Costly Desalinated Water Looms In Our Future

By James Donahue

The problem of providing enough potable drinking water to supply the needs of an overpopulated and polluted world has been an unspoken world crisis for some time. Wars both large and small are raging in many parts of the world over water rights. A changing climate brought on by global warming is bringing drought in populated areas that are intensifying this dilemma and bringing it to public awareness.

There is a solution. There is a process of separating salt from seawater called desalination that makes it drinkable, but it is costly and subsequently has been slow to catch on. World navies, especially submarines and other ships that remain at sea for months at a time, have used desalination for years. As the water crisis grows, however, the existence of large desalination plants has grown more and more common, especially in other parts of the world. A plant capable of desalinizing 25 million gallons of water a day opened in Tampa, Florida, in December, 2007, and a plant twice that size is now under construction in Southern California, and the State of Texas currently has over 100 smaller plants up and running.

The world’s largest desalination plant, capable of producing 300 million cubic meters of fresh water per year, is now operating in the United Arab Emirates, and another super sized new desalination plant is planned for Southern Australia to ease the crisis caused by a serious drought in that part of the world. There are about 1,500 such plants now operating in the world and the number is growing.

The down-side of this story is that in addition to generating more costly water for consumers, the process of desalination also produces greenhouse gasses. The process utilizes distillation of the water through heating, which separates the water from salt and other elements. The same technique can be used on brackish and polluted groundwaters inland, thus providing drinkable water in areas where potable water is not available in ground aquifers.

The good news is that new technology is being developed that is already making the process of desalination less costly to operate, and reducing the amount of greenhouse gasses produced. Solar heating systems may be just around the corner.