Employees in the News. Emergency Management. Survey Manual. Humans cannot drink saline water, but, saline water can be made into freshwater, for which there are many uses. The process is called "desalination", and it is being used more and more around the world to provide people with needed freshwater. A floating solar still is used to desalinate small amounts of seawater, using evaporation and condensation. Credit: Landfall Navigation. No, don't take us literally! Humans cannot drink saline water.
But, saline water can be made into freshwater , which is the purpose of this portable, inflatable solar still it even wraps up into a tiny package.
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 freshwater for drinking purposes. But, freshwater can be in short supply in many parts of the Nation and world. And, as the population continues to grow, shortages of freshwater 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. The "simple" hurdle that must be overcome to turn seawater into freshwater is to remove the dissolved salt in seawater. That may seem as easy as just boiling some seawater in a pan, capturing the steam and condensing it back into water distillation.
Other methods are available but these current technological processes must be done on a large scale to be useful to large populations, and the current processes are expensive, energy-intensive, and involve large-scale facilities. What do we mean by "saline water? 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, ppm of dissolved salts, then one percent of the weight of the water comes from dissolved salts.
The scarcity of freshwater resources and the need for additional water supplies is already critical in many arid regions of the world and will be increasingly important in the future. Many arid areas simply do not have freshwater resources in the form of surface water such as rivers and lakes. They may have only limited underground water resources , some that are becoming more brackish as extraction of water from the aquifers continues. Solar desalination evaporation is used by nature to produce rain , which is the main source of freshwater on earth.
Another way saline water is desalinized is by the "reverse osmosis" procedure. In most simplistic terms, water, containing dissolved salt molecules, is forced through a semipermiable membrane essentially a filter , in which the larger salt molecules do not get through the membrane holes but the smaller water molecules do. Reverse osmosis is an effective means to desalinate saline water, but it is more expensive than other methods. As prices come down in the future the use of reverse osmosis plants to desalinate large amounts of saline water should become more common.
Distillation desalination is one of mankind's earliest forms of water treatment, and it is still a popular treatment solution throughout the world today. 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.
Distillation is perhaps the one water treatment technology that most completely reduces the widest range of drinking water contaminants. In nature, this basic process is responsible for the water hydrologic cycle. The sun supplies energy that causes water to evaporate from surface sources such as lakes, oceans, and streams.
Filtering the salt from seawater can take a lot of energy or specialised engineering. A thin membrane made of porous wood may be able to fix that. In membrane distillation , salty water is pumped through a film, usually made of some sort of polymer with very narrow pores that filter out the salt and allow only water molecules through.
Jason Ren at Princeton University in New Jersey and his colleagues developed a new kind of membrane made of natural wood instead of plastic. One side of the membrane is heated so that when water flows over that side it is vapourised.
My Cart. We are America's leading supplier of high quality drinking water systems and information source. Water and Health. Water Quality. Water Can Heal.
Contaminants Facts. Air and Health. Water Filtration or Purification — Key Differences Why do we need to remove chlorine from our whole house? Top 5 Hard Water Problems for Homeowners.
See Also. More related topics:.
0コメント