Asbestos reinforced concrete (ARC) pipes were commonly used for drinking water distribution
networks in North American, primarily from middle1940s to early 1980s. In the City of Regina, Canada
approximately 68% of all water mains are ARC pipes, to a total length of 535 km. In this preliminary
research it was found that bacteriological activities within the internal surface coating (patina) as well as
within the concrete could induce bio-deterioration, which eventually leads to pipe failures. Identification
of the bacterial consortia was performed using the S43048 protocols for the chromatographic detection
of the C5 to C20 fatty acids methyl esters (FAME). Using proprietary library software, high similarity
indexes were statistically generated, confirming the ubiquitous nature of the bacterial community
(consortium) within the patina (a distinctively fibrous internal coating) of various pipe samples.
Bacteriological activities caused deterioration to the ARC pipes was primarily related to acid producing
bacteria. . These bacteria are fermentative in the reductive environments, generating sufficient fatty
acids that would reduce the pH into the acidic range of 3.5 to 5.5 and could cause structural failures in
the concrete.
Keywords: Asbestos reinforced concrete (ARC), Patina, Microbiologically influenced corrosion, Acid
producing bacteria