Another major expansion is eyed for the Annacis Island Wastewater Treatment Plant in Delta.
To accommodate population growth, the plant has been undergoing several expansion works to increase treatment capacity to serve 1.5 million people.
A new Digester No. 5 is proposed to be constructed by Metro Vancouver, and the long-range capital plan has identified a total budget of $456 million for design and construction of the project, which would be reviewed further in the Definition Stage.
Digesters convert organic sludge into biosolids in the overall wastewater treatment process.
A regional district staff report, recommending the Greater Vancouver Sewerage and Drainage District Board approve advancing to the Definition Stage, notes that due to continued population growth in the region and the upgrade of Iona Island Wastewater Treatment Plant and Lions Gate Wastewater Treatment Plant to secondary treatment, the amount of primary and secondary sludge produced from Metro Vancouver’s regional wastewater treatment plants is expected to more than double over the next decade.
A review of options confirmed the need for an additional digester at the Annacis Island plant to accommodate that growth as well as to allow the facility to continue to provide regional digestion capacity during the planned maintenance or process changes at the other plants.
The analysis also recommended that a subsequent new digester, called Digester No. 6, be considered in the future, the report notes, adding that staff are currently considering including a design for Digester No. 6 within the Digester No. 5 project to leverage design efficiencies, and it will be explored further within the Definition Stage.
As far as the cost, the report explains, “The cost estimating framework includes a rigorous approach to addressing challenges inherent in estimating future costs on large, complex, high risk, and lengthy projects, including using forecast cash flows to estimate escalation, as well as a contingency/risk reserve which are identified, managed, and quantified according to a standardized risk review process.”
The approved budget for the definition phase is included in the preliminary design phase budget of $6.9 million.
Construction would begin in early 2029 and completed by 2032.
