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

The province of Ontario is Canada's most populous province with over 8 million residents out of a total population of 27 million, The Provin ce is situated in the eastern portion of North America and stretches f rom 41 degrees N to 50 degrees N, All the Great Lakes fall within Onta rio's boundaries and the Province is estimated to have over 280,000 la kes, The area along Lake Ontario is home to 5 million of the residents who are serviced by 11 large sewage treatment plants. The remaining 4 03 treatment plants are scattered throughout the province, with an ave rage 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 va rious types of sewage treatment plants, as well as potential areas wit hin each plant where significant energy savings could be generated. By using this information, Ontario Hydro hoped to assess the potential t o 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 initiative s. It was found that several major opportunities existed, These includ ed: that up to 25% of power currently used can be reduced by introduci ng energy efficient measures of all the unit operations in wastewater treatment plants, aeration accounts for 42% of the power usage, influe nt and effluent pumping - 20%, and dewatering - 6%. Of this influent a nd effluent pumping, specifically influent represented the best target area as significant aeration system upgrade had already taken place.