The operator of Pine Bend Landfill, one of four landfills that will expand to handle the Twin Cities metro area’s growing municipal waste needs, proposes to increase the height of the landfill by 85 feet. This increase will expand the landfill's capacity by nearly 8.2 million cubic yards and extend its operational life through 2045.
Our role
In November 2023, the MPCA released both the environmental assessment worksheet (EAW) and a draft air permit for the Pine Bend Landfill. Along with the landfill’s solid waste permit, the EAW and the air permit assess the potential for significant environmental effects and put measures in place to protect the environment and nearby residents from pollution generated by the landfill.
Location
Operated by Republic Services, the Pine Bend Landfill is located on 225 acres in Dakota County, south of Inver Grove Heights and roughly a mile and a half west of the Mississippi River. The landfill is adjacent to industrial facilities and farmland and near some residential properties.
Project information
The Pine Bend Landfill is one of multiple sites that accept mixed municipal waste from the seven-county metropolitan area. This service area generates 3.3 million tons of garbage annually and sent 30 percent more waste to landfills in 2022 than in previous years.
Pine Bend Landfill’s EAW reviewed potential impacts to air, local geology, soils, groundwater, surface water, and other potential environmental impacts. Some key findings include:
- The project will not absorb groundwater and is not located within protection areas for wells or drinking water supplies. The facility has an existing groundwater monitoring network in place and would continue to monitor groundwater quality.
- Liquid that leaches from the landfill, referred to as “leachate,” will be collected by systems that are already constructed and in place.
- An existing liner system is in place over certain sections of the landfill. A new composite liner is planned for future installation.
- New well heads are proposed to capture and transport methane gas via pipeline to an adjacent recovered natural gas facility.
- Sampling for perfluoroalkyl substances (PFAS) at 22 monitoring wells is required in the landfill’s solid waste permit. Most recent sampling shows levels at or above permit levels at 12 wells and two springs. Testing over time shows a decrease of PFAS at some well locations and an increase at others.
The updated air permit includes three minor amendments:
- Emissions generated from the larger landfill, as well as the facility’s renewable natural gas plant and diesel-fired tipper, remain below permit thresholds.
- Emissions of volatile organic compounds (VOCs) from the vertical expansion will increase by 0.25 tons/year.
- Emissions from the installation of the renewable natural gas plant decreased for most pollutants but increased by 7.4 tons/year for VOCs.
The air permit also requires the landfill’s renewable gas plant — which began operating in 2022 to capture methane generated from decomposing waste and transform it into natural gas used by Xcel Energy — to install and maintain controls to reduce emissions:
- A thermal oxidizer will combust gases that are either removed as waste during processing or do not meet pipeline quality standards.
- An open flare will combust landfill gas that cannot be accommodated by the renewable gas plant and/or pipeline.
This expansion project is part of the short-term solution to expand four area landfills to help address the growing problem and ensure continued safe and proper management of waste materials.
In addition to the Pine Bend Landfill, the other three landfills in the process of expanding or under review for expansion include the Burnsville Sanitary Landfill, which is increasing capacity by nearly 1.7 million tons; the Rich Valley Landfill beside the Pine Bend Landfill, which will increase capacity by 893,899 tons; and the Dem-Con Landfill in Shakopee, which will increase capacity by 627,244 tons.
Each of those facilities may need to complete the environmental review and permitting process. If for some reason a facility isn’t permitted to accept additional garbage, the tonnage will be reallocated to other facilities capable of accepting the waste.
Next steps and timeline
The public comment period for the EAW and air permit closed on December 15, 2023. A public meeting for community members was held during that comment period on November 30 to discuss the expansion project in detail. MPCA staff are currently reviewing comments received and will provide responses to all comments that included specific questions pertinent to the project. Comments will be used to determine if additional environmental review is necessary and if changes are needed to the air permit. If no changes or additional review are needed, then the project will proceed.
The solid waste permit for Pine Bend Landfill is currently under MPCA review and should be released for public comment in early 2024.
The MPCA anticipates that construction for this next phase of landfill expansion will begin in early 2024.