Flush toilets get the job done. They also require a network of piped water, sewer and electrical connections, the kind of vast infrastructure developing nations don't have, and likely won't, for years.
That translates into a potentially lethal situation for the 2.5 billion people in the world who don't have access to modern sanitation. Last year, the Bill and Melinda Gates Foundation launched the Reinvent the Toilet Challenge, a competition aimed at developing a new generation of Johns, crappers and loos that can capture and process human waste and turn it into useful resources, such as energy and water.
The end goal is to improve sanitation in a world where 1.5 million children die every year due to diarrhea caused by food and water tainted with fecal matter.
The competitors could design just about whatever kind of toilet they wanted. The toilets just had to be affordable and able to operate without traditional modern infrastructure such as piped water, sewer or electrical connections. The Gates Foundation brought in 50 gallons of fake feces made from soybeans and rice for the demonstrations, which were held this week in Seattle.
And the winners are ...
The California Institute of Technology earned the $100,000 first prize for designing a solar-powered toilet (pictured below) that generates hydrogen and electricity.
The toilet uses a solar panel to power an electrochemical reactor. The reactor breaks down water and human waste into fertilizer to be used for agriculture, and hydrogen, which can be stored in hydrogen fuel cells as energy. The treated water can be reused to flush the toilet or for irrigation.
Loughborough University in the UK won the $60,000 second prize for a toilet that produces biological charcoal, minerals and clean water. The University of Toronto won the third-place prize of $40,000 for a toilet the sanitizes feces and urine and recovers resources and clean water.
The toilet challenge isn't over. The Gates Foundation has awarded grants to four universities to develop the 2.0 toilets for the next round of the challenge.
Cranfield University received an $810,00 grant to develop a prototype toulet that removes water from human waste and vaporize it using a hand-operated vacuum pump and membrane system. The remaining solids are turned into fuel that also can be used as fertilizer. The water vapor is condensed and can be used for washing or irrigation.
Eram Scientific Solutions Private Limited received $450,000 grant to make public toilets more accessible to the urban poor via the eco-friendly and hygienic "eToilet." RTI International received a $1.3 million grant to fund the development of a self-contained toulet system disinfects liquid waste and turns solid waste into fuel or electricity through a biomass energy conversion unit. And the University of Colorado boulder received nearly $780,000 to help develop a solar toilet that uses concentrated sunlight, direct and focused with a solar dish and concentrator, to disinfect liquid-solid waste and produce biological charcoal that be used as a replacement for wood charcoal or chemical fertilizers.
Photos: The Bill and Melinda Gates Foundation