Duffin Creek Wastewater Treatment Plant Expansion & Upgrades

The Duffin Creek Water Pollution Control Plant Expansion Project, including Headworks, Elec­trical Substation, and Enhanced Phosphorus Removal Facility, was an expansion to the existing plant to take the average dry weather flow to 630ML/d. The overall combined project was valued at $220 million CDN.

The liquids phase of the project consisted of over 83,000 cubic meters of concrete, 12,000 tons of rebar, 133,500 cubic meters of excavation, and 550,000 total combined civil, mechanical & electrical man hours of labour productivity.

The overall scope of work consisted of the addition of the following processes:

• Equipment and piping systems within tunnels and galleries
• Electrical distribution
• Six new longitudinal sludge primary clarifiers; six new fine bubble aeration tanks
• A new blower building
• Six new longitu­dinal secondary clarifiers
• Two new chlorine contact tanks
• A new disinfection building
• A new effluent pumping station
• New effluent channels
• New & upgraded electrical power feeds
• New HVAC and building services
• New SCADA system for the expanded facility

Commissioning of the plant required sewage from the new headworks facility and a joint tie-in of influent chambers. Timing of the tie-ins and headworks commissioning was critical to ensure the Liquids Modules contract was commissioned on schedule. Tie-in of the new effluent tunnel into the existing outfall chamber had to take place with zero interruption of existing outfall ser­vices. Along with the mass excavation, several concrete encased duct banks and HV feeders, and un­derground process piping along with yard piping were also a major portion of the scope of work.

Careful planning and coordination was required among NAC’s multi trade workforce to ensure installations were completed with a high regard to quality.