Helping people embrace biogas as source of energy

The growing demand for wood fuel for energy use in East Africa including Uganda has resulted in pressure being exerted on the environment.

Trees are being cut to provide wood and charcoal for cooking and burning of fossil fuels has had damaging effects on the environment.

Smoke from burning fuel wood is a hazard to human health and in addition the cost of domestic fuel is higher than what most households in Uganda can afford.

Biogas which is considered to provide a cheap alternative source of energy for cooking and lighting is now being promoted by different players among communities in the country including those living in rural areas.

There exists Uganda Domestic Biogas Programme which aims at addressing this gap by developing and disseminating domestic biogas in rural and semi urban areas offering the Ugandan population the benefits derived from the use of clean biogas for cooking and lighting and using the bio slurry to increase agricultural yields with the ultimate goal to establish a sustainable and commercial biogas sector in Uganda.

When any organic matter, such as cow dung, crop residue and chicken wastes, is fermented in the absence of oxygen, biogas is generated as a result of methanogenic microorganism activity.

Biogas contains flammable methane amounting about 60-70% along with carbondioxide comprising 30-40%, and traces of other gases.

Biogas is not noxious; it is colourless and odorless and is an ideal fuel that can be used for a variety of applications such as cooking, lighting and motive power.

The used waste that comes out of the biogas plant after the gas is produced is excellent organic manure that improves soil fertility.

In addition to the high quality cooking and lighting fuel, biogas offers a number of direct and indirect benefits such as environmental where fuel wood can be saved for other purposes such as electricity polls.

Other benefits include improved health arising from avoidance of smoke, quality fertiliser and time saving among others.

Apart from several initiatives provided by different players one such an initiative is being carried out by Agricultural scientists at Agricultural Engineering and Appropriate Technology Research Institute, Namalere (AEATRI) with famers in cities and those in rural areas as well.

Mr George Walozi a research officer in charge of Energy Engineering at the Institute explains that the programme involves activities such as fabricating equipment which can be used for biogas energy as well as renewable energy including farm power equipment.

His team is engaged with farmer groups and other community members living in different parts of the country such as Jinja, Mbale, Soroti Kabale, Mbarara, Masindi, Arua, Mpigi, Masaka among others.

Communities get to know about the energy project through exhibitions which the team conducts at different events where the National Agricultural Research Organisation (Naro) is involved.

Apart from engaging communities on use of biogas produced from cow dung, Mr Walozi and his team also sensitise communities in the use of wind energy where the team makes wind pumps for drawing water underground to be supplied to a source of need for irrigation as well as for animals to drink.

Farmers engaged in fish pond farming can also air rate their ponds using the wind pump although this is still undergoing research.

Crop residues

Looking at Biomas usage, the best the team is doing is telling the communities to use crop residues as well as use of animal waste with the main aim of reducing cutting of trees for making charcoal which is a major source of energy in the entire country.

A case study of the biogas initiative was done with farmers living in Kawempe a Kampala Suburb where farmers keeping cattle under zero grazing where selected and trained to use the cow dung for making biogas.

Mr George Makubi, a research assistant at the institute in charge of water harvesting and storage programme explains that a project that was funded by the French government through Makerere University in the year 2007 identified a number of dairy farmers in Kawempe sensitizing them on the use of biogas as source of energy and the scientists at AEATRI where brought on board to sensitize farmers about the construction and importance of the biogas plants in their homes.

The team trained Mr John Sserwada as an individual since he expressed interest in making biogas for cooking.

According to Mr Mukiibi, the project focused on people living close to the city because they were looking for a way as to how a farmer keeping cattle under zero grazing can utilize the waste for making biogas.

Other activities the team carries out in terms of Biogas use involves farmers living in rural areas such as Jinja.

One of the products of the waste is methane which is a contributor of global warming but the team advised these farmers to use the final waste as fertilizer.

The team ensured that animals must be kept under zero grazing and when mixing the cow dung with water the ration should be one to one and thereafter it is directed to the digester.

As pressure builds up which is caused by bacterial inflammation, then biogas is produced. This is directed by a pipe constructed from the inlet all through to the kitchen where the gas is used for cooking.

The scientists emphasize that the cow dung used for producing this gas should be pure and it can be mixed with urine but no stone gravels or any other decomposing substance because this may cause yellow flame instead of the normal light blue flame colour which is the best for cooking.

When mixing the cow dung with water, the farmer uses a strainer and it is let into the digester minus any stones. The digester is constructed using concrete material but smooth clay is smeared at the outlet which is kept moist to avoid any cracks.

In case of any leakage, the digester which is 4 meters wide has to be mended and after digesting these materials for the gas to escape through the pipe, the remaining waste is kept in the expansion chamber which is later used as fertilizer. If the mixture is full, the farmer can use the gas for cooking for two

Farmer’s story
My name is Mr George Makubi yand I am lucky to have been part of a group of over 20 farmers in Kawempe, Kazo village trained by scientists from AEATRI, Namalere in use of Bio gas produced from cow dung.

This was under a project implemented through Makerere University and the French government through its agencies offered the construction materials to a number of farmers in this village.

I happened to be part of this initiative because I already had three heads of cattle which I keep under zero grazing mainly for getting milk for my family.

It was therefore the farmer to decide which end user material to purchase for him or herself such as lamp and cooker, but I decided to purchase the cooker because I wanted to use the biogas for cooking although I have plans to purchase the lump for lighting the house.

I have a family farm in Luwero where I am grow crops like cassava, bananas, beans mainly for home consumption and the fertilizer I get from the biogas plant I use it on my farm and if there is excess manure I sell it to farmers in my neighborhood in Kawempe.

While embracing this system of biogas for cooking I alternate it with use of firewood because I have quite a number of people in the family including my grandchildren.

In setting up my small dairy farm including construction of the Biogas plant, I invested about Shs10 million which I do not regret because I am now saving a lot in terms of charcoal use and firewood.

Looking at the size of the plant, it is 16 meters deep with radius of 205 cubic meters with each cubic meter containing 1,000 liters of the mixture. When the family is preparing light meal like preparing Matoke, boiling water for bathing and tea we use biogas.

I used to use 5 bags of Charcoal which now has reduced to one in a month and all I can say is that I am saving about 80% in terms of purchasing charcoal.

I am not yet using biogas for lighting because I need to purchase the requirements such as lamp holder.

The beauty of using biogas for cooking is that it is environmentally friendly because the cow dung used to attract a lot of flies which has reduced tremendously because even the waste obtained as fertilizer is pure and it does not smell.

I encourage fellow farmers keeping cattle to use the waste matter for processing biogas and they will not regret.

It is a good thing for the rural woman because rural women spend a substantial portion of each day gathering fuel wood and cooking meals.

In addition, they also have farming, household management and childcare responsibilities, and as a result work up to 16 hours each day.

The use of biogas can be estimated to reduce the daily search for fuel wood, cooking and washing up time by 3 hours, benefiting rural women directly.
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