An Overview of the Anaerobic Corrosion of Underground Metallic Structures, Evidence for a New Mechanism

Abstract

Anaerobic corrosion of iron occurs throughout the world and, from an economic standpoint, is quite costly. Sulfate-reducing bacteria, primarily of the genus Desulfovibrio, are responsible for this type of corrosion. It has been postulated that corrosion by these bacteria is caused by their removal of hydrogen from the surface of iron causing it to go into solution. Evidence is presented which indicates that this mechanism may not be responsible for the main corrosive effect of these organisms. These bacteria appear to cause corrosion by producing extracellularly, under anaerobic conditions, a highly corrosive product in addition to hydrogen sulfide. The factors controlling the fate of iron in anaerobic environments, conducive to the growth of sulfate-reducing bacteria, may depend on whether iron sulfide film formation by hydrogen sulfide occurs first, thereby inhibiting corrosion, or whether the highly corrosive substance comes in contact with the iron before film formation has occurred, thereby accelerating corrosion. The antagonistic actions of these two compounds, hydrogen sulfide and the corrosive product, on corrosion produced by sulfate-reducing bacteria, could explain the conflicting observations on anaerobic corrosion noted by investigators in the field and laboratory.

Utilization of Cathodic Hydrogen by Desulfovibrio vulgaris (Hildenborough)

“…XRD analysis showed them to consist mainly of crystals of vivianite, with sulphur also present, probably as iron sulphide. Booth et al (1962) and Iverson (1981) have also found vivianite on iron and steel in anaerobic environments where SRB have been active. They have both found vivianite to inhibit rather than promote the corrosion of iron.…”

“…On the other hand several workers have shown that the conversion of sulphides to the highly corrosive elemental sulphur might be the cause of high corrosion rates (Farrer & Wormwell, 1953;Hardy & Bown, 1984;Maldonado-Zagal & Boden, 1982;Schaschl, 1980). Iverson (1968Iverson ( , 1981. however, has presented contradictory evidence indicating that anaerobic corrosion is due to the production of highly corrosive phosphide compounds by the SRB.…”

The Ecology of Microbial Corrosion

“…[From Pankhania (1988 There has been considerable controversy surrounding the mechanism of anaerobic microbial corrosion. Studies by Iverson and co-workers (Iverson, 1981(Iverson, , 1984Olson, 1983, 1984;Iverson et al, 1986) suggest an even more complex mechanism involving both sulfide and phosphides. Although there is some recent support for the involvement of phosphides, the mechanisms are still far from clear (Weimer et at., 1988).…”

“…The relationship between sulfate-reducing bacteria and anaerobic corrosion has been extensively reviewed (Iverson, 1981;Hamilton, 1985;Pankhania, 1988). The large range of organic substrates and metabolic versatility of the organisms, including limited oxygen tolerance, explain the ubiquity of these bacteria.…”

“…The literature has been extensively reviewed (Crombie et at., 1980;Iverson, 1981;Tiller, 1982;Gragnolino and Tuovinen, 1984;Hamilton, 1985;Pankhania, 1988). In this review, we intend to focus on aspects of microbial corrosion that have received little attention despite an increasing awareness of their importance.…”