To meet the needs of Metro Vancouver’s growing population, Annacis Island Wastewater Treatment Plant is undergoing a major expansion that will increase its treatment capacity, while continuing to protect public health and the environment.
The plant, located in Delta, serves about 1.25 million people in the region. The expansion will allow the treatment plant to provide wastewater treatment for an additional 250,000 people.
A new outfall — the pipe that takes treated wastewater from the plant to the Fraser River — is required to support the plant expansion, construction of which started in the summer of 2019 and will continue into 2024.
A five-metre-diameter tunnel, approximately one kilometre long and 40 metres underground, will link the plant to the river, where a diffuser system will be installed on the river bed. The diffuser system consists of a 250-metre-long, 2.5-metre-diameter pipe buried in the riverbed, with 24 diffuser ports that discharge treated wastewater into the river over a large area. The diffuser ports have duckbill-shaped, one-way valves that allow effluent to be discharged out into the river while preventing river water from entering the outfall system.
The new outfall will be earthquake resilient, adaptable for sea level rise associated with climate change, and reduce the environmental impact of the discharge.
Read more about the expansion on the Annacis Island Wastewater Treatment Plant project page.