Located in northwest Calgary, the Bearspaw Water Treatment Plant provides drinking water to more than half of the city’s one million residents. Commissioned in 1972, the treatment plant has undergone several expansions to increase capacity, improve process efficiencies, as well as improve the quality of the treated water supply. A major plant upgrade program, which began in 2003, introduced a high-rate ballasted flocculation process for pretreatment, and added residuals treatment and sodium hypochlorite disinfection.
The new treatment processes coupled with the age of the existing electrical equipment, highlighted the need to evaluate the plant electrical infrastructure. The City of Calgary Water Resources retained Associated to complete an Electrical Master Plan for the plant. The Master Plan included a plant-wide electrical equipment assessment and evaluation of the emergency power capacity of the plant, currently being provided by two, 2.8 Megawatt diesel generators. The project team strategy proposed a four-phase solution to accommodate future upgrades.
The two existing 13.2 Kilovolt – 4160 volt and two 13.2 Kilovolt – 480 volt transformers were replaced with six new transformers to provided double-redundancy. Two existing 480 volt switchboards and motor control centres were also replaced with a new main-tie-main breaker arrangement providing power supply redundancy and switching options for maintenance and operational servicing.