Importance of Manholes
Manholes are an important part of a wastewater collection system. They allow access to the sewer line, they join together sewers, align and/ or change the flow direction, as well as provide ventilation so gases & odors can be released from the sewer lines. They provide access in order to clean, inspect, maintain and rehabilitate sewer lines but unfortunately, if manholes are not properly maintained, they will contribute to an excessive amount of I & I (inflow and infiltration) which leads to the deterioration of that same wastewater collection system.
There are a wide range of ways to rehabilitate or seal manholes in order to eliminate these leaks. There are 3 main types of rehabilitation options: cementitious mortar linings, polymer linings and cured-in-place manhole (CIPM).
Cementitious Mortar Lining
These linings can be installed quickly, and though they require stopping infiltration and cleaning the manhole, they do not require the structure to be completely dry.
Polymer Lining
Spray- or hand-applied polymer linings include epoxies, polyurethanes or polyureas.
Cured-in-Place Manhole (CIPM) Lining
CIPM lining is a solid liner that is made up of a felt tube saturated with resin to form a solid liner. This method works well with any size and shape manhole and is water resistant.