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City of Kennewick CIPP Project

Introduction

J-U-B Project Manger, Ben Haws, PE,  likes living and working in the Tri-Cities, WA area because he feels directly connected to the community that he is serving. For the past couple of years, we have been working on rehabilitating some of the City of Kennewick’s major sewer trunk pipes. Here is a summary of one success we have had right here in our backyard.

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Background

Corroded pipes are a little bit unsettling (see Figure 1). The City ran across some corroded manholes and pipes as part of their proactive asset management program. This happened to be a major trunk serving a large portion of the City. To further complicate matters, this trunk in the Union Pacific Railroad right-of-way is right next to the Columbia Irrigation District Canal.

The City selected our Kennewick Office to assist them with this critical project. A team of players was needed to investigate, find a solution, and carry out the plan. This was a team of local staff backed by expertise throughout many J-U-B offices.

Summary

In 2018 J-U-B performed manhole inspections and reviewed the Closed-Circuit Television (CCTV) information that the City had taken of the existing sewer pipes. We also contacted the Union Pacific Railroad (UPRR) and began the coordination and paperwork process to get review and approval from the UPRR.

We conducted sewer gas monitoring by dropping some odor loggers into strategic manholes to find the source of the H2S gasses that are responsible for the corrosion of the concrete pipes and manholes. With this information, the City was able to address the source of the corrosion.

We assisted the City in evaluating the best course of action – eventually selecting a trenchless rehabilitation versus a complete re-construction. We decided to split the project into 2 phases, which helped to get the most critical pipelines rehabilitated soonest. Phase 1 involved the installation of 2,000+ LF of cured-in-place pipe (CIPP). This involved insertion of a felt fabric “sock” that is inflated inside the existing concrete pipe and then injected with steam to create a chemical reaction that turns the sock into a solid pipe. Phase 1 also involved the installation of 2 new manholes and 35 LF of 24-inch diameter pipe. Existing manholes were then coated on the inside to provide corrosion protection.

The Phase 2 project allowed for two types of CIPP – UV cure or Thermal (steam or water) cure. The awarded Contractor opted to do UV cure on 2,000+ LF of pipe and was one of the first projects in J-U-B’s history to do UV CIPP. The project also involved 500+ LF of 8-inch forcemain, boring under the UPRR tracks, and coating of existing manholes.

The project has been a success for the City and J-U-B. We have cost-effectively extended the life of a very important asset – saving the ratepayers money that would otherwise be spent on re-constructing this very expensive asset. The City operators and managers sleep a little better at night knowing that their north sewer interceptor has been protected from collapse. It has also strengthened our relationship with one of our most important Clients and has allowed us to give value back to the City that we love. This is J-U-B’s Core Purpose in action – “Helping Each Other Create Better Communities.”