The City of Toronto pled guilty to one violation under the Ontario Water Resources Act foroperating its sewage works in not accordance with its Certificate of Approval. It was fined $150,000 plus the victim fine surcharge.
The City operates the Ashbridges Bay wastewater treatment plant. In December 2006, the plant discharged partially treated sewage into Lake Ontario as a result of heavy rains and a bypass gate remaining open. There were no impacts to drinking water as a result of this incident. Since it was winter, there were no impacts to local beaches.
Specifically, on December 1, 2006, the plant bypassed partially treated sewage, due to heavy rainfall. This bypass was permitted by its Certificate of Approval. Once the rainfall subsided, city staff instructed the plant’s computerized system to close the bypass gate and believed the bypass gate had been closed. But the gate remained open for another three and a half days before being discovered, allowing partially treated sewage to continue to be discharged into Lake Ontario.
A ministry inspection after the incident found a required flow measuring device had failed to monitor and measure the bypass as expected.
Since this incident, the city has made improvements to the plant including upgrading the gate valve mechanisms and other enhanced hardware and physical inspections to help prevent incidents like this from happening again.