University of Toronto is working on building a better toilet. It could benefit billions.
For 2.6 billion people, a better toilet would mean a better life, with fewer water-borne diseases like dysentery and cholera, which affect millions annually. To combat this problem, the Bill and Melinda Gates Foundation has divided $3 million (US) among eight institutions around the world, to be spent on rethinking the toilet for the developing world. One of the recipients was the University of Toronto.
The Gates Foundation has a few requirements for the toilet prototypes. “The challenge was to come up with a toilet that could work off the grid—no running water, no sewage, no electricity—and would process the human waste in about 24 hours,” said Professor Yu-Ling Cheng, director of the Centre for Global Engineering (CGEN), who will lead U of T’s effort. Affordability is another requirement: the toilet must cost less than five cents per person per day to operate. Cheng’s team decided to design a model that would process the waste into useful products, like clean water, ash for fertilizer, and energy.
Waterless—or “composting”—toilets already exist and can create fertilizer out of human waste, but are fairly low-tech and have a turnaround of weeks to months, whereas the Gates Foundation is seeking a model that can work in hours. Cheng’s team is aiming to use mechanical dehydration on the waste to extract fluids, then smoulder (meaning, heat without fire) the remainder for sanitation. In addition, membrane filtration and ultraviolet disinfection—common practices in biotechnology—will be used to sanitize urine.
Cheng’s team’s proposal and those of the other grant winners (read about all those proposals here: [PDF]) will be shown in Seattle next summer.
The impact of safe and affordable sanitation would be huge. According to the World Health Organization, in addition to the health benefits, there would also be up to $9 billion in productivity gains and savings from reduced healthcare costs, as well as social benefits for women and girls, whose safety would be improved by easier access to toilets.
Cheng is aware that part of the challenge in designing the toilet, even if it goes unstated, is to create with the user in mind. “We have to take into account the users—their cultural assumptions, their financial considerations, the weather,” she says. The research will involve making a better user experience—one that could have appeal beyond the intended demographic. “If we could make a toilet that didn’t require water, sewerage and power, and we add a splash of First World stylishness,” said Cheng in a press release, “who wouldn’t want to use it in Toronto?”