The Town of Slave Lake is located in the north-central area of the Province of Alberta, Canada.
The Town receives its water supply from Lesser Slave Lake. The existing conventional
treatment plant was constructed in 1982 and has a hydraulic capacity of 7 ML/d (1.85 MGD). As
part of the improvement program, chemical feed systems are upgraded based on jar test
optimization findings. A new powdered activated carbon feed system was installed by utilizing
the unused space of an old clearwell. New feed systems for polymer, acid and caustic were also
installed. This enabled the Town to practice enhanced coagulation to achieve required organic
removals, taste and odor control, and to stabilize plant performance. Other upgrades included
incorporation of tube settlers into two of the three clarifier basins (to achieve future capacity),
installation of automated sludge collection systems in the clarifiers, and the conversion of a third
clarifier to a disinfectant contact tank to achieve required Giardia and viral inactivation. Filter
underdrains and media were also replaced.
With such improvements and the practice of optimized enhanced coagulation, the water
treatment plant achieved all of its treatment goals (<0.05 NTU turbidity, <20 particles [>2 um]
counts/mL). The upgrades also allowed the Town to extend the service life of the treatment
facility beyond its original prediction, which could postpone a membrane upgrade by many more
years. The success of this plant upgrade and process optimization enabled the conventional
facility to produce water that is comparable to microfiltration-produced water. This paper
describes the above upgrades and implementation of upgrades while maintaining production. Includes 6 references, table, figure.