Kenya's Gold Feature | CONCRETE BIOGAS SYSTEMS

Added: 2026-05-27

[00:00:06]Often when we go to farmers' fields we find a very different biogas that is built using paper.

[00:00:14]But here we find out how biogas that is built using a chimney works? How is it built? It's news you'll want to sit down and read. But let me inform you that there is a farmer who raises more than 20,000 chickens but uses biogas for heating. Note that this biogas also has the power to push and drive the turbines as well as to generate power for the generator. For you, it's important to read with us so that you can learn how this energy works at home. You don't need to go to gasoline, [music] steam, or diesel fuel. Your job is to sign up with us so you can read. Let's go to work.

[00:00:56][music] My name is Kalebilwa and I work with home biogas in Kenya. Home biogas In Kenya we are building biogas plants that use food waste, animal waste and human waste. Now when you have waste like livestock, we look at chicken, cow and pig waste as food waste. For food waste, we use fruit peelings like those from bananas, watermelon, any fruit peeling that contains sugar, or waste like ugali, rice, things like starch that are rich in energy. All food that gives energy to the body is very good for biogas. Then we also use human waste, but we mostly use school waste because human waste also requires a lot of waste and you get an estimate and average on average a human produces about 100 grams per day so you get it is very difficult to build a home for a few people biogas mostly we do it with instruction here is feeding the biogas for the feeding thing we do we mix cow dung and water the ratio is one to one. So if you put one bucket of cowang, you put 20 L of water. So after the mixing, if there are any stones and something like nepia grass, they are also removed, yes, to make sure it is completely fine because when you allow these things inside, they cause blockage to the biogas plant, then they do that clogging, so you will find that your biogas plant is blocked. So when you are mixing you have to make sure you remove the grass, you remove the stones and any other substance that will have gotten into the sand.

[00:02:49]Now it's flowing it enters the digester as it continues to enter you will find it pushing the same cowment from the other side it starts from there we have two different designs of biogas there is the balloon pvc or it is called either a tent the kind of system bag and there is the concrete or fixed dome design so the pvc one is what some call paper some call it balloon or the bag one over there the concrete system is the stone one like the one we have made here now like the one we have built here this is a concrete design it is 48 cubic meters it needs an average of 24 cows it can provide gas of an age of 20 cubic meters on this farm with that estimate you are able to kurun all the brothers of the 23,000 chicks that you have.

[00:03:44]Why the farmer wanted this solution was mostly because of theuding and he had told us before that he was using on average he said he was using like 20,000 in every 3 days and that's the big LPG cylinders that he was using so when we contacted him we explained to him that he already has waste and he has cows here we can use this waste to convert into energy then he can get the same biogas so when you look at this machine there is an inlet that is a feeding chamber Then where I am standing here we have the concrete the digester there is the west it comes in it ferments then when you look here in front we have the digester which produces waste going to the farm so the two products are gas then the sl gas can be used for many things like on this farm we use for those four things for brothers for cooking with a generator and for chafkata If you look at the gas we have given from here it has entered then there are these valves to turn on and off.

[00:04:52]So if I want to turn it on, you'll realize I turned on the gas and turned it on. So there is a difference between biogas and LPG. when I switch off this biogas then I turn it on like this if it was LPG this this flame will jump here and you will find it is burning so if it is full in the room you can get it it can explode but for it cannot until you turn it on from that point the place where it is happening now if I turn it on and here it cannot burn but if I return this fire to the place where it is happening gas will find it is burning so even for the kids this tells that biogas is very safe.

[00:05:35]So it can only burn at the point where it comes out, but even if it fills the room, if you light a match, it can burn.

[00:05:46]We also have a plan to show farmers how they can feed themselves and save 50%. On average, if we say he has one sack of chekh when we mix it with almost 200 L of salari, he will have doubled the amount of feeds he has and research shows that chickens grow faster than those that lay eggs, they also produce very large eggs, so it can also save in terms of fertilizer, it is also good for the farm because the plant will grow faster and this is 100% organic fertilizer.

[00:06:24]So often we look at biogas, the farmer should have it, mostly it is either he has cows, he has pigs or he has chickens. With these, we can build biogas from the smallest size, which is 6 cubic meters, to as big as possible, depending on the waste we have.

[00:06:41]The commercial systems we mostly build are 124 cubic meters. How much biogas or raw materials does a farmer who wants to use biogas on a small scale need?

[00:06:52]Okay. For the small farmer for whom a 6 cubic meter biogas size would be suitable, he needs two cows.

[00:06:59]We talk about two cows in terms of like two buckets of cow milk every day. And with that, he will be able to get biogas which will support the main kitchen, and also with an employee, he will be able to get gas. So on average, let's say they will have gas for 6 hours per day.

[00:07:22]So when we are given a job by a farmer, the first thing we do is make a side visit to show him what location would be good for placing that plant. After that excavation now corresponds to the place. If you look at places like Kiambuu and Moranga, it's very soft. Excavation is one day.

[00:07:38]Some places may be rough, it may take time, but from the point of excavation to build that biogas, we want between 8 to 12 days. After we finish building, we give it around 14 to 21 days for it to cure. From there, we start adding fertilizer. Now, for the farmer who has decided to build biogas using the concrete, how many years will this biogas last when we build it for the farmer? It should last for 30 years, an average of 30 years. If I use it properly, it should last that long. The first thing that can make biogas potentially problematic is feeding. Feeding should be done with a 50 to 50 ratio of cow dung to water. Suppose if you have a wheel barrow of manure, there should be one water trough. Now that mixing ratio should be good. If it is good, the fermentation process for digest will be good and you will also get a flow of slurry and the gas flow will be the same.

[00:08:33]But when he says, "What about the nepia grass, stones get in, sand gets in, it will block the biogas and it's annoying, it will bring constant maintenance attention, but when the farmer follows the instructions, there will be no need for us to come back to sit with him once we've finished, we've taught him how to feed and how he uses it, it becomes very easy. Things that can also cause damage are, let's say, small bacteria that are stuck inside and don't want to be disturbed."