Microbial corrosion of metals

Microbial Corrosion of Metals

  Biocorrosion, Microbial Corrosion, or Microbial Influenced Corrosion (MIC) can be defined as an electrochemical process in which microorganisms are capable of initiating, facilitating, or accelerating corrosion reactions without any changes in their electrochemical nature. Researchers have reported that approximately 20-40% of corrosion damage is caused by microbial corrosion, making it the most destructive type of corrosion. Microorganisms can actively modify the surrounding environment of the metal surface to facilitate the corrosion process. Microbial involvement in corrosion is rarely done through a single mechanism or a single species of microorganisms. These microorganisms can cause or exacerbate corrosion by changing and altering environmental conditions in most systems. Estimated corrosion damage in industrialized countries is about 2-4% of their Gross National Product (GNP), but for countries like Iran that do not usually use corrosion prevention methods, the damage and costs resulting from corrosion are often hidden in repair expenses, and the corrosion damage rate can increase up to 5% of the GNP, which will be a significant figure.

Corrosion is an electrochemical process in which a metal gradually corrodes and disintegrates by losing electrons and releasing metal ions into its surrounding environment. In most cases, corrosion can occur when the metal surface is exposed to water or moisture, under both aerobic and anaerobic conditions. One of the conditions that facilitates and accelerates corrosion, especially under anaerobic conditions, is the accumulation of microorganisms on the metal surface. Corrosion caused by the accumulation and activity of microorganisms is called microbiologically influenced corrosion (MIC). This phenomenon is a major factor in the creation and expansion of deep corrosion in structures and facilities in various industries, especially water, wastewater, oil, and petrochemicals. The cost incurred by the economies of major world countries as a result of metal corrosion has been estimated to be several billion dollars. Corrosion in metals used in facilities reduces the efficiency of the system and devices. For example, in water supply and sewage treatment systems, microbiological corrosion and its effects cause unpleasant odor, color, and taste in the water, create blockages in water transfer pipes, and severely affect the performance of pumping and treatment systems. Therefore, dealing with microbiological corrosion is of great economic importance. The main factor in creating microbiological corrosion is the formation of a biofilm on metal surfaces. A biofilm is a collection of various microorganisms that, through their activity and growth, accelerate the corrosion process. The earlier the biofilm and the dominant bacteria that make it up are identified, the easier, more effective, and less costly it is to prevent and remove biofilm from metal surfaces. Therefore, access to a method for timely tracking of microbiological factors that make up biofilm is essential.