Water story: Willmar's new wastewater treatment plant a vast improvement

With the start-up of Willmar’s new wastewater treatment plant, one of the largest sources of phosphorus is now being greatly reduced in the Minnesota River.

The new plant went online in fall 2010, vastly reducing the amount of phosphorus, ammonia, bacteria, and particles entering Hawk Creek, a tributary of the Minnesota River. What’s more, it finished ahead of schedule and under budget.

Previously, Willmar’s wastewater was one of the single largest contributors of phosphorus to the Minnesota River. While a vital nutrient, too much phosphorus contributes to excessive algae growth, a cause of water pollution.

“We’re doing a fine job of removing ammonia, BOD, TSS, and phosphorus, as well as fecal coliform,” says Colleen Thompson, plant superintendent. “Overall we’re doing an excellent job just starting out. We’ll be removing some 650 pounds of phosphorus per day. This is a big improvement for Hawk Creek and the environment, and downstream.”

When the city of Willmar decided to replace its old, out-dated wastewater treatment plant, it built two. The new $86 million facility separates industrial and municipal waste water, which allows more efficient and effective treatment.

On a tour of the plant, noticeably absent are unpleasant odors you might expect. Standing next to the various units – separators, oxidation ditches, clarifiers, and sludge tanks – you’ll detect more of an “earthy” odor. That’s due to billions of bacteria breaking down and consuming waste.

Near the end of the treatment process, entering one of three domed clarifiers treading a catwalk above a large tank, you might say the water smells clean as it slowly spills toward the ultra-violet treatment building and out to Hawk Creek.

A short distance downstream from the outlet, the Hawk Creek Watershed Project regularly takes water samples, testing for phosphorus and total suspended solids. Since the new plant went online, there has been dramatic reduction in phosphorus. “This is definitely very encouraging to see,” says project coordinator Cory Netland. “If the point sources are addressed, then we can focus on the non-point sources.”

Willmar is home to Jennie-O-Turkey Store, one of the nation’s largest producers of turkey products. Its two processing plants in the city generate millions of gallons of wastewater. The city’s old wastewater treatment plant could no longer provide sufficient treatment. And as the city grew, the plant became surrounded by business and residential development.

Located about five miles southwest of the city, the new plant will exceed treatment requirements for years to come, and there’s plenty of room for expansion. It can handle up to 7.5 million gallons of waste water per day, well above the current daily average of about 5 million gallons per day. Most of the $86 million cost is being covered by loans, which will be repaid primarily by service fees paid by residents and businesses.