Turning pig droppings into an energy source

Wednesday May 6 2015

By Pauline Bangirana

Pig farming can be a profitable business for the farmer. However, the major challenge many farmers face is how to deal with the waste. Did you know that the smelly droppings can be converted into a source of energy?
Wambizzi Cooperative Society and Green Heat Uganda Limited launched a biogas plant so that farmers can manage pig waste and prevent any contamination that could arise.
According to Emily Ouma, the project coordinator, the biogas plant will not only manage pig waste but also help in improving the sanitation around the abattoir by eliminating the bad smell.

How it works
The gas is made from a biogas plant and to make one at home, some of the requirements which are determined by the capacity you are collecting include; a mixer, flexible balloon digesters that can each carry up to 10 cubicmetres of gas, and pipes that connect to the digester and the kitchen or to the final place where the gas collected will be used.
These carry gas from the digester to the cooking stones/stoves. The mixer is about 10 centimetres above the ground and the end area where the byproduct collects from is slightly lower. The byproduct is slurry and it can be used as a liquid fertiliser. The slurry liquid can also be fed to the animals.
Each balloon digester generates gas that can be used for about four to five hours of cooking which are equivalent to water boiled to scald for a day. According to the chairman of the Wambizzi Society, Paul Sserubizi, the plant saves one between Shs10,000 and Shs20,000 which is spent on firewood on a daily basis.

The concoction
The biogas plant’s major purpose is to help save on money used on firewood that is used for boiling water. The water is used in scalding the pig before it is slaughtered.
The pig waste used in making biogas consists of pig droppings, mixed with affluent from the intestines of the pig which is then mixed with water. However, when mixing the affluent, one should ensure that the mixture is porridge-like, with no hard particles left because they could interfere with the process in the digester.
When in the mixer, it gets to the digester through the pipes.
In a regular mixture, it should be paste-like, similar to when making porridge.
Each digester depending on its capacity can carry about 150 kilogrammes of waste every day and produce 10 cubicmeters of gas.
The balloons can take about two to three days to become full depending on the capacity it holds.

Maximum output
If one has a farm of about 10 pigs or more, an estimation of Shs3m to Shs7m is required to start up a biogas plant.
Robert Muyige Mukayi, a biogas engineer explains that some of the requirements to start a bio gas plant are an enclosed place, “a source of waste” and the need for energy.
Depending on what you need the energy for; this will dictate how much you are able to collect.

Important to note
It helps cut down costs of cooking in terms of money spent on charcoal or fuel.
It also helps in managing waste although it is equivalent to the human stomach because when not fed, it will not produce the gas.

This and other technologies are some of the many things that will be covered in the Seeds of Gold farm clinic on May 30.