Microbially Influenced Corrosion (MIC)
Microbiologically Influenced Corrosion (MIC) refers to corrosion caused by the presence and activity of microorganisms such as microalgae, bacteria, and fungi. Microorganisms do not produce corrosion, however, accelerate and shift the various corrosion mechanisms.
MIC is the leading cause of internal pipeline corrosion, which in turn is the leading cause of pipeline failure. MIC is the activity of microorganisms such as planktonic algae and sessile bacteria growing inside the pipeline as a result of the presence of water. As water drops off to the lowest point in the pipeline in a less than turbulent flow, MIC will begin consuming metal and activating pipeline corrosion.
Microbial action contributes to the rapid corrosion of metals and alloys exposed to soils, seawater, produced water, freshwater, crude oil, hydrocarbon fuels, processed chemicals and sewage. Many industries and infrastructures are affected by MIC, including oil production, power generation, transportation, water and waste water.
Techniques to identify MIC are nonstandard and subject to interpretation. The areas we suspect MIC are at interfaces where scale, wax, and other solids can settle or precipitate. Areas downstream of welds (where cleaning pigs have difficulty removing deposits), dead legs, low-velocity areas, and tank bottoms where solids, bacteria and biofilms accumulate, are also susceptible to corrosion. Pitting is often isolated, with one hole surrounded by a number of shallower pits.