Reinventing the Toilet

Some might call it the most important chair in the house but for 2.5 billion people around the world, access to safe and sanitary toilets isn’t an option. Researchers at RTI International are reinventing a toilet that is self-sustaining and doesn’t require plumbing or a regular water source, which will benefit the developing world.

RESEARCH TRIANGLE PARK — It’s time to talk toilet, because there are plenty of clever and colorful words for what we all do in the bathroom.

Number one and number two. Pit stop. Doing a download.

It’s easy to joke about our visits to the restroom, the water closet, the loo or what some people call the most important seat in the house, because in industrialized countries like the United States people take bathrooms for granted. Clean water, sewage facilities, and sanitation are in good supply. But in developing countries — such as India — sanitation, clean water and sewage facilities are in short supply, which is a real health problem.

People, especially children, die from diarrhea, a symptom of fecal-borne illnesses spread by contaminated water. One and a half million children died last year from such illnesses.

“There are two and a half billion people around the world who have no access to safe and effective sanitation," says Brian Stoner, an investigator with RTI International. “So something we take for granted is not available to about 38% of the world’s population.”

For years, scientists have focused on improving access to clean water and the water supply as the way to prevent diarrhea illnesses. And while it is one aspect of solving the crisis, researchers say there’s another issue. 

So, in a garage at RTI International in Research Triangle Park, Stoner and a team of engineers say toilet talk to them means building a better toilet to be used in places with no sanitation. “The words feces and urine just sound too technical and they get boring to say after a while,” says Stoner. “We use the word ‘interact’ to describe what happens in the bathroom, even though our project involves more than just the part of the toilet you interact with.” 

Stoner’s team is developing a toilet that is a self-contained waste treatment system. The goal is to treat all of the waste on site — liquids and solids — so that whatever is discharged from the system is safe for use or reuse. The reimagined toilet centers on a biological and chemical fact about the tinkle and doo-doo that come out of us. Just like in the natural world, the fact is the dirty stuff can be converted to clean stuff. One organism’s waste is another’s nutrient.
The design begins with the traditional European style footpad for a toilet, not the more western style commode. Solid and liquid waste is separated, and the solid waste is pushed into a large drum where it is dried and turned into fuel pellets. The fuel pellets don’t smell. And it’s the burning of these waste pellets that fuels everything else in the system.

The fuel is burned and used to dry incoming waste. It is also converted to electricity. That electricity is then used to convert liquid waste to salts and chlorine, which disinfects the liquid waste and converts it to non-potable water, which is used to flush the toilet.

The system uses about one and a half liters of water. Modern low-flow toilets use five or more liters.

As with the human body, what goes in must come out. And there is no waste in this safe, self-cleaning, self-contained sanitation machine.

“We keep numbers on every bit of material that goes into that system,” says Mike Snow, a lab technician. “We know the weights and measurements and everything is processed and used.”

The system is designed to serve a small village, which is about 12-15 families. A prototype is being tested in India.

“There are plenty of technical issues in designing something like this, but there are a lot of social issues as well,” explains Myles Elledge, RTI International Senior Director. “One of the things we need to find out is whether or not people are comfortable using a shared toilet. We also want to know if the concept of recycling water, the urine we collect and clean, is culturally acceptable, and whether people are comfortable with the burning of human waste.”

So far, researchers find that people are accepting the self-contained toilet and are excited about how it can improve their lives. The designers of the high-tech toilet are pleased their invention has the potential to make a significant and life-saving difference in the lives of millions of people.

“I like to say clean water is sexy,” says Tate Rogers, a research associate on the project. “People like to see a little child drinking clean water on TV because it hits home. But people don’t like to see a little kid defecating in the open. However, that’s the biggest issue facing the developing world right now and we can make a difference in that.”

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