How Queensland’s Oldest and Largest Sewer Was Upgraded While the City Slept

Abstract

Deep under Brisbane’s CBD lies Brisbane’s oldest and largest sewer pipeline. Averaging 1.5 meters in diameter, the S1 Main Sewer runs a total of 12km, stretching from Toowong to the Eagle Farm pump station and is buried eight stories beneath the ground. Built back in 1915, the S1 serves over 750,000 people, carrying 60 percent of the city’s wastewater. The 100-yearold sewer needed an upgrade. Works involved rehabilitating a section of the pipeline between James Street in Fortitude Valley to the Eagle Farm pump station, spanning a 5.7km distance. Asset owner Urban Utilities first awarded the rehabilitation works to leading pipeline infrastructure company, Interflow, back in 2015. Since then, Interflow relined 40 individual sections (averaging 160m) of pipeline using a spiral-wound lining system. The upgrade of Brisbane’s oldest and largest pipeline undertaken below one of its busiest roads, makes it one of the most challenging sewer upgrades to be completed on Australian soil. The increasing depth of the sewer meant the relining solution had to be incredibly strong to withstand the extra pressures. Working closely with technology partner, Sekisui Rib Loc Australia, Interflow identified an innovative way of reinforcing a spiral-wound liner with steel. The new solution, called RibSteel, involved clipping continuous stainless steel strips into the outside of the PVC strip in the lined pipe, which makes it exceptionally strong. The seven-year project is now complete, and the impressive yet hidden piece of infrastructure will go on to serve the Brisbane community for generations to come. 1 No-Dig Down Under 2023 How Queensland’s Oldest and Largest Sewer Was Upgraded While the City Slept Simon Carr1 and Steven Latimer2