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Microbiologically Induced Deterioration and Protection of Concrete in Municipal Sewerage System: Technical Review

2019; American Society of Civil Engineers; Volume: 11; Issue: 1 Linguagem: Inglês

10.1061/(asce)ps.1949-1204.0000424

1949-1204

Vinayak Kaushal, Mohammad Najafi, Johnny Love, Syed R. Qasim,

Water Treatment and Disinfection

Microbiologically induced deterioration (MID) of concrete sewers is a common problem that requires a considerable amount of rehabilitation investment every year. MID is the result of dilute sulfuric acid dissolving the cement matrix. The acid is produced by a complex series of chemical and biochemical reactions. Hydrogen sulfide (H2S) is produced by sulfur reducing bacteria (SRB) in the liquid phase, and then in time, this gas is converted by sulfur oxidizing bacteria (SOB) into sulfuric acid (H2SO4). The last conversion occurs above the liquid level under aerobic condition. The objective of this study is to present a literature review and authors' experience on progress acquired over years in understanding causes and effects of MID of concrete in municipal sewerage systems, methods to prevent and control MID from happening, and rehabilitation of already damaged pipes and structures. Published papers were identified that directly or indirectly reported MID of concrete in sewer structures over a period from 1980–2018. The literature review and authors' data suggest that deterioration of concrete is a complex process that involves varied surface interactions. Many empirical inputs that vary with installation and repair of various structures have been identified. The addition of liquid antimicrobial additive per standard procedure shows resistance of concrete to MID. Additionally, results show that resistance of concrete to MID increases with increase in the mixing time of the admixture. Further research is needed to study the concrete–microorganism interactions to have a better understanding of the microbiologically induced culture that leads to concrete deterioration in the sanitary sewerage systems. Additionally, there is a need to identify and develop more effective coatings, and safe antibacterial agents that can be used during construction of sewers to inhibit colonization of SOB over the exposed portion of the sewers.