Principal Factors Affecting Microbiologically Influenced Corrosion of Carbon Steel

Laboratory-scale batch experiments (semicontinuously fed) were conducted using a two-level factorial experimental design to investigate principal factors and interactions affecting microbiologically influenced corrosion (MIC) of carbon (C) steel. Factors considered included the C source as chemical oxygen demand (COD), sulfate (⁠$SO42−$$SO42−$⁠) concentration, calcium carbonate (CaCO₃) precipitation, and bacteria inoculation at20°C. Yates’ algorithm was applied to calculate main and interaction effects, and an empirical model indicating major trends was obtained. Experimental results showed CaCO₃ precipitation played a significant role in influencing the biocorrosion tendency of steel. In the supersaturated condition, $SO42−$ concentration and bacterial inoculation had no appreciable effects on corrosion. In the undersaturated condition, the corrosion rate was affected significantly by $SO42−$ concentration and bacterial inoculation. The effect of each factor on corrosion rate was explored.