Biogas - clean energy from animal dung

Farmers can generate clean gas for cooking and lighting through use of a biogas digester
© WRENmedia
Biogas expert, George Kamau, demonstrates how farmers can generate clean gas for cooking and lighting, through use of a biogas digester. Animal manure is fed into an underground tank on a daily basis. As this is ‘digested’ by bacteria, methane gas is produced which is piped to the house, reducing the household’s need for firewood or electricity. Paschal Bagonza visits a farm in Kiambu district to the north of Nairobi, to see the system in action.
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Bagonza I am standing in the compound of Mr Ibrahim Njuguna, a farmer in Thakwa Village, Central province of Kenya. Behind me, is his well built house with a cosy sitting room fixed with a set of cuddly sofas. On my right, is a wooden storied structure he uses for rearing poultry on top, while his exotic breed of cows are beneath it. On my left, there is another wooden single storied structure, housing about ten healthy looking goats. The goats' droppings are used as manure in the small vegetable garden in front of their structure. The smell of cow dung is heavy in the air. Behind the wooden structures, is a biogas digester, a round concrete structure filled with semi-solid dung which is collected from the four cows. The Napier grass near the biogas digester are very green; they dance with satisfaction to the sound of the whispering wind. Njuguna uses the dung from his cows to produce biogas for cooking and light. George Gichuhi Kamau is an expert in installing biogas projects in people's homesteads.
Kamau So this is the gas outlet pipe. We have ballcock here. The size of this plant is 12 cubic metres. These are the slats that cover the slurry that is here. This is used to maintain the pressure so that the gas can have the pressure to go to the kitchen.
SFX Njuguna's kitchen.
Bagonza It is almost lunchtime. I am in Njuguna's kitchen. His home is one of the few Kamau installed with biogas. He talks about cooking with biogas.
Kamau I usually tell the farmers to make sure that this is like now this is good, but this is bad. There is excess. A lot of energy is getting lost. So we have to regulate.
Bagonza Biogas is a clean and alternative source of energy. Kamau explains some of the benefits.
Kamau Biogas, once you construct, that's all. The rest is just adding the slurry. The rest there is no bill. For example, instead of using lightning, electricity you use lamp. Cooking you use biogas instead of using electricity or other gases.
Bagonza Firewood?
Kamau Yes. The only expensive thing is construction, setting up the plant, you have to use a lot of money, not very much. Once you construct, no more expenses.
Bagonza Homesteads with biogas don't feel the pinch of load shedding. Homes are assured of constant power supply and their expenditure on electricity is very low.
Kamau Those who have constructed they are seeing now the bills have come down to a great extent. Cooking using electricity is very expensive. So if you use biogas it is very cheap. Then we have other times where we have blackouts. They just use this one.
Bagonza Biogas production goes through a process, which connects to the house to provide light and energy. Kamau demonstrates how a biogas lamp is used.
Kamau This is where we open the lamp, there we have, it is supposed to function automatically. If it doesn't, we use matches. So this has no other additions. It can't spoil your eyes. The light is somehow yellowish but you can see anything, everything. Like now, most of the time they use this one at night instead of electricity.
Bagonza For Njuguna, raw materials for biogas are readily available. It can be human waste. It can be cow dung. If homesteads had money to install biogas, they would enjoy, clean, safe and cheap alternative source of energy. End of track
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