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Sealing Manholes from I&I Solves Lift Station Overload

Sealing Manholes from I&I Solves Lift Station Overload

By Ryan Cooper and Christian Smith September 10, 2025

The date is March 11, 2025, and the spring rains famous for creating flood conditions all along the Mississippi River in that stretch between Illinois, Mississippi, and Iowa (near Davenport) was forthcoming. Fact is, Rock Island Arsenal is located in the middle of the Mississippi River — a precarious place to conduct the business of the U.S. Army.

In advance of the spring rains, timing was perfect for the three-week project to restore 30 manholes, some as deep as 30 ft. The urgency was real and palpable. A rise in the water table would have been detrimental to an already dangerous situation. The problem: Groundwater infiltration was so intense, the excess water was overwhelming the lift stations and unable to perform.

What became brutally obvious, the excess flow coming from the annulus space between the host pipe and cured-in-place pipe (CIPP) liner was the hydraulic seals at the manhole end points had failed. In fact, these seals are often destroyed at installation only to be discovered later. This repair was not part of the original specification, but Critical Pipeline Repair crews installed new stainless steel Weko Seals to reduce the excess flow at the pipe connection. Testing each seal before moving to the next, every joint passed inspection — zero infiltration.

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Every manhole was unique including a few square vaults. All were precast concrete, either 48- or 60-in. width at various depths. Flow through plugs were utilized to reduce flow enough to properly perform surface preparation. Acutely aware of the importance of surface prep, CPR attacked this phase with a vengeance, beyond that of 5,000 PSI power sashing.

Injection grouting and hydraulic cement were utilized to stop active leaks. Rebuilding broken pipe required creativity including grinding existing pipe in the bench and using a combination of hydraulic cement and Mainstay ML-72 to rebuild the structure before installing the Weko Seals.

There is no silver bullet technology or technique for rehabbing manholes, but those that required a dry substrate to enhance adhesion of restoration materials would NOT stand a chance on this project. Fact is, Mainstay restoration mortar materials from Madewell Products prefers a damp surface to enhance adhesion and it encourages the protective epoxy topcoat by applied within four hours while the mortar is still green (uncured). This unique single curing process is an advantage for contractors and for owners as there is less chance for surface contamination and bottom line, it saves on labor hours and project cost.

By all standards, this federal project met the approval of the military engineering team.

Ryan Cooper is owner of Critical Pipeline Repair. Christian Smith is general partner at Critical Pipeline Repair.

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