EMERGING TRENDS IN ELECTRICAL ENERGY USAGE AT CANADIAN (ONTARIO) MUNICIPAL WASTEWATER TREATMENT FACILITIES AND STRATEGIES FOR IMPROVING ENERGY EFFICIENCY

The province of Ontario is Canada9s most populous province with over 8 million residents out of a total population of 27 million. The Province is situated in the eastern portion of North America and stretches from 41°N to 50° N. All the Great Lakes fall within Ontario9s boundaries and the Province is estimated to have over 280,000 lakes. The area along Lake Ontario is home to 5 million of the residents who are serviced by 11 large sewage treatment plants. The remaining 403 treatment plants are scattered throughout the province. with an average size of 20 000 m 3 /d. Ontario Hydro commissioned a study of the wastewater treatment plants to identify the main power users at the various types of sewage treatment plants, as well as potential areas within each plant where significant energy savings could be generated. By using this information, Ontario Hydro hoped to assess the potential to reduce the load and identify any electrical efficiency improvements, fuel switching and load shifting opportunities that may exist as well as the impact of environmental regulations on power saving initiatives. It was found that several major opportunities existed. These included: ■ that up to 25% of power currently used can be reduced by introducing energy efficient measures ■ of all the unit operations in wastewater treatment plants, aeration accounts for 42% of the power usage, influent and effluent pumping - 20%, and dewatering - 6%. Of this influent and effluent pumping, specifically influent represented the best target area as significant aeration system upgrade had already taken place.