Epcor `water sommeliers' ramp up run-off water testing

Warming weather means Epcor's “water sommeliers” are readying their noses in anticipation of spring runoff.

On Thursday at the utility company's water excellence lab in Rossdale, near the edge of the North Saskatchewan River in central Edmonton, more than a dozen glass flasks in the process control lab hold water from various parts of the treatment plant.

Some contain murkier liquid, likely raw river water from earlier stages in the treatment process, but all samples are incubated before a tester gives them a swirl, pops the stopper and takes a whiff, said Jeff Charrois, Epcor's senior manager of analytical operations and process development.

“Our lab technicians — the chemistry and microbiology technicians, which we also call our water sommeliers — are doing their own odour panels,” he said.

“We do that a couple times a week right now. That'll probably increase to daily as we get more into the main body of spring runoff.”

With spring temperatures on the horizon, melting snow can wash sediments such as decomposing vegetation and other organic materials from the land and into the river, where Edmonton sources its water supply, giving the wet stuff an earthy or musty smell, Epcor says on its website.

A taste and odour wheel pinned to the lab wall offers testers a guide for interpreting the results as they rate the water on a scale of zero to three, the former meaning no odour and the latter a very strong smell.

“They basically use one of our best analytical instruments in the entire lab, which is the human nose,” Charrois said, adding that the lab doesn't do any taste testing.

The results of those tests are then forwarded to Jamie Gingrich, senior manager of operations for Edmonton water treatment plants, as well as his team, to modify treatment if required, Charrois said.

When water first enters the plant, it flows through screens that remove leaves, grass and other debris before flowing into a large tank that allows sediments to settle, Gingrich said, adding that a subsequent filtration process helps remove the stuff that settles at the bottom.

“The last step is disinfection,” Gingrich said.

“We add chlorine and also treat with UV light to ensure that any harmful bacteria and other microbes are taken care of.”

Epcor prepares for annual spring runoff with the addition of activated carbon powder early in the water treatment process to help remove compounds before removing that carbon as well through sedimentation, Epcor's website says, and while residents shouldn't see any change to the appearance of their drinking water, some may still notice a temporary change to the smell.

“Carbon absorbs the organic compounds in the water, some of those being the precursors to taste and odour,” Gingrich said. “We're trying to anticipate when spring is here. Water quality changes very rapidly, and that requires us to adjust our treatment process to react to that.”

But they're not acting alone. Every year Epcor enlists about 300 Edmontonians for feedback on the taste and smell of the water flowing from their taps.

The utility company's Spring Home Analysis run-off Program (SHARP) had about 93 per cent of respondents who “favourably assessed” the flow at their faucets in 2022, the utility provider said.

While Epcor reminds Edmontonians that “your water is absolutely safe to drink during spring runoff,” it recommends running tap water for at least three minutes, adding lemon slices to drinks and properly maintaining water filtration devices if odours persist.