Cleaner water in three easy steps

A team of Dartmouth undergrads have successfully scaled down the filtering process used in water treatment plants to fit into three five-gallon buckets. Phil Wagner. Lindsay Holiday, and Dana Leland, all engineering students at Dartmouth College, recently won the 2009 Collegiate Inventors Competition for their simple solution to removing arsenic from the drinking water in Bangladesh, Nepal, and other South Asian countries.Every year tens of thousands of people become ill when arsenic in rock seeps into drinking water supplies. In Nepal, the groundwater typically contains up to 200 parts per billion (ppb) of arsenic, far above the safety standard of 10 ppb recommended by the World Health Organization (WHO). To counter this natural occurrence, the students developed a system of electrocoagulation that can easily be made out of local materials.

The process begins by sending a simple electric current through two steel plates in a bucket of water, causing iron oxyhydroxide precipitates to release and bond with the arsenic in the water. The water is then poured through a second bucket of clean sand with a hole in the bottom. The sand collects the iron-arsenic particles, leaving arsenic-free water in a third bucket. Although simple in design, the device functioned exceptionally well in testing. The team reported that their device filtered water contaminated with 200ppb arsenic to less than 1ppb arsenic, well under the 10ppb safety mark for drinking water.

Although originally completed for a capstone design course at Dartmouth, the project went on to win the undergraduate category of the 2009 Collegiate Inventors Competition. Sponsored by the National Inventors Hall of Fame Foundation, the competition rewards students who use their ingenuity to create solutions to global problems. For the students, the real reward is the knowledge that they are working towards bettering the lives of numerous people around the world. In a press release, Wagner said, “Engineering balances both a science aspect and a human aspect, which makes it endlessly interesting.”

As a judge, The United States Patent and Trademark Office (USPTO) Director David Kappos regards the competition as a starting point for future technology. In a press release, Kappos said “maintaining America’s technological edge is vitally important in today’s world economy. The highly talented and creative collegiate inventors who participated this year renew my confidence that this nation’s innovative tradition will continue to endure.”