Title
Resolution to Approve Amendment No. 1 to the Professional Services Agreement with GeoTrans, Inc. ($111,559.00)
Memorandum
Attached for your review and approval is a resolution to approve Amendment No. 1 to the Professional Services Agreement with GeoTrans, Inc. We are requesting an amendment to the existing contract with GeoTrans, Inc. for hydrologic modeling. A conceptual model will be developed for the landfill to provide the basis for analysis and identification of appropriate remediation strategies.
To satisfy the requirements of the Michigan Department of Environmental Quality (MDEQ), the groundwater and air in the vicinity of the landfill must be sampled and analyzed quarterly. GeoTrans has been performing these services at the landfill since July 2007.
For many years the landfill has had an offsite plume of 1,4 dioxane contamination primarily in Southeast Area Park, northeast of the landfill. A slurry wall was constructed along approximately 4/5ths of the boundary of the landfill to eliminate groundwater passing through the landfill and three purge wells were installed to capture the offsite contamination.
Over the past year, the concentration of 1,4 dioxane in monitoring wells north of the landfill has increased. Additional monitoring wells were installed but the cause of the increased concentration remains uncertain. In discussion with our consultants, there are different potential situations that may be contributing to the increased concentration in this area as follows:
Scenario 1: The slurry wall is not working as designed and therefore a source of 1,4 dioxane is not being captured and this source is causing the increase. This would lead us to either close off the northern section of the landfill slurry wall, at an estimated cost of $300,000.00 to $500,000.00, or install additional extraction wells along the northern boundary of the landfill. The capture wells currently discharge to the sanitary sewer system. The closure of th...
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