Re: Searchmont Ski Resort –…

Re: Searchmont Ski Resort – Proposed Wastewater Treatment Plant (WWTP) – Submission to the Environmental Registry of Ontario

To the Ministry of the Environment, Conservation and Parks,

I am submitting this comment in response to the proposed wastewater treatment plant (WWTP) for the Searchmont Ski Resort. These concerns are based on a summary of findings from an independent wastewater treatment expert who reviewed the design brief.

Peak Flows May Be Higher Than the Design Assumes

The design uses a peaking factor of 2.0, but existing data from the resort shows peaks closer to 2.0–2.4, especially on weekends and holidays.

Without flow equalization, underestimating peak flows could lead to hydraulic overloading and reduced treatment performance during busy periods.

The design proposes an average daily flow (ADF) of 180 m³/day and a peak daily flow of 360 m³/day, which represents a peaking factor of 2.0. For a resort facility with highly variable occupancy — including weekends, holidays, and seasonal surges — a peaking factor of 2.0 appears low. Resorts typically experience sharp, short‑duration spikes in water use, and the expert review noted that a higher peaking factor would be more realistic for this type of facility.

Based on the existing flow data already collected by the proponent, the actual peaking factor appears to range from approximately 2.0 to 2.4. This means the design is using the lowest end of the observed range, rather than the upper end that would provide a margin of safety. Underestimating peak flows can lead to hydraulic overloading of the SBRs, reduced settling performance, increased solids carryover to filtration, and reduced UV disinfection effectiveness.

Given the sensitivity of the receiving river and the importance of accurate design flows, I request that MECP require the proponent to justify the selected peaking factor and demonstrate that the plant can reliably handle peak flows at the upper end of the observed range (2.4), not just the minimum value.