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In places where fresh water is hard to come by, how do you come up with clean drinking water? Easy — get the water from poop.

It's a scientifically sound idea, and Bill Gates has a video to prove it. In the video, released this week, he stands in front of the Janicki Omniprocessor, a giant new machine that can turn human waste into clean drinking water in minutes. He waits patiently as Peter Janicki — the engineer who invented the contraption — fills his glass with crystal-clear water from the machine.

Without the slightest hesitation, Gates takes a sip. "The water tasted as good as any I've had out of a bottle," he wrote on his blog. "And having studied the engineering behind it, I would happily drink it every day. It's that safe."

The Omniprocessor is one of the latest projects funded by the Gates Foundation (which also supports NPR), and the philanthropist wants the rest of the world to back it up as well. The machine's purpose is to help the 783 million people living without clean water and the nearly 2.5 billion who don't have adequate sanitation.

"You go into a community and you open the tap. What comes from this is even worse than [the water] you get from the roof when it's raining," says Doulaye Kone, senior program officer at the foundation.

Here's how the Omniprocessor works. Sewer sludge feeds into the machine and is boiled inside a large tube. That separates water vapor from the solid waste, and then the two part ways. Water vapor travels up and through a cleaning system that uses a cyclone and several filters to remove harmful particles. A little condensation takes place and voila — out comes clean drinking water!

One machine is designed to continually provide water for up to 100,000 people, says Kone.

What about all that dried solid waste left behind? That's cooked and turned into steam, which powers the Omniprocessor. Any leftover electricity is funneled into the community.

The first machine outside of U.S. will be tested in Dakar, Senegal later this year, Kone says. The hope is that local entrepreneurs will run the processors, collecting sludge to produce the water and energy.

The thought of drinking water derived from poop might make some cringe, but here's the thing: The idea isn't new. Treatment facilities in the U.S. and in Singapore, for example, have long turned sewage into clean water that's technically safe for human consumption.

Take Orange County, Calif., says Dr. Dick Luthy, an environmental engineer at Stanford University and director of the National Science Foundation's Center on Re-Inventing the Nation's Urban Water Infrastructure. "You have additional treatment steps here in California — microfiltration, reverse osmosis and ultra-violet light disinfection," he says. "When you go through all that, the water is essentially safe to drink."

It's just that most of the recycled water doesn't go directly into our water supply. Rather, it goes right back into the ground. "What it does in the ground is that it sort of loses its identity," Luthy says. "It stays in the ground and mixes with ground water for a few months — maybe six — before it's pumped out."

Luthy says the Omniprocessor is a good start for what needs to be done in the future as fresh water and energy becomes scarce. The U.N. predicts that by 2030, almost half the world 's population will face water scarcity.

And consider this: "People die in hospitals [in lower-income countries] simply because there's no water running into the tap," Kone say. "Can this be an opportunity to supply the hospitals with clean water for basic [services] or for school where kids don't have any water to drink during the day?"

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