Microsoft mogul Bill Gates is looking for ways to flush out contaminated drinking water across the word by throwing out the conventional porcelain throne.
The United Nations estimates that disease caused by unsafe sanitation is responsible for about half of all hospitalizations in the developing world. About 1.5 million children die from diarrhea diseases annually, and that's why Gates is hosting a "Reinvent the Toilet Fair" in Seattle this week.
All entrants to the fair were required to operate without running water, electricity, or a septic system at a cost of five U.S. cents per day.
"The current design has a real problem," Gates said. "It uses a lot of water and requires a very expensive system to bring in very clean water."
Scientists from all over are taking Gates up on his challenge, and many prototypes recycle waste into usable substances like animal feed or water for irrigation.
The California Institute of Technology created a self-contained, solar-powered toilet that has its own wastewater treatment system. The solar panel produces enough power for an electrochemical reactor that is designed to break water and human waste into hydrogen gas that can then be stored as backup energy.
Gates tweeted that the toilet was invented in 1775, but then innovation stopped -- until today.