Established in 1994, the U.S. Environmental Protection Agency’s Lowry Landfill cleanup plan embraces a “containment” strategy that’s common to most Superfund sites around the country. With protective measures designed to prevent the spread of contaminants beyond the landfill, the plan:
- Avoids the public health and environmental risks associated with removing and transporting large volumes of hazardous materials;
- Accepts the relatively low long-term threat posed by leaving hazardous materials in place; and
- Acknowledges that treatment of hazardous materials is impractical because of the size and diversity of landfill contents.
The key components of Lowry Landfill’s cleanup and containment plan—which have proven themselves to be “protective of human health and the environment,” according to the U.S. Environmental Protection Agency—are:
- Underground Barrier Walls: A system of subterranean walls protects fresh groundwater and prevents contaminated groundwater from leaving the site.
- Onsite Water Treatment Plant: A water treatment plant was built on the site in 1984 and replaced with a new, more modern facility in 2000. Further upgraded in 2004, the plant treats approximately 1.5 million gallons of contaminated groundwater every month.
- North Toe Extraction System: A trench at the northern limit of the former landfill area collects contaminated groundwater. The North Toe Extraction System extracts and pumps that water to the site’s water treatment plant.
- Gas-to-Energy System: Hazardous landfill gases—mostly methane and carbon dioxide—are the byproduct of decomposing waste that was buried underground at the landfill. Completed in 2008, the site’s gas-to-energy system extracts the gases, burns them and converts them into electricity for a local utility company.
- Landfill Cover: The former landfill area is covered by 4 to 12 feet of compacted clay and soil. The “cap” reduces infiltration of rain and snow into the soil, which minimizes further groundwater contamination.
- Groundwater Monitoring Wells and Compliance Program: Consisting of dozens of monitoring and compliance wells, an ongoing groundwater monitoring program verifies on a continuing basis that cleanup efforts remain effective at protecting public health and the environment.
- Waste Pits: Contaminated liquids have been removed from two of three waste pits to prevent groundwater contamination. The third and final waste pit is in the final phase of product recovery.
- Surface Water Action: Construction of a permeable subsurface channel and clay barrier in the unnamed creek prevents clean surface water from coming into contact with contaminated groundwater flowing underneath the creek.
Although not part of the U.S. Environmental Protection Agency’s formal cleanup plan, Denver and Waste Management as an added precaution purchased properties around the former landfill. Ownership of these properties prohibits future groundwater use and controls future development around the site so that the only allowable land uses are compatible with cleanup and containment objectives. The properties are one-half mile wide on the east, west and south sides of the site. (No such zone was purchased to the north because the active Denver Arapahoe Disposal Site facility adjoins the Lowry Landfill site at the north end.)