Decommissioning of Willmar's former treatment plant progresses
WILLMAR -- The big dome structure that everybody saw from the street is gone and other structures are being dismantled as decommissioning of Willmar's old wastewater treatment plant continues. The $2 million decommissioning project is part of the $86.2 million wastewater treatment facility project.
Reiner Contracting Inc. of Hutchinson, which excavated the new plant site west of the city, received the decommissioning contract. Since Nov. 28, Reiner has had trucks and four big backhoes demolishing and hauling out debris from 24 of the 28 buildings and treatment structures at the old site.
By the time decommissioning is scheduled to be substantially complete June 15, four structures will remain: the former administration building, the garage, the electrical generator building and the former fine-screen building, according to Dean Sjoquist, local project representative for Donohue and Associates, the city's engineering consultant on the wastewater project.
Renovation and remodeling of the former administration building includes changing the lab into an archive storage area and updating restrooms for handicapped accessibility. The attached garage will continue to be used for performing heavy maintenance.
The filters in the fine-screen building were removed and the building will probably be used for storage. Also, the electrical generator building is being retained.
Buildings and structures being removed are excess flow basins, the big dome that housed the trickling filter, the small chlorine station, the effluent pump station, the clarifiers and digesters. The bottoms of structures built 15 to 20 feet below ground surface are also being removed.
Reiner equipped one backhoe with a hydraulic hammer to break up the concrete structures and equipped another backhoe with a device bought specially for the Willmar project to break the chunks into smaller pieces.
"It takes concrete 12 to 16 inches across and it's like the jaws of death. It breaks the concrete off the reinforcing bar,'' Sjoquist said.
He said concrete and reinforcing bar will be recycled. The curved Fiberglas pieces that comprised the rotating biological contactors are also being recycled.
"Just about everything they are pulling off is being recycled,'' Sjoquist said.
He said the project is going well. As Reiner removes the buildings, the contractor will excavate to the bottom of the structures, leaving a large hole that will eventually be used as a storm water detention pond.