City investigating increased wastewater flow

City Council approved the awarding of a contract to investigate increased sewer inflow and infiltration last week. For $97,000, Sewer Technologies Inc. are identifying the root causes of the influx in wastewater, including possible leaking sewer laterals and cross connections. 

North Bay’s Wastewater Treatment Plant is set to undergo more work after City Council unanimously approved the awarding of a contract to investigate and address increased volumes of wastewater flowing into the plant.

The contract, which cost somewhere in the neighbourhood of $97,000, was awarded to Sewer Technologies Inc. for sanitary sewer inflow and infiltration investigation and remediation.

A report given to City Council states the plant has experienced an increased amount of wastewater flowing into the plant due to heavier than usual rainfall events.

The plant’s current capacity is 54,480 cubic metres each day. But, as has been noted, this summer’s rainfall totals have far exceeded the average of years past. As of the end of August, North Bay recorded over 500mm of rainfall in the summer alone, up from the usual average of close to 300mm.

PHOTO BY LIAM BERTI

“On a typical day, we’re actually well below the capacity of the facility,” said Coun. Chris Mayne. “We’re still looking to expand that capacity, but if there’s a correlation between rainfall and sewage overflow, it’s clearly related to storm sewers, either city or residential, run-off lines running into the sewer.”

According to the report submitted by the city, a preliminary study has discovered that inflow and infiltration as the specific sources of the influx in wastewater.

The study identified leaking sewer laterals and possible cross connections from the building foundation drains, which they deemed worthy of further investigation. Mayne said the new study will study cross connections, pipe leaks and hopefully identify exactly where the groundwater is coming in.

“Every time there’s a heavy rainfall, unfortunately, the water treatment plant can’t handle the inflow,” Mayne explained. “We partially treat some of the water, but we’re having to discharge almost half of it directly into the lake, so partially treated sewage water.

“The issue is, whenever there’s a rainfall event, there’s more water coming into the plant and there shouldn’t be that correlation; it should simply be sanitary sewers coming into the sewer treatment plant,” Mayne continued.

The money for the project has been allocated in the Sewer and Water Capital Budget under the Infiltration Reduction and Flow Monitoring Program.

The news comes almost a month after the city approved a plan to spend $5.2 million on a grit removal facility at the plant. At that time, Coun. Mayne said the city was originally expecting to pay up to $6 million on that project. 

It has been said that the treatment plant is one of the city’s most expensive assets. Due to reported inadequate maintenance prior to the city taking control of the plant from the Ontario Clean Water Agency, the city approved a plan almost a year ago to spend some $20 million over a 10-year period to upgrade the plant.