WILLMAR - Two changes in the construction contract for the sanitary sewer lift station and sewer line improvement project in northeast Willmar - which cost $2.421 million - received support this week from the City Council’s Public Works/Safety Committee.
The committee will recommend the changes to the council Monday night.
The first change was a $34,020 reduction in the cost of the “cured-in-place,’’ no-dig process used in the sewer line improvement portion of the project.
The cured-in-place process involves blowing a fibrous sock impregnated with styrene pellets into the existing sewer line and heating the sock with steam, which causes the sock to adhere and harden against the inside of the sewer pipe and extend the useful life of the pipe.
Paul Jurek, project engineer with Bollig Inc. of Willmar, explained that the cost of the cured-in-place process was reduced because engineers discovered the diameter of the sewer pipe, constructed in the 1950s, was 15 inches instead of 18 inches as previously contracted, which resulted in a reduction in the sewer pipe lining.
The committee voted to recommend the council approve the reduction in the contract.
Besides the sewer line work, the project includes replacing the aging sewer lift station at the MinnWest Technology Campus and installation of new sewer pipes under upper Lakeland Drive.
The project stretches from the tech campus to a location just south of U.S. Highway 12.
The second change was an $18,659 increase in the construction cost of the new lift station. Jurek said that during excavation by Duininck Inc. of Prinsburg, a large underground concrete tank was encountered and needed to be removed prior to construction of the new lift station, resulting in additional costs for removal and disposal.
The tank, known as an Imhoff tank, was part of an old, unused waste treatment system.
