Biocorrosion Issues and Mitigation Strategies in Concrete Sewers and Wastewater Collection Systems

The collection and treatment of wastewater with subsequent sewer infrastructure are important for public health and modern civilization. The integrity and sustainability of those sewer materials ensures proper collection and treatment of wastewater while avoiding pipe fractures. The primary materials used in sewer pipes are concrete and steel, and they are subject to environments that are not only highly corrosive but also contain a myriad of microbial species that accelerate the corrosive attack. Failure occurs in sewer materials due to electrochemical processes and the environment associated with the pipes, including constituents in wastewater, air, and soil. As most of the infrastructure is comprised of concrete, many of the documented failures involve attack and degradation of aggregate and cement constituents. While selected to withstand corrosive environments, given extended service time, sewer and treatment components tend to fail from microbial, sulfur, and chloride attack. This presentation will detail the most common materials used in wastewater and sewage processes and their susceptibilities to biocorrosion and inorganic corrosion. The presentation will further highlight the details of novel prevention methods (e.g., coatings and concrete additives) and improved maintenance strategies to enhance the service lives of sewer systems.