Why implement seasonal disinfection?
UV lights use large amounts of electric power. Shutting off the UV systems during the winter months (November 1 to April 30):
- reduces electricity usage
- lowers greenhouse gas emissions
- potentially extends UV equipment life
- allows for an annual maintenance overhaul of the UV systems.
The annual greenhouse gas reductions and cost savings are estimated to be:
- total energy saved: 1,572,000 kWh per year (equivalent to the annual usage of approximately 157 average NS households/year)
- total cost savings: $148,000
- total GHG Reduction: 1,100 Tonnes per year (equivalent to removing approximately 234 vehicles from the roads)
Does this approach affect or impact the harbour?
There will be no negative environmental impacts to the harbour during seasonal disinfection. Effluent released into the harbour will still undergo all other treatment processes.
Water clarity will remain the same and there will not be any smell related to the program. Bacteria in the water may rise; however, this will have no significant impact on other life in the harbour.
Are there any public health concerns?
Because seasonal disinfection happens during the winter months, when there is little or no direct contact use of the harbour, Halifax Water simply asks that anyone fishing or scuba diving during the program take proper precautions when cleaning and preparing fish and when cleaning scuba gear.
There are no additional public health concerns during the summer months as a result of seasonal disinfection. Based on previous testing data, once the UV systems have been turned back on, bacteria levels are expected to drop to safe swimming levels within 2 to 3 days.
What about the Polar Bear Swims?
The UV lights will be activated from December 25th to January 2nd to accommodate Harbour Polar Bear swims. This will allow bacteria levels to drop to safe swimming levels.
Is seasonal disinfection allowed under environmental regulations?
Halifax Water is undertaking the seasonal disinfection program with the approval of Nova Scotia Environment.
Numerous jurisdictions in Canada and the US allow for seasonal disinfection. The criteria under which seasonal disinfection is allowed varies in each jurisdiction. Below is a list of some of the jurisdictions, and the receiving waters (where the wastewater treatment facility discharges) for each location:
- New Brunswick Dept. of Environment and Local Government (fresh and marine/salt waters)
- Quebec Dept. of Sustainable Development, Environment and Parks (fresh and marine/salt waters)
- Ontario Ministry of Environment (fresh waters)
- Saskatchewan Ministry of Environment (fresh waters)
- British Columbia Ministry of Environment (fresh and marine/salt waters)
- NW Territories Environment and Natural Resources (fresh and marine/salt waters)
US (East Coast)
- Maine Dept. of Environmental Protection (fresh and marine/salt waters)
- New Hampshire Dept. of Environmental Protection (fresh and marine/salt waters)
- Massachusetts Dept. of Environmental Protection (fresh and marine/salt waters)
- Connecticut Dept. of Environmental Protection (fresh and marine/salt waters)
- New York Dept. of Environmental Conservation (fresh and marine/salt waters)