Friday, September 28, 2012

A Water Desalination Plant for San Diego

Only 1% of Earth’s water is fresh water; 97% is saltwater and the remaining 2% is frozen in glaciers. Worse yet, water is not evenly distributed around the world. Growing cities frequently have problems getting enough fresh water to supply their needs.

The city of San Diego, after years of dealing with water shortages and expensive water sources, has decided to take matters into its own hands. The city signed a deal this week to purchase all of the output of what will be the largest desalination plant in the Western hemisphere, if/when it is completed in 2016. The new plant, to be located in Carlsbad, California, is expected to produce 50 million gallons of freshwater a day

Desalination of seawater may seem like a good idea, but it has yet to catch on in a big way. For one, desalination uses a lot of electricity, and thus is still fairly expensive compared to most natural sources of water. In addition, by removing the salt from seawater and returning it to the sea, desalination plants can raise the local seawater salinity, affecting sea life if the salt is not sufficiently disbursed.

The Carlsbad desalination plant is likely to be watched with interest by officials from other coastal cities with water shortages. Either it will prove to be a one-of-a-kind project that didn’t go quite as well as planned, or it will lead the way to the development of other desalination plants for supplying water to other thirsty coastal cities.

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