Revelstoke council voted to spend another $120,000 to address odour problems coming from the sewage treatment plant.
“This is, as far as I’m concerned, the number one issue in Revelstoke right now,” said Mayor Mark McKee, who took the lead on addressing the issue and responding to questions at Tuesday’s council meeting. “Since the last time this was brought up at council we’ve had issues with lagoon number one. It’s on its last breath, and its last breath smells a little bit.”
The latest problems emerged when a report from Mike Thomas, the city’s director of engineering, revealed that the recent stench emerging from the plant and plaguing Southside likely came from the sewage lagoons. The unseasonably warm weather changed the conditions in the first lagoon, causing the smell.
Thomas’ report outlined the steps undertaken to improve the condition of the lagoon. Staff increased aeration of the first lagoon, they pumped effluent from the second lagoon into the first one, they held the sewage in the first lagoon for longer to give it more time to digest, and they’ve added sodium nitrate to oxygenate the lagoon.
“These protocols have seen an apparent improvement in the health of the pond, however as temperatures have continued to increase, the odour has continued,” wrote Thomas.
The city is also looking at the sewage mix to see if people are dumping things into the system that they’re not allowed to, like chemicals, septic waste, oils, greases, and high and low pH liquids.
On Tuesday, council voted to act on recommendations by Stephen Horsman, an engineer with the firm AECOM. Horsman produced a 2014 report indicating the source of the smell coming from the treatment plant was the headworks building, where sewage is processed before entering the lagoons. In that report, he attributed the odour to hydrogen sulfide (H2S) caused by the treatment process. The highest concentrations of H2S were in the headworks building, where it topped out at 13.3 parts per million. Readings around the lagoon maxed out at a miniscule 0.006 parts per million.
In an e-mail sent to Thomas sent last week, Horsman wrote the recent odour was likely coming from the lagoons. As the temperature rises, biological activity in the lagoons increases, resulting in reduced oxygen levels and increased release of H2S, he explained.
He recommended adding mixers to the lagoon to improve the amount of oxygen and reduce the odour coming from the ponds
On Tuesday council voted to approve $120,000 to purchase the mixers. The money will come out of the sewer reserve fund, which currently has $550,000 in it.
“I would like to have it here at the same time the headworks filtration is finished,” said McKee. Work installing an odour scrubber on the headworks building is set to be finished by about June 15. That work is costing the city about $360,000, bringing the total cost of addressing the odour issue to almost $500,000.
Thomas said this would be a long-term fix. “This is a solution that’s been used elsewhere to deal with this problem,” Thomas said. “This is not a short-term fix, this is a long-term fix that will be added to the lagoon and will be there as long as we need it.”
However, Horsman recommends the city “conduct a more in-depth evaluation of the capacity, overall effectiveness and long-term suitability of the city lagoons.”
The City of Revelstoke’s five year financial plan includes $1.2 million in 2019 for expanding the sewage treatment plant. Thomas said this will address capacity and effluent issues.
Southside residents, especially those living near the sewage treatment plant, are taking a wait-and-see approach, crossing their fingers and holding their nose that their problems will be solved.
“I want to stress to the community how important this is to everyone at city hall,” said McKee. “The impression is we’re doing nothing when the fact is we’re doing lots.”