An influx of motor oil from an unknown source caused major problems at Castlegar's South Sewage Treatment plant last week.
On July 10, city crews were notified that something unusual was happening at the plant. Upon arrival, they observed a strong smell of engine oil.
According to a statement from the City of Castlegar, an inspection confirmed that a chemical consistent with engine oil had entered the plant.
The oil killed the microorganisms in the cell causing dissolved oxygen levels to drop. The plant reacted by automatically increasing the air blowers' speed. This created excess foaming which spilled over the edge of the cell onto the floor.
Given the nature of this spill, the city reported it to Environment Canada and it was cleaned up by the following day.
The city says that after an event like this the South Sewage Treatment Plant takes over a week to recover and can contribute to increased odours in the area.
Issues around people putting cooking oils, motor oils and other harmful materials into the city’s sewage system is an ongoing problem.
The city is planning more public education regarding what shouldn't be put down the city's drains.
They are also planning on reaching out to Recycle BC to see if anything can be done to encourage the creation of a motor oil drop off in Castlegar. The previous recycling drop off at Ernie's Used Auto Parts has closed and the nearest oil recycling option is in Trail.
Meanwhile, Castlegar's municipal services director Chris Hallam reported to city council on June 15 that crews were still working through initial challenges after the installation of new geotubes at the plant this spring.
The geotubes are intended to enhance sludge dewatering and biosolids storage. They are a closed system that prevents biosolids from being exposed to open air.
Hallam said it is too early to tell if the geotubes are going to help solve ongoing issues with odours at the plant. He said crews are continuing to work with experts to try to find answers.
"We are operating the plant the way it is meant to be operated and following procedures that are industry standard, so it is a difficult problem to solve," added operations manager Samuel Shine.
Neighbourhood residents have complained about the odours for years, but Hallam says part of the problem in simply logistics.
The construction of the treatment facility pre-dates the housing subdivision that has grown up around the plant. When it was built, there was just farmland surrounding it.
The city has another $3 million in capital projects scheduled for its sewage systems in the next year.
