When toilets fly

In many of the world's overcrowded urban slums, residents must choose crowded public toilets, open defecation, or expensive private pit latrines that can't be emptied safely. To offer an alternative, Kory Russel and Sebastien Tilmans, civil and environmental engineering graduate students at Stanford, co-founded an initiative called re.source. Under the guidance of Associate Professor of Civil and Environmental Engineering Jenna Davis, the Stanford team is developing portable, affordable dry household toilets and entrepreneurial service models for the developing world.

A woman moves her dry, portable toilet into her home in a slum of Cap-Haïtien, Haiti.

"Sanitation is so much more than a fancy toilet," Tilmans said.

Customers can subscribe to the toilet service for a monthly fee of $5 – less than 3 percent of average monthly expenditures for households in a re.source study in Cap-Haïtien, Haiti – and they can take their toilets with them when they move. Mobile tracking technology monitors waste collectors' performance, maximizes efficiency and minimizes service costs.

Working with the Water, Health and Development program of the Stanford Woods Institute for the Environment, where Davis has a dual appointment as the Higgins-Magid Senior Fellow, Tilmans and Russel have tested multiple toilet models with users. Their tests have included a free pilot phase with 130 households in Shada, a Cap-Haïtien slum where people commonly dispose of their feces in plastic bags known as flying toilets or hélicoptères that they throw into waterways. As a result, waterborne diseases such as cholera are a constant threat.

Of the households that used the service for the three-month pilot phase, 87 percent described themselves as "very" or "generally" satisfied, according to research led by Russel, and scheduled for publication this fall. Russel and Tilmans have used the insights from this research to advise the nongovernmental organization Sustainable Organic Integrated Livelihoods, re.source's partner in Cap-Haïtien, to expand the service to about 2,500 customers in more than 300 paying households, and to start a second service in Haiti's capital, Port-au-Prince.