E.L. Smith Water Treatment Plant Upgrade

Continued population and economic growth in the Edmonton capital region is increasing overall customer demand for treated water. With the support of Associated Engineering, EPCOR increased the E.L. Smith Water Treatment Plant production from 240 million litres per day (ML/d) to an ultimate capacity of 600 ML/d — a 150% increase in production capacity with only a 20% increase in plant footprint.

The upgrades included a new river water intake line, new raw water pump house and transmission main, treatment process upgrades, new water disinfection systems, general site upgrades, and a 560-m long potable water transmission main extension drilled 10 metres below the North Saskatchewan river bed.

Reusing infrastructure

EPCOR challenged Associated Engineering to reuse existing infrastructure as much as possible in their design of the upgrade.

Large increases in plant capacity can rarely be achieved without a commensurate increase in the plant footprint or an extensive retrofit of the existing plant process equipment. In this project, however, the capacity was expanded reusing the existing process equipment in innovative ways.

The infrastructure had to be fitted into components that had a very different set of design parameters and criteria. In addition, the engineers had to develop construction staging plans to ensure that existing systems continued to operate and that the treated water quality was never com- promised throughout the construction and commissioning periods.

By reusing structures that may have otherwise been decommissioned or demolished, the project greatly reduced the need for new materials and infrastructure and for disposing of old structures. Minimizing the overall footprint of the plant also minimzed the building’s energy demand and associated greenhouse gas emissions.

Environmentally friendly disinfection

To reduce the potential environmental and safety risks associated with transporting and handling chlorine gas for disinfection, Epcor decided to replace the chlorine gas system with an on-site sodium hypochlorite generation system. The new system uses salt to generate a weak (0.8%) sodium hypochlorite solution as the disinfectant. The on-site generation of hypochlorite offers fewer environmental and safety risks. It also can be run during off-peak periods, thus reducing peak power generation demands. When it was commissioned in 2008, this plant’s on-site sodium hypochlorite generation system was the largest system of its kind in Canada.

River water intake and fish return

The Department of Fisheries and Oceans required that the fish return system would achieve a 95% fish survival rate. Following extensive computational and physical modeling, the intake was designed with a very low suction velocity so most fish can easily swim away. Further, any fish that do become drawn into the raw water pump house are gently returned to the river with a unique, mechanical, fish-return system. Since the implementation of this facility, at least two other projects have been designed based upon its intake design.

The upgraded plant was officially opened in June 2008, three years after preliminary design began. The final construction cost was $140 million.

Project: E.L. Smith Water Treatment Plant Upgrade, Edmonton

Award-winning firm -prime consultant: Associated Engineering (Ian P.D. Wright, P. Eng., Hans U. Wolf, P. Eng., Steve Croxford, P. Eng., Austin Kanagasuriam, P. Eng., Jennifer J. Plamondon, P. Eng., Matt S. Henney, P. Eng., Sean Bolongaro, P. Eng., Dusanka Stevanovic, P. Eng., Chris Bredo, P. Eng., Alan Miller, P. Eng.)

Owner: EPCOR Water Services

Other key players: AMEC, D.E. Schaefer Architect, Northwest Hydraulic Consultants, Golder Associates, Gibbs & Brown Landscape Architects.