Microbiologically Influenced Corrosion
Many microorganisms are capable of degrading pipework and alloy surfaces leading to costly repairs and hazardous working environments.
Microbiologically influenced corrosion (MIC) is a phenomenon that has been estimated to cost industries in the region of US$3 billion per year. This is somewhat surprising considering there are many accessible and affordable microbiological monitoring methods to gauge microbiological presence in systems to help implement preventative measures and mitigate losses.
It is true that the industry is well informed of the risks from MIC and its widespread occurrence, but it is probably the least understood of all corrosion mechanisms. Despite this, we know that where there is presence of water and nutrients, there is likely to be microbial growth, even in extreme conditions such as high temperature, high salinity, high pressure and toxic chemicals; this means many industries are at risk, including Oil and Gas.
MIC takes place on the surface of pipes, tanks or vessels, where microorganisms settle and colonise in the form of sessile populations. This community can be very diverse where many microbes synergistically survive and grow some of those are capable of metabolic action that can accelerate the degradation of metal and alloy surfaces through metal ion and electron transfer and displacement mechanisms.
Considering the threat MIC presents it is vital that you incorporate microbial testing practices into your integrity management systems. Generation of microbial data allows tracking and trending of potentially harmful microorganisms which can assist in chemical management (biocide dosing schedules and efficacy) and facilitate timely remedial action if an issue becomes apparent.
MIC can be very problematic in cargo tanks, diesel fuel tanks and oil pipelines, alongside other forms of chemical and physical corrosion mechanisms which should be holistically monitored; further information on wider corrosion management can be found on our Capcis homepage.
