Long-term external microbiologically influenced corrosion of buried cast iron pipes in the presence of sulfate-reducing bacteria (SRB)

This paper presents the long-term effect of sulfate-reducing bacteria (SRB) on the corrosion of buried cast iron pipes in soil and culture medium which has no previous research in literature. The comprehensive experimental design for investigating the external corrosion of buried pipes in soil and culture medium is developed in the current research. Coated specimens except their one side simulating the exterior surface of buried pipes are exposed to the SRB for 365 days in both the media. From the test results of corrosion rates and maximum pit depth, significant microbiologically influenced corrosion (MIC) of cast iron in the soil is observed as compared to the culture medium. The test results suggest that the testing of specimens in simulated soil so-lutions or culture medium instead of natural soil may lead to underestimated corrosion mea-surements for the buried pipe. The findings of this paper have practical applications for the prediction of failure of buried cast iron pipelines.