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.
Women, reluctant to do their business out in the open, typically take long walks to secluded places, and this puts them at daily risk for rape and sexual
assault. Girls often drop out of school as they approach adolescence because there are no separate facilities for them; according to UNICEF, 46 percent of
schools don't have separate toilets. "There's an entire generation of young women, when they reach puberty, who are forced to drop out," said Jain. "I
mean, where are they going to change their pads? It's absurd."
Despite the health and safety benefits of its product, Humanure still might face an uphill climb when it comes to getting people to adopt its new toilets.
Ajith Kumar, of the World Bank's Water and Sanitation Program, explained via email that open defecation is less a matter of poverty than one
might assume. For a long time, he said, there was no social norm in Indian society against it. In fact, Kumar notes, since the Indian government made
sanitation a priority in 1986, a focus on building toilets led to success when, in some areas, it was adapted to include strategies for behavior change.
One of the more notable efforts has been the "No Toilet, No Bride" campaign in the northern state of Haryana. (Martha Stewart's not the only one who can
set the tone for matrimonial must-haves.)