How does the presence of sulfate reducing bacteria affect metal corrosion?

The presence of sulfate-reducing bacteria (SRB) has a significant influence on metal corrosion, primarily by accelerating the corrosion process. These bacteria thrive in anaerobic conditions and utilize sulfate as an electron acceptor, leading to the production of hydrogen sulfide (H2S) as a metabolic byproduct. This process increases the overall corrosivity of the environment.

As H2S forms, it can react with metal surfaces, creating metal sulfides that are not protective and can lead to localized corrosion, such as pitting. Additionally, the metabolic activities of SRB often contribute to the depletion of dissolved oxygen in the surrounding environment, which can result in an anaerobic condition conducive to further corrosion.

The activity of sulfate-reducing bacteria not only alters the local chemistry but also enhances the electrochemical reactions that lead to metal deterioration, hence accelerating corrosion rates significantly in impacted structures and materials. Understanding this effect is vital for managing corrosion in environments where SRB are likely present.