Biogas


Biogas reactor in laboratory scale. Photo: Micans

The production of biogas occurs through the microbial decomposition of organic material, with methane as the final product. The methane gas is an environmentally friendly source of energy, since the production does not release any extra carbon dioxide into the atmosphere. It also has a lot of different areas of usage, with bio fuel being the most common one.

In the production of biogas, organic materials such as food waste and sewage sludge are decomposed through several different microbiologic processes. It goes through hydrolysis, fermentation and anaerobic oxidation before the final methane production occurs as the last step of the symbiotic process.

In order to optimise the production and get biogas with as high methane yield as possible, the decomposition needs to be stable. This can pose as a challenge as every biogas plant has a different composition of microorganisms, and due to the fact that some growth factors are necessary regardless of the bacterial content. If the pH levels are low, or if essential minerals are missing, the decomposition process can become unstable and therefore result in low levels of methane gas.

In our well-equipped lab we have several gas chromatographs that can be used in analysing both the presence and the amount of different gases, such as methane and carbon dioxide. We can also do DNA-analysis, for example to identify Acetogens and Methanogens, important bacteria in the biogas production. It can also be used to learn if a facility has the optimal growth factors, and to control how different substrates affect the quality of the gas.

We have used organic materials from real biogas plants and created lab scale reactors, in order to study how different parameters can affect the efficiency of the reactors.