Hamilton Wastewater Treatment Plant has exceeded its capacity for the second time in December and released wastewater into Hamilton waterways for over 12 hours.
In a media release, the city said that the Woodward Wastewater Treatment Plant entered bypass mode because the extreme wet weather and melting snow exceeded the treatment plant's capacity.
The plant can hold around 409 million litres of wastewater and can accommodate up to 600 million litres for a short amount of time, reported CBC.
The bypass ended the same day and the release does not indicate how much wastewater was released during that time, according to CBC.
This is the city's second notification of a bypass at the treatment plant since its pledge to post an announcement each time one occurs.
The protocol was mandated after a gate was left partially open at one of the city's combined sewage overflow (CSO) tanks, which allowed 24 billion litres of untreated storm water runoff and sewage to flow into Chedoke Creek for over four years, reported CBC.
The city council knew about the leak but did not disclose its magnitude to the public.
The first notification of a bypass occurred in early December when the treatment plant reached capacity during a major winter storm and released 78 million litres of partially treated wastewater over 12 hours into Hamilton Harbour, reported CBC.
"It's a very common practice that within the city...we never talk about issues that are under investigation because things can change," said Ward 12 Councillor and Public Works Committee Chair Lloyed Ferguson. "We don't have the conclusions yet, so we simply don't talk about it."