Around the world, many of the 783 million people who don't have clean drinking water also don't have access to electricity. A new design from an Australian high school student aims to solve both problems at once: While the device purifies wastewater, it uses pollutants in the water to boost power production in a separate compartment.
17-year-old Cynthia Sin Nga Lam, one of 15 finalists in this year's Google Science Fair, started researching renewable electricity generation last year, and quickly realized that she could incorporate water purification into her process.
Her prototype, called H2Pro, is a portable device powered only by sunlight. Dirty water goes in one end, and a titanium mesh, activated by the sun, sterilizes the water and sends it through an extra filter. The photocatalytic reaction also splits the water into hydrogen and oxygen—so someone can flip a switch and start feeding a hydrogen fuel cell to produce clean power. Detergent, soap, and other pollutants in the water help make more hydrogen.
"There are some technologies for purifying water that are similar, but you'd need an extra source of electricity," says Lam. "For this one, you only need sunlight and titania. It can generate a very efficient source of clean electricity as well." The device is also low-cost, and because of the simple construction, would be easy to maintain over time.
Though Lam built a small, portable prototype, she envisions the same technology could be used at a larger scale. On a rooftop, for example, wastewater could be sent through a titanium dioxide net and then directed through different pipes to produce power and provide purified water. The tech could also be used along with solar panels to provide even more electricity.
"I think people around the world don't really understand how serious water pollution and the energy crisis is," says Lam. "I'd really like to finalize the design, because it could potentially help people in developing countries. It would be great to have clean water and electricity supplied sustainably, without needing any outside help. It would be awesome."
The winners of the Google Science Fair will be announced on September 22.