“Reduce, recycle, reuse.” We’ve heard it a zillion times. Interestingly, repurposing sewage as fuel ticks all three of these boxes!
Today from Quartz:
A Kenyan company is taking the excess fecal waste from residents in Nakuru and transforming it into a usable fuel source for cooking and heating.
Human waste contains, on average, about 30% combustible solids. Here’s how it works: solid waste is dried in vats, then baked in a kiln at extreme temperatures to eliminate potentially harmful volatile compounds, and carbonize the remaining material. Those potentially harmful volatiles? They’re what makes poop stink – so after this step, poop is indistinguishable from charcoal.
The next step grinds the waste into a fine powder and blends it with molasses as a binding agent. (We had NO IDEA molasses was used to make charcoal briquettes, so we had to look it up… Seems like molasses makes a better binder than some toxic alternatives, like tar. Why not use it as food instead?) The finished product looks like round fist-sized lumps of coal and sell for $.50 per kilo.
How do they work? Quartz reports, “Customers say that the fuel burns longer and with less smoke than charcoal and firewood.”
Using human waste as a fuel source isn’t a new idea (see phys.org’s discussion of waste gas recovery and the vast energy value of human waste). We can transmute poop into charcoal, as described above – AND collect the biogas (mostly methane) produced during the bacterial decomposition of poop and other organic matter in an anaerobic system.
Here’s why this matters: about 2.5 billion people, about 1/3 of the world’s population, don’t have access to bathrooms and modern sanitation facilities. One billion people don’t have toilets at all. Lack of sanitation contributes to diseases like cholera (this is what can happen when you don’t use proper sanitation), typhoid fever, and parasites like hookworms or roundworms. That’s one of the reasons the Bill and Melinda Gates Foundation has spent so much time working on recycling sewage.
We applaud the initiative of the Kenyan company in repurposing what might otherwise become a source of sickness in their community. Check out the video below to see the process at work.
(There’s no green gadget here today – just what we hope is an inspiring and hopeful story!)