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Wastewater disposal systems consist of concrete pipes, cast iron pipes, PVC pipes, manholes, pump stations and interceptors. Sanitary sewer pipeline collection systems and manholes are a vital component in every city’s infrastructure. These systems are designed to transport wastewater from residential areas to treatment plants. Failure of sewer pipes due to traffic loads is brought about primarily by the cyclic live loads transferred to sewer pipes via manholes on paved road surfaces. The causes of sewer pipe failure include subsidence of the area around a manhole, loosening of sewer pipe joints caused by such subsidence, seepage due to such loosening, cavities caused by seepage induced runoff of sand, and collapse of the ground due to such cavities. The structural integrity of the concrete components is severely compromised by corrosion. This erosion of the infrastructure by corrosion is causing a nationwide premature replacement of failed structures. Billions of dollars are being spent worldwide on the repair and maintenance of sewer systems and roads. Microbially-induced corrosion causes damage via micro-organisms. Deterioration is caused by acid excretion which etches the surface of concrete, penetrating the mortar surface, especially in sewer systems. The mechanisms of concrete and reinforcement deterioration in sewer environments and microbially-induced corrosion is discussed in detail in this paper. A comprehensive review is given of the role of hydrogen-sulphide and micro-organisms in the deterioration of concrete in sewer environments and of repair and rehabilitation measures, including the modification of the materials used in construction of sewer pipes; the coatings and the sewer treatments. A complete review of the microbial deterioration of concrete and its remedies is also included.
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