Following its public announcement of a major combined sewage discharge, the City of Hamilton, Ontario has introduced a series of new measures, which notably includes an enhanced public notification protocol for bypasses at its wastewater treatment plant as well as combined sewer overflow (CSO) locations.
News of the notification system changes comes just as Hamilton officials clarified the extent of a major stormwater runoff and sanitary sewage discharge that occurred in 2014 and leaked for four-and-a-half years. Due to a bypass gate in a CSO tank, the City estimates that approximately 24 billion litres of combined sewage discharged into Chedoke Creek during the time that the gate was unexpectedly open.
“We apologize to the residents of Hamilton for the failure to publicly disclose the volume and duration of the discharge of stormwater runoff and sanitary sewage into Chedoke Creek when it first became known to the Council in 2018 and at subsequent Committee and Council meetings,” Hamilton Mayor Fred Eisenberger said in a December statement released to media, noting that the City is unaware why the bypass gate ever opened.
The spill, dubbed “sewergate” in local media, represents approximately 4% of the annual volume of flow to Hamilton’s wastewater treatment plants. In its apology about the lapse in notification, the City released 10 relevant reports to shed more light on the discharge and processes around duties such as water sampling.
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Now, a new order (PDF) from the Ontario government means that a damage report about the Cootes Paradise protected marshland that Chedoke Creek flows into will be due by May 2020.
The City completed surface cleaning in Chedoke Creek in summer 2018 to remove “floatable material” in the area.
Phase One of the City’s new notification process means that if there is a bypass at Hamilton’s wastewater treatment plant, the City will post a notice on its website. Phase Two, which is set to launch in spring 2020, will include automated notifications for bypasses at the treatment plant, as well as overflows at the City’s CSO outfall locations, plus historical data of previous bypasses and overflows where information is available.
Throughout Hamilton there are 14 monitored CSO outfall locations. The tanks for these locations hold more than 314,000 cubic metres of diluted wastewater. The City of Hamilton owns and operates one of the largest and most complex combined sewer systems on the Great Lakes. As a result it has a number of CSOs that protect the system against surcharges and overflows during severe wet weather events, when the amount of wastewater entering the system exceeds the capacity of the treatment plant. In tandem with the new notification system, the City also released an educational video about how CSOs work.
“If the combined sewer system didn’t have the designed overflow option to release wastewater to the Harbour, large areas of Hamilton would experience flooding, which would impact homes, businesses, roadways, public spaces and public health,” City officials explained in a recent news release.
Following “sewergate”, the City of Hamilton has added four additional staff as part of its 2020 Water, Wastewater and Stormwater Budget, to improve the routine physical inspection and preventative maintenance programs for Hamilton Water Infrastructure, including water and wastewater treatment plants, pumping stations, and combined sewer overflow tanks, as well as one water quality technologist to sample and analyze water and wastewater quality.
Hamilton has also been working to implement sensors and information systems that help staff make data-based decisions around directing the flow of wastewater during wet weather.