Between 2017 and 2020, Nelson含羞草研究社檚 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 received primary treatment (filtering and settling out of solids) but not the usual secondary treatment (remaining material broken down by bacteria and by ultraviolet light).

These incidents occurred during severe rainstorms. Many of Nelson含羞草研究社檚 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含羞草研究社檚 public works director Colin Innes says having storm water and sewage in the same pipe was considered acceptable when Nelson含羞草研究社檚 infrastructure was built in the 1960s. He says that currently some of the storm water flows directly in to the lake, as it should, but some of it is still connected beneath city streets, to the sewer system in unknown and unmapped locations. City crews separate them whenever they are discovered in the course of their work, and Innes says the goal over time is to have all storm water diverted directly to the lake and away from the sewage treatment plant.

The sewage treatment plant is located on the shore of Kootenay Lake near Grohman Narrows and releases its effluent into the Kootenay River after primary and secondary treatment.

The effluent looks clear, Innes says, but he wouldn含羞草研究社檛 drink it. To be drinkable it would have to undergo tertiary treatment 含羞草研究社� treatment by more advanced bacterial processes, which the plant is not capable of.

Other instances of sewage spills into the lake have stemmed from leaks in a large sewer pipe, known as the force main, that runs along the floor of the lake from the vicinity of the airport to the sewage plant. On several occasions, sewage plant operators have noticed a surprisingly low flow into the plant, and divers have discovered leaks in the force main that have resulted in unknown amounts of raw sewage released into the river. Innes says this has happened four times in the past five years.

On several occasions since 2017, the province ruled that the city was out of compliance with regulations because of data or test results that were not submitted or not monitored often enough, including data related to fecal coliform, total suspended solids, biological oxygen demand, turbidity, and ultraviolet light transmittance.

On 203 occasions between 2017 and 2020, the amount of material flowing through the system has exceeded the plant含羞草研究社檚 legal volume limit, although those excesses did not release untreated sewage into the river.

These various releases of effluent and incomplete data are documented in a series of six warning letters and non-compliance letters to the city dated between 2018 and 2021 from regulators at the Ministry of the Environment and Climate Change Strategy. These documents can be searched for at .

The city has never been penalized for any of these compliance problems.

Innes says none of the warning letters come out of the blue, and that his staff are in regular dialogue with regulators.

含羞草研究社淲e get the inspectors coming through, and we do have really good talks with them. We certainly show them everything that they want to see. If you just read these letters on the surface, it would seem like maybe we含羞草研究社檙e in a tenuous relationship. I don含羞草研究社檛 believe that to be the case.含羞草研究社�

Innes says the plant is not designed for some of the things the city含羞草研究社檚 provincial sewage permit requires, which causes some technical problems with compliance.

Another issue is an increase, over the past few years, of an unusually concentrated effluent arriving at the plant from the city, the result, Innes says, of the increased number of breweries and restaurants in the city. It takes longer for the plant to break this organic material down, leading to some of the regulatory problems.

含羞草研究社淎ny place that does food prep is a source of a high-strength effluent,含羞草研究社� Innes says, 含羞草研究社渏ust because there含羞草研究社檚 so much nutrients that that winds up in the water. And so any organic loading of any kind is going to present a challenge.含羞草研究社�

An additional issue is FOG materials 含羞草研究社� fat, oil, and grit 含羞草研究社� that build up and clog pumps and pipes and has to be vacuumed out and disposed of. The city has been dumping this material for several years at a site separate from the treatment plant and on Sept. 1, 2021, received a letter from the province prohibiting this disposal. Innes said the city has since had to hire a contractor to take this FOG material to the landfill.

Nelson含羞草研究社檚 sewage plant and infrastructure was constructed in 1968, with some upgrades since.

含羞草研究社淲e含羞草研究社檝e got an older plant that含羞草研究社檚 worked for a long time here and really done a lot of heavy lifting for the city,含羞草研究社� Innes says. 含羞草研究社淲e含羞草研究社檙e pretty much at the outside edge of what it含羞草研究社檚 able to handle.含羞草研究社�

In the next few years Nelson will spend millions of dollars upgrading or replacing the plant, and expects to get most of that money as grants from senior governments. The consultant Urban Systems is already working on research and monitoring for the project, developing a master plan for the city含羞草研究社檚 sewage.

The need for improved system is made more urgent by climate change, Innes says.

含羞草研究社淭his is something we really need to tackle,含羞草研究社� Innes says. 含羞草研究社淲e need a plant that含羞草研究社檚 going to be able to handle 含羞草研究社� projected impacts of climate change. From what I understand, we含羞草研究社檙e going to be seeing more intense rainfall events.含羞草研究社�

bill.metcalfe@nelsonstar.com
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