10 Miles of Interceptor CIPP Rehabilitation on the Rillito: Fid-Bau Portal

10 Miles of Interceptor CIPP Rehabilitation on the Rillito

Poppe, Mark / Foley, Dan / Ortiz, Noel

The North Rillito Interceptor (NRI), located in Pima County, Arizona, was installed in the early 1960s and was reaching its end of useful life. This project involved cured-in-place pipe (CIPP) rehabilitation of approximately 53,000 linear feet of 15-in. to 36-in. diameter sanitary sewer interceptor, rehabilitation and replacement of 126 manholes and access structures, and flow management up to 15 million gallons per day (MGD). Manhole and access structure rehabilitation utilized various technologies including epoxy coatings, rigid polyurethane coatings, and structural fiberglass inserts. Manhole and access structures replaced were increased up to 10 feet in diameter with precast polymer concrete. Throughout the interceptor project, residential development, vegetation overgrowth, riparian habitats, private property encroachment, and Pima County Natural Resources, Parks, and Recreation improvements made access and maintenance difficult for Pima County Regional Wastewater Reclamation Department (PCRWRD). Gaining access to the interceptor easements was a significant challenge for contractors during the pipeline rehabilitation. To prevent disruption to the entire 10-mi alignment at one time, the project was divided into six phases. Throughout the project extensive public communication was provided. The project resulted in a fully rehabilitated interceptor with improved hydraulics, reduced odor generation, and a renewed pipeline life of 50+ years. Easements were re-established for PCRWRD to access and maintain the system, while preserving riparian habitats, implementing a plant preservation plan, and minimizing disruption to the Rillito River bike path system. Shared flow management between other PCRWRD projects attributed to substantial project cost savings.