Cleaning up hazardous waste at the WDE Landfill

The site has three protection systems — two groundwater extraction/treatment systems and a landfill gas extraction system for methane — to reduce health and environmental risks from the contamination. A fourth system installed in 2013 extracted vapors from the hazardous waste pit; it was decommissioned in 2018 after removing the readily available vapors.

The Minnesota Legislature appropriated $12 million in 2017 to clean up the hazardous waste pit. In 2018, the Legislature approved an additional $6 million to address greater-than-expected levels of contamination, but the funds were tied up in a lawsuit brought by a coalition of environmental groups over the source of the funds (the Environment and Natural Resources Trust Fund). In the meantime, the MPCA learned that site cleanup would cost $4.3 million more than expected. In 2019, the Legislature approved $10.3 million to cover the $6 million allocation and the additional $4.3 million; a total of $22.3 million is now dedicated to the cleanup. Site preparation work has begun, and excavation of the hazardous waste pit will begin later this summer.

Background

The WDE Landfill is the only mixed municipal solid waste landfill in Minnesota ever permitted for disposal of hazardous waste. Starting in November 1972, hazardous waste was accepted for disposal in a pit separate from the rest of the landfill. Management of the hazardous waste pit was generally poor. An early inspection of the area noted that some barrels had been opened and their contents spilled on the ground. In addition, a truck entering the area had broken through the pit's asphalt liner. When the pit was closed in January 1974, it contained an estimated 6,600 barrels of hazardous waste.

The whole landfill closed in 1983, and in 1986, a group tried to study what was in the pit. The study was cut short due to concerns for worker safety. In the past 30 years, several systems have been installed to control pollution at the landfill, which is now largely surrounded by residential areas. The systems installed in the 1990s to keep groundwater contamination and landfill gases from migrating off site treat 30 million gallons of groundwater and burn off about a million pounds of methane per year.

In 2011, polychlorinated biphenyls (PCBs) were discovered leaking from the hazardous waste pit. MPCA staff began studying ways to address the problem. A separate system was installed in 2012 to treat PCB contamination in groundwater. A vapor extraction system operating between 2012 and 2018 collected volatile organic compounds in the pit, making the site safer and paving the way for excavating the hazardous waste. .

Despite the systems addressing pollution at the landfill, risks remain high, particularly if the systems fail. In addition, $13.7 million has been spent to construct, operate, and maintain these systems since 1995.

The risk of exposing nearby residents to unacceptable levels of vapors precluded this work from being considered earlier. The vapor extraction system in the hazardous waste pit has lessened this risk. With funds from the Legislature available, removal of the hazardous wastes now would both reduce the risk to nearby residents and be more cost-effective than continuing to operate remediation systems for the pit.

Timeline

1962 – Site opens as the Grow Township dump.

1971 – Site permitted by the MPCA as a mixed municipal solid waste landfill.

1972 - 1974 – Landfill accepted hazardous waste in pit that covered about a third of an acre and was lined with 18 inches of clay topped off with 6 inches of asphalt

1983 – Landfill stops accepting waste.

1992 – Groundwater extraction and treatment system installed (as part of federal Superfund Program). About 30 million gallons of groundwater treated per year.

1993 – Multilayer soil cap installed.

1995 – Landfill enters MPCA’s Closed Landfill Program.

1996 – City of Andover adopts ordinance that prohibits building enclosed structures within 200 feet of waste limit.

1998 – Landfill gas extraction system installed. More than one million pounds of methane burned off each year.

2011 – PCBs discovered leaking from the hazardous waste pit. MPCA begins studying treatment options.

2012 – Separate treatment system installed onsite to treat PCBs in the groundwater collected beneath the pit

2013 – Vapor extraction system installed to collect volatile organic compounds from the hazardous waste pit. About 8,300 gallons of condensed gases have been collected to date and sent out of state for disposal.

2017 – Site investigation shows extent of contamination much larger than predicted. Additional money needed to pay for proposed cleanup.

2018 – Lawsuit ties up $6 million in funding appropriated by 2018 Legislature. Cost of cleanup increases $4.3 million due to additional requirements for securing the site during excavation and cleanup work and higher costs for waste transport. Vapor extraction system in the pit is decommissioned after removing more than 8,300 gallons of condensed gases.

2019 – The Legislature approved another $10.3 million for site cleanup. Site preparation begins and all waste will be removed from the site by the end of the year.

Frequently asked questions about the project

Will private wells be tested as part of this cleanup project?

No, the MPCA will not be testing private drinking water wells as part of this project. Anoka County does have a well water testing program. For more details, visit their Environmental Services webpage.

How can I figure out how deep my drinking water well is?

The Minn. Department of Health (MDH) stores information about many private wells:  Minnesota Well Index Online. If you are unable to access information about your well through this application, you can call 651-201-4600, 800-383-9808, or email health.minnesotawellindex@state.mn.us for assistance.

Anoka County may have additional information about your well. Contact their Environmental Health Services Department at 763-324-4260 for more information.

You can also hire a private well driller to help you determine your well’s depth:  Licensed Well and Boring Contractor Directory (MDH)

Is Coon Creek contaminated with pollutants from the landfill? Is it safe to swim and boat in?

The MPCA has been testing the water quality of Coon Creek for 30 years, and currently does not detect pollutants associated with the landfill or the hazardous waste pit in the creek. A series of groundwater extraction wells located between the landfill and the creek keep pollutants from reaching it.

In general, Coon Creek is safe for boating and swimming, but it is polluted with contaminants that are frequently found in urban rivers and streams. Learn more on the MPCA’s Coon Creek Watershed District webpage.

You can also look at raw water quality data using the agency’s surface water data application.

Besides PCBs, what other chemicals are in the hazardous waste pit?

Recordkeeping at the landfill was generally poor, so we don’t know exactly what types of wastes may have been disposed of in the hazardous waste pit. But records do show that chemicals such as paint sludge, paint strippers, degreasers and petroleum solvents were disposed of in the pit.

How long will the project to excavate the hazardous waste pit take?

An accurate estimate of how long this project will take won’t be available until after additional investigation at the site is complete. Recent work at the hazardous waste pit has found more contaminated soil underneath the hazardous waste pit than initially thought. The MPCA is in the process of determining the extent of this contamination.

Once the project gets underway, what will the work schedule at the closed landfill site be like?

The work schedule at the site will typically be 7:00 a.m. to 5:00 p.m., Monday through Saturday.

Contact

Cliff Shierk (651-757-2371), Twitter: @cliffMPCA

For site photos visit the MPCA Flickr site.