WILLMAR -- A milestone was reached when construction of 29,145 feet of interceptor sewer line in Willmar's $86.2 million wastewater treatment project was completed in December, eight months ahead of schedule.
The line generally follows 28th Avenue/30th Avenue Southwest and runs 5½ miles between the new plant and a point near The Home Depot store, where the line joins a shorter section of interceptor built in 2006 and 2007 between the old treatment plant on Willmar Avenue Southeast and the new interceptor. When the plant be-gins operation in October, the interceptor will carry municipal waste by gravity from the collection point at the old plant to the new plant.
The city divided the longer interceptor project into two smaller projects and those were bid as separate contracts because officials felt they could get more bidders if the projects were smaller, according to Rhonda Rae, program manager in the Willmar office of project consultant Donohue and Associates.
But it turned out the same contractor, S.R. Weidema of Maple Grove, submitted the low bid for both parts and was awarded the contract for both, said Rae. One Weidema crew began working on the eastern end of the interceptor and another Weidema crew began working on the western end.
The milestone occurred on Dec. 15 when crews made the connection where the two projects meet at County Road 15, which is the line's approximate mid-point. Rae said coordination of the two projects was made easier because Weidema had the contract for both.
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The meeting point was scheduled purposely, said Rae.
"It makes a nice place to make connections and it broke the projects into almost equal size,'' she said.
During construction, traffic continued unabated when the pipe was tunneled under South First Street because the contractor recommended and the city approved the use of a guided boring machine to remove boulders. Otherwise, the boulders would have had to have been removed by digging a tunnel shaft straight down from the surface.
Rae said using the machine was a good choice.
"There were so many boulders,'' said Rae. "This machine dug them out, pulled them out through the shaft you already had and moved on.''
Rae said Weidema ran into contaminated soils at a site just west of First Street along 28th Avenue. The site had been the location of a junk yard.
"It smelled like gas. We shut down the crews, made sure it was safe to work in, pulled in a special environmentalist to handle the soil, and stockpiled the soil. We made sure the residents and crews were safe, and did appropriate disposal of the soil,'' she said.
"Whenever you hit something that doesn't smell right or looks right, you need to take precautions because you don't know what it is.''
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Construction of the forcemain to carry industrial waste from the Jennie-O Turkey Store plant on Benson Avenue and the plant on Willmar Avenue is nearing completion. Weidema built the forcemain from the new treatment plant to County Road 15, and Voss Plumbing of Paynesville is building the forcemain from County Road 15 to the Willmar Avenue pump station.
Also, two forcemain pump stations -- one for each plant -- have been built and interior work is under way.
Work on the 20 buildings and structures at the plant site ranges from 80 percent to 100 percent complete. Rae said between 50 and 60 workers are installing electrical, plumbing, piping and treatment equipment. Also, the interior road at the plant site is completed.
Of the $86.2 million budget, $59,601,395 has been spent, she said. The project is being financed with a combination of state and federal loans and grants and city revenue.
Rae reported on the progress of the treatment project to the City Council's Public Works/Safety Committee on Tuesday afternoon.
