Continual Manhole Rehabilitation Helps Utility District Avoid Replacements

Lakehaven Utility District, located in Washington State, consists of 312 miles of sewer lines and 32 pump stations.Taking an active role in consistently rehabilitating their sanitary sewer lines, the Lakehaven Utility District routinely evaluates and addresses deteriorating infrastructure.

Recently, Lakehaven restored 70 precast concrete manholes (860 vertical feet) that were exhibiting medium to heavy deterioration with exposed aggregate. Having completed various projects throughout the past three years for the Lakehaven Utility District, including 102 manhole rehabilitations, applicator Pro-Vac had the extensive experience necessary for successful manhole rehabilitation. Pro-Vac was well prepared to assist the city in finding an epoxy coating solution that would provide protection against corrosion caused by high levels of H2S.

Pro-Vac has been a part of Epoxytec’s Certified Applicator Network since 2013. Their extensive experience using CPP Sprayliner extends to a variety of different applications, including water holding tanks in Mossy Rock, the Pool Pump Station at Wilsonville Water Park, a hospital pump basin, and numerous manholes throughout Washington and Oregon.

Prior to surface preparation, Pro-Vac took measures to protect the flow lines, then removed all material from the inside of the structures and pressure washed the interior. On the heavily deteriorated structures, Epoxytec’s Mortartec Silicate, a cementitious base coat, was applied to create a smooth finish. Once cured, the structure was pressure washed again, and CPP Sprayliner was applied at 120 mils. Spark tests and a pull test were used as a final measure to ensure proper application.

No two rehab applications are exactly the same. “The first project went well, but the second project had challenges because the easement lines ran parallel to a creek with a bad access road. We also experienced heavy rain and mud mixed with high flows in the lines,” noted Ralf Lopez of Pro-Vac. “Additionally, the third project was behind a house and ran through a park, making it difficult to access.” These challenges are simply part of the job when it comes to manhole rehabilitation: that’s why training and experience are an integral part of the process.  Pro-Vac was able to meet and overcome those challenges, to the satisfaction of Lakehaven Utility District.


*Project profile featured in the January 2023 edition of Cleaner Magazine