To date, only a limited number of desalination plants have been built along the California coast, primarily because the cost of desalination is generally higher than the costs of other water supply alternatives available in California e.
However, as drought conditions occur and concern over water availability increases, desalination projects are being proposed at numerous locations in the state. Desalination costs are decreasing as technology improves and more plants are built. Today there are more than 15, desalination plants in countries. About half of the world's desalted water is produced with heat to distill fresh water from seawater.
The distillation process mimics the natural water cycle in that salt water is heated, producing water vapor that is in turn condensed to form fresh water. One such treatment process is called Multi-Stage Flash Distillation. Another desalination treatment process with the most expanded use is membrane-based reverse osmosis.
Last update: 20 August Record number: Veuillez activer JavaScript. Por favor, active JavaScript. Bitte aktivieren Sie JavaScript. Si prega di abilitare JavaScript. Fundamental Research. This process can be imitated artificially and more rapidly than in nature, using alternative sources of heating and cooling. Remember looking at the picture at the top of this page of a floating solar still?
The same process that drives that device can also be applied if you find yourself in the desert in need of a drink of water. The low-tech approach to accomplish this is to construct a "solar still" which uses heat from the sun to run a distillation process to cause dew to form on something like plastic sheeting.
The diagram to the right illustrates this. Using seawater or plant material in the body of the distiller creates humid air, which, because of the enclosure created by the plastic sheet, is warmed by the sun. The humid air condenses water droplets on the underside of the plastic sheet, and because of surface tension , the water drops stick to the sheet and move downward into a trough, from which it can be consumed. Water is everywhere, which is fortunate for all of humanity, as water is essential for life.
Even though water is not always available in the needed quantity and quality for all people everywhere, people have learned to get and use water for all of their water needs, from drinking, cleaning, irrigating crops, producing electricity, and for just having fun. Surface tension in water might be good at performing tricks, such as being able to float a paper clip on its surface, but surface tension performs many more duties that are vitally important to the environment and people.
Find out all about surface tension and water here. Do you wear contact lenses? If so, you most likely use a saline water solution to clean them. But what else do we use saline water for and do we really use that much?
Read on to learn all about the use of saline water. In your everyday life you are not involved much with saline water. You are concerned with freshwater to serve your life's every need.
But, most of Earth's water, and almost all of the water that people can access, is saline, or salty water. This paper uses chemical and physical data from a large U. Geological Surveygroundwater dataset with wells in the U.
The leading process for desalination in terms of installed capacity and yearly growth is reverse osmosis RO Fritzmann and others, The RO membrane processes use semipermeable membranes and applied pressure on the membrane feed side to preferentially induce water permeation through the membrane while rejecting salts. Reverse osmosis plant membrane systems. People all over the world use low-tech techniques to obtain the valuable resource salt.
Really, take some ocean water, put in it a pan, hopefully in the sun, and wait for the water to evaporate.
Skip to main content. Reducing these impacts is possible, but it adds to the costs. Despite the economic and environmental hurdles, desalination is becoming increasingly attractive as we run out of water from other sources. We are overpumping groundwater, we have already built more dams than we can afford economically and environmentally, and we have tapped nearly all of the accessible rivers.
Far more must be done to use our existing water more efficiently, but with the world's population escalating and the water supply dwindling, the economic tide may soon turn in favor of desalination.
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