Behind one group's plan to turn human waste into electricity
"I wake up at 5:30 in the morning to go to the fields to relieve myself."
This call of (and deposit in) nature was something Anoop Jain heard about over and again while doing community health surveys in the village of Sukhpur in Bihar, India's poorest state. He found it "ridiculously alarming." Around 90 percent of the community was defecating outside--and they were taking long, sometimes dangerous walks to go do it.
Now, multiply the problem. In India, according to UNICEF/World Health Organization 2010 estimates, 626 million people, over half the population, has no access to toilets. To put that in context, that's more than twice the population of the United States, all relieving themselves outside. At the same time, there's the parallel issue that over 400 million people in India live without electricity. It's a devil of a problem with two horns.
But as the children's book teaches us, everyone poops. That crude reality, if properly contained and converted, may also prove to be a renewable resource. This is the idea behind the Humanure Power Project, an effort led by Jain, an environmental engineer turned grad student, and a group of three other Tulane University students, who are combining existing technologies to tackle both the sanitation and power crises. Applying a $30,000 award recently won in Dell's Social Innovation Challenge, Humanure will build community blocks of toilets that convert human waste into energy, charging 12-volt batteries for household use.
Here's how it works: human waste, like any other organic waste, consists of carbon and hydrogen bonds. The team is building blocks of twenty toilets (ten for men, ten for women) that all feed together into a closed, oxygen-free biogas digester. Over twenty to forty days and in that anaerobic state, bacteria break down the waste and create two byproducts: fertilizer and a high-methane bio-gas. Like other gas, the methane can be combusted and used to fuel a generator, which in turn creates electricity. This, Jain clarifies, is not a new development -- Humanure's partner Sulabh International has been building generator toilets, with established safety protocols, for years. Energy from those toilets is regularly piped into homes to power appliances like stoves. But for villagers living off the grid, there has not yet been a way to transport home the energy produced by the generators.
Humanure is solving the distribution problem by advancing the technology and using the generator to charge 12-volt batteries that will be up for rent at about $0.20 apiece. "In our system," said Jain, "one toilet will eventually create the revenue to build another one. We have essentially used the batteries as a vehicle to provide more toilets."
All told, powering the batteries is a fairly efficient conversion. In a serious twist on the old joke, one might ask exactly how much waste it takes to light a light bulb. Jain's answer: one human produces enough waste each day to power a 60-watt light bulb for six hours.
The heart of the project though, is improving public health. Poverty has many measures, but not having a pot to -- well, you know the adage -- can have devastating consequences. There are obvious health implications like contaminated food and water, the rapid spread of communicable disease. Katherine Theall, epidemiology professor at Tulane and Jain's adviser, sees reduced risk of diarrheal disease as one of the immediate health effects of better toilet access. Theall also points to factors that are harder to measure -- dignity, self-esteem, and mental health -- as well as increased safety for women.