Missing Pre Treatment …

Missing Pre Treatment (Screening and Grit Removal)

The Kresin Design Brief does not include any information on initial pre treatment of sewage before it enters the SBR tanks. For a facility of this type and size, this is a significant omission. Most wastewater treatment plants using SBR technology incorporate screening and grit removal as standard practice to intercept rags, plastics, food debris, grit, and other solids that are routinely discharged from kitchens, accommodations, and public washrooms.

The expert review noted that pumping raw, unscreened sewage directly into an SBR basin is not typical and presents several risks, including:

• damage to pumps, valves, and aeration equipment
• reduced settling performance within the SBR
• increased solids carryover to tertiary filtration
• higher maintenance requirements
• potential operational upsets

The Napier Reid design documentation explicitly states that pre treatment equipment is excluded from their scope of supply. This means the proponent must provide it, yet the design brief does not address it at all.

Given the significant proportion of wastewater expected from restaurants and commercial kitchens—where solids, grease, and debris loads are substantially higher than domestic sewage—pre treatment is essential to protect downstream equipment and ensure reliable plant performance.

I respectfully request that MECP require the proponent to:

1. Clarify how raw sewage will be screened and protected before entering the SBR system.
2. Include appropriate pre treatment equipment (e.g., screening and grit removal) in the design.
3. Demonstrate that the SBR and filtration systems will not be exposed to deleterious materials that could compromise treatment performance or equipment longevity.

These steps are necessary to ensure the WWTP is designed to operate reliably under real world conditions and to prevent avoidable operational failures.