Microbially Influenced Corrosion in Epoxy‐Ceramic Coated Carbon‐Steel Cooler

ABSTRACT Crevice corrosion and corrosion products were observed during the maintenance of a carbon steel cooler repeatedly treated with a commercially produced anticorrosive coating. This prompted a case study to investigate possible microbially influenced corrosion (MIC) in a system operating at moderate temperatures with treated, chlorinated cooling water. Cooling water, corrosion products, sediments, and swabs were analyzed for microstructural, chemical and microbiological characteristics. The cooling water contained sufficient nutrients to support microbial growth, along with chlorides that could compromise material integrity. Chemical analysis of the corrosion products revealed elevated sulfur levels, suggesting microbial activity. Molecular‐genetic analysis showed a significant abundance of sulfur‐oxidizing, nitrate‐reducing, sulfate‐reducing, and methylotrophic bacteria in the corrosion products. Our results indicate that the synergistic activity of these bacteria was the primary cause of MIC in the carbon steel cooling system, despite the use of anticorrosive treatments, highlighting the need to revise the mitigation strategy.