Cathodic protection and sulphate-reducing bacteria: A complex interaction in offshore steel structures

Abstract

Microbiologically influenced corrosion (MIC) caused by sulphate-reducing bacteria (SRB) is an important issue, particularly in the offshore industry where cathodic protection (CP) is commonly used to prevent the corrosion of steel structures. However, its relation with MIC remains unclarified, as the interaction between CP and microbial activity is still far from understood. Under overprotection conditions, the water reduction reaction can lead to atomic hydrogen uptake, which may result in hydrogen embrittlement (HE). This uptake is influenced by calcareous deposits, i.e. inorganic compounds formed during CP. Additionally, SRB are argued in literature to enhance hydrogen uptake. This review explores various perspectives on the interaction between microbial activity, particularly SRB, and CP, as well as their individual and combined impact on hydrogen uptake in an offshore context.