Microbial corrosion


Thick coatings of microbial corrosion products that covers large areas of a sheet pile in the waters of the Balctic Sea. An iron bacterium called Gallionella ferruginea is speeding up the corrosion on the sheet pile. The picture is taken under water by our divers. Photo: Micans

When corrosion occurs in places where it should not be able to, or where corrosion damage appears to happen faster than anticipated, it could be due to bacteria and/or fungi.

Corrosion where bacteria are involved is called ‘microbial corrosion’ or ‘microbial induced corrosion’ (MIC). Depending on which type of microorganisms involved, they can either speed up an already existing case of corrosion or be the reason for corrosion in environments where materials should not normally corrode.

MIC is present in both aerobic and anaerobic environments. In anaerobic environments MIC often cause so called “pitting corrosion”, which means small, deep holes in the corroding material. The pitting corrosion can cause the damage to go deeper in less time than first expected. MIC can also be associated with clogging issues in piping.

At Micans, we are specialists in determining the presence of MIC and to identify which type of microorganisms that is responsible for the corrosion. By analysing the chemical and physical conditions in the environment, we can also develop methods for decreasing their activity.

Some examples of environments where we have been assigned to examine MIC are different types of piping networks, disposal systems, corrosion in nuclear power plants, drainage pipes, fire water systems, corrosion in bridge constructions, tunnels, docks, and the risk of corrosion in repositories for nuclear waste material.