This is a story I’ve found on the www.takamotobiogas.com blog.
“Friends from the US have started a sanitation company in Kenya, called Sanergy, that makes a profit from turning human waste into electricity via biogas. They are finishing their studies at MIT business school and asked me to manage a small project for them. We had a lot of fun on this project. And I learned a ton about managing projects in Kenya. We built two Sanergy-style latrines in Mathare, a slum in Nairobi.
This is the toilet that is currently used in Mathare 10 where we installed the latrines. The human feces fall into the river. I have photos of what the “toilet” looks like behind the thin privacy wall but I don’t want any one to vomit on their computers when they read this post.
First we had a small site visit to see where we would put the two toilets. The area is very low-lying so we debated about how high to elevate the toilets. Should the toilets withstand a one year flood or a 10 year flood? (Most slums are in nearly uninhabitable locations which makes the design work that much more interesting.)
One of the latrines would be for the children at a school. This is the front door of the school. It felt strange to know that the toilet would be nicer than the school. The other toilet would be for the use of the whole community. The community would decide how much each use would be charged. Something around 0.04 USD.
The foundation of the toilet is constructed of ferro-cement.
The shelter was constructed from corrugated steel (or mabati as it is known here). I shopped around and gave the job to the welder who offered the best price. As it turned out, more factors should have entered my calculation.
We were a bit pressed for time on this project as commissioning of the project already had a firm date set. The day we intended to install the toilets we moved the two shelters out of the work shop.
But we realized that these shelters were a bit big and the path out of the workshop was a bit small.
Then we reached a bottleneck that the shelter couldn’t pass through. No matter how hard we tried. The problem was so classic I had to laugh. I wanted to blame the welder but I guess it was my fault. I thought we might have to build a new shelter somewhere else. And we only had a few days until commissioning. Luckily Kenyans are very resourceful, which is a good way to make up for lack of planning. We put the shelter over the roof of the obstructing edifice.
Tom, my second in command, rode in the back as we transported the foundations to the site. He read a newspaper on the way.
I discovered that digging in a slum is very difficult work. The soil is so full of plastic bags and cloths that a shovel cannot pierce through the ground. If this is how much non-biodegradable rubbish can build up over 40 years we could be in trouble in the future. The whole slum, I realized, was built on trash. To stabilize our toilet we added rocks to the bottom of the pit.
Backfilling with rubbish. Real soil is hard to find in a slum and our laborers would have spent a lot of time just carrying the soil to the site of use as there are no roads for a lorry to pass. Some things we take for granted. Like soil.
Completed Latrine. Ideally the latrine would be at ground height. But after consulting with the laborers (who were from the area) we found that elevating the toilet to this height should be enough to withstand some of the worst floods. If the toilet flooded with water the waste could contaminate runoff water, which is exactly what we were trying to avoid by building this latrine. Next time I would insist that we find higher ground for the toilet to be on the safe side. Commissioning is on the 12th of May if you are around. I won’t be unfortunately as I will be doing some last minute things for my company upcountry before I return to the US for a short visit.
I am disappointed that I will miss the commissioning. I would be interested to see what reaction people have. I didn’t get a chance to talk to many people in a casual way, but a friend at the site said at least a handful of people told him how thankful they were for this toilet.
Note: In the Sanergy-style toilet design, the toilets are squat-style with urine diversion. The separated wastes go into two different plastic containers. When the containers are full, Sanergy provides the service to cap and remove the containers and replace the containers with clean ones. The waste is transported by wheel barrow to a centralized waste processing facility.”