Cold Spring Opens Only Water Treatment Facility in Minnesota Using Bacteria to Control Nitrates

(KNSI) — The City of Cold Spring is now home to the state’s only drinking water treatment facility that uses bacteria to control nitrate levels.

Commonly found in fertilizer and manure used on farms, the city is one of the hundreds in Minnesota, estimated by Public Works Director Jon Stueve, that struggle to keep the chemical in check. Some wells registered 14 milligrams per liter of nitrate, above federal standards. The new system can bring levels to zero but is set right now to be about five. Stueve says there are a couple of options when limiting nitrates and explains why bacteria made the most sense for Cold Spring.

“Ion exchange is basically just a big water softener and everybody knows what a water softener does, it uses salt. And then that brine goes into the waste stream. So, we didn’t want to send that to our wastewater plant and create a problem down there so we went with this,” he says.

Wastewater treatment plants are regulated strictly, too, in addition to drinking water facilities. Stueve says if they chose the wrong system at the one, it would affect the other.

Stueve says the city is growing fast, and the new treatment facility is just one piece of infrastructure improvements needed to handle the change.

“I’ve been here eight years and one of the things I tell some of my colleagues are what I’ve got to experience in eight years so far in Cold Spring, most people don’t experience in a 35, 40-year career. It’s been complicated, obviously. There’s a lot of moving parts but pretty cool to see.”

The tanks are washed every one to two days, which keeps the bacteria colony under check. According to Stueve, biological organisms have been used in sewage treatment for hundreds of years. Using bacteria in drinking water treatment is also common in Europe.

___