Wastewater Treatment

The City provides reliable wastewater collection and treatment services to protect public health and the environment and support the current and future needs of Orillia. The Wastewater Treatment Centre safely processes hundreds of thousands of cubic metres of wastewater each day, ensuring used water is treated in a responsible and sustainable manner.

Wastewater annual reports

The Wastewater Treatment Centre Annual Performance Report and the Wastewater Collection System Annual Performance Report outline annual performance reports for the City's Wastewater Treatment Centre and Wastewater Collection System, meeting regulatory reporting requirements.

Septage receiving station

The septage receiving station at 125 James St W, Orillia, ON L3V 6Y3 operates 24 hours a day, 7 days a week. An approved septage receival application will provide an access code, PIN, and key to use the service. 

Wastewater treatment process

The Wastewater Treatment Center serves the collection system through 19 pump stations that discharge to the main pump station. All influent is screened and passed through grinders prior to entering the treatment process.

Preliminary treatment includes coarse screening and aerated grit removal. Primary treatment is provided by three clarifiers, with primary sludge pumped directly to anaerobic digestion.

Secondary treatment consists of a six-cell activated sludge system operating as a plug-flow reactor, followed by five secondary clarifiers. Return activated sludge is recycled to the aeration basins, and waste activated sludge is thickened via dissolved air flotation prior to digestion.

Tertiary treatment is achieved using two cloth disk filters designed to remove phosphorus and suspended solids. Final disinfection is provided by a two-bank ultraviolet system prior to discharge through the outfall.

Solids are stabilized through two-stage anaerobic digestion. Biogas generated during digestion is used for heating, with excess gas flared. Digested sludge is stored in lagoons and land-applied to agricultural fields twice annually, typically in the spring and fall.

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