Wastewater Treatment Plant Expansion and Improvements

A new secondary clarifier and concentric ring bioreactor is being built. This major upgrade will increase treatment capacity, provide system redundancy, increase seismic and flood resiliency, improve plant performance and effluent quality, decrease biosolids production and associated energy usage, and decrease carbon emissions and handling costs. 

The Squamish Wastewater Treatment Plant is reaching full capacity and requires upgrades to meet population growth forecasts and redundancy requirements in accordance with the Municipal Wastewater Regulations. This refers to the need for 75% biological treatment capacity with the largest unit out of service. Currently the plant has 55% redundancy which would be reduced further based on projected future flows.

The existing treatment units are approaching end of life and and do not meet current seismic and flood protection design considerations. The new post-disaster infrastructure will be able to withstand seismic and flood events, which is of critical importance in light of recent catastrophic flooding events across British Columbia. 

The scope of work includes:

• Construction of new secondary clarifier and concentric ring bioreactor.
• Conversion of an old clarifier tank into a primary clarifier (optimize existing infrastructure and create ongoing value from old infrastructure throughout its remaining useful life).
• New septage receiving station (septic systems from Squamish and recreational sites along the Sea to Sky corridor will benefit from the improved septic receiving station).
• Electrical and control system upgrades.

Construction is anticipated to take place through summer 2025.

The total project cost is estimated at $20.2M. The project is funded by Developer Cost Charges and grants. $8,080,808 of this project is proposed to be financed by debt to spread the cost of the project out over time, ensuring that future taxpayers also support the upgrade. The annual utility bill impact represents approximately $5.00 per residential property.

A budget amendment was presented to Council on April 18, 2023, due to cost escalation related the project’s Request for Proposals (RFP) bids being significantly higher than anticipated when the financial plan (FP) was originally drafted. Read the Report to Council. 

Cost escalation factors: 

General cost escalation due to post-Covid pressures:  

1. Supply chain issues, delays and shortages.
2. Increased materials cost.
3. Increased labour costs.

Project-specific cost escalation: 

1. Ground improvement for improved seismic resiliency. Deep soil mixing was chosen due to tight space constraints and proximity to nearby infrastructure. Low vibration method, that reduced risk of settlement to existing infrastructure. Higher cost than alternative methods (stone columns, compaction piles). Cost $2.2M.
2. BC cement shortages last summer due to supply chain issues and exacerbated by Lafarge plant fire. Further Increased costs for deep soil mixing which required a large volume of cement; and
3. Contaminated soils were encountered onsite. Unknown condition at the time of budgeting. Expensive to delineate, remove and dispose of.