Role of anaerobic and aerobic bacteria in localised corrosion: field and laboratory morphological study

Abstract

Bacterial evidence was found in the biofilm deposited on the surface of an API X52 steel coupon following exposure to flowing seawater within a pipeline for 60 days. Extensive corrosion pitting was observed on the steel surface after removing the biofilm. Several types of anaerobic and aerobic bacteria were isolated from the biofilm. The anaerobic bacteria were cultured and grown in API RP 38 culture medium and the aerobic bacteria were grown in a general heterotrophic culture medium. The morphological and chemical characteristics of the bacteria were determined. Subsequently, separate specimens of API X52 pipeline steel were inoculated with each bacterial strain in under laboratory conditions. The specimen exposed to the anaerobic bacteria showed several micropits of different sizes on its surface while that exposed to the aerobic bacteria showed freedom from surface pits.CEST/2094

The Effect of FeSO₄ Containing Solution on Microbiological Influenced Corrosion by Desulfovibrio Baculatus Bacteria on API 5L X65 Steel

“…Robert Jefrey and Robert E Merchers (2002) found a globular corrosion product at the surface of the samples after certain period of corrosion test. Analysis on this product shows that this globular corrosion product is iron hydroxide [6]. This type of hydroxide was found also at the sample no 16 (figure 2) that was immersed for 21 days as shown on figure 10.…”

Induction of pitting corrosion on stainless steel (grades 304 and 316) used in dairy industry by biofilms of common sporeformers

“…Romero et al . () suggested that the formation of a biofilm on a metal surface changed local conditions and associated changes in gradients of pH, dissolved oxygen, chloride and sulphate, which then created conditions associated with localised corrosion. Xu et al .…”

“…One likely reason is that EPS form a layer on the surface, which cuts off the oxygen supply to the cells that are directly in contact with the metal surface, hence creating anaerobic conditions, which could induce corrosion on metal surfaces having biofilms. Romero et al (2004) suggested that the formation of a biofilm on a metal surface changed local conditions and associated changes in gradients of pH, dissolved oxygen, chloride and sulphate, which then created conditions associated with localised corrosion. Xu et al (1999) suggested that biofilms result in pitting, crevice corrosion and stress corrosion cracking due to the metabolic processes of the living organism.…”

THE EFFECT OF FeSO4 CONTAINING SOLUTION ON MICROBIOLOGICAL INFLUENCED CORROSION BY DESULFOVIBRIO BACULATUS BACTERIA ON API 5L X65 STEEL

“…Robert Jefrey and Robert E Merchers (2002) found a globular corrosion product at the surface of the samples after certain period of corrosion test. Analysis on this product shows that this globular corrosion product is iron hydroxide [6]. This type of hydroxide Figure 10.…”