WCW24

ARROW Utilities (formerly Alberta Capital Region Wastewater Commission) serves a large geographical area surrounding Edmonton. It operates the 3rd largest WWTP in Alberta, serving 400,000 residents in 13 municipalities with a conveyance system including 138 km of gravity sewers and 58 km of forcemains. ARROW identified 3.2 km of 1350 mm diameter concrete pipe in need of repair or replacement. A design/build request for proposal was issued, and CIPP lining was selected as the rehabilitation method. The pipe alignment runs through an environmentally sensitive area and is close proximity to residences in other areas. The project was planned to minimize liner installations to reduce impacts to these areas while optimizing cost effectiveness. The project was installed in five segments, with the longest over 700 m. The liners required for these long installations far exceeded the allowable transport weight. The project was only feasible using a unique process, over the hole wetout (OTHW). For the vast majority of CIPP lining projects, the dry liner is shipped from manufacturing to a regional wetout facility where it is impregnated with resin. For the OTH process, the dry tube is transported to installation site, where a mobile wet out facility is constructed, and the resin is introduced. This is one of few OTH installations in Western Canada. This presentation describes the project background, design and tendering, and installation with the OTH system. It discusses key considerations including environmental impact mitigation, site for curing equipment and resin tankers, and the overall OTH process.