To: Ontario Ministry of the…

To: Ontario Ministry of the Environment, Conservation and Parks (MECP)

I am writing to provide comments on the proposed wastewater treatment plant (WWTP) for the Searchmont Ski Resort. My submission is based on a detailed technical review conducted by an independent wastewater treatment expert, who examined the Kresin Engineering Design Brief, the Greenland Assimilative Capacity Study (ACS), and the Napier Reid treatment system documentation.

The expert’s review identifies several significant concerns that warrant further clarification, redesign, or additional supporting information before an Environmental Compliance Approval (ECA) is issued. These concerns relate to influent characterization, flow assumptions, treatment system sizing, redundancy, monitoring, and the adequacy of the assimilative capacity dataset.

Below is a summary of the key issues, with specific technical details and values drawn directly from the expert’s review.

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1. Influent Strength Appears Underestimated (Major Concern)

The design assumes influent wastewater is “typical domestic strength,” with values such as:

- BOD: 110 mg/L
- TSS, TKN, TP also within weak–medium domestic ranges

However, approximately 50% of the resort’s daily flow will originate from restaurants and commercial kitchens, which are well documented to produce significantly higher concentrations of:

- BOD (often several hundred to several thousand mg/L)
- TSS
- TKN
- TP
- Fats, oils, and grease (FOG)

The design brief does not acknowledge the impact of commercial kitchen wastewater on influent strength, nor does it provide evidence that the proposed influent concentrations were derived from actual site data.

Implications of underestimating influent strength include:

- Undersized biological treatment capacity
- Insufficient aeration/blower sizing
- Inadequate tank volumes
- Higher sludge production than accounted for
- Risk of failing to meet ammonia and phosphorus limits

The expert identifies this as the most significant risk to treatment performance.

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2. Flow and Peaking Factor Concerns

The design uses:

- Average Daily Flow (ADF): 180 m³/day
- Peak Daily Flow (PDF): 360 m³/day
- Peaking factor: 2.0

Existing flow data show peaks ranging from 2.0 to 2.4, and resort operations (weekends, holidays, events) are likely to produce even higher variability.

Additional concerns include:

- The 225 L/bed value used for hotel units does not align with Ontario Building Code (OBC) values.
- OBC specifies 500 L/person for resort hotels and 250 L/room for regular hotels/motels.
- OBC values represent peak day flows, not average flows.
- No upstream flow equalization is included in the design.
- The only flow meter appears to be post treatment, located in the Napier Reid tertiary system.
- This will not measure true influent flows entering the plant.

The expert recommends installing a raw sewage flow meter at the influent pumping station.

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3. Missing or Inadequate Pre Treatment

The Kresin Design Brief does not describe any pre treatment (screening or grit removal) prior to pumping raw sewage into the SBR basins.

Napier Reid explicitly lists pre treatment as excluded from their scope.

This is a major concern because:

- Raw sewage from restaurants will contain debris, solids, and grease
- Lack of screening can damage pumps, valves, and SBR equipment
- Grit accumulation can reduce tank volume and impair biological processes

Most WWTPs of this type include at least coarse screening and grit removal.

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4. Treatment Technology – Capability and Limitations

The expert confirms that SBRs are proven and reliable, and Napier Reid has a strong track record. However, performance depends on:

- Accurate influent strength
- Adequate aeration and alkalinity
- Proper winter insulation
- Skilled operation and maintenance

Phosphorus Removal
The proposed chemical precipitation + cloth disk filtration is standard and capable of meeting low TP limits.

Comparable plants cited by the expert:

- Havelock WWTP:
- Limit: 0.14 mg/L
- Achieved: 0.07 mg/L (2020 data, 65% capacity)

- Teeswater Formosa WWTP:
- Objective: 0.1 mg/L
- Limit: 0.15 mg/L
- Achieved: 0.1 mg/L (2024 data, 74% capacity)

However, these results depend on accurate influent assumptions, which are currently in question.

Ammonia
Summer ammonia targets are low but achievable if:

- Influent TKN is accurately estimated
- Aeration capacity is sufficient
- Alkalinity is adequate (chemical addition is included in design)

If influent nitrogen is higher than assumed, nitrification performance may be compromised.

Nitrate
The ACS appears to mix units (NO₃ vs NO₃ N).
The CCME guideline of 13 mg/L applies to NO₃, equivalent to 2.93 mg/L as N.

The creek data are reported as nitrate as N, so the comparison should use 2.93 mg/L, not 13 mg/L.

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5. Lack of Redundancy in Key Treatment Components

While the SBR system includes four parallel trains (good redundancy), the tertiary systems do not:

- Only one UV disinfection unit
- Only one cloth disk filter

The expert recommends splitting these into two parallel units to allow continued operation during maintenance or equipment failure.

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6. Winter Conditions and Insulation

Insulation is listed as an exclusion in the Napier Reid documentation.

The expert notes:

- Biological processes slow significantly at low temperatures
- The design assumes wastewater temperatures as low as 5°C
- Achieving 5°C requires proper burial and insulation of tanks

Without insulation, winter performance may be compromised.

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7. Inflow & Infiltration (I/I) Risks

Given shallow groundwater conditions, the expert stresses:

- Tanks and piping must be fully sealed and watertight
- Excess infiltration can cause hydraulic overloading and treatment failure

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8. Backup Power Not Mentioned

The design brief does not reference backup power for the WWTP.

This is a critical omission for any surface water discharge, as power outages can lead to untreated bypasses.

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9. Monitoring Plan Not Provided

Neither the Design Brief nor the ACS describes a monitoring program.

The expert recommends:

- Influent monitoring
- Effluent monitoring (weekly is typical for surface water discharge)
- Surface water monitoring (upstream and downstream)

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10. Assimilative Capacity Study (ACS) – Insufficient Dataset

The ACS uses 16 months of creek data.

Based on the expert’s experience, MECP typically requires 2–3 years of data to capture:

- Seasonal variability
- Year to year variability
- At least two summer low flow periods, when the creek is most sensitive

The proponent could have continued collecting data after initial submission to strengthen the dataset.

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Conclusion and Request

Based on the expert’s detailed review, there are several critical uncertainties and omissions in the current proposal that should be addressed before an ECA is issued. These include:

- Underestimated influent strength
- Questionable flow assumptions and lack of influent flow monitoring
- Missing pre treatment
- Lack of redundancy in UV and filtration
- Missing insulation
- No backup power
- No monitoring plan
- ACS dataset shorter than MECP’s typical expectations

I respectfully request that MECP require the proponent to address these issues through revised design documentation, updated influent characterization, and additional ACS data collection before approval.

Thank you for considering these comments.