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New Mexico State University

New Mexico State University

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Desalination could mean new water for New Mexico

Drought in New Mexico may be an ongoing problem, but attempts to find solutions to this monumental challenge are not drying up.



Karl Wood, director, Water Resources Research Institute. (NMSU photo by Darren Phillips)


For centuries, ground water has been lifted and used in New Mexico. A major problem is that three-fourths of the ground water in the state, in such places as the Tularosa Basin, Pecos Valley, Estancia Basin and Four Corners area, is brackish or salty.

Water is considered brackish or salty if it contains more than 1,000 parts per million (ppm) of dissolved solids. Much of New Mexico's brackish ground water is less than 10,000 ppm, but some ground water in the Tularosa Basin contains more than 300,000 ppm, which is 10 times saltier than ocean water.

"New Mexico's salty ground water is a big new source of water for the state," said Karl Wood, director of New Mexico State University's Water Resources Research Institute.

The cost of desalination for municipal use is comparable to treating river water. This new source will be important for cities as well as small, rural communities in New Mexico, Wood said, adding that desalination is still too expensive for most agriculture irrigation.

A principal cost associated with desalination is getting rid of concentrates that are left over after desalination. Wood said the three different methods used - deep well injection, hauling and disposing of concentrated brackish water, and evaporation ponds - are all expensive.

Deep well injection is the preferred option, but favorable deep geologic formations must be found. The second option, hauling and disposing, is feasible only near oceans. As for the third option, Wood said El Paso and Fort Bliss will desalinate nearly 30 million gallons of water a day, but in the near future, the city will need a large evaporation pond of about one square mile to evaporate water from the salt. Such a pond carries with it many environmental concerns, including the need to dispose of the dried salt.

In the summer of 2005, Congress approved money for the U.S. Bureau of Reclamation to build a national inland desalination research center near Alamogordo. Researchers from government agencies, national laboratories and private companies, including a dozen from NMSU, will work at the center.

"This research center will be unique because it will work with inland waters that have salts other than sodium chloride and this will require unique pre-treatments and membrane technologies," Wood said.

Also, NMSU will be involved with the University of Texas at El Paso and the Texas A&M Research Center in El Paso in a partnership called the Consortium for Hi-Technology Investigations in Water and Wastewater, or CHIWAWA, a water management and desalination research and education consortium. One idea CHIWAWA is working on for the disposal of concentrate involves agriculture.

"The possibilities are nearly limitless," Wood said. "Using plants that grow in concentrated water to take up chemicals will produce many plant genetic engineering opportunities."

The beneficial use of saline water in agriculture has great potential and will have widespread application, Wood said. Preliminary research is already being conducted by Bernhard Leinauer, an assistant professor of turfgrass science and management in NMSU's College of Agriculture and Home Economics. Leinauer is using salt-tolerant turfgrasses that could be used on golf courses, in parks, and for parking lots.

Summaries of a number of projects on improving desalination technology and applications can be found at the Water Resources Research Institute's Web site: wrri.nmsu.edu.