Ashbridges Bay Treatment Plant – Effluent Disinfection System

The Ashbridges Bay Treatment Plant, Ontario’s oldest and largest wastewater treatment facility, has been operational since 1917. The Effluent Disinfection System project involves replacing the existing chlorine-based effluent disinfection system with a modern ultraviolet (UV) disinfection facility, ensuring compliance with federal regulatory requirements. This upgraded facility eliminates reliance on chlorine, supporting more environmentally friendly and sustainable wastewater treatment practices.

The project’s scope includes excavation and backfilling of the ash lagoon, upgrades to the plant water pumping station, and improvements to the seawall substation and gates. A new Disinfection Building was constructed, housing advanced UV treatment systems, effluent and bypass channels, underground service tunnels, mechanical service rooms, chemical storage and dosing areas, electrical power distribution facilities, and office spaces. Additional developments include new west and east bypass conduits, final UV effluent channels, sample buildings, a truck weigh scale, lighting installations, roads, and landscaping.

Extensive cast-in-place concrete activities involve pouring over 29,000 cubic meters of concrete. Approximately 200,000 cubic meters of contaminated soil are also being removed, significantly enhancing the plant’s operational efficiency and capacity and contributing to the preservation and restoration of Lake Ontario’s water quality.