Microbes aggressive

Biofilms can promote corrosion of fouled metal surfaces in a variety of ways. This is referred to as microbiaHy influenced corrosion. Microbes act as biological catalysts promoting conventional corrosion mechanisms the simple, passive presence of the biological deposit prevents corrosion inhibitors from reaching and passivating the fouled surface microbial reactions can accelerate ongoing corrosion reactions and microbial by-products can be directly aggressive to the metal. 

Corrosion in ships can also be caused by MIC. In this type of corrosion, microbial organisms present in the environment can accelerate corrosion. For example, SRB, which are present in stagnant water of many harbors, can build up on the hulls of ships. Other corrosion-causing bacteria, such as acid-producing and anaerobic bacteria, are also present in ballast tanks as well as in the liquid products that some tankers carry. The microbes cause a localized change in the environment, which can promote aggressive pitting and other types of corrosion. 

The second method includes chemical treatment of the corrosive environment, for decreasing its aggressiveness, by changing its pH, salt and moisture content, existing microbes, and existing bacteria, when it is economically and technically feasible. 

The presence of aggressive microbes may also be quite severe in industrial water-handling systems, for example, cooling water and injection water systems, heat exchangers, wastewater treatment facilities, storage tanks, piping systems, and all manner of power plants, including those based on fossil fuels, hydroelectric, and nuclear [8]. Table 7.2 lists potential problem areas by industry [9]. 

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