A breath of fresh air

Folks who said they almost gagged from the odor of Willmar's old wastewater treatment plant can breathe easier now that the old plant is shut down and the new treatment facility located about five miles west of the city is operating.

Wastewater treatment facility
An aerial photo shows the overall layout of the new wastewater treatment facility for the City of Willmar and the Eagle Lake Sewer District. The $86.2 million facility is located west of the city, as opposed to the old site, located on the east side of town near the Kandi Mall and a residential area.

Folks who said they almost gagged from the odor of Willmar's old wastewater treatment plant can breathe easier now that the old plant is shut down and the new treatment facility located about five miles west of the city is operating.

Not only is the site -- in the midst of corn fields -- far from the former residential and commercial location, the smell is different.

"Earthy'' is how consultants and city staff who worked on the $86.2 million facility and conveyance project describe the smell. But odors from nearby farming operations such as manure spreading may also be present.

"When you first drive up, you may think it's the wastewater treatment plant,'' said Rhonda Rae, program manager in the Willmar office of project consultant Donohue and Associates of Sheboygan, Wis. However, she points out there is a farm odor as well as the plant odor.

Willmar residents can test the air for themselves during an open house from 1 to 5 p.m. on Friday at the facility, located at 3000 75th St. S.W., near the city brush site. A dedication program will be at 1:30 p.m., followed by walking tours.


City and Donohue officials are hoping a large number of people will attend the event.

"This has been a project that has been ongoing. We've probably been talking about it for 20 years,'' said Colleen Thompson, facility superintendent. "I just hope that the community is interested and they want to come out and take a look at the investment. I'm proud of this whole project, too.''

Process operation

going smoothly

Kenneth Sedmak, Donohue senior project manager, is equally pleased.

"I've never had a project come up to process operation so smoothly and just to meet water quality standards is a lot of it,'' said Sedmak, who has 40 years of civil engineering experience on 300 to 400 projects around the United States and in other parts of the world.

He said Willmar's project "is No. 1 as far as process start-up.''

Thompson said city staffers were heavily involved in the planning, design, construction and start-up of the new facility. She said the project has consumed city staff's workload for the past six years, including but not limited to engineering, finance and administration.


"I want the community to know that city staff was heard, meaning our input was sought during all phases of the program,'' Thompson said. "By being so involved in all phases of the program, staff will have a better understanding of how the plant works.''

Moving plant

was longtime topic

Moving the old treatment plant, located just east of the Kandi Mall, had been a topic of discussion for many years. Residents and businesses said the old plant smelled bad, and environmental regulators said effluent from the plant's failed technology did not comply with water quality standards.

The first wastewater plant was built in 1930 at the Willmar Avenue Southeast location. As the city grew, the plant was upgraded twice to increase the capacity to 5.04 million gallons per day and to address industrial load. The plant serves Willmar and the Eagle Lake Sewer District.

Additional modifications were made to the treatment process, including an odor control project, industrial pretreatment, biosolids storage and three maintenance and improvement projects.

In September 2004, the City Council voted to move the treatment plant and improve the conveyance system to address more stringent requirements for phosphorus and ammonia removal and to meet projected population and industrial growth to 2030.

The council voted in January 2005 to hire Donohue to relocate and develop the new facility. From 2005 through 2007, Donohue team members and the city worked on management, expansion and design plans.


Work began Sept. 29, 2008, and included construction of the treatment plant, two pump stations and separate pipelines for conveying the industrial waste from the Benson Avenue and Willmar Avenue Jennie-O Turkey Store plants and municipal waste.

Flow to new plant begins Aug. 25

After nearly two years of work, the flow to the new plant started on Aug. 25, 2010, and staff began to incrementally redirect flow from the old plant to the new plant. On Sept. 28, all flow to the old plant was cut off and was redirected to the new site.

The old plant is being decommissioned. The process includes circulating bleach to minimize odor and removal of solids from the old treatment equipment. Toward the end of October, demolition will begin on 17 of the 20 structures, leaving the former administration building for a maintenance site, the generator building and cold storage building. Demolition will be completed and the site preliminarily graded by July 15, 2011, for potential use as a storm water detention area.

Dean Sjoquist, Donohue resident project representative, said all concrete will be reclaimed and crushed into 1-inch-size or smaller pieces and stockpiled by the city. Crushing will take place not before 7 a.m. and not after 6 p.m. Monday through Friday and will be completed in two to three weeks. The reinforcing iron in the concrete will be separated out.

Treatment is four-step process

Treatment of wastewater at the new plant involves a four-step process:

n Pretreatment -- removal of inorganic debris.


n Biological treatment -- aerobic environment that removes pollutants. Microorganisms in huge tanks called oxidation ditches clean pollutants from the water by consuming "waste'' as food and creating biomass. Aerators keep the microorganisms suspended and mixed and provide oxygen for the "bugs'' to breathe.

n Chemical treatment -- removes phosphorus, controls acidity and alkalinity, and disinfects. Clarifiers provide a place where the microorganisms settle, leaving clear water that goes to final treatment. The settled microorganisms either start over again in the pretreatment process to absorb more waste or are moved to the solids handling process and eventually land-applied on farm fields.

n Final treatment -- the water passes among ultraviolet light bulbs to prevent diseased organisms from leaving the plant and entering Hawk Creek.

The new administration building is the center of activity for maintenance, communication, control, analysis and personnel needs. The state-certified and highly specialized laboratory is equipped to check plant operation efficiency and effluent quality.

Electrical power is supplied by Willmar Municipal Utilities. Two 1,750-kilowatt standby generators will start automatically in the event of a power disruption.

Sedmak said the treatment process is working very well and is removing 99.3 percent of pollutants. Removal at the old plant was 97.2 percent.

"To get those extra percentages is very difficult,'' said Sedmak. "But we're removing ammonia and phosphorus, which the old plant did not remove.''

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