Town looks for wastewater solutions

A recent failure in the acute lethality testing of the Town’s wastewater is not a cause for alarm, says Town Administration.

Shelley Terry, the General Manager of Municipal Services for the community, says the acute lethality testing of wastewater is a requirement of the federal department of Oceans and Fisheries and is in place to ensure that the wastewater being released into the environment is safe for the species that live in it.

The Town has a lagoon based system in place to treat the community’s wastewater. Terry says there have been studies done across the province that shows lagoon based wastewater systems struggle to remove two substances that can be toxic to fish: ammonia nitrogen and phosphorus. Because lagoon based systems rely on bacteria to function effectively there can be struggles during the winter and spring when there could be ice on the lagoons.

“It happens in the cold months, normally,” says Terry. “And you’ll possibly have some [failures] in the first and second quarter of the year because of the ice coverage on the lagoon, so you can’t release that gas to try to do it more naturally. The cold temperatures also slow down how our bacteria perform in the lagoons.”

She says for the most part, any municipality in the country that has a lagoon based system is struggling with this same issue. However, a pilot project the Town was trying out in 2023 has had promising results.

The quarterly tests require the Town to send out a sample of their wastewater every quarter to a third party company. Once the company has the sample, it stabilizes the pH of the water and then adds ten Rainbow Trout to the sample. Technicians monitor the fish for a period of 96 hours. If five fish perish, the test is deemed a failure as the potential of all fish living over an extended period of time is unlikely.

Terry says the point of the testing is to ensure that the wastewater being released into the North Saskatchewan River will not harm any fish in the river.

“Rainbow Trout are the least resilient fish out there,” says Terry. “So if you can pass against a Rainbow Trout, you can pass against any fish.”

While the use of Rainbow Trout is understandable, Terry says it’s not really practical for the area as there are no Rainbow Trout in the North Saskatchewan River.

Since it failed its most recent test, the Town has now been entered into accelerated sampling. This means the Town is required to send in wastewater samples every 14 days until they can manage to pass the test three times in a row. If they fail to pass the test, they will have to continue to submit tests at the accelerated schedule.

When the testing was first introduced in 2013, the level of those substances did not meet the necessary requirements. At that point, the Federal Government instructed the Town to figure out the cause and to come up with some mitigation strategies.

“Ultimately there was not a lot we could do after we did our research, due to the fact that we’re just a lagoon,” says Terry. “ We have no mechanical treatment; no way to remove those nutrients.”

However, in 2022, Alberta Environments issued new approvals that contained changes to the requirements surrounding the two nutrients.

The Town was tasked with upgrading the wastewater system by December 31, 2026 to meet the new regulations.

Terry says once they received that direction from the Province the Town immediately started brainstorming ideas to come up with a feasible solution.

Changing the lagoon system to a mechanical system would have been expensive, says Terry, both with capital costs and operating and maintenance costs.

“Our lagoons perform well,” says Terry. “They just can’t remove these two specific things to the required parameters.”

In 2023, the Town piloted a submerged attached growth reactor (SAGR) system to see if it could bring the levels down to where it was needed, while also remaining affordable for the community.

“It proved to be very successful last year when we piloted it,” says Terry.

She says the system is essentially a rock bed filtration system that gives the bacteria a place to be sheltered from the colder temperatures. This would allow the bacteria to perform at optimal levels year round.

Now that the Town has moved on from piloting the project to the planning phase, those nutrient levels have once again increased. Until they get the grant funding and can get the SAGR system in place for the deadline, Terry says there will likely still be a struggle with keeping those nutrient levels down.

The Town, the Province, and the Federal Government have all been in close contact regarding the issue.

“We provide the Federal Government with monthly updates,” says Terry. “We’re not the only ones in this situation. They’re just happy to see that there is movement in our project. And as long as we continue on that path, they will leave us alone.”

Amanda Jeffery, Local Journalism Initiative Reporter, Drayton Valley and District Free Press