The billionaire philanthropist kicked off the Reinvented Toilet Expo in China and unveiled a new toilet that does not require water or sewers, and uses chemicals to turn human waste into fertilizer, Reuters reported.

We are all here for one reason: because more than half the world’s population doesn’t have the safe sanitation they need to lead healthy and productive lives,” Gates said in a speech on Tuesday in Beijing.

Gates tweeted a video Monday that described his and his foundation’s mission to improve sanitation for countries that do not have or cannot afford to build the sewer infrastructure to remove waste.

To drive home the importance of safe sanitation, Gates brought a jar of feces with him during his keynote in Beijing.

You might guess what’s in this beaker—and you’d be right. Human feces. This small amount of feces could contain as many as 200 trillion rotavirus cells, 20 billion Shigella bacteria, and 100,000 parasitic worm eggs,” the Microsoft co-founder said.

A typical toilet needs water, but many of the new approaches don’t require any water at all, some of them don’t need electricity either, others run on solar power, he added. “All of them remove the pathogens from the waste and, most importantly, they don’t have to be connected to the sewer system.”

The next step for the project is to pitch the concept to manufacturers, Gates told Reuters. He estimated that the market for the toilets will be more than $6 billion by 2030.