PRELIMINARY ASSESSMENT ON BACTERIAL DETERIORATION OF ASBESTOS REINFORCED CONCRETE PIPES FOR WATER DISTRIBUTION

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.