Location

Annacis Island, British Columbia

Client

Metro Vancouver

Delivery

2019 2023

Contract type

Lump sum, in partnership

Project

As part of a major upgrade of the wastewater treatment facilities, build a new outfall system to meet the needs of a growing population and safely release treated wastewater into the Fraser River. The plant treats about 175 billion litres of waste- water every year.

Challenges

Technically complex project: Construct two tun- nels for a total of 820 metres, two 40-metre deep on-land shafts and a marine diffuser in the Fraser River.

Ensure the outfall system operates in the event of an earthquake.

Solution

Use a tunnel-boring machine which will be assem- bled and launched in one of the two vertical shafts, and lifted when the tunnels are excavated in the second shaft.

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