A supervisor for the day-to-day operation of Hamilton’s water plants and facilities admits the city did discharge a ‘very large volume’ of ‘untreated’ wastewater into the local harbour in 2019.
The director of Hamilton Water, Andrew Grice, told the city’s public works committee on Wednesday that the Woodward Wastewater Treatment (WWT) plant had 34 bypass events last year causing 3,067 million litres of only partially treated water to leak through the Red Hill Creek and into Hamilton Harbour.
That’s a significant increase from 2018’s total in which the city executed 17 events at the plant pouring 1,868 million litres into the harbour. The five-year average, according to public works, is around 1,771 million litres a year.
“Our primary level treatment is is certainly quite strong, so we would like to put it through our entire process, but certainly bypass is not a good news event,” Grice told the committee.
Grice said the bypasses stemmed from a number of issues including periods of heavy rainfall, snowmelt, and elevated levels from the Great Lakes water system.
At present, the WWT plant is struggling with the increase as it goes through a large scale upgrade to add a third level of treatment to allow the plant to reach discharge targets set by the Hamilton Harbour Remedial Action plan. The scheduled completion for the upgrade is 2022.
Currently, much of the city’s core uses a combined sewer system in which a single sewer collects and handles both the sanitary sewage and storm water runoff over an area of approximately 52 km, according to a report presented to the committee.
The city has nine combined sewage overflow (CSO) tanks that hold untreated wastewater until the WWT plant has the capacity to treat it.
A bypass happens when CSO tanks are overwhelmed with untreated water and flow down to WWT plant. The bypass is essentially a safety valve to avoid damage to the plant’s infrastructure.
“What happened in 2019 with the elevated lake levels is that lake water was making its way into our sewer system and subsequently down to our wastewater treatment plant, which means we did not have as much buffer before we were required to bypass at the facility,” Grice told the committee.
In comparison, neighbouring Toronto had a similar issue in 2019 having to expel 4.383 million litres of partially treated sewer and stormwater. That amount was up from the 2.093 million litres released in 2018.
Niagara released 2,178 million litres in 2019 which was exactly 600 million litres less than 2018.
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