Biocorrosion microbial corrosion

Microbial activities that produce sulfides, organic, or inorganic acids causing direct metal oxidation are major driving forces in biocorrosion. Biochemical corrosion is enhanced by stagnant water, soil, and organic products. 

Dexter, S. C., Chandrasekaran, P., Zhang, H. J, and Wood, S., "Microbial Corrosion in Marine Environments Effect of Mi-crofouling Organisms on Corrosion of Passive Metals," Proc., Biocorrosion and Biofouling, H. Videla, Z. Lewandowski, R. Lutey, Eds., Buckman Laboratories, Int., Memphis, TN 1993, p. 171. 

Biocorrosion Biodeterioration Microbial corrosion Microbiologically induced corrosion... 

Biocorrosion has been estimated to be responsible of 10% of corrosion cases in the UK [17]. MIC has caused a lifetime reduction of flow lines in Western Australia from the designed 20h- years to less than 3 years [18]. hi addition, microbial corrosion has been addressed as one of the major causes of corrosion problems of underground pipelines [19]. 

In previous chapters, the importance of biocorrosion and its possible mechanisms were discussed. We also looked at some crucial factors that could increase the likelihood of MIC in a given system The particular focus of the chapter was the avoidance of microbial corrosion. However, almost all the time, what happeais in real life is that the system of concern has already been contaminated and the outstanding question is no longer how to prevent, but rather how to estimate the severity and extent of MIC. For instance, while for SRB-induced MIC, some investigators believe that no relationship exists between the corrosion rate and the number of the bacteria cells [1] the number of acid-producing bacteria in a system has a profound effect on the corrosion rate. 

SRB have been implicated in localised pitting corrosion, commonly referred to as microbially influenced corrosion (MIC). These and other anaerobes cause biocorrosion due to production of adds and other by-products (e.g.hydrogen sulphide), that cause cathodic depolarisation of metal surfaces. SRB also cause discoloration problems and production of foul odors. They are susceptible to bioddes, and can be controlled. Many other types of anaerobes may be present in the mill system, including the common helical-shaped, motile bacteria Spirillum. These corkscrew-shaped anaerobes are often seen under the microscope swimming in deposit samples and soured stock. 

Videla HA (1996) Manual of Biocorrosion, pp. 74-120 and 193-196, CRC press, Inc. Newman RC, Rumash K, Webster BJ (1992) The effect of pre-corrosion on the corrosion rate of steel in natural solutions containing sulphide Relevance to microbially influenced corrosion. Corrosion Science 33(12) 1877-1884... 

In general, biodeterioration is described as the undesirable degradation of materials by microorganisms. The term biodeterioration also implicitly includes biocorrosion and biodegradation. All three terms, corrosion, degradation, and deterioration, will be used in this chapter. In the following sections, microbial deterioration of metals, polymeric materials, concrete, and stone will be discussed. 

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