His black faded shirt, and khaki pants are practical — the same no-frills mien pervading the organization’s Spartan office with its simple wooden tables, perfunctory computers and bare white walls. “I’ve always been considered a tinkerer. Things would be kept away from me because I would tear them apart. My sister will never forgive me for borrowing her new cassette player half an hour after she got it as a birthday present when we were younger. After I was done with it, she never heard it play.”
A lot of the gadgets Wanjihia has developed since his School years at St Mary’s School in Nairobi, have revolved around energy and farming, but it is in the world of biogas that he has cut a niche. His recent innovation — the flexi-biogas system, a portable tube that processes cow dung and other waste, has come to the attention of outside governments and local manufacturers, some of whom have ordered units in the hundreds for pilot projects. “The Rwandese government ordered one hundred units from us to distribute to low-income farmers and in schools.”
Wanjihia takes pride in the affordability of his innovation to local folk, as well as its ability to produce more than conventional systems. “In East Africa, a conventional small system costs about Sh200,000 ($2,300) but it won’t produce enough gas to cook githeri for three hours, and poorer people still can’t afford it.
Ours comes in three sizes cost Sh40,000 ($460). for the small, Sh55,000 ($650) for the medium and Sh70,000 ($800) for the large and is enough to cook for hours and do other things.” Another departure from convention: Wanjihia’s flexi-biogas system needs only one cow on hand to operate and apart from cow dung, it can run on kitchen, chicken, pig, elephant, human and other animal wastes.
“The regular dome systems need four to five cows to produce 1,000 litres of gas. They are constructed underground and you need to own the land. How many people have Sh200,000 ($2,300) to spare, own a piece of land and four to five cows?” While other systems take up to a week to install, Wanjihia’s system is up in a few hours and running in days.
To generate biogas, farmers put dung and water into the portable PVC digester, which eventually produces a constant supply of energy as long as it is fed daily. A nature enthusiast, he explains that one of his motivations in engaging in the fuel was to reduce the cutting down of trees, starting explorations in biogas after a challenge thrown by his sister, a wildlife conservationist. “She asked me to come up with a solution to the rapid deforestation behind the Nairobi National Park caused by Maasai community members who were shedding the nomadic life.” The community did not adapt his technology, but other farmers took interest in it, encouraging the innovator to go on.
Apart from its use in cooking, biogas finds other uses on farms. It is disposed of while at the same time pumping water, powering chaff cutters, milking, cooling and drying machines. Its solid waste can also be used as organic fertilizer. With the help of a generator, Wanjihia demonstrates to us how it can produce electricity and light bulbs. “You can use it for absolutely anything.”
Embarking on his biogas journey spurred him to come up with more innovations. He built a vegetable and fruit drier, which runs on the gas, a Sh30,000 ($345) innovation that gives farmers an alternative from throwing away excess produce after harvesting. Wanjihia also shows us a biogas powered chick brooder he built to keep newly hatched chicks warm, a large cooker for schools that cuts cooking time by more than half.
A bio-digester with gas generated
He does not see himself as doing anything particularly radical, averring that his inventions are simple innovations of existing knowledge, using local material. He is enthusiastic about knowledge being accessible, putting the descriptions to some of his designs online on maker websites. “A lot of the tools I have designed are to alleviate challenges and help people. I don’t have the time or energy to sell these products to people, I would rather they get their fundis to make them.” Choosing not to attend college or university, all his knowledge was self-taught.
“I was fed up with being told what to do by teachers. I was a free spirited kid.” His earlier inventions include a device to talk under water and an overhead bridge for monkeys to avoid getting knocked down by cars, which is used today in Madagascar and Australia. He has also produced tools, water pumps, electric solar devices for fuel, and an anti-malarial device.
Wanjhia is currently setting up a fuel station that can enable tuk tuks to run on biogas. Wanjihia does not give figures for how much these may retail at, but mentions that a large cylinder of compressed gas, which can run four households for a month, sells at Sh1,500. ($18)) “Millions of tuk tuks in India are running on natural gas.
What we’ve invented and patented here is the scrubber, which cleans up biogas and turns it into bio methane, which is the same as compressed natural gas. We’re localising the technology at affordable rates” Localisation and affordability are key themes in his work. “We put three criteria into the making of things: sustainability, affordability, accessibility. I’ll make everything from here, I’m not going to import anything, apart from the digester where the pipes and tarpaulin are not locally available.”
Plans for a biogas fuel station will take a few months, but he eventually hopes to have a commercial agent model where other people can become independent power producers. Another plan he aims to implement is to build a floating platform in Lake Victoria, using hyacinth as food stock to produce energy.
Apart from coming up with practical innovations, Wanjihia also wants to inspire and nurture the growth of youthful inventors through Simply Logic, an incubation platform for young techies interested in furthering their inventions.
email: koboideas@gmail.com
The pit method of biogas construction is the easiest that can last for a long time, unlike the bag digester. I plan to start from there. Most of these technologies are very old but it baffles me how people will react when they see one.
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