Bill Gates appeared on the "The Tonight Show Starring Jimmy Fallon" to talk about the Omniprocessor, his latest philanthropic effort to improve sanitation in low-income countries.
Gates said the system inexpensively transforms sewer sludge into clean drinking water and electricity. He said diseases caused by poor sanitation kill some 700,000 children every year.
"I watched the piles of feces go up the conveyer belt and drop into a large bin. They made their way through the machine, getting boiled and treated," Gates said, in a blog post earlier this month. "A few minutes later I took a long taste of the end result: A glass of delicious drinking water."
While on the "Tonight Show," Gates challenged Fallon to what he calls "the ultimate taste test," in an effort to see if he could taste the difference between so called poop water and bottled water.
Watch how Fallon reacts to the challenge... if you can stomach it.