Wastewater Treatment Plant Expansion and Improvements

1. Deconstruction of existing storage sheds was completed in May 2022 - 95% landfill diversion was achieved by salvaging useful materials, source separation, recycling of materials, and relocation of intact buildings off-site for continued use.
2. Environmental and Archeological Permits obtained May 2022 - Due to the nature of the activities at the WWTP site, significant contamination drilling, testing, mapping and reporting were required before any excavation activities could commence. This was required to determine and delineate any potential contamination and provide recommended rehabilitation. Due to the location of the site and the higher archeological potential, numerous archeological test digs, reporting and consultation with First Nations assessed the site before any excavation activities commenced.
3. Relocation of impacted utilities and mass excavation under the proposed new circular treatment tank was completed in September 2022 - All impacted utilities were decommissioned and/or rerouted around the circular excavation. This included the installation of 100m of 900mm storm main. All contaminated soil was removed and disposed of following strict environmental regulations and practices. To reduce offsite removal and trucking costs, excavated materials were repurposed for Public Works facility preload.
4. Ground improvements were completed in October 2022 - Deep soil mixing was implemented to densify the ground under the proposed circular tank to prevent ground liquefaction during an earthquake and increase seismic resistance. This was required as this infrastructure is designed to be a post-disaster structure.  Low-strength concrete panels were drilled to a depth of 13m. An onsite concrete batch plant was constructed to reduce concrete truck traffic and ensure consistency in product and delivery. 
5. Detailed Design and Tendering for the next phase completed in September 2022 - Eight contractor proposals were received and reviewed.

Next Steps: Contract award for the next phase of construction

We are currently interviewing contractors for the next phase of construction. Next phase of work includes; tank construction, piping, septage receiving station, rehabilitation and reuse of some existing tanks. The anticipated contract award is December 2022 with construction expected to start back up in early Jan 2023. Timeline for project completion is Q1 2024.

• Stormwater management established. Dewatering of excavation is on going. Erosion sediment control measures are in place.  
• Environmental monitoring during construction ongoing.
• Underslab piping fabrication, excavation, pipe installation and pipe encasement completed.
• Centre column foundation excavation, rebar install and concrete poured.
• Mud slab poured

Site Plan:

New Clarifier Design

• The District currently produces 45,000kg of CO2 emissions annually from trucking biosolids to the Callaghan Composting Facility. This project will reduce biosolids production by approximately 10% resulting in a considerable reduction in CO2 emissions.
• This upgrade will reduce aeration requirements in the treatment process resulting in a 35% reduction in electricity consumption for aeration helping the District to achieve its municipal energy and emissions reduction targets.

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.