Burnsville | Freeway Landfill and Dump contamination

The Freeway Landfill (Burnsville, Minn.) accepted waste from 1969 to 1990. The Freeway Dump was a separate disposal area that operated from 1960 to 1969. Compared to modern landfill programs, there were few design and operational standards for older landfills when they were initially built and operated. There are a number of environmental concerns associated with the landfill and dump that need to be addressed to ensure protection of human health and the environment.

Health and environmental concerns

The two unlined sites together contain over 6 million cubic yards of waste over 174 acres. The waste disposal occurred without the needed protections modern landfills have to manage landfill leachate and landfill gas.

The landfill and dump are a future threat to the drinking water supply of Burnsville and Savage, and to the Minnesota River because of expected future changes in the area groundwater movement. Drinking water supply wells in the area are tested regularly, and the water currently meets drinking water standards.

The uncontrolled release of landfill decomposition gases into the atmosphere contributes to climate change. The movement of landfill gas underground is also a potential threat to adjacent buildings.

When the Freeway Landfill began operating in 1969, there were few restrictions on waste accepted at landfills. Environmental investigations suggest that the material is predominantly municipal solid waste (MSW) with pockets of construction and demolition (C&D) debris and industrial waste. Historical records indicate that a variety of other waste may have been disposed of in the landfill.

Due to the significant dewatering at the adjacent Kraemer Quarry, the groundwater table at the site has been artificially depressed throughout the operational life of the landfill, continuing to the present. Prior to that, the site originally included wetlands adjacent to the Minnesota River. Projections show that groundwater levels will eventually rebound to natural conditions when the quarry pumping stops.

When the quarry stops operating and this pumping ends, groundwater levels will rise, and chemicals and other substances from the waste materials in the landfill will come into direct contact with the groundwater, causing additional contamination. The contaminated groundwater under the landfill will flow towards the MN River and towards the lake that will form in Kraemer Quarry when the quarry eventually fills with water

When waste decomposes, it can also create several types of air pollutants. The primary concern is the generation of methane, which can be explosive at certain concentration ranges. This gas can cause possible public safety hazards by migrating from the waste in the landfill to the surrounding soils and into nearby structures.

Groundwater contamination

A network of groundwater monitoring wells has been installed around both the Freeway Landfill and Freeway Dump to investigate the presence and movement of groundwater contamination. The sampling results show that groundwater contamination is widespread within the waste footprints, and recent testing shows that the contamination has migrated beneath and outside of the waste footprint. At most locations sampled, this contamination has been detected at levels exceeding regulatory criteria. The most common contaminants include heavy metals and chemicals of emerging concern like per- and polyfluoroalkyl substances (PFAS) and 1,4-dioxane, though many other contaminants were also detected.

The current groundwater pumping operations at the Kraemer Quarry are preventing contaminated groundwater from impacting the cities of Burnsville and Savage's drinking water wells. Analysis of samples collected from the drinking water wells has not detected contamination above regulatory standards.

Recent environmental investigations performed by the MPCA have identified contamination related to both the Freeway Landfill and Freeway Dump. The most recent investigation was a ‘Focused Remedial Investigation’ conducted in accordance with the EPA Superfund process. This investigation was conducted in two phases in 2018 and 2019.

Methane

Sampling for methane has been performed during several environmental investigations, including an extensive investigation within the waste footprint of Freeway Landfill in 2005. Methane has been found above regulatory intervention limits at most locations within the waste footprints at both Freeway Landfill and Freeway Dump and in many locations outside of the waste footprints.

Projects and timeline

Two options were designed to clean up the contamination.

  1. Build a new modern landfill on the property. Three variations were considered.
  2. Move the waste from the landfill and dump off the property to another modern landfill.

Option 1: Build a new landfill on the property

This option would first dig up the existing landfill to allow a new modern landfill to be constructed on the landfill property, replace the waste then move the Freeway Dump waste to the Freeway Landfill. The Freeway Dump totals 27.5 acres, and this area may be available for re-use once the waste was removed.

There were three variations of this option developed. After an evaluation of the options and a review of public comments, the MPCA has selected a variation that balances the waste footprint size and the landfill height and offers a few notable benefits; it preserves the natural landscape of the Minnesota River Valley, provides area for redevelopment along the Interstate 35W corridor, and offers greater flexibility if waste quantities vary during construction.

The estimated cost to build a new landfill on the property and replace the waste is estimated to be around $117 million.

Option 2: Move the waste to another landfill

This option would involve excavating the waste from the Freeway Landfill and Freeway Dump and hauling it to a different open, permitted landfill for final disposal.

The cost range of this option is currently $165 million – $538 million. This wide range is due to unknown waste disposal costs.

Next step and timeline

One of these options will be selected through the legislative process to fund the project and move forward to clean up the contamination.

Public input

In June 2020, MPCA completed the public comment process for redesign of the Freeway Landfill and Dump. Public comment was requested on the three variations of the dig and line option, which is a process to dig up the waste to allow a new modern landfill to be constructed at the same location to contain the dug up waste. During this process, MPCA received 23 responses from citizens and interested parties including comments from the three adjacent cities of Burnsville, Bloomington, and Savage. A few consistent themes emerged:

  1. Concerns about final landfill height and/or placement.
  2. Cost as the most important factor. These commenters prefer lowest cost options and do not want taxpayers to finance a private redevelopment.
  3. A position that the only option is dig and haul, which removes the waste from the landfill and transports it to a new permanent site. These commenters felt strongly that the dig and line option is not viable and did not want to suggest that it was an option by commenting on the design variations.

MPCA provided responses to all comments that included specific questions pertinent to the project.

Facebook Live event and public meeting

The MPCA held a Facebook Live event on May 18, 2020, to introduce this issue. Following the Facebook Live event, the MPCA held an online public meeting May 18 and provided the landfill redesign options in more detail. The public meeting was via Webex. There are two links to the Webex session (we had a technical issue with the full recording of the meeting). During the public comment period (May 10 until June 12, 2020), the public was invited to provide feedback on the landfill redesign. These comments are now part of the official record.

Site history

The Freeway Dump is located directly east of the Freeway Landfill and accepted waste from 1960 to 1969. This 28-acre property has a vegetated soil cover and is currently used as a golf driving range. The waste footprint of the Freeway Dump extends past the property boundaries and covers approximately 34 acres. The estimated volume of waste in the Freeway Dump is 790,000 cubic yards.

The landfill operator purchased the property that would become the Freeway Landfill in the 1960s. The Freeway Landfill site is bounded on the north by the Minnesota River. The eastern boundary is Interstate Highway 35W (I-35W). On the southern edge is the Kraemer Quarry, which is still in use, and on the west is another quarry that was formerly mined by the landfill operator and is currently operating as a concrete recycling operation.

Before the landfill began operating, this area was a floodplain with wetlands and agricultural fields. While a landfill would never be sited in that type of area today, it was not a prohibited land use at that time.

The Freeway Landfill began accepting waste from the Twin Cities area in 1969 under a conditional use permit issued by the city of Burnsville. The MPCA issued the landfill a solid waste permit in 1971.There were few landfill regulations at that time. Permits usually covered some very basic requirements such as hours of operation, control of blowing trash, pest control, and restrictions on the disposal of a few types of waste.

In the late 1970s and 1980s, environmental knowledge and landfill regulations advanced dramatically. Landfills were required to be properly lined and operated to prevent water and air pollution. Landfill operators were given two years to make upgrades to their facilities, or to stop accepting waste. The Freeway Landfill stopped accepting waste in 1990.

At the end of its operational lifetime, approximately 5.3 million cu. yd. of waste had been disposed of at Freeway Landfill. The waste disposal area — about 140 acres — was covered with soil.

The area of waste at Freeway Landfill and Freeway Dump was mapped using historical aerial photography, along with environmental drilling and test excavations.

More information

Draft designs for the dig and line option

These documents are 90% design drawings. They include the relevant construction plans and specifications for a project but minor changes may be required before designs are finalized.

Draft designs for moving the waste option

These documents are 90% design drawings. They include the relevant construction plans and specifications for a project but minor changes may be required before designs are finalized.