1 Microbiologically Induced Corrosion of Concrete in Sanitary Sewerage System: A Review of Processes and Control Mechanisms Vinayak Kaushal, Ph.D., PACP, M.ASCE 1 and Mohammad Najafi, Ph.D., P.E., F.ASCE 2 1 Assistant Professor of Instruction and Researcher, E-mail: vinayak.kaushal@mavs.uta.edu 2 Professor and Director, E-mail: najafi@uta.edu 1,2 Center for Underground Infrastructure Research and Education (CUIRE), Department of Civil Engineering, The University of Texas at Arlington, Box 19308, Arlington, TX 76019. ABSTRACT Microbiologically induced corrosion (MIC) of concrete sanitary sewers is a common problem that demands a large rehabilitation investment every year. MIC is the result of dilute sulfuric acid (H2SO4) 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 H2SO4. The last conversion occurs above the liquid level under aerobic condition. The objectives of this paper are (1) to present a literature review of MIC processes and factors influencing them, and (2) to discuss control mechanisms and authors’ experience on development over years in understanding MIC of concrete (MICC) in sanitary sewerage environment (SSE). Published papers were identified that reported MICC in SSE for the past 30 years. The literature review and authors’ on-site and laboratory investigations suggest that MIC of concrete is a complex process that involves varied surface interactions. The addition of liquid antimicrobial additive as per standard procedure shows resistance of concrete to MIC and its direct relation with mixing time of admixture. Many empirical inputs like corrosion areas, corrosion rates, impact of cement and aggregate types varying with installation and repair of sewer structures are identified. The review results show variation in corrosion rates and other empirical inputs obtained on-site and through laboratory studies due to different testing procedures. Further research is needed to establish quantitative relations between empirical inputs related to MICC in SSE. Identification and development of more effective coatings and safe antibacterial agents will help inhibit colonization of SOB over exposed sewers and better understand environmental microbiology. INTRODUCTION AND BACKGROUND Sewer networks have been important public infrastructures for the society. A significant development of modern sewer systems could be dated back to the 19th century, due to the increasing concerns on public health (Wu et al. 2020). Microbiologically induced corrosion (MIC) of concrete is recognized as one of the main processes for degradation of concrete-based wastewater networks worldwide. It has been increasingly triggering high economic expenses, as