RTI International receives additional funding from Gates Foundation to advance toilet reinvention

New funds will accelerate research, allow for faster transition from testing to prototype

RESEARCH TRIANGLE PARK, N.C. - RTI received additional funding from the Bill & Melinda Gates Foundation Reinvent the Toilet Challenge to further develop an off-grid toilet—targeted at developing nations—that converts human waste into burnable fuel, stored energy and disinfected, non-potable water through a new biomass conversion unit.

The novel waste treatment system could significantly improve public health and quality of life among people in less developed countries.

In August 2012, RTI was awarded a grant under the Bill and Melinda Gates Foundation Reinvent the Toilet Challenge. In August and September 2013, RTI received two supplemental awards.

The first award will allow RTI to accelerate development of the toilet system and move from testing the system with simulated material to testing with human waste.

The second award will allow RTI researchers to move the project from component testing to a full prototype. The prototype will include a partnership with Roca (in Spain), the largest toilet manufacturer in Europe, to develop a user interface.

The Gates Foundation launched the Reinvent the Toilet Challenge endeavor in 2011 to encourage new efforts to create a stand-alone toilet unit that does not require piped-in water, a sewer connection or outside electricity. The Reinvent the Toilet Challenge aims to spur the development of toilet units that cost no more than 5 cents per person per day and are easy to install, use and maintain.

RTI experts in engineering, international water and sanitation policy, user-centered design, and social science (e.g., economics) are collaborating with researchers from Duke University, Colorado State University, NASA’s Ames Research Center and the U.S. Naval Research Laboratory to create this prototype toilet for the developing world.

“This is the perfect project for an interdisciplinary research institute like RTI,” said Brian Stoner, Ph.D., senior fellow in materials and electronic technologies at RTI and the project’s principal investigator. “Because our team includes researchers who are experts that span disciplines from materials science to economics to international development, we are uniquely qualified to lead such grand challenges, transitioning engineering concepts from the lab to products and services for the countries and people that need them.”

The team leveraged NASA’s decades of research and experience in developing waste treatment systems for spaces with similar limitations on energy and water usage.

In the RTI-led design, the solid waste drying process uses a combination of mechanical, solar and thermal energy. A mechanical screw-like device separates out liquids and begins the process of converting solid waste into combustion fuel. Solar energy, natural drafts and heat from burning waste further aid the drying process.

As it dries, the waste is broken down into uniform-sized pellets, which are burned using the RTI-developed Thermoelectric Enhanced Cookstove Add-on device, a self-powered unit that captures a portion of heat and converts it into electricity. This electricity will run a combustion blower and be stored in a battery to power the water treatment functions.

Liquid waste—including urine and liquid that is removed from the solid waste—is disinfected through electrochemical processes using carbon-based electrodes (developed in partnership with Advanced Diamond Technologies, Inc. and Duke University). The disinfected water will be suitable for use as rinse for the toilet and other non-potable applications.  

A new waste system could significantly impact many of the world’s 2.5 billion people who are without suitable sanitation resources by reducing deaths from waste-borne illnesses, increasing clean water supplies and improving quality of life.  In India, one of the many areas where sanitation is a critical need, deaths from diarrheal disease are estimated at one child per minute.

“The ultimate goal of our system is to be fully self-contained so it could be used anywhere and to be developed in a way that maximizes performance and minimizes maintenance and cost to users,” said Brent Rowe, senior economist at RTI and the manager and commercialization lead for the project.  “Throughout this effort, this combination of purely technical and adoption-related factors has driven and will continue to drive our development process so that the system we develop will have the greatest chance at success.”

See more information on the project at www.abettertoilet.org.