Canadian Consulting Engineer
Lakeview Water Treatment Plant ExpansionEngineering
The Region of Peel's Lakeview Water Treatment Plant in Mississauga west of Toronto, provides drinking water to over one million people. In June 2007 the Region commissioned a 360 ML/d Phase 1 expansio...
The Region of Peel’s Lakeview Water Treatment Plant in Mississauga west of Toronto, provides drinking water to over one million people. In June 2007 the Region commissioned a 360 ML/d Phase 1 expansion to the plant, increasing its capacity to 820 ML/d.
CH2M HILL managed the class environmental assessment (Schedule C) for the project, as well as the conceptual design, process pilot testing, detailed design, regulatory approvals, and construction and equipment supply contracts.
After reviewing over 20 different options using value engineering, the design team selected a treatment process that includes ozone, biologically active carbon and ultra-filtration membranes. The plant is the world’s largest application of this process train.
The chosen solution provides the best water quality, most consistent performance, smallest plant footprint, and favourable lifecycle costs.
The ozone and biologically activated carbon contactors provide taste and odour control and disinfection, and the ultra-filtration membranes provide control of particulates, including pathogens. The plant accommodates the future addition of ultraviolet disinfection as an additional barrier to control pathogens.
Advantages of the process train
The selected treatment train provides multiple barriers for disinfecting the water supply, for controlling its taste and odour, and for removing turbidity. The train also provides the best practice treatment of emerging trace contaminants such as endocrine disruptors and personal care products.
The oxidation and biological phases work in synergy to remove taste-and odour-causing organics, without using a coagulant.
The oxidation-biological process converts soluble compounds to a biogrowth which is removed from the contactors by backwashing. The biogrowth is also effective in capturing particulates in the raw water. This allows the membrane fibres to operate with lower fouling rates and the membrane back pulse wastes to be essentially innocuous.
By avoiding coagulation the process reduces the amount of solids residuals and associated treatment costs. Waste solids of the ozone-biologically active carbon-membrane (OBM) process are 90% less in mass than the equivalent conventional treatment process. As well, 97% of the process residual comes in the form of chemical-free spent membrane backwash that can be returned to Lake Ontario via an outfall without further treatment. Because the plant uses fewer chemicals in the production of potable water than conventional treatment processes, there is less truck traffic associated with delivering chemicals to the plant and disposing of its residuals.
The oxidation-biological process is also particularly effective at handling excursions in raw water quality.
Compactness and Energy Efficiency
The ozone-biologically active carbon-membrane (OBM) process provides 40% more treatment capacity in half the footprint compared to the conventional treatment process.
The compactness of the process not only leaves space for a future expansion of the process train within the plant, but it also means the above-ground structures are not so large that they had to encroach on land that had historically been used by the community for recreational purposes, such as a baseball diamond to the north. With construction on site completed, the diamond can be returned to the community.
The client made a significant effort to maximize energy efficiency in the process and the facility. For example, horizontal split case pumps with high efficiency motors were selected over end suction models. The 10% increase in pumping efficiency over the life of the project justified the additional capital and engineering cost. In addition, the client elected to recover heat from the adjacent 760 ML/d high lift pumping station to provide heat for the treatment facilities.
The total project was completed on schedule in June 2007 and was just below the $154-million budget (of this, the OBM facility was $99.5 million)
Name of project: Lakeview Water Treatment Plant Expansion, Phase 1, Mississauga, Ont.
Award-winning firm (prime consultant): CH2M HILL Canada, Toronto (Norm Huggins, P. Eng., Ken Mains, P. Eng., Bob Pickett, P. Eng., Bob Christopher, P. Eng., Erik Dullerud, P. Eng., John Mills, P. Eng., Laurie Boyce, M. A. Sc., Julian Maclean, P. Eng., Jesus Garcia-Aleman, P. Eng., Brian Cooper)
Owner/client: Region of Peel
Other key players: GeoCanada (geotechnical), North American Construction, Kenaidan Contracting, Bennett Contracting (Millgrove), Detra Builders (contractors), OCWA (operating authority)