PORT-AU-PRINCE, Haiti — Port-au-Prince is a city with problems. The devastating January 2010 earthquake caused many of them.
But while houses wait to be rebuilt and people rehoused, the city might be closer to solving another problem: finding viable sources of clean, renewable energy.
The problem here is that city residents use charcoal to cook, heat, and fuel their lives.
So an NGO named Viva Rio is today using something which is in endless supply to create a sustainable alternative: biodigesters that convert human excrement into methane gas — a natural, anaerobic process which takes around four months.
It's not a new idea.
Biodigesters have been used widely across Asia, Africa, and Latin America, with cow dung commonly used to make the clean-burning gas, which is used for cooking or to power generators.
But it turns out that humans provide the best raw material for this green contraption.
“Human waste is very rich in fibers. The quality is actually better than cow dung,” says Mattia Vianello, Viva Rio’s environmental project manager. "The problem is we do not make enough of it — just 300 grams [10.5 ounces] per day per person,” says Vianello.
But in a crowded city such as Port-au-Prince, there are enough people contributing their 300 grams to keep 50 biodigesters going, with more planned for the future.
This use of human rather than animal waste makes Viva Rio’s biodigester toilets a little different than most. They also have other advantages. “In Haiti, in Port-au-Prince especially, there is not a general, structured system of sanitation,” Vianello explains.
Biodigester toilets require little maintenance and over time the waste in them simply turns to compost — it goes away.
Moreover, the anaerobic process produces water as well as gas, which is nutritious and clean enough to grow lush gardens and raise fish for human consumption, which in turn — thanks to the call of nature — can be digested, and once again, converted into more human fuel.