Billionaire activist Bill Gates recently put his advocacy work where his mouth is when he drank a cup of water that was once human poop.

"The water tasted as good as any I’ve had out of a bottle," Gates wrote in a blog post on his eponymous site. "And having studied the engineering behind it, I would happily drink it every day. It’s that safe."

The Microsoft co-founder has long been committed to bringing clean water to the millions of people who lack it and this latest innovation could be key in solving the issue.

According to the World Health Organization, 1.8 billion people use a source of drinking-water that is contaminated with fecal matter.

An estimated 1 billion people still defecate in the open, an issue that leads to water contamination and other debilitating issues, including diarrheal disease -- which is the second leading cause of death of children under 5.

Areas with latrines but no modern sewage systems are also at high risk. There, truckers dump human waste in the nearest river, ocean or at a treatment facility that doesn’t treat the sewage, Gates wrote.

The contaminated feces then ends up in the water supply.

Because it's complicated and expensive to introduce Western toilets to these developing countries, Gates is putting his faith in innovative projects like the Omniprocessor, which converts poop into drinking water.

Designed and built by Janicki Bioenergy, a Seattle engineering firm, the machine burns human waste to produce electricity and water.

The processor powers itself through the use of a steam engine and because it runs at such a high temperature, the H2O doesn’t emit an odor.

Janicki is already working on improving the model that wowed Gates.

The next-generation processor is anticipated to handle waste from 100,000 people, produce up to 86,000 liters of drinkable water a day and a net 250 kw of electricity.

The company plans on piloting the Omnipressor in Dakar, Senegal, later this year. And Gates is confident that it has the potential to be a game-changer.

"The processor wouldn’t just keep human waste out of the drinking water; it would turn waste into a commodity with real value in the marketplace," Gates wrote. "It’s the ultimate example of that old expression: one man’s trash is another man’s treasure."

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