Test boring of county landfill plume will proceed
WILLMAR -- An experimental test that will involve drilling a vertical soil boring and taking water samples every five feet from contamination plume at the Kandiyohi County landfill will proceed.
Kandiyohi County Commissioners approved the test Tuesday after they were assured the cost would be $7,000 to $9,000 and not $25,000 for the single test hole.
The test will determine if the process wo-rks and how much it could cost to drill 14 more holes in the 12-acre target zone where the underground contamination plume has spread from the original landfill.
Last month, commissioners rejected bids for the 14 borings because the cost was more than double the engineer's $84,845 estimate. They also rejected a proposal to conduct one test drill that may have cost $25,000.
The Minnesota Pollution Control Agency is requiring the county to take numerous vertical water samples every five feet through the depth of the plume, which could be about 90 feet deep.
Gary Gilbert, an environmental engineer with Environmental Concepts & Design of St. Paul, said the uniqueness of the test requirement makes the project challenging for contractors to bid and to perform.
While using the same hole drilled in one spot, equipment must go down five feet and retrieve a water sample that's brought to the surface for sampling.
The pipe must be decontaminated and go down 10 feet to retrieve another sample. The process is repeated every five feet until the bottom of the plume is reached. The process has to ensure that there's no cross-contamination of samples taken at the different levels.
Gilbert said it's common for the MPCA to require a vertical profile of water samples but it's difficult to find the methodology to achieve it.
The consultants will work with a contractor to do the test boring and determine if that method should be used for the entire testing project.
The county has an $825,000 contract with Environmental Concepts & Designs to conduct various testing of pollutants at the landfill. Gilbert said about half of that is dedicated to mapping and testing the plume to determine how far it has spread.
County Administrator Larry Kleindl said the landfill presents many challenging environmental issues and said "the days of how the landfill was operated is probably at a turning point."
The contamination plume -- which was likely the result of industrial paint buried there decades ago -- as well as methane and limited space means the county needs to look at alternatives ways of operating the landfill and managing garbage.