Revolutionary toilet could change the world

It hasn’t been reinvented in ages – until now.

While available to many, the flush toilet remains non-existent to a vast majority of the developing world. Jason Gerhard, associate professor in civil and environmental engineering, hopes to play a key role in bringing safe, reliable and sanitary toilets to billions around the world.

Through a $3 million project funded by the Bill & Melinda Gates Foundation, eight universities across Africa, Asia, Europe and North America are participating in the challenge to reinvent the toilet as a stand-alone unit without piped-in water, sewer connection or outside electricity – all for less than 5 cents a day.

A team at the University of Toronto, one of the selected universities, approached Gerhard thanks to his soil remediation research at Western.

“They had a lot of good ideas, but did not know how they were going to deal with the solid waste after separation of the liquids,” says Gerhard, Canada Research Chair in Geoenvironmental Restoration Engineering. “The reinvented toilet requires total disinfection within 24 hours, so biological methods would not work.”

A member of Toronto’s team saw one of Gerhard’s STAR (Self-sustaining Treatment for Active Remediation) presentations and asked if it could apply to human waste.

STAR is an innovative technology for remediation of contaminated soils Gerhard co-founded with Jose Torero from the University of Edinburgh.

The working principle involves the smoldering combustion of contaminates in soil. Smouldering is the process by which combustion takes place in the absence of flame (for example, a glowing red charcoal briquette in a traditional barbecue). It converts organic material, plus oxygen, into water, carbon dioxide and heat.

“It is self-sustaining, which means once you get it going then it generates enough energy to keep itself going until all the fuel (organic matter) is gone,” Gerhard says.

There are many organic liquids that pollute our environment, such as coal tar and oil, for which no acceptable cleanup options are available. “By smouldering the oil, we can clean up contaminated soil and polluted sites using very little energy,” he continues.

Routinely, greater than 99 per cent of contaminant mass is destroyed in the process.

But can STARs technology be transferable to this latest project?

“Theoretically, it should be possible. But it has never been proven,” Gerhard says.

The team will try to adapt the process for destroying the organic waste in the toilet, allowing the waste to be disinfected without using much energy or water.

Gerhard and Torero, also invited to join the Toronto team, will conduct the initial work at the University of Edinburgh combustion laboratory.

“It is a new application of combustion science to environmental engineering problems, and crosses this unusual boundary between fire and water,” Gerhard says.

While excited to push STAR’s capabilities, Gerhard recognizes the bigger picture.

“One of the reasons we got involved in this project is the potential impact for billions of people,” he says. “The majority of my career has been spent on cleaning up industrial pollution, which is a serious problem, but one that primarily affects first world countries.

“We are working on many different ‘fun’ challenges. But for this work, I am particularly excited to be part of a project which such important positive implications for the developing world.”