Reinventing the Toilet with Bill Gates

Last week the Bill and Melinda Gates Foundation announced the winners of its Reinvent the Toilet Challenge with the top prize going to a solar powered model built by the California Institute of Technology.

The California Institute of Technology team won a $400,000 grant last year that enabled them to produce a toilet which can run without water and does not generate any pollutants – for only about 5¢ per day per user. As the winner of the Reinvent the Toilet challenge, the Caltech team won another $100,000 to perfect the device.

Caltech’s toilet is like any other toilet at the surface. The magic happens after the flush, rather than going into a septic tank or sewer, the water and waste is collected in an electrochemical reactor. The reactor, powered by solar panels, breaks down the waste into hydrogen gas, water, and solids. From here, the gas can be used to generate electricity, the water can be reused, and the solids, being inert, organic material, can be used as fertilizer.

Second place in the challenge was won by Britain’s Loughborough University for a toilet that produces biological charcoal, minerals, and clean water, earning them $60,000. The University of Toronto secured third place, earning $40,000, with a toilet that cleans waste, returning nutrients and clean water.

The goal of the challenge was to produce a low-cost toilet than can capture and process human waste without running water, sewer or septic access, electric connections, or sewage treatment systems. Being free of all these amenities allows the technology to be applied to developing areas of the world where it is needed most.

"Worldwide, there are 2.5 billion people without access to safe sanitation – including one billion people who still defecate out in the open and more than one billion others who must use pit latrines." – Bill Gates

Gates said he hopes that some of the new technologies will be commercialized within the next 2-4 years.