By: Cyrus Farivar
Imagine eating food that was cooked using natural gas generated from your own human waste. Thousands of prisoners in Rwanda don't have to imagine it -- they live it.
Prisoners' feces is converted into combustible "biogas," or methane gas that can be used for cooking. It has reduced by 60 percent the annual wood-fuel costs which would otherwise reach near $1 million, according to Silas Lwakabamba, rector of the Kigali Institute of Science, Technology and Management, where the technology was developed.
Last month, the Rwandan prison biogas facilities received an Ashden Award for sustainable energy. The award, which comes with a prize worth nearly $50,000, is given by the Ashden Trust, a British charity organization that promotes green technologies.
"It's turning a negative social situation in terms of the Rwandan genocide into something that can benefit local people in the local area," said Corrina Cordon, spokeswoman for the Ashden Awards.
Many of Rwanda's 120,000 prisoners are incarcerated because of the genocidal campaign. The prisons are overcrowded by a factor of 10, Lwakabamba said.
He added that prison overpopulation has created a situation where the facilities have significantly increased energy needs. The overcrowding also leads to large amounts of human waste that the prisons cannot adequately process.
Lwakabamba said that prior to the construction of biogas facilities at a prison situated atop a hill at Cyangugu in southwestern Rwanda, some human waste was being thrown down the hill, near natural bodies of water such as Lake Kivu.
"It got started when we went to these prisons and we realized that so much human waste was going into these rivers and we had to try something," he said.
The univesity rector said that the Rwandan biogas facilities, which are currently in half of the 30 prisons around the country, now contribute half of the energy needs for cooking and lighting in each location.
Rwanda's biogas facilities are among the most ambitious in the world, given their size and scope. They range up to 1,000 cubic meters in something resembling a beehive shape.
The process requires putting a given amount of human or other animal waste into a "digester," which ferments it using bacteria to release methane gas that can be captured and then burned as fuel. Attached is a "compensating chamber" that replenishes the supply of bacteria to keep the operation self-sustaining.
The lead engineer on the project, Ainea Kimaro, says that within four weeks, 100 cubic meters of waste can be transformed into 50 cubic meters of fuel.
Biogas is being used around the world, including in homes in Nepal and to power trains in Sweden.
Kimaro said that while waste smells bad initially, the biogas that is produced has no foul odor. He added that the Rwandan prisoners are not put off by the idea of using the byproduct of human waste to cook.
"Our people are very adaptive," he said. "They see it working; they want to use it."
Once the methane is produced, the remaining waste is used as an odor-free fertilizer for the gardens at the prison.
Martin Wright, an Ashden Awards judge who traveled to Rwanda and visited the prison at Cyangugu, got down on his hands and knees to take a whiff of the manure.
"I've sniffed the residue and there is no smell at all," he said.
As remarkable as the odorless fertilizer is, Wright said that he was even more impressed by the idea that the new energy project involves people being held on charges of genocide in Cyangugu, just across the border from the volatile civil war raging in the Democratic Republic of the Congo.
"(That) they've become the site for this amazing pioneering project means that you're taking something that's a consequence of human misery and producing something hopeful out of it," he said.