The Thornbury Wastewater Treatment Plant was completed in 1994, with a rated capacity of 3580 m3/day. This project will include the construction/installation of all equipment required for operation of the Extended Aeration treatment system to increase capacity to 5,330 m3/day.
Step 1
Civil site prep work
Step 2
Addition of one extended aeration tank, including aeration system, required accessories, and alum addition
Addition of one clarifier and associated mechanical system
Increase the current Ultraviolet disinfection system to meet 5,330 m3/day
Replacement of existing air blowers, including required valves, controls, instrumentation and distribution piping
Additional 14,000 m3/day mechanical screen and associated hardware to be added
Incorporate energy efficiency throughout the plant
Construction of a new outfall pipe to Georgian Bay
Expansion of the plant was approved as part of the 2020 Town Budget. It is anticipated that the detailed design will be completed in Q3 2022. Construction will be completed in two steps to allow for scheduled advancements. The first step is scheduled to be completed in Q3 2022, with the second step beginning immediately afterwards. The project is expected to be completed in Q4 of 2026.
Why Now?
To replace end-of-life equipment and ensure the Thornbury Wastewater Treatment Plant is capable of providing reliable service in line with the forecasted growth of the community.
Project Updates
August 28, 2025
The Town has hit a key milestone in the Thornbury Wastewater Treatment Plant Expansion project. All new operational equipment has been installed, and NAC has handed operations of the facility over to the Town's Wastewater team for a 45-day test period of the new hardware and monitoring equipment. This test period will allow the Town's Wastewater Operators to familiarize themselves with the new equipment, and to log any deficiencies or issues to be addressed before the project is completed. While there still a few restoration tasks yet to be completed such as paving and hydroseeding, this test period is a crucial step towards the completion of the project.
August 5, 2025
A portion of the Beaver River Trail between Grey Street South and Arthur Taylor Lane will be closed on Wednesday, August 6 and Thursday, August 7. This closure will be in place to allow a contractor to complete work related to the Thornbury Wastewater Treatment Plant Expansion project. Trail users are asked to use the detour route as indicated.
July 21, 2025
The Town is starting to enter the final stages of Phase 1A of the Thornbury Wastewater Treatment Plant Expansion. Finishing touches are being made on the administration building, site grading is underway in preparation for restoration, and all three of the facility's aeration tanks are back in service. Detailed work continues as the Town's contractor looks to wrap up the project in the coming months.
March 25, 2025
The Town's contractor has been working on upgrades to multiple systems throughout the plant. The headworks, aluminum sulphate system and ultraviolet disinfection system are all being upgraded to meet the needs of the plant's final capacity targets..
December 24, 2024
2024 has been an extremely successful year for the Thornbury Wastewater Treatment Plant Expansion. The Town’s contractor has completed construction of the new aeration and secondary clarifier tanks, while also installing new functional components in the pre-existing aeration and clarifier tanks. These additions and new systems will ensure that the plant runs as efficiently as possible for years to come.
In the new year, work will continue on installing the new electrical and plant monitoring systems, along with various pumps and treatment systems. An additional screening system will be installed in the Headworks Building, and the plant’s Ultraviolet Treatment Building will be expanded to handle the increased plant capacity. To ensure that the treated effluent is clean enough prior to being discharged while this expansion is being completed, NAC has installed a standalone temporary UV system.
October 10, 2024
The Town's contractor continues to work on installing the functional components of the new aeration and secondary clarifier tanks, and refreshing the components of the existing tanks. New aeration systems are being installed in the new aeration tank #3 and existing aeration tank #1. Concrete grouting is being completed on the new secondary clarifier #3 in preparation for leak testing, and secondary clarifier #1 has passed leak testing and is ready for functional testing. Additionally, pumps have been installed in the new Activated Sludge Building and the south expansion of the Ultraviolet Disinfection Building has been completed.
July 8, 2024
The Stage 2 Archaeological Field Study for the installation of the Thornbury Wastewater Treatment Plant's new outfall pipe will be taking place on Thursday, July 11 and Friday, July 12. The work will take place on the Grey Street road allowance extension between Bay Street East and Georgian Bay. The contractor does not plan to use any mechanized equipment, and will be reinstating the test sites to pre-existing conditions following the work.
June 28, 2024
The Town's contractor continues to make great progress on the Thornbury Wastewater Treatment Plant Expansion project. Work continues on the new aeration tank #3 including the installation of the channel walls and air header piping along the upper walkway. The walls of the new secondary clarifier #3 have been completed and have undergone concrete testing. Upgrades to the existing secondary clarifier #2 have been completed, and work is under way on upgrades to the existing secondary clarifier #1. Excavation around the base of the Ultraviolet Disinfection building has begun to allow for expansion of that facility, and work also continues on the installation of utilities within the new Activated Sludge building and on upgrades to the Administration Building.
April 3, 2024
Work has continued to progress at the Thornbury Wastewater Treatment Plant. The new aeration tank has been leak tested, and the walls of the new secondary clarifier are under construction. The Town's contractor has also installed the upper walls and roof of the new Activated Sludge building, and work has begun on upgrades to the Administration Building. For more information, watch the project update video above.
December 6, 2023
The Town's contractor has made great progress on construction of the new aeration tank, clarifier and Activated Sludge building. NAC is closely monitoring each and every concrete pour, and utilizing insulated tarps, temperature sensors and other tools to ensure that the concrete cures properly. For more information, watch the project update video above.
October 20, 2023
The Town's contractors have been working on building and installing the formwork and rebar for the walls of the new Activated Sludge building and aeration tank. Hydrostatic testing of the piping that will be located beneath the base of slab of the new secondary clarifying tank has also been completed. Work will continue over the coming weeks to prepare for the next round of concrete pours, which will include the walls for the aeration tank and lower walls for the activated sludge building. Upgrades to the existing Secondary Clarifier No.2 are scheduled to start in early November.
August 3, 2023
Site excavation work has been progressing well. The Town's contractor has completed the majority of the excavation work required for the new aeration tank, clarifier and Return Activated Sludge / Waste Activated Sludge (RAS/WAS) building. The initial concrete pour for the bases of the new aeration tank, RAS/WAS building and Mixed Liquor Chamber is scheduled for this week. Following that, they plan to begin installation of the underground piping for the new clarifier as well as the formwork and rebar for the new aeration tank.
July 5, 2023 - Construction Notice issued
The Town has issued the Construction Notice for the Thornbury Wastewater Treatment Plant Phase 1A Expansion. This Notice has also been mailed to property owners within the immediate vicinity of the project site.
Staff Report CSOPS.23.017 was presented at a Special Meeting of Council on Friday, April 14. The report requested that the budget for the Thornbury Wastewater Treatment Plant Expansion Phase 1A construction be increased by $4,873,000, to a total budget of $29,000,000 to allow staff to award the construction tender. The request was carried as Council voted to approve the request.
This staff report was brought directly to Council as there is an urgency to keep the project on schedule, and ensure there is adequate capacity at the treatment plant to meet the ongoing needs of the Town.
March 27, 2023 - Upcoming geotechnical work on Grey Street North
On behalf of the IBI Group, a contractor will be completing additional geotechnical work to inform the engineering of the new outfall line for the Thornbury Wastewater Treatment Plant. The geotechnical work will be completed over 1-2 days in the month of April. A track-mounted drilling rig will be used to drill boreholes on Grey Street North and along the unopened Grey Street North road allowance between Bay Street East and the shore of Georgian Bay. Formal notices have been hand delivered to all neighbouring properties.
February 21, 2023 - Site preparation and tree removals
Site preparation work for the Thornbury Wastewater Treatment Plant Expansion will begin this week. A contractor will be onsite to begin required tree removals. These trees are being removed to accommodate the realignment of the plant entrance and associated site grading. An Arborist Report and a Species at Risk Screening Report were completed for the site, and no concerns were found. A buffer of trees between the Treatment Plant and Highway 26 will be maintained, and the Town intends to plant additional trees on the site to enhance buffers following the completion of construction.
November 30, 2022 - Offshore surveying work
Survey crews will be completing water depth measurement work by boat offshore from Grey Street in Thornbury on Wednesday, November 30, 2022. The work will include surveying the bottom of the lake to aid with the detailed engineering phase of the new Thornbury Wastewater Treatment Plant outfall line.
September 13, 2022 - Upcoming topographical survey work
The IBI Group’s topographical survey crew will be on site Thursday, September 15 and Friday, September 16 from 9:00 a.m. to 4:00 p.m. to survey areas related to the new Wastewater Treatment Plant outfall line that was identified in the May 3, 2022 Staff Report.
May 3, 2022 - Expansion update and request for budget increase
A Staff Report was presented to Committee of the Whole on Tuesday, May 3 providing an overview of the progress on the Thornbury Wastewater Treatment Plant Expansion Phase 1A.
The report also asked Council to approve an increase of $4,500,000 to the original project budget which was approved in 2019, and to approve the negotiated procurement of engineering services for the design of a new outfall line.
Staff Report OPS.25.015 is scheduled to be presented to Committee of the Whole on Tuesday, March 18. The report provides an update on the staging site for the construction of the new Thornbury Wastewater Treatment Plant Outfall pipe. Given multiple factors, staff have identified Lora Bay Park as the location for the assembly of the new outfall, and Council has approved this location. The outfall will be assembled at Lora Bay Park in segments, and then towed across Georgian Bay for installation north of the Grey Street road allowance in Thornbury. The report includes a communications plan, along with a set of Frequently Asked Questions covering how Lora Bay Park was selected and what the impacts to the public will be.
Contractors are expected to be on site at Lora Bay Park on Tuesday, March 18 to begin topographical surveying. This information will be used to assist with the development of a site plan for the future construction work.
Staff Report CSOPS.23.017 was presented at a Special Meeting of Council on Friday, April 14. The report requested that the budget for the Thornbury Wastewater Treatment Plant Expansion Phase 1A construction be increased to allow staff to award the construction tender. Council voted 6-0 to approve the request.
Council discussion of the Staff Report begins at the 4:30 mark of the meeting recording.
Staff Report CSOPS.22.025 was presented at a Special Committee of the Whole meeting on May 3, 2022. The report provided an update on the Thornbury Wastewater Treatment Plant Expansion project, and requested Council approval for an increase to the project budget and for the design of the new outfall line to be awarded to IBI Group. Committee of the Whole voted 4-2 in favour of the recommendations. This was adopted by Council at their meeting on May 24, 2022.
Committee discussion of the Staff Report begins at the 4:07:00 mark of the meeting recording.
Staff Report CSOPS.21.065 was presented at a Special Meeting of Council on September 2, 2021. The report provided a summary of the next steps leading up to a planned third-party review of the Thornbury Wastewater Treatment Plant Expansion plans. Council voted 6-1 in favour of receiving the report and directed that $25,000 be set aside from the Wastewater Reserve Fund for the review.
Council discussion of the Staff Report begins at the 20:20 mark of the meeting recording.
Initial excavation workFormwork for new extended aeration tankFormwork for new extended aeration tankGround level of new RAS/WAS BuildingLeak testing new extended aeration tankSite overview during construction
Outfall Installation
A new outfall is to be constructed to accommodate the approved increased capacity to the Thornbury Wastewater Treatment Plant. The new outfall alignment extends from the Treatment Plant to the shoreline of Georgian Bay, following within the existing Grey Street road allowance. The outfall alignment includes the crossings of King Street East (MTO Highway 26 at Grey Street) and at Bay Street.
The outfall extends 1500 m to the north from the shoreline into Georgian Bay. The first 600 m of the outfall pipe from the shoreline will be dredged, and the remaining 900 m will lay on the lakebed in the deeper water. Due to fisheries windows, the marine portion of the outfall will need to begin no earlier than July 15, 2025, and be completed no later than September 30, 2025.
