Water Safety

A Berkeley student brings clean water technology back home.
By Sandra Chung

Fermin Reygadas, M.S. ’07, left Mexico to study physics at Berkeley. But his desire to work on humanity’s most basic problems led him back to his hometown of La Paz, where he now teaches ranchers to use a simple device called the UV-Tube to disinfect their drinking water.

Access to clean water is the world’s most urgent health issue. Contaminated water spreads diseases such as cholera that kill or debilitate hundreds of millions of people each year. Reygadas found that many of the La Paz ranchers’ wells contained traces of human and animal waste, probably from nearby latrines and livestock. But he knew that helping the ranchers wouldn’t be as easy as simply distributing off-the-shelf water purifiers.

Researchers have been testing low-cost water treatments in remote and impoverished areas since the 1990s. Many of the treatments performed well in studies, but people often stopped using them after the studies ended. To get the ranchers to continue purifying their water after he left, Reygadas would need to offer them treatment technology that was not only effective, but also cheap, attractive, and easy to use.

He and his colleagues adapted the UV-Tube so that it could be made cheaply with local materials. A spigot feeds water from a five-gallon plastic bucket into a metal tube the length of a child’s arm. A special lightbulb inside the tube bombards the water with ultraviolet light. Reygadas and his team mounted the device on a small table with a hand pump to dispense clean water from a connected storage jug. They called the setup mesita azul, or little blue table. The ranchers power the tables with solar panels from a rural electrification project funded by the Mexican government.

A year after the first 120 blue tables were installed, more than 100 were still in use. But Reygadas hit a snag in the early stages of the project. Although the ranchers drank UV-disinfected water in the mornings and evenings, they did not drink it when it became warm in the afternoons. When the water inside the clear plastic storage jugs warmed to bath-like temperatures, they drank the cooler but contaminated water in their traditional stone containers. Reygadas came up with a simple solution: Wrap the plastic jugs with wet cloth so that the moisture evaporates and cools the jugs throughout the day.

Reygadas plans to install more units in low-income communities in 2011. He’s currently studying how effective the UV Tubes are at reducing waterborne disease. His research has taken him to Sri Lanka and Bolivia, where he has consulted on other projects and also helped create unique water sterilization kits for local communities.

But he’s also just happy to be back in his hometown. “I came back because I love and admire the people,” Reygadas said. “They are the most friendly people that I’ve ever met.”

From the Winter 2010 Inside Out issue of California.
Filed under: Science + Health
Image source: Courtesy of Fundacion Cantaro Azul
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