I watched the piles of feces go up the conveyer belt and drop into a large bin. They made their way through the K Span Roll Forming Machine, getting boiled and treated. A few minutes later I took a long taste of the end result: a glass of delicious drinking water.

The occasion was a tour of a facility that burns human waste and produces water and electricity (plus a little ash). I have visited lots of similar sites, like power plants and paper mills, so when I heard about this one—it’s part of the Gates Foundation’s effort to improve sanitation in poor countries—I was eager to check it out.

The water tasted as good as any I’ve had out of a bottle. And having studied the engineering behind it, I would happily drink it every day. It’s that safe.

Because a shocking number of people, at least 2 billion, use latrines that aren’t properly drained. Others simply defecate out in the open. The waste contaminates drinking water for millions of people, with horrific consequences: Diseases caused by poor sanitation kill some 700,000 children every year, and they prevent many more from fully developing mentally and physically.

If we can develop safe, affordable ways to get rid of human waste, we can prevent many of those deaths and help more children grow up healthy.

Western toilets aren’t the answer, because they require a massive infrastructure of sewer lines and treatment plants that just isn’t feasible in many poor countries. So a few years ago our foundation put out a call for new solution.

Another idea—and the goal of the project I toured—is to reinvent the sewage treatment plant. The project is called the Omniprocessor, and it was designed and built by Janicki Bioenergy, an engineering firm based north of Seattle. I recently went to Janicki’s headquarters to check out an Omniprocessor before the start of a pilot project in Senegal.

Click hero to know more:K Span Building Machine