In many of the world’s overcrowded urban slums, residents must choose between open defecation, crowded public toilets or expensive private pit latrines that can't be emptied safely. A Stanford team working on a sustainable solution recently won a $15,000 grant from the U.S. Environmental Protection Agency (EPA) and the opportunity to compete for up to $75,000.

The Stanford team is developing portable, affordable dry household toilets for the developing world, and testing the prototypes in Cap-Haitien, Haiti. Civil and Environmental Engineering Ph.D. students Sebastien Tilmans and Kory Russel co-founded the initiative, called re.source. They are advised by Jenna Davis, an associate professor of Civil and Environmental Engineering and Higgins-Magid Senior Fellow at the Stanford Woods Institute. The project received seed funding from Woods’s Mel Lane Student Grants Program in 2013.

The EPA awarded the grant as part of the first phase of its annual People, Prosperity and the Planet Student Design Competition for Sustainability (P3), which is focused on developing “sustainable, alternative methods that address environmental challenges.” The Stanford team was among 42 across the country competing for the EPA grants.

"These students are coming up with cutting-edge solutions for the most challenging environmental issues facing California, and the world," Jared Blumenfeld, EPA's Regional Administrator for the Pacific Southwest, said in a news release. "Each year, the projects created by student teams surpass our expectations."

The re.source toilets separate solid and liquid waste into sealable containers that are regularly removed by a service, which recovers resources such as compost from the waste. Customers can subscribe to the toilet service instead of buying a toilet at a prohibitive up-front price, and they can take their toilet with them when they move. Mobile tracking technology monitors waste collectors' performance, maximizes efficiency and minimizes service costs.

“Container-based sanitation systems have the potential to reach the urban poor with convenient, hygienic services that include treatment and reuse of collected wastes,” Davis said. “This award helps us take a promising concept and keep refining it into a solution that could scale to millions of users,” Tilmans added.

Working with the Water, Health and Development program at Woods, Tilmans and Russel have tested several toilet models with users before deploying toilets to more than 130 households in the Shada slum. They worked in collaboration with the nongovernmental organization SOIL, which has expanded the service to about 2,500 customers, and started a second service in Port-au-Prince. The initiative’s latest design improvement adds a standardized dose of dry cover material after each use to more closely mimic the action of a water-flush toilet.

In April 2015, the Stanford team will bring its design to Washington to participate in EPA’s National Sustainable Design Expo, where they will compete for an additional grant of $75,000 to further develop their designs and prepare them for the marketplace.