THUNDER BAY — The City of Thunder Bay plans to investigate the origins of the grease blockage in a sanitary sewer on Arthur Street that caused sewage to enter a storm sewer and flow into the Neebing River.
Crews continued to perform cleanup operations Tuesday, including around a storm outfall at James Street and Riverview Drive.
"We are hopeful that, within the next day or two, we should be able to have most of the system cleaned out. We'll begin to do inspections after that to verify if we've gotten everything we need out of there," said David Warwick, superintendent for water distribution/wastewater collection in the city's Environment Division.
This is far from the first time that accumulated grease has caused problems in the city.
"I'd say it happens a minimum of once a year. Some years there are more. In general, the sources are fat, oil and greases discharged from sewer connections for restaurants, homes, businesses. They accumulate in the watermain. Once they cool down they congeal and cause those blockages. It's a common issue," Warwick said.
He said homeowners are encouraged to avoid contributing to the issue.
"A simple rule of thumb is: don't dump any fat, oil, greases down the drain. Dispose of them properly in the garbage, and you won't have any problems."
Grease interceptors are designed to trap the unwanted substances before they enter the sewer system, but generally are not installed in homes.
However, Warwick said provincial regulations require restaurants to install the devices in their kitchens.
"These units are supposed to be inspected and maintained. They should have records of this, if asked to do so."
He said the city has an online reporting program for restaurants to document the cleaning and inspection of interceptors, but it's on a voluntary basis.
"Once these units are installed, that's where the hole lies because there are no mandatory inspections. It is just good practice to do it, but you know it does get overlooked."
After the current problem is dealt with, the city will conduct additional cleaning activities in the sewer system in that area, followed by an inspection to try to identify where the grease, oil and fat is coming from.
If the evidence points to specific businesses, the owners will be asked to inspect their systems and file maintenance reports.
"This incident was quite serious. There was sewage that was discharged to the environment. We take these situations very seriously, and do everything we can to mitigate this from happening again," Warwick said.
He added that blockages in mains pose the potential to cause sewer backups in multiple homes and businesses, "which is not a pleasant situation...and can cause a lot of damage."
