McLoughlin Point Wastewater Treatment Plant Outfall

A $775m multi-year programme to provide tertiary wastewater treatment, one of the highest levels of treatment available, prior to discharge into a body of water between British Columbia, Canada and the state of Washington, USA.

AECOM and its joint venture partner, Graham Construction, designed and facilitated the construction of North America’s largest solid wall High Density Polyethylene (HDPE) outfall, a critical component of the integrated wastewater treatment programme for the Capital Regional District (CRD).

Completion of the $775m, multi-year project provides tertiary wastewater treatment, one of the highest levels of treatment available, prior to its discharge into a body of water between British Columbia, Canada and the state of Washington, USA. The project has ended decades of historical debate and public concern related to the area’s unsustainable waste management.

The outfall’s unique and innovative features include construction in two distinct segments: a 120-metre-long inshore segment, constructed with steel pipe by “wet exit” microtunnelling; and an 1800-metre-long offshore segment, with a HDPE pipe and installed by “float and sink” construction. Minimizing its impact to the surrounding environment, the outfall supports increased infrastructure capacity with long-term resilience.

North America’s largest solid wall HDPE outfall has a 1.92 kilometres long, 2250-millimetre DR26 HDPE pipe, ending the area’s decades-long history of untreated wastewater.

In fact, the CRD was the last major coastal community in North America to discharge untreated sewage into the marine environment. Canada’s federal regulations, which were introduced in 2012, required that the CRD set up and run its treatment plant by the end of 2020.