This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Mambo from Tanzania! We’ve been living and working in northern Tanzania for a little over a month now, building a kiln, getting quite muddy, experimenting with traditional Tanzanian cooking, and filling ourselves with Swahili. As I’ve learned, we know just enough Swahili to be dangerous. I successfully navigate the requisite greetings of a conversation and the man I’m speaking to is so surprised and happy that a mzungo can converse in Swahili that he continues in a rather one sided conversation for a bit while I bumble along behind him, understanding bits and pieces and mumbling any words that come to mind. Fortunately our neighbors and acquaintances are thrilled to teach us Swahili and laugh good naturedly at our mistakes.
The four of us are a part of the Bioenergy project of Dartmouth Humanitarian Engineering (DHE), living in Tanzania for the summer to continue our work with promoting sustainable and cheap cooking fuel. After a year of working with briquettes, pyrolysis, and all things fuel back on campus, we are putting our knowledge to work in Arusha, Tanzania. We hope to build capacity of local Tanzanians to produce their own cooking fuel. Specifically, we are working on small scale charcoal production and briquetting—creating small fuel bricks out of waste biomass carbonized into charcoal—through our work with several NGOs and local communities.
We arrived in Dar es Salaam on June 17th for a week of Swahili classes before heading on to Arusha in northern Tanzania. During our very first cab ride in Dar from the airport to our hotel, we spotted many shops selling cooking fuel and bikes piled high with bags of charcoal. Our driver, Mbaraka, told us that the forests are disappearing, and though more people are beginning to use gas to cook in Dar, charcoal and firewood remain entrenched in the markets and the kitchens across Tanzania. We spend the week in a hostel in an apparently sketchy part of the city. A friend from the city warned us that we needed to be careful as people in the area “have lots of tricks.” Note taken, though we had no troubles during our stay.
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The biggest danger we faced was the traffic. The narrow streets, the unaware pedestrians, the massive bumps and lumps in the road. Any object, be it a person, a pika pika (motercycle), a dala dala (one of the micro buses that can fit 30 people on board), a car, a bike, or a cart, can occupy any given space at any given time. For the most part, traffic flows on the left side of the road, but if you miss your turn and you're on a two lane divided highway, you can always just do a u-turn and drive the wrong way up the road into oncoming traffic back to your turn. And no one will honk at you. Bad traffic on the road? Take the sidewalk. There are no traffic lights in the city center probably because the lights that do exist on the larger roads on the outskirts of the city are ignored—red light ahead, as long as there isn't a bus physically blocking your way, you're free to gun it. Being on the road feels rather like an amusement park ride. With no safety break.
After our week of Swahili classes concluded, we headed on to Arusha where we’ve settled into our new home in Leganga, a 45 minute dala-dala ride outside of Arusha town, surrounded by fresh air and beautiful views of Mt. Meru. This summer, we will be continuing our partnership with the Enterprise and Rural Development Community Initiatives (EARD-CI). EARD-CI is an organization based out of Arusha that has established small community banks, called VICOBAs, with the purpose of improving the financial stability and health of rural families, as well as promoting environmental conservation.
Now it’s time to get our hands (and some pants) dirty. As DHE, we set up our own briquetting operation at EARD-CI so that we might refine our techniques before teaching others. With space generously given to us by EARD-CI, we began construction of our tanuru, our charcoal kiln.The idea behind the kiln is to produce charcoal out of biomass which can then be pressed into briquettes. By first pyrolyzing biomass (heating up the biomass in the absence of oxygen) and turning it into charcoal, the remaining carbon structure of the material will burn cleaner when burned in a cook stove.
But what about the detrimental effect of the emissions released from the kiln during pyrolysis? Does it matter that the biomass is being pre-burned and converted into charcoal before being used as fuel in a cook stove? There are two main reasons for making charcoal in this manner for the briquettes (besides the fact that consumers prefer charcoal briquettes). First, we have designed our kiln to allow the syngas (gases including hydrogen, oxides, and others) produced by the burning biomass to undergo complete combustion before leaving the kiln.
In other words, when making the charcoal we burn away the harmful emissions. If the biomass were burned straight in a cook stove, it could release that carbon monoxide and other gasses in the syngas into the space where the cook is breathing. Secondly, biomass in the form of charcoal is much more energy dense than un-carbonized biomass making it more appealing for cooks who want to spend less time tending their fire.
We built our kiln on a beautifully sunny afternoon, perfect for mixing mortar (also called mud) with our fingers, smearing that mud over bricks and our clothing, and building our kiln up, up, up. Five hours, many pictures, and several wheel barrows of dirt later we had a kiln. We’re very proud of it. Fire and biomass go in and charcoal comes out. Or alternatively, as was suggested to us, fire and dough could go in and homemade bread could come out as our kiln resembles quite a lovely bread kiln. Another very tempting option we should look into.