Clarkson Wastewater Treatment Plant Expansion, Biosolids Complex

Alberici Constructors, Ltd. was awarded the contract for the Clarkson Wastewater Treatment Plant Expansion. The work involved construction of a new biosolids handling complex. The project included installation of three rotary drum thickeners, two dewatering centrifuges, a dewatered sludge conveyor system, high pressure cake pumps and associated piping. A sludge storage hopper, truck loadout facility, polymer make up systems, odour control scrubbers and chemical tanks are part of the installation scope of this project. Alberici installed a portion of the new piping gallery tunnel between the new sludge digestion facility and biosolids complex. Modifications were also made to existing piping and associated new piping, as well as the pumping, electrical, instrumentation and mechanical works necessary for a fully operating biosolids handling facility.

The expansion is comprised of a large reinforced concrete foundation located approximately 10 metres deep, which ties into existing shale rock with rock anchors. The anchors were drilled into the lowest level of excavation and grouted into place inside the rock.

The excavating within the shale rock native materials presented a challenge to Alberici and subsequently slowed the concrete foundation program. However, subcontractor co-ordination and working in adjacent areas assisted in maintaining the site progress and expediting the foundation work.

The expansion also contained underground concrete storage and process tanks on either side of a complex mechanical pump station room. Large sludge digesters and hoppers are housed within the building and fed by shafted screw conveyors.

The construction allows the plant to reform municipal sludge and process it into cake form where it is eventually transported via truck to another Region of Peel site for further processing.

This project forms part of the Region of Peel's plan to increase the capacity of the Clarkson Wastewater Treatment Facility from 163 million litres per day to 200 million. Alberici mobilized its forces in August 2004 with a completion date of May 2006.