Forget Everything You Know About Toilets—These 4 Designs Flush Without Water

When's the last time you used a chamber pot? If you’ve spent most of your time in the industrialized world, we're guessing the answer is “never.” But for thousands of years, squatting over one was the only toilet game in town, and our ancestors couldn’t think of another sanitation solution. Similarly, most of us probably assume that our modern S-shaped-pipe porcelain thrones are what the toilets of the future will look like too.

Except, toilets as we know them aren’t sustainable: Access to water, sewage systems, and electricity is often limited across the globe. That means every day 2.5 billion people are without a safe and affordable hygienic sanitation option. To rethink the toilets of tomorrow, the Bill & Melinda Gates Foundation launched the Reinvent the Toilet Challenge in 2011.

The goals of the challenge include separating people from their feces and the pathogens in them. Poop jokes are funny; getting poop on yourself? Not so much. The pathogens in it carry the viruses that cause hepatitis. The kinds of scary bacteria you learned about back in biology class also swarm through human waste: fecal coliform, amoebas, and multi-celled parasites—such as hookworm—all cause forms of potentially deadly dysentery.

The Reinvent the Toilet Fair also looks at sanitation solutions that are off the grid—designs that don't connect with established municipal sewer systems or use imported water or energy.

The second annual fair just wrapped up in New Delhi. Our colleagues at TakePart Live were there producing a special hour-long episode set to air April 10 on sister network Pivot. But today, we're giving you a sneak preview of four of the coolest designs on display at the fair. Keep this in mind: They're simply demonstrations of potential solutions to a problem that requires multiple fixes. So put aside everything you think you know about toilets, and behold the latrines of tomorrow.

The University of Colorado’s Sol-Char System

In the future, fuel for your grill might come from the University of Colorado's Sol-Char toilet. The system, which is built to last for 20 years, is essentially a ginormous solar-powered oven that incinerates fecal matter. It turns it into a pathogen-free charcoal that the designers have dubbed "biochar." (Just think: Everyone will wonder why your barbecue is so tasty.)

Beijing SunnyBreeze Technology Inc.

This waterless toilet, which will last for 10 years, has more bounce to the ounce. It uses Super Balls—yes, the kids' toys—to mash your poop. After you flush, the balls come tumbling into the toilet from an overhead storage unit, then move along a cylinder with a giant corkscrew inside, taking the fecal matter along for a smashing ride. Meanwhile, a solar-powered heater dries out the poop and turns it into fertilizer.

National University of Singapore

Flushing the National University of Singapore's toilet is as simple as pushing a turnstile. The energy generated when a person exits this public toilet's turnstile door moves a conveyor belt that simultaneously flattens excrement and exposes it to solar-powered heat. The result is a diluted fertilizer that can be sold to farmers. The system can last 12 years and has an operating cost of $0.01 per user per day.

California Institute of Technology

Caltech's all-in-one toilet, bidet, and sink is so gorgeous—it's designed by Kohler— that you might find yourself wanting to hang out in it. Beyond being lovely to look at, it runs on a high-tech electrochemical reactor that breaks down poop into fertilizer and hydrogen. This can then be turned into fuel cells. The operating cost is about 1 cent per user per day.

Global health and development coverage on TakePart is supported in part by the Bill & Melinda Gates Foundation.