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Water taste a mystery

Water Plant Supervisor, Kris Knudson, takes a look inside one of the Ozone tanks at the Moorhead Water Plant. CHRIS FRANZ / chrisfranzphoto.blogspot.com

BY JOHN ENGER
engerjo@mnstate.edu

Drinking water, like nearly everything else in Moorhead, is affected by rising flood waters.

“I was eating this green apple and it was so pure,” said sophomore Weston Honkomp, “then I took a swig of water and it just tasted terrible. After that clean apple it seemed really funky. It’s just flood season. I noticed the same thing last year.”

Over the last three flood seasons, there have been complaints about the taste and odor of Moorhead’s drinking water, but no one knows exactly what causes the smell.

One of the two softening basins at the Moorhead Water Plant is currently active. CHRIS FRANZ / chrisfranzphoto.blogspot.com


“One of the unfortunate things is, we have had some taste and odor issues over the last three years in the flood,” said Troy Hall, Moorhead public service, water division manager.
“We don’t know exactly. We haven’t pinpointed what it is, but it is some sort of organic compound that isn’t broken down by our ozone treatment.”

The aforementioned ozone treatment consists of pumping a small amount of ozone gas through the water. Since ozone is a very reactive molecule, it causes reactions that break down organic matter. This is the second in a three-stage water treatment process that has actually won Moorhead’s water utility Minnesota’s best tasting water award for the past two years running.

“We do lime softening, then we go through an ozone process and then we filter the water,” Hall said. “And some of the bigger utilities in the state will do the lime softening such as we do. They’ll do the filtration part, but we are the only plant in Minnesota that has the ozone and that’s really what does a really good job as far as taste and odor and putting out real good water.”

The current water supply is using 50 percent river water and 50 percent well water. CHRIS FRANZ / chrisfranzphoto.blogspot.com


The process that turns out 4.25 million gallons of award-winning water every day through most of the year is somehow disrupted by the flood. Exactly why is a mystery, but there are a few theories.

“We did see (on March 26) something come through on the Red (River) which we picked up with our instrumentation,” Hall said. “(There were) high levels of organics that came through for about a 12-hour window and that’s what we figure got into our system. We made the decision to switch to more well water during that time (and) kept up in terms of all the EPA requirements to make sure it’s safe and so forth.”

The switch to well water gives rise to another odor theory. During flood season the water plant goes from using 85 percent river water to only using about one-third river water and two-thirds well water, which should not be affected by runoff or organic compounds in the river.

In theory, the flood season water should have less flavor and odor than normal. It could be that the flood season taste is really just a matter of personal taste.

Gauges inside the ozone room at the Moorhead Water Plant. CHRIS FRANZ / chrisfranzphoto.blogspot.com


“Every town’s water has its own specific taste that people get used to,” Hall said. “We’ve had some complaints a few times when we have switched to 100 percent well water because people are used to the taste of our treated river water.”

Theories aside, the Moorhead water plant is taking steps to fix the flood flavor problem.

“One, we are going to try to identify what those compounds are,” Hall said. “Two, we’ll do an evaluation to figure out if there is technology out there, maybe do some testing to see, you know, what that would cost and see if we can address it. It’s not an easy problem to solve.”

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