City removes unneeded wastewater treatment structure from co. ditch
WILLMAR -- A structure designed to help Willmar comply with state wastewater standards in the 1980s has been removed from a county ditch just southwest of the city because the structure was no longer needed and was falling apart.
About 25 years ago, the cascade effluent discharge structure, as it was called, was built and placed by the city in County Ditch 46 near the intersection of 30th Street and 30th Avenue Southwest.
The city had received permission from Kandiyohi County in the early 1980s to discharge treated wastewater from the old plant through a force main into Ditch 46, which flows into Hawk Creek.
However, the quality of the effluent was below the state standard for oxygen for sustaining aquatic life, recalls Dale Swanson, former city engineer. He said the Minnesota Pollution Control Agency requires a certain amount of oxygen in effluent and the city was under the standard.
"At that point in 1986, the effluent did not have enough oxygen in it,'' said Swanson in an interview on Monday. "What they said was you've got to get your oxygen up, and I had gone to a plant that had a cascade structure and they said that really helped in raising the oxygen.''
Swanson returned to Willmar and had a similar structure built. He signed plans for it on Aug. 14, 1986.
He said MPCA didn't have to approve the plans; the agency just wanted the oxygen up.
The structure was placed at the end of the force main and the effluent was directed to the top of the structure. The liquid picked up oxygen as it tumbled down the steps and the problem was solved, said Swanson.
"If I remember right, that thing cost less than $10,000 and it was a really cheap fix, for the first (MPCA) fine would have probably been way more than that and it did the job, too,'' said Swanson.
"I don't think they ever had anymore problem with oxygen as long as that thing was used,'' he said.
Swanson said the structure had nothing to do with a lawsuit over ditch odor problems filed in 1983 by nearby homeowners against the city, the county, and the contractors who designed and built the old treatment plant. The lawsuit was settled out of court.
"It really didn't have anything to do with the odor,'' Swanson said. "It should not have affected the odor one way or the other.''
Last week, the City Council approved a request from Donohue and Associates, which designed Willmar's new treatment facility, to remove the structure. The council amended a contract with Reiner Contracting Inc. of Hutchinson to remove the structure at a cost of $6,000.
Rhonda Rae, program manager in Donohue's Willmar office, said the structure was falling apart, was an eyesore, had no use and could be a safety hazard.