What is Desalinated Water?

No water in the desert! How about we drink seawater?
Humans cannot drink the seawater as it contains salt and is saline water.
But, luckily saline water can be made into freshwater, so that there is enough water for drinking washing and growing crops and for everyday use.
Many parts of the world such as dry desert areas simply do not have enough fresh water from surface water such as rivers, lakes.  They have little rainfall and then it may only be seasonal.

The scarcity of fresh water and the need for additional fresh water is already critical in many arid regions of the world and will be increasingly important in the future. It is very likely that the need for fresh water will soon be considered, in the same category as   oil and energy resources, and to be one of the determining factors of world stability and the prosperity of nations. So a regular dependable supply of water is needed in these areas to enable them to have water to grow crops and build their countries to prosper. As our world populations grow we need to be able to guarantee this basic need and avoid which shortages of fresh water. The solution is to look to the abundant supply of sea water and turn salty water into freshwater for drinking.

Desalination is far more expensive than using water from land supply sources
The cost is very high and so it cannot be afforded by everyone who needs it, but because the desalinisation technology is improving fast, so the costs are beginning to fall, making it more affordable to countries and islands that need it.

You cannot drink the sea
People cannot drink sea water as sea water causes the human body to become more dehydrated. Nobody, except for a saltwater fish, is designed to drink saltwater. So if you find yourself stranded out at sea it’s better to hope for rain than to drink seawater. Or catch and eat a fish – that’ll give you a less salty source of fluids.

Water from the sea is saline but what do we mean by saline water?
Water that is saline contains high levels (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. One good method used to desalinate seawater is the “reverse osmosis” method.

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
Moderatly 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.

Desalination is not modern science, it is a natural process
Sun or solar desalination is used by nature to produce rain which is the main source of fresh water on earth. All available man-made distillation systems are duplication on a small scale of this natural process.

Some desalination facts

  • The most important users of desalinated water are in the Middle East, (mainly Saudi Arabia, Kuwait, the United Arab Emirates, Qatar and Bahrain), which uses about 70% of worldwide capacity; and in North Africa (mainly Libya and Algeria), which uses about 6% of worldwide capacity.
  • Among industrialized countries, the United States is one of the most important users of desalinated water (6.5%), especially in California and parts of Florida.

The Product Water

The desalinated product water is usually more pure than drinking water standards, so when product water is intended for municipal use, it may be mixed with water that contains higher levels of total dissolved solids. Pure desalination water is highly acidic and is thus corrosive to pipes, so it has to be mixed with other sources of water that are piped onsite or else adjusted for pH, hardness, and alkalinity before being piped offsite. In the desalination process calcium is added to the water to stabilise it, and chlorine is added to kill any bacteria.
In the future more and more people will be looking the sea as a natural resource for water and many areas and islands are now working on desalination projects.

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