Biogas for cattle farmers
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CTA. 2008. Biogas for cattle farmers. Rural Radio Resource Pack 08/3. Wageningen, The Netherlands: CTA.
Permanent link to this item: http://hdl.handle.net/10568/57410
How livestock can improve on-farm energy flows
Biogas for cattle farmers Cue: What form of energy do you use to cook your food or light your house? You probably use more than one kind: kerosene, firewood and perhaps electricity as well. But for those who own livestock, there is another possibility. Biogas, a combination of methane and carbon dioxide, is formed when organic matter, such as animal dung, decomposes by the action of bacteria. If this gas is captured and stored, it can be a useful fuel, powering lamps and cookers. It is a popular technology in parts of Asia, but few people in Africa have adopted it. What you need to produce biogas is a large, cement chamber, usually underground, and known as the digester. You need to regularly ? usually twice day ? feed in manure for the microbes to work on. As the biogas forms, it collects in a reservoir tank from which pipes lead to lamps or a stove in the farmer?s home. Setting up a biogas system is not cheap, and it needs daily attention to keep up gas production. But for farmers with sufficient livestock to provide the necessary dung, it can be a good, long-term source of energy. Dr Elias Aklaku is a biogas specialist from the Kwame Nkrumah University of Science and Technology in Kumasi, Ghana. He spoke recently to Adu Domfeh about the potential of biogas for livestock farmers. IN: ?Biogas will become very important ? OUT: ? or large-scale farmers.? DUR?N: 5?12? BACK ANNOUNCEMENT: Dr Elias Aklaku, discussing the potential of biogas energy for cattle farmers. The interview comes from a resource pack produced by CTA. Transcript Aklaku Biogas will become very important and crucial if you are using the so-called zero grazing system. That is, we don?t allow our animals to go wild and be grazing around, but we confine them and we bring the fodder to them. So if you confine your animals and you bring the fodder to them and they defecate around, they soil the area, you must get rid of this. That is the sanitation aspect of it; that is animal hygiene. But in terms of agriculture also, those who have cattle which even go around and come back, they do deposit something around them and this can even be utilised. It may be enough to give them light. They can cook with it instead of cutting down trees for firewood. Domfeh In a sense livestock are very important in improving energy flows around the farm. Aklaku Well that is it. Livestock are very important. So if you have large stocks of animals around you, the best thing to do is to go into this aspect of biogas technology. And not only that; farmers even in the oil palm industries, shea butter industries, where you have organic waste that is both from plant and animal origin, it can be handled to produce biogas. Domfeh So how best do the farmers collect, store and use the manure to improve their farming practices? Aklaku Manure is already in use in Ghana. In northern parts some of them, they dry it and even burn it as fuel. Some collect it and throw on the field. But if you have a kraal and the animals are in and they are in a large quantity, both their droppings and their urine, if all this will be gathered then it means you have a permanent head. You know I have twenty cattle permanently, or I have thirty cattle, and then you can know that you will have, for example, eight cubic metres of biogas out of this per day. And then you know that this can do this lighting system for you, or can cook these meals for you. A better way is to organise them, as you know they also use energy in roaming about, especially during the dry season. If you organise them very well you can bring the fodder to them. Then instead of using their energy walking about, they use energy to give you foetus or give you milk or give you meat. But once you have enough, then you can make use of the biogas technology. Domfeh So what do you mean by enough? Aklaku You must have about ten or more cattle, or better twenty, forty. But to have one or two cattle, and then you allow them to roam about the whole day and then you keep them overnight. I don?t know, sometimes they may not give you much dung at all to do anything with. So for a family of say four to six, if you have ten to twenty cattle, that must be able to give you one or two lights ? a biogas plant about eight cubic metres will give you one or two lights and cook about two or three meals for you in a day. And I think that should cater for your energy demands in terms of kerosene, or in terms of firewood. Domfeh Is fish farming another good form of energy generation? Aklaku Yes. With fish farming the whole issue is about feeding. You need to have enough feed for them because they are multiplying, we are harvesting them, they are multiplying, we are harvesting them. This is why, for example, if you have a large inflow of liquid waste, after treating it in a biodigester, the effluent which is a biofertiliser, if you allow this to seep into where the fish ponds are, if the sun shines, this helps algae to grow, and the fish feed on the algae and you can be harvesting the fish. So this treatment of organic waste can also become a source of feed material for fishes growing in ponds. Domfeh What practical tips can you give a farmer who rears livestock, to make better use of the livestock in terms of supplying farm energy? Aklaku You see, even if you can?t make use of all the droppings of all the animals, out of a hundred cattle you may have about one-tenth of them which are female ones about to calve. Normally you can seclude these ones. Cement an area, or have an area for them with a gentle slope. You can use a rake down the slope. When they drop their faeces, and their urine too drops, it washes along these rills into a container and that will be the entrance point for your biodigester. And with those ten cattle that are housed there overnight, before you are aware you have enough energy for you, and then the effluent which comes out, you can even grow your gardens around your place there. And before you are aware, you wife doesn?t depend on kerosene, and she doesn?t go to fetch firewood. So I would advise, maybe there should be a biogas programme for small-scale farmers, or large-scale farmers. End of track