Between 2017 and 2020, Nelson’s sewage treatment plant, on 15 separate occasions, accidentally released a combined total of more than 3,000 cubic metres of partially treated sewage into the Kootenay River, according to provincial government documents.
The sewage had been treated with primary treatment (filtering and settling of solids), but not with secondary treatment (remaining material being broken down by bacteria or by ultraviolet light).
These incidents occurred during severe storms. Many of Nelson’s storm sewers drain directly into the sewage plant, and in rainstorms the storm flow overwhelms the plant, bypassing and flowing around the sewage treatment process.
The city’s public works director Colin Innes says having storm water and sewage in the same pipe was considered acceptable when Nelson’s infrastructure was built in the 1960s. Although some storm water is flowing into the lake as it should, Innes says some storm water is still connected below city streets to the sewer system in unmapped and unknown locations. They are separated by city crews whenever they are found. Innes stated that the goal is to eventually have all stormwater diverted to the lake and away form the sewage treatment plants.
The sewage treatment facility is located near Grohman Narrows on the shores of Kootenay Lake. It releases its effluent into Kootenay River following primary and secondary treatment.
The effluent looks clear, Innes says, but he wouldn’t drink it. To be drinkable it would have to undergo tertiary treatment – treatment by more advanced bacterial processes, which the plant is not capable of.
Leakages in a large, sewer pipe known as the force major that runs along the lake floor from the airport to sewage plant have caused sewage spillages. Operators of sewage plants have noticed a surprising low flow into the plant. Divers have also discovered leaks in this force main, which has resulted in unknown amounts raw sewage being released into the river. Innes states that this has happened four more times in the last five years.
Since 2017, the province has ruled that the city was not in compliance with regulations due to data or test results not being submitted or not monitored frequently enough. This includes data related to fecal bacteria, total suspended solids and biological oxygen demand.
On 203 occasions between 2017 and 2020, the amount of material flowing through the system has exceeded the plant’s legal volume limit, although those excesses did not release untreated sewage into the river.
These various effluent releases and insufficient data were documented in six warning letters and noncompliance letters sent to the city by regulators at the Ministry of the Environment and Climate Change Strategy. They were sent between 2018 and 2021. These documents are searchable at https://bit.ly/3x9Y27q.
The city has never been penalized in any way for these compliance issues.
Innes claims that none of the warning letters are random and that his staff is in constant dialogue with regulators.
“We get the inspectors coming through, and we do have really good talks with them. We show them everything they need to see. If you just read these letters on the surface, it would seem like maybe we’re in a tenuous relationship. I don’t believe that to be the case.”
Innes says the plant is not designed for some of the things the city’s provincial sewage permit requires, which causes some technical problems with compliance.
Another problem is the unusually high concentration of effluent that has been arriving at the plant from the City over the past few decades. Innes states this is due to the increased number and quality of restaurants and breweries within the city. This organic material is more difficult to break down than it should, which can lead to some regulatory problems.
“Any place that does food prep is a source of a high-strength effluent,” Innes says, “just because there’s so much nutrients that that winds up in the water. And so any organic loading of any kind is going to present a challenge.”
An additional issue is FOG materials – fat, oil, and grit – that build up and clog pumps and pipes and has to be vacuumed out and disposed of. The city has been dumping the material at a separate site from the treatment plant for several years. However, the province issued a notice on Sept. 1, 2021 prohibiting such disposal. Innes stated that the city had to hire a contractor in order to transport the FOG material to the landfill.
Nelson’s sewage plant and infrastructure was constructed in 1968, with some upgrades since.
“We’ve got an older plant that’s worked for a long time here and really done a lot of heavy lifting for the city,” Innes says. “We’re pretty much at the outside edge of what it’s able to handle.”
Nelson will spend millions on the plant’s renovation or replacement over the next few years. He expects to receive most of the money in grants from senior government officials. The consultant Urban Systems is already working on research and monitoring for the project, developing a master plan for the city’s sewage.
Innes states that climate change makes it more urgent to improve the system.
“This is something we really need to tackle,” Innes says. “We need a plant that’s going to be able to handle … projected impacts of climate change. From what I understand, we’re going to be seeing more intense rainfall events.”
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