Will recycling urine into drinking water solve the problem of water scarcity?
On May 20, three astronauts held up silver pouches to toast a new beverage available onboard the International Space Station. The containers looked like Capri Sun, but they weren't filled with juice drink. It was water recycled from their urine.The new $154-million water recycling system-which creates a day's worth of water from urine, sweat, and exhaled air-will reduce the $12 million per year NASA hemorrhages ferrying water to the ISS. It also doubles the number of permanent crew that the ISS can support, from three to six members. "I can very easily foresee water-recycling systems on Earth," says Bob Bagdigian, project manager for NASA's Environmental Control Life Support System. "I hope that what we're doing on the space station will help demonstrate and validate the approach."Urine-recycling projects were kicked off in the late-1990s-concurrently with NASA's efforts. Orange County, California, opened its $427-million Groundwater Replenishment System in late 2007 to stop the encroachment of Pacific Ocean water on its groundwater basin, which supplies potable water to 500,000 residents from the Santa Ana River, a tributary of the Colorado. To keep the Pacific at bay, the Orange County Water District started injecting super-pure water into the basin to create a "water dam" between the brine and the groundwater. The injection stream comes from the one plentiful source the district had at its disposal: wastewater. It purifies 70 million gallons of water daily from treated sewage supplied by the local sanitation department. A primary filtration method is reverse osmosis-the same method used in desalination. Several independent audits found that the district's purified water was of higher quality than the water in the groundwater basin where it's injected.If the water is so pure, why not just send it directly to the people? Aside from a handful of natural-health proponents who claim that drinking your own urine has health benefits, there are few who are comfortable with the idea-even if the water has been cleaned. "There's a deep emotional revulsion that is counterpoised by this being good for the environment and safe," says Paul Rozin, a University of Pennsylvania psychologist who studies the emotion of disgust. Detractors of recycling systems have developed terms such as "toilet to tap" to play up the "yuck factor" with direct recycling. (The only plant that actually practices toilet-to-tap recycling is in Windhoek, Namibia, the driest African country south of the Sahara.)Orange County counteracted people's attitudes with aggressive outreach, giving hundreds of presentations to community organizations and offering samples of its recycled water. "From a public-education standpoint," advises Shivaji Deshmukh of the Orange County Water Distict, "make sure you don't hide anything and you start early." Today, Singapore and cities in Australia, as well as Los Angeles and San Diego (both cities that recently caved to public dissent on recycling systems) are developing reclamation.These plans can be a key component of any plan to combat water scarcity. So it's a good thing that most people Rozin has surveyed accept it as a cost of civilization. For those whose disgust persists, Deshmukh offers this reminder: "Most of the water we use has been recycled. In Southern California, five or six states have used (and put back) water from the Colorado River before we ever get to it."