In 2011, the Gates Foundation launched the "Reinvent the Toilet Challenge" — a program to design toilets that capture and process human waste without the use of piped water, sewers or electrical connections, and transform it into useful resources, such as energy and recycled water, at an affordable price.

"It’s time to move on from the era of the classic toilet. Forty percent of the world’s population still lives without proper means of flushing away excrement," Bill Gates said, at the program’s launching ceremony in the United States. "But just giving them Western-style toilets isn’t possible because of the world's limited water resources."

In August 2013, the foundation focused the challenge at China, looking for innovative sanitation solutions in poor urban areas. It has invested $5 million to support Chinese inventors and drive research, development and production of the "next-generation toilet".

In the first round, in 2014, 34 projects were considered for sponsorship. The number was whittled down to four: the vacuum toilet; a membrane-permeation process to separate waste solids and liquids; bio-electrochemical technology; and solar power. The second round of projects is currently at the planning stage.