There's not much room on the International Space Station, so everything must be recycled?including urine and sweat, which can end up back in the water astronauts drink. Quenching your thirst with what was once flushed down the toilet seems repulsive, but it's necessary in space?and we may be doing it here on Earth before long.
"If you go on the street and ask anyone if they'd like to drink their own wastewater, they're going to say 'no,'" says Ron Wildermuth of the Orange County, California water district, where a major water reuse plan is being considered. "But we explain to people, the quality of water ends up higher than what they already drink." Wildermuth has spent 5 years selling the idea of recycling wastewater for drinking to Orange County residents, and now they are collaborating with the county's sanitation district to build a $600 million sewage-purification system similar to the ones used in the shuttle or planned for long-term space travel.
"On the space shuttle, every pound counts and water is heavy," says NASA?s Karen Pickering. "So we're working on systems to recycle water from hand washing, showers, urine and humidity." By "humidity," Pickering means sweat and the breath people exhale. Right now, a Russian-designed system on board the International Space Station recycles about 50 percent of its water from moisture collected from dehumidifiers that extract liquid from the breath and sweat of astronauts and lab animals. Pickering is designing a system to launch in 2005 or 2006 that will recycle up to 99 percent of water on the station, including urine.
Urine, sweat and other liquid waste will collected and pumped through a water processor containing special bacteria that consume the contaminants in the water, producing carbon dioxide and solid matter as side products. The filtered water is then pressed through sheets of plastic membranes that separate the dirty water from the clean water in a process known as reverse osmosis. The same process is now commonly used in Israel to remove the salt from seawater. If done right, the water is so pure, it's tasteless.
Orange County says their water is safe, although they did get a scare when a tiny amount of a suspected carcinogen ended up in the treated water. The chemical was traced to a plastics plant upstream.
Some cities can?t face the idea of drinking recycled water. San Diego rejected plans to recycle wastewater three years ago and a water reuse project was abandoned in Castro Valley, California. But if it?s done right, recycling produces the purest water on Earth (or in Space). Maybe they should bottle it and sell it as Spacewater.
We may not know what we?re drinking, but we don?t know what we?re eating either. Find out what?s in the foods you buy from ?Eating in the Dark? by Kathleen Hart, click here.
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