Powell River Consolidated Wastewater Treatment Plant

Located in Powell River, the Consolidated Wastewater Treatment Plant and Linear Works project involved the construction of a new greenfield facility to centralize wastewater treatment from multiple existing sites across the region. This initiative marked a major step forward in meeting future regulatory commitments, significantly improving wastewater treatment performance, and reducing environmental impact on the marine ecosystem.

The new facility uses an activated sludge process with secondary clarification, followed by ultraviolet (UV) disinfection to meet treatment objectives and effluent quality standards. Upstream of the secondary treatment system, fine screening and a vortex grit removal unit reduce solids and grit entering the process. Sludge treatment includes a Dissolved Air Flotation (DAF) system for thickening secondary sludge, followed by aerobic digestion and dewatering with centrifuges. Approximately 50% of the treatment equipment was novated, ensuring a seamless transition in ownership and integration.

Graham was also awarded the associated Linear Works and Lift Stations project, scheduled for completion alongside the main plant. This scope included approximately 12 km of new conveyance piping—ranging from 100 mm to 450 mm in diameter—installed using both conventional cut-and-cover and horizontal directional drilling (HDD) methods. Trench shoring was implemented where required. The lift station works comprised two fibreglass-reinforced plastic (FRP) stations, one cast-in-place reinforced concrete station, and one precast concrete station.