Creative energy solution in Rwanda
High school students start energy company to meet demands
The next time you're sitting on a toilet, consider that you are about to flush away a valuable source of energy.
That energy is too valuable to waste in the fast-developing African nation Rwanda. As the country's industry quickly builds up, their natural resources are being consumed more quickly than ever before. Facing a deforestation crisis and with money in short supply, it has taken students at a technical college to come up with a solution that is increasingly popular.
Students like Gilbert Twizere at ETO Gitarama Secondary School made sure they’d get a little bit of value for every flush of the school's toilets. They built a bio-gas chamber that converts their waste into a much-needed energy supply. Not only is their school reaping the benefits of cost-savings on fire wood – they’ve also started a private company to build the chambers.
The company is part of a solution to two problems: rampant deforestation in Rwanda, and a cash shortage faced by the technical school.
“Rwanda has a problem with the environment because forests are being used for firewood,” says Twizere, one of the seven employees of the chamber-building company. The school also makes a profit when they are hired to build a chamber.
The bio-gas pit consists of three different chambers. Pipes connect toilets to the main digester, the largest pit. Any excess water funnels out to the exit chamber, while the compost catches other solid waste.
From there, bacteria breaks down the waste to produce methane gas. That is then piped into the school’s kitchen for cooking. It also can run generators to provide electricity.
“The reason we’re doing this is sheer necessity,” says Mark O’Kane, the school’s Australian head master. “We don’t have enough money from school fees and what the government pays through the province to cover our operating costs.”
The gap between income and expenses is $60,000 USD a year, adds O’Kane. That is why they are looking for new income through their bio-gas chamber production company.
They have built one for Gitarama school Etaca, making a profit of Frw 1,050,000 (about $1,800 USD). They are also planning to build another one soon for the local Kabgwai Hospital. For the pit to work properly, you need a lot of people using a common washroom.
“If you have students, you have material for the gas,” O’Kane says with a smile. “Schools are ideally suited for bio-gas chambers.”
Twizere and his peers build the chambers using pick axes, shovels, and wheelbarrows to remove the dirt. The Chinese-type chamber is 7 m in diameter and 5 m deep.
“I feel I learned a great deal building that digester,” Twizere says. “I would consider doing this as a career.”
The initial cost of Frw 7 million ($14,000 USD) for a bio-gas chamber is eventually earned back through energy savings, O’Kane explains. Less firewood is used in the kitchens for cooking, and a petrol generator can run entirely on methane gas. A diesel generator saves 60 per cent on fuel.
But the system does crap out sometimes. ETO has been having problems with their chamber not working after flooding with too much water.
“To produce the gas from the human feces and cow manure, it has to be solid for the bacteria to compost it,” Twizere explains.
By using plastic toilets that don’t flush in future projects, this problem can be overcome. There will be less water and the waste will move into the chamber at a slower rate.
The school hopes to rely on their bio-gas chamber producing company into the future, O’Kane says. The company will hire the school’s recent graduates and aim to build one chamber a month.
Maybe the next time you flush your toilet, it won’t be such a waste.
