BIOFOULING AND MICROBIALLY INFLUENCED CORROSION

Biofouling and microbially influenced corrosion (MIC) are mediated by micro-organisms attached to the metal surface and/or embedded in a gelatinous organic matrix (the biofilm). Microbial adhesion processes lead to an important modification of the metal/solution interface, inducing changes in the type and concentrations of ions, pH, oxygen levels, flow velocity and buffering capacity of the liquid microenvironment or the interface. This feature drastically changes the classical concept of electrochemical interface used in corrosion studies. Metal dissolution at a biofouled surface will be conditioned by two different processes occurring at the metal/solution interface. passivity, directed from the metal to the solution, and biofouling settlement, orientated towards the metal substratum. Electrochemical concepts, adapted to the characteristics of the biologically conditioned interface to interpret the corrosion process, and process analysis to interpret biofouling are used in a unified approach for understanding biofilms, MIC and their interactions.