Kasozi AS Margaret Ssemukasa, went on crushing her banana peels, with a blender in the kitchen, she tells me how her daughter Kirabo knew that biogas would only be got from cow dung. Until she saw her mother carry out the real process, she like me, was convinced there was no other way to tap biogas, than from the dung. (In the picture: Ssemukasa (extreme right) directs her daughter to fed the digester, as Kavuma looks on)

Ssemukasa reveals; “During our tour of St Jude Family projects in Masaka, we were told that biogas is produced from cow dung. The projects are owned by the presidential model farmer in Masaka, Josephine Kizza.” She adds as she steps out of the house with the pounded peels, to mix them with water; “To some of us, that shuttered our dreams, as we did not expect to even own a cow.”

But, sometime later when she visited Jinja, hope returned to Ssemukasa. At the Farmers’ Show in Jinja, Ssemukasa came to know that biogas could be tapped from other materials besides cow dung.

As she pours the liquidified peels into a digester, she tells Ismail Kavuma, executive director of Appropriate Rural Technology Institute (ARTI), Uganda, how her livelihood is boosted by biogas.
ARTI is the organization behind the Compact Biogas System (CBS) project.

ARTI’s CBS uses food waste like discarded flour, vegetable residues, food, fruit peelings and rotten fruit at home, schools and hotels rather than manure as feedstock.

She says she uses the organic wastewater from the digester as fertilizers for her backyard garden plants like tomatoes and vegetables. “The wast water can also be used in the newly installed digester for the first time.”

According to Kavuma, the digester needs two kilogrammes of feedstock to produce 500g of methane that produces a nonluminous fire. “There is no danger of explosion,” he asserts.

The biogas plant is made of two standard high-density polyethylene (HDPE) Crestank water reservoirs whereby the larger tank acts as the digester and the smaller one is inverted and placed into it to serve as a gas-holder.

The 1,000 litre digester that is initially fed with water and 80kgs of dung, cradles the 750 litres biogas (methane) tank. After installation and feeding, gas fills up in fourteen days after being worked on by methanogens (methane producing micro-organisms), which belong to a group of bacteria called Archebacteria.

They can convert human food into biogas within a period of about 24 hours. One kilogramme (dry weight) of human food yields about one kilogramme (about 800 litres) biogas. The waste material to be fed into a biogas plant should contain only digestible organic material.

To get the same quantity of biogas from dung, one needs about 40kgs of dung and a fermentation period of about 40 days. Because of the lower quantity of feedstock and lesser fermentation time, the size of the kitchen waste biogas plant is much smaller than that utilizing dung.

Ssemukasa says that after that, she starts feeding the digester with a minimum of ten litres of water and a kilogramme of crushed banana or sweet potato peels every morning. “Everyday, biogas cooks for about three hours, non-stop, reducing sixty-five percent reliance on hydro-electric power.”

“Whenever, the digester is fed, waste water goes out. It never fills up and the bacteria continue to feed on the waste. During the sunny period the gas holder goes up. Three-quarters of holder is supposed to be above the digester,” Kavuma explains.

Today, Ssemukasa is the chief executive officer of Centre for Private Sector Development (CPSD), a nongovernment organisation based in Masaka Municipality. It is registered to operate within the greater Masaka region, which comprises the districts of Sembabule, Rakai, Lyantonde, Kalangala (Ssesse Island), Mpigi and Masaka.

She reveals that together with other members, she took keen interest in the CBS, when they visited the Jinja Farmers’ trade show. “We saw it as an opportunity, because our areas are experiencing firewood scarcity. Rakai and Sembabule are the most hit districts in the greater Masaka. They are located in the cattle-corridor belt,” says Ssemukasa.

“In Rakai, it is hard to come across one-acre of a private natural high forest. The greatest dense vegetation you can come across is a scattered bush. A kilometre away from home, we had a high forest called Namagooma, but it has been replaced with buildings,” she observes, adding that it acted as a water catchment area feeding the spring supplying Kalisizo Town Council.

Additionally, she says this programme is relevant to women and girl-children, who suffer the brunt of fetching firewood and water. “The distance to fetch firewood is increasing year by year. As the girl-child goes out to fetch firewood, the chances of being defiled or worst sacrificed, are high.”

She says, “The peels we used to throw away have now become a vital fuel resource. As more come to learn about the CBS, they look interested in acquiring the system, back in their own homes”. In November 2009, ARTI trained thirteen women from different groups in the region, in biogas and briquette making. Ssemukasa was one of the model farmers.

The gifted woman had become a needed statistic for CBS, which aims at reducing people’s dependence on traditional fuels like charcoal, petroleum gas and paraffin. The biogas plant can be used in urban households, because they take up little space for the host.

Ssemukasa, a visible beneficiary of the plant, says it can be acquired on leasing, whose money can be paid back between four and five years.

Ssemukasa says the plant generates clean fuel, organic fertilizers in the form of spent slurry and wastewater. It is easy to use and maintain because it is above ground. There is no smell, mosquitoes, flies or frogs, where the plant is located.

The accomplished farmer says the CPSD energy project was sponsored by UNDP, while UNCST backed ARTI. The training has been spiced with the installation of a biogas system at Ssemukasa’s home for demonstration purposes.

Ssemukasa is a resident of Kalisizo North, in Kalisizo Town Council.