Equipment failure at Hamilton’s Woodward Wastewater Treatment Plant

HAMILTON, ON – During the heavy rain fall overnight on October 3 to 4, 2021, the City of Hamilton’s Woodward Avenue Wastewater Treatment Plant experienced an equipment failure that resulted in wastewater being discharged into Hamilton Harbour without treatment.

Due to the storm, Hamilton’s treatment plant experienced a wastewater bypass, which often occurs during significant wet weather. Typically, when the plant enters secondary or primary bypass mode, there is some level of treatment to the wastewater before it is discharged into Hamilton Harbour.

However, due to an equipment failure, wastewater was unfortunately discharged into Hamilton Harbour without treatment. At this time, the volume of wastewater discharged is being calculated.

The issue occurred in the screening area of the treatment plant – where two of the plant’s four bar screens failed and forced a temporary full plant bypass to avoid permanent damage to the facility and surrounding infrastructure. This was a very unusual circumstance and something the City has not experienced since 2015.

The equipment was quickly repaired and the plant has been restored back to its full capacity.

The City has followed all of the necessary reporting requirements in our Environmental Compliance Approval and have reported the incident to the Ministry of the Environment, Conservation & Parks (MECP). 

In addition to the bypass at the Woodward Wastewater Treatment Plant, the City also experienced overflow events at four of our combined sewer overflow tanks (Royal Ave, Main/King, Greenhill Ave and Red Hill Valley Pipe) and four other monitored locations (Pleasant/Edenbridge, Wellington St. N, Wentworth St. N and Strathearne Ave. N) during the recent storm.

As a reminder, details of current and historic overflow and bypass events are available on the City’s website: www.hamilton.ca/WastewaterMonitoring.

Details for the overflow and bypass events related to the October 3 to 4 storm will be added to the website within the coming days.

Additional resources

• Wastewater Monitoring Map
• Video: Combined Sewer Overflows in Hamilton

Update (October 5, 2021 at 2 pm)

By way of a brief update to the media release distributed earlier today regarding the equipment failure at Hamilton’s Woodward Wastewater Treatment Plant, please be advised that we have now completed the calculations for the volume(s) and duration(s) of wastewater discharged during the bypass events.

Three types of bypass were experienced between October 3 and 4, 2021:

• Plant Bypass - Resulting from the equipment failure and providing no treatment for the wastewater. A plant bypass occurred for a duration of 5.81 hours, with a volume of 48 million litres discharged.
• Headworks Bypass - Resulting from the heavy rain and providing some level of treatment to the wastewater. A headworks bypass occurred for 4.12 hours, with a total volume of 40 million litre discharged.  
• Secondary Bypass - Resulting from the heavy rain and providing most (but not full) treatment of wastewater. A secondary bypass occurred for 23.4 hours, with a total volume of 265 million litres discharged.

In total, 353 million litres was discharged into the Harbour as a result of the significant wet weather and the equipment failure. As mentioned, staff have followed all of the necessary reporting requirements in the City’s Environmental Compliance Approval and have reported the incident to the Ministry of the Environment, Conservation & Parks (MECP).