Manhole Rehabilitation
SPS can effectively rehabilitate manholes and other sanitary sewer structures such as wet wells and lift stations, with a sprayable calcium aluminate cement mixture.
Solution
SPS can effectively rehabilitate manholes and other sanitary sewer structures such as wet wells and lift stations, with a sprayable calcium aluminate cement mixture. This spray creates a dense and durable concrete lining that repairs the deteriorating surface and provides protection for years.
The coating is resistant to biosulfuric acid corrosion and extreme temperature variance. SPS can also help minimize, if not eliminate, structural inflow and infiltration problems.
Calcium aluminate has been used worldwide to rehabilitate ductile iron, steel and concrete structures for over 60 years.
Problems Solved
In the diagram below, you see several problems encountered: Infiltration, Structural Fatigue, and Corrosion.
Infiltration
Leaking rings, loose mortar, stub outs, precast joints, cracks, groundwater cyclic loading, overburdened treatment plants, increased treatment costs, surcharged lines, and environmental pollution are the results of infiltration.
For years, efforts to reduce or correct infiltration and its associated problems have concentrated on rehabilitating the mainlines although manholes and other underground structures commonly account for 25 to 30 percent of a system's infiltration. As shown in the illustration above, this infiltration typically occurs at manhole rings, through loose mortar and precast joints, and around mainline and stub out connections.
With the implementation of more frequent and sophisticated flow monitoring programs, there has been increased awareness for the need to rehabilitate each component of the sewer system.
Structural Fatigue
Subsidence from traffic loading, shifting and expanding soils, temperature variation, and cyclic ground water loading seriously weaken manholes and other sewer system structures. Over time, groundwater under hydrostatic pressure will find its way through fatigue cracks and weakened joints, leading to further deterioration of the structure. Fallen bricks and mortar can block the sewer flow, and may eventually lead to collapse, seriously endangering the surface and surrounding environment.
Corrosion
Micro-Biological Action, Hydrogen Sulfide Sulfide-rich effluents, a warm, humid environment, and long retention times create the perfect conditions for microbiologically induced corrosion (MIC).
MIC, a result of acid-producing bacteria known as Thiobacillus (concretivorous), is the principal cause of corrosion in a municipal sewer system. These microorganisms metabolize elemental sulfur oxidized from H2S sewer gas and produce sulfuric acid as a waste product, which then attacks the substrate. This sulfuric acid can quickly destroy ordinary concrete-based materials in a municipal sewer system.