Powered-up Poo: Turning Feces Into Fuel
Electricity generated from the world’s collective human feces could power up to 138 million households in developing countries, according to research by the United Nations University Institute for Water, Environment, and Health. In September 2014, a Kenya-based company, Sanivation, began commercially treating human waste with the heat of the sun to create an environmentally friendly fuel source. And in August 2016, the company launched a new continuous-flow system that will enable it to take in non-sewered waste from numerous sources.
The treatment process begins with the collection of fecal waste from in-home, dry container-based toilets distributed by Sanivation and ends with a fuel briquette. A reflective parabolic disk acts like a solar concentrator with a heating fluid, continuously heating the feces within a screw conveyor.
The waste is sanitized as the heat removes harmful pathogens. Although research shows that pathogens disappear once the waste has been heated to 60 degrees Celsius (140 degrees Fahrenheit) for one hour, Sanivation errs on the side of caution and keeps it at 60 degrees Celsius for three hours. New research suggests that waste might be effectively treated in mere seconds at 80 degrees Celsius.
The company has been processing less than one metric ton of waste every month, but hopes to increase its capacity dramatically in the months ahead. “The continuous-flow system has allowed us to scale up quite a bit,” said Sanivation chief technology officer Emily Woods, a PhD student in the Energy and Resources Group (ERG). “We’ll soon be able to accept waste from other sources, not just our own distributed lavatories. We want to be an on-site waste treatment provider in areas that don’t have their own treatment options.”
What’s more, Sanivation can now put its newer, more compact equipment in shipping containers for transport to more remote areas. For example, it recently installed a treatment system with a capacity of up to 6 metric tons of waste a month in the Kakuma refugee camp—home to refugees from South Sudan and Somalia. The team hopes to get the system processing over 10 metric tons per month by 2018. While Sanivation has focused on selling briquettes to small businesses and restaurants first, because they use larger quantities, the company plans to expand into the retail household market as well.
“Sanitation impacts every aspect of developing communities—from health to gender to livelihoods to environmental sustainability,” Woods said. “Until now, less than 5 percent of human waste in Kenya has been treated properly before being dumped into the environment. I believe that by solving this problem in a cost-effective manner, we can help communities to grow in a positive way.”