The Arrowhead Wastewater Treatment Plant (WWTP) is one of the City’s facilities that treat up to five millions of gallons per day and discharges and pumps its Waste Activated Sludge (WAS) into a 6-inch pipeline that carries that material to a large trunk main which itself transports the wastewater three and a half miles to a larger west valley plant. This pipeline was installed 35 years ago when the plant was constructed, and was realized with epoxy-lined ductile iron pipe.
Over the past five years, there were a number of leaks and issues found with the pipeline that led to an assessment to be completed by GHD Inc., a global civil engineering firm with a local office in Phoenix. Their team completed an assessment of the pipelines and air valves, as well as some CCTV inspections of selected sections and found that the pipe had wall loss on the crown due to air valves not operating, as well as damage at the joints where corrosion had been taking place due to damaged epoxy from when the joints were pushed together. From this assessment project, the City determined that the pipeline would need to be replaced or rehabilitated.
Glendale then hired Achen-Gardner Construction and GHD to work together on a Construction Manager at Risk delivery method (CMAR) for the design and construction of the project. Due to the high traffic, business, and residential corridor, the City determined that remove and replace or a parallel pipeline was not an option. Review of multiple rehabilitation technologies was conducted, and because of the limited laydown area for materials at trenches, multiple vertical and horizontal bends, and operating pressure of the pipeline, Primus Line® was the chosen technology for the rehabilitation of the pipeline.
