshwater, which everyone needs everyday. The process is called desalination, and it is being used more and more around the world to provide people with needed freshwater.

 

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.

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.

Here are our parameters for saline water:

Fresh water – Less than 1,000 ppm
Slightly saline water – From 1,000 ppm to 3,000 ppm
Moderately saline water – From 3,000 ppm to 10,000 ppm
Highly saline water – From 10,000 ppm to 35,000 ppm

By the way, ocean water contains about 35,000 ppm of salt.

Source: Saline-water resources of North Dakota, USGS Water Supply Paper 1428, 1958.

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