2012年3月高级口译下半场阅读理解第二篇原文

More Western towns adopt \'toilet to tap\' strategy to water conservation
www.csmonitor.com

This summer, Texas\' drought of the century is an uncomfortable reminder that often there just isn\'t enough water to go around. But the 40 consecutive days of triple-digit temperatures and minuscule rainfall may also be boosting the case for a new freshwater source being developed in Big Spring, Texas, and surrounding cities.

With a waste-water-to-drinking-water treatment plant now under construction, Big Spring will soon join the growing list of cities that use recycled sewage water for drinking water – a practice that the squeamish call "toilet to tap."

The trend is expanding as climbing temperatures and dry weather across the West force environmentalists, politicians, and citizens to find newer, better solutions to freshwater resources.

Heat wave: Four things that will rise with the temperatures

"It\'s really a natural and cost-effective [solution] when you don\'t have another resource available," says David Sedlak, professor of civil and environmental engineering and codirector of the Berkeley Water Center at the University of California, Berkeley. "We have to recognize that as the population of the country continues to move out into the West and as climate change continually reduces the water supply, these issues are going to become more and more important."

The $13 million Big Spring Water Reclamation Plant, due to open early next year, will pump 2 million gallons of water each day to Big Spring and three nearby cities – Stanton, Midland, and Odessa – using the waste water produced by area residents.

"The neat thing about it is that we\'ll be able to use 100 percent of the water, 100 percent of the time," says John Grant, general manager of Colorado River Municipal Water District, which serves Big Spring.

Mr. Grant, who began looking into alternative water supplies nearly 12 years ago, says public feedback runs the gamut from "There\'s no way I\'m going to drink this" to "Why haven\'t y\'all done this sooner?"

Water reuse plants are not new, and municipalities in states from California to Florida have them.

How it works

In southern California, the largest water purification plant in the world produces 70 million gallons of water every day using recycled sewage water. The $480 million Groundwater Replenishment System (GRS) in Orange County takes already-treated waste water from the sanitation district next door and sends it through a rigorous three-step cleaning process to produce high-quality water that tastes like bottled water, says Michael Markus, general manager of the Orange County Water District.
The water first undergoes microfiltration to eradicate suspended solids, protozoa, bacteria, and some viruses. Second, it undergoes reverse osmosis – a process commonly used for improving water for drinking by forcing it through a filter. Finally, high-intensity ultraviolet light combined with hydrogen peroxide destroys any remaining organic compounds.

"We need to find ways to find more reliable sources of water, and recycling is, in our mind, the best way to do that," Mr. Markus says. "This is a source we can count on, because we can control it."

The GRS is classified as an indirect potable reuse plant, which means its purified output doesn\'t go directly into the drinking water distribution system. Instead, the water is piped to a large ground water basin, where it sits for about six months. The aquifer serves as an environmental buffer between the purification plant and the tap.

"From a public perception standpoint, if you take [the water] back to the environment, the public\'s memory of where it\'s been is taken away," says UC Berkeley\'s Mr. Sedlak.

Public\'s resistance

The biggest hurdle in water reuse is public acceptance – or the "yuck factor," say experts. "Toilet to tap" is unappealing to many people even though the water is high-quality and pure.

"That\'s a stigma that people need to get over," says Davis Ford, adjunct professor at the University of Texas at Austin and an expert in environmental and water resources engineering. "[Water reuse] is not new science. It\'s absolutely safe with the disinfection we have ... it\'s good-quality water."