The Municipality of Grey Highlands is undergoing a Municipal Class Environmental Assessment (EA) to assess the capacity of the Markdale Wastewater Treatment Plant (WWTP). The EA process will look at the ability of the Markdale WWTP to accommodate increased demands from future development. If improvements are needed to the treatment process, both operational and infrastructure improvements will be identified.

This Assessment will consider the following key issues:

• Project future sewage flow and loadings from industrial users.
• Determine the adequacy of the existing WWTP at the projected flow and recommend improvements to allow the WWTP to meet future flow requirements. Review the suitability of the current WWTP system and biosolids management strategies against the future organics loading.
• Evaluate whether further re-rating of the facility can be accommodated, or it long term and robust solutions are needed.
• Determine the feasibility of a headworks being incorporated into the WWTP.

The Municipality is working with consulting engineers J. L. Richards & Associates Limited for this project.

The EA is being conducted in accordance with the Phases of the Municipal Engineers Association Municipal Class Environmental Assessment for a Schedule C project.

• Phase 1 - Identify the problem or opportunity.
• Phase 2 - Identify alternative solutions to address the problem or opportunity by taking into consideration the existing environment, and establish the preferred solution taking into account public and review agency input. At this point, determine the appropriate Schedule for the undertaking and document decisions in a Project File for Schedule B projects, or proceed through the following Phases for Schedule C projects.
• Phase 3 - Examine alternative methods of implementing the preferred solution, based upon the existing environment, public and review agency input, anticipated environmental effects, and methods of minimizing negative effects and maximizing positive effects.
• Phase 4 -Document, in an Environmental Study Report, a summary of the rationale and the planning, design and consultation process of the project as established through the above Phases. Make this documentation available for comment by review agencies and the public for 30 days. Wait another 30 days after the comment period to see if the MECP issues a ‘Section 16 Order’ or a ‘Notice of Proposed Order’. Under either Order, the project can only proceed to Phase 5 after all the Order’s conditions are fulfilled.
• Phase 5 - Complete contract drawings and documents. Proceed to construction and operation, monitor construction for adherence to environmental provisions and commitments. Where special conditions dictate, also monitor the operation of the completed facilities.

The most recent updates for this project will be found at the top of the page.

A Notice of Public Open House #2 was issued on November 25, 2025 and added to the Document Library.

Following PIC No.1 on September 28th, 2023, the preferred solution was identified to be upgrading the existing Markdale Wastewater Treatment Plant (WWTP). This will allow for a 50% increase in capacity, equivalent to a total WWTP flow rating of 2,580 m3/d. During Phase 3, several design concepts for the preferred solution were assessed. The recommended option consists of a new mechanical headworks building, an upgraded aeration system, and an expansion of the rapid infiltration basins (RIB).

The main tasks of Phase 3 were to undertake field studies to refine the preferred design solution. A Stage 2 Archaeological Assessment (AA) is nearing completion for the site. A hydrogeological study is also in progress. A Terrestrial Ecology Report was finalized during Phase 3.

Consultation is a key element of the Class EA process and has continued with various agencies, Indigenous groups, and stakeholders throughout this project. The purpose of Public Information Center No.2 is to solicit feedback on the recommended design concepts for the preferred solution.

Date: Thursday December 11, 2025
Location: Walter Harris Memorial Library - 75 Walker St, Markdale
Time: 4:00 p.m. to 6:00 p.m.

Phase 3 Field Studies are underway:

• Hydrogeology
• Surface Water Assessment
• Stage 1 Archeology
• Cultural Heritage Study
• Terrestrial Ecology
• Stage 2 Archeology

The display boards have been added to the Document Library from the Public Information Session hosted on September 28, 2023.

The Notice of Study Commencement and Public Information Session was issued on September 7, 2023 and has been added to the Document Library.

This Class EA will assess the ability of the Markdale Wastewater Treatment Plant (WWTP) to accommodate increased demands from future development in the serviced area. The purpose of this Schedule C Class EA is to evaluate and select the preferred wastewater treatment alternatives and design concepts for the Markdale WWTP.

A Public Information Session is being hosted to provide an overview of the project and findings to date.

Date: September 28, 2023
Location: Markdale Hall - 75 Walker St, Markdale
Time: 6:00 p.m. to 8:00 p.m.