Saturday, October 18, 2008

Las Vegas Blooms in the Desert

Las Vegas is the most arid city in the United States, with less than 4 inches of precipitation per year. Yet it has has bloomed, swelling from a population of just 1,205 people in 1905 to 1.4 million by 2000. There are 5,000 new residents and 1,200 new homes a month. Groundwater alone could not supply the ever-increasing population.

In 1974, Las Vegas began pumping water from the Colorado River for the first time to supply its growing need. By 1985, a return flow credit system had been established, whereby for every liter of purified wastewater Las Vegas returned to the Colorado River, it could withdraw another liter of potable water. Las Vegas lies north of Hoover Dam and Lake Mead, and also several major cities. This makes the quality of Las Vegas’ treated water particularly important. Fortunately, the Southern Nevada Water Authority has gone to great lengths to ensure the water’s quality, and Las Vegas’ water treatment is in the 99th percentile nationwide.

Shane Snyder, who came to speak at Duke, is Research & Development Project Manager for the Southern Nevada Water Authority in Las Vegas. He has spent most of his career investigating pharmaceuticals and endocrine disruptors in water, even testifying before a Senate subcommittee about the risk of pharmaceuticals in water. Water contamination with these compounds is a major issue because many water purification systems are incapable of removing them. This is a major obstacle for water recycling efforts, because hormones and pharmaceuticals can have very adverse effects on humans and wildlife that ingest them.

However, Snyder has led the effort to remove hormones and pharmaceuticals from water, pioneering technologies for effectively removing these contaminants. During the lecture, Snyder discussed the effectiveness of treating water with UV radiation, chlorine, and ozone, among others. He noted that many pharmaceuticals and endocrine disruptors don't disappear with treatment, but transform into other products.

Snyder also recognized that water treatment can require a vast amount of energy. In fact, according to Snyder, 19% of California's energy grid is used to treat water.

“I believe that the future lies in making water treatment efficient and making sure that the public is confident that the water will not be harmful to them or their offspring,” Snyder said.

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