Four projects were located at the Duffin Creek WCPC; WPCP Liquid Modules Expansion, Dewatering and Incineration Facilities, WPCP Stage 3 Liquid Expansion, and the Electrical Substation.
Primarily retrofit work at Duffin Creek Water Pollution Control Plant consisted of modifications to the existing process systems involving; conversation of eight aeration tanks from surface aeration application to fine bubble diffusers; the addition of two new blower buildings and associated air piping and equipment to support the retrofitted aeration tanks; modifications to the existing mechanisms for the eight secondary clarifiers; expansion to the existing chlorine contact tanks by the addition of new channels requiring sequenced tie-ins during operational flows; underwater modifications to the existing plant outfall; significant yard piping; and new RAS pump and chemical feed buildings.
The concrete sub-grade package associated with the $200 million solids phase expansion to the existing facility was negotiated directly with the client as a change order to NAC’s existing $ 154 million liquids phase in order to maximize the benefit of labour forces currently onsite in meeting critical milestone completion dates. This work consisted of an additional 60,000 cubic meters of excavation, 11,000 cubic meters of concrete, 1,400 tonnes of rebar and 69,000 additional manhours.
The work at Duffin Creek consisted of a major capacity expansion to the existing facility totaling some $ 400 million of construction over 36 months.
This first phase of work dealt with the liquids stream expansion. This work was sequenced with the solids expansion to the facility for a synchronized timely completion of both liquids and solids phases. The liquids phase consisted of some 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, piping systems and 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; and a new SCADA system for the expanded facility
The work of this contract added an additional 10,000 cubic meters of concrete to the previously secured $ 172 million liquid & concrete sub-grade phases of the project bringing the total concrete volume for the site to 104,000 cubic meters. The work also consisted of; 4 new mechanical bar screens; 4 aerated grit tanks; augers & pumps; new blowers, coarse bubble aeration; chemical tanks & metering pumps; grit classifiers and conveyors; a new odor control system; grit tank covers; CPP yard pipe installations; electrical distribution; and HVAC & plumbing systems.