Microbiological influenced corrosion of light alloys

Background: Pipe systems are part of our manmade environments. They can be found in urban environment where it is usually used to transfer water or sewage, in an industrial environment where it can carry hazardous waste (for instance, in the chemical industry), or oil and its products in the petroleum industry. Leakage in all pipe systems is an unwelcome event. The physical presence of microbial cells on a metal surface, as well as their metabolic activities, can cause Microbiologically Influenced Corrosion (MIC) or biocorrosion. The presence of bacteria can cause about tenfold increase in corrosion rate that can cause failure of corrosion resistant pipeline within a year or two. Objectives: Developing a model system of light alloys and beneficial bacterial biofilms for controlling MIC. Methods: We investigated the phenomenon of MIC by testing the effect of different bacteria, different light alloys (commonly used in chemical industry, construction and piping) and different environments. We determine corrosion rates by using three different measurements: weight loss, Potentiodynamic and Impedance spectroscopy in order to have a comprehensive and as accurate as possible data. Conclusions: We found significant differences in the bacterial corrosiveness tested at the various conditions. We will present our data from experiments in which alloys were first incubated with beneficial bacteria producing biofilm, and then, sequentially corrosive bacteria were added and the effect on corrosive rates was mesured. We would like to suggest the idea of "probiotic" bacteria to piping, i.e. "good bacteria" will generate biofilm inside piping and protect it from MIC.