The City of Toronto has selected Stantec to deliver design and construction administration services for a new High Rate Treatment Facility (HRTF) at the Ashbridges Bay Wastewater Treatment Plant, according to a report published 23 August 2026 by Environmental XPRT. The selection was also reported on 30 August 2026 by Water Finance & Management.
Key takeaways
- Toronto has picked Stantec for design and construction administration of a 600-million-litre-per-day High Rate Treatment Facility at Ashbridges Bay, reported on 23 August 2026 by Environmental XPRT.
- The plant is a component of the Don River and Central Waterfront Wet Weather Flow System, which the city calls its largest and most significant wet weather flow program, reported by Water Finance & Management.
- Treatment is described as primary treatment for excess wet weather flows, with the aim of cutting combined sewer overflows to the Lower Don River, Taylor-Massey Creek, and Toronto's Inner Harbor, per Environmental XPRT.
- Delivery model is construction manager at risk; the project is in design and engineering, with construction scheduled for completion in 2036, per Water Finance & Management.
What happened: the award
Stantec has been selected by the City of Toronto to provide design and construction administration services for a new High Rate Treatment Facility, according to Environmental XPRT. The facility will be sited on the new landform at the Ashbridges Bay Wastewater Treatment Plant, the same report said, and forms part of the Don River and Central Waterfront Wet Weather Flow System, which the city describes as the largest and most significant wet weather flow management program in its history. Water Finance & Management also identified the HRTF as one of the final projects within that program.
Treatment scope is primary treatment for excess flows captured during wet weather events, with a stated design capacity of 600 million litres per day, per Environmental XPRT. The two outlets agree the facility is intended to reduce combined sewer overflows into the Lower Don River, Taylor-Massey Creek, and Toronto's Inner Harbor, and to build on the network of tunnels and infrastructure that already manages combined sewage and stormwater across the city, per Water Finance & Management.
What happens next: delivery model and schedule
Stantec will work with the city and the construction team under a construction manager at risk delivery model, which brings the construction manager into the project early to advise on design, constructability, scheduling, and cost management, per Environmental XPRT. The work is currently in the design and engineering phase, with construction scheduled to be completed in 2036, according to Water Finance & Management.
Commenting on the award, Jeff Berg, vice president and project manager at Stantec, said: "Toronto is making an important investment in protecting its waterways and preparing its infrastructure for the future. We're pleased to work with the City to provide a solution that enhances water quality, safeguards public health, and strengthens climate change resilience," as quoted by Environmental XPRT.
Specification read: what this means for a 600 MLD wet weather plant
The reported treatment capacity is 600 million litres per day, which converts to 600,000 cubic metres per day, a flow class typically associated with a large municipal wet weather works, per the 600-million-litre-per-day figure reported by Environmental XPRT. On a population-equivalent basis, a wet weather primary clarification train at this hydraulic capacity would commonly be benchmarked in the low millions of PE depending on per-capita loading, a figure that is a general industry range and not from the sources. A 600 MLD wet weather plant of this class would typically include coarse and fine screening, grit removal, and a high-rate primary stage such as enhanced ballasted flocculation or chemically assisted primary clarification, ahead of disinfection and outfall screening; the reported scope here is the primary treatment step, which is the rate-limiting stage for combined sewer overflow control. This event bears on the primary treatment step of the train, not on biological or tertiary nutrient removal.
For an operator running a wet weather flow program in the 300,000 to 600,000 m³/day range with combined sewer overflows to a sensitive receiving water and tightening consent limits, this Toronto project signals continued municipal investment in high-rate primary capacity as the lever for wet weather compliance, as framed by Water Finance & Management. Plant teams weighing similar upgrades can compare it against Integrated Sewage Treatment configurations and the broader Municipal applications catalogue, and benchmark screening and clarification choices against adjacent guides such as DAF vs Clarifier for Mining/Metals Wastewater in Nome, US: 2026 Factory Guide and DAF vs Clarifier for Transportation Equipment Wastewater in Egg Harbor City: 2026 Factory Guide. The full scope of sectors HydropureWater serves is listed under Industries We Serve.
FAQ
What is the headline capacity of the Toronto High Rate Treatment Facility? The plant is reported at 600 million litres per day, which is 600,000 m³/day, providing primary treatment for excess wet weather flows, per Environmental XPRT. The figure covers wet weather capture capacity, not dry-weather throughput.
When is the Toronto HRTF expected to be completed? Construction is scheduled to be completed in 2036, with the work currently in the design and engineering phase, per Water Finance & Management. That implies roughly a ten-year build window from the August 2026 award reported by Environmental XPRT.
What delivery model is being used, and why does it matter for suppliers? Toronto is using construction manager at risk, which brings the contractor into design early for input on constructability, scheduling, and cost management, per Environmental XPRT. For equipment vendors this typically shortens the front-end specification window and pushes selection decisions earlier than a traditional design-bid-build tender.
What does this award signal for a wet weather plant manager elsewhere? It signals that large municipalities are still funding high-rate primary capacity as the primary tool for combined sewer overflow control, with treatment scope limited to primary treatment for captured wet weather flows, per Water Finance & Management. Operator teams scoping a similar upgrade should expect demand to focus on screening, grit removal, and high-rate clarification packages, with biological and tertiary stages generally outside this scope. Lead times and capital cost for high-rate primary packages are project-specific and not reported in these sources.
