Landfills

Scope

Landfills are facilities that are engineered to receive specific types of waste, namely municipal solid waste (MSW), industrial waste, and hazardous waste. Most landfills are regulated under the Resource Conservation and Recovery Act (RCRA), but a few are considered to be Toxic Substances Control Act hazardous waste landfills.

Landfills must follow strict designs to protect the environment from leaks, dust, and other contaminants. They may not be located in floodplains or environmentally sensitive areas, such as over an aquifer used for drinking water. Modern landfills make use of robust monitoring systems to watch for the buildup of methane and other gases, leachate, dusts, and groundwater contamination.

Regulatory citations

• 40 CFR Part 257 Subpart A — Classification of Solid Waste Disposal Facilities and Practice
• 40 CFR Part 257 Subpart B — Disposal Standards for the Receipt of Very Small Quantity Generator (VSQG) Wastes and Non-Municipal Non-Hazardous Waste Disposal Units
• 40 CFR Part 258 — Criteria for Municipal Solid Waste Landfills
• 40 CFR 264 Subpart N — Landfills
• 40 CFR 265 Subpart N — Landfills
• RCRA Subtitle D – Solid Waste Statute Sec. 4004
• RCRA Subtitle C – Hazardous Waste Statute Sec. 3004, 3005

Definitions

• Action leakage rate: The maximum design flow rate that the leak detection system (LDS) can remove without the fluid head on the bottom liner exceeding 1 foot.
• Active portion: That part of a facility or unit that has received or is receiving wastes and that has not been closed in accordance with 258.60 of this part.
• Aquifer: A geological formation, group of formations, or portion of a formation capable of yielding significant quantities of groundwater to wells or springs.
• Construction and demolition (C&D) landfill: A solid waste disposal facility subject to the requirements in part 257, subparts A or B, that receives construction and demolition waste and does not receive hazardous waste (defined in 261.3) or industrial solid waste (defined in 258.2). Only a C&D landfill that meets the requirements of 40 CFR part 257, subpart B may receive conditionally exempt small quantity generator waste (defined in 261.5). A C&D landfill typically receives any one or more of the following types of solid wastes: roadwork material, excavated material, demolition waste, construction/renovation waste, and site clearance waste.
• Facility: All contiguous land and structures, other appurtenances, and improvements on the land used for the disposal of solid waste.
• Groundwater: Water below the land surface in a zon of saturation.
• Hazardous waste landfill: A facility used specifically for the disposal of hazardous waste.
• Industrial solid waste landfill: A landfill designed to collect commercial and institutional waste.
• Landfill: Facilities that are designed and managed for the disposal of solid waste.
• Leachate: The liquid that forms when rainwater filters through wastes placed in a landfill. This liquid may draw ou chemicals or constituents from wastes placed in a landfill.
• Municipal solid waste landfill (MSWLF): A landfill designed to receive household waste, as well as other types of nonhazardous wastes.

Summary of requirements

• Municipal solid waste landfills
  • Locate landfills in suitable geological areas away from faults, wetlands, flood plains, or other restricted areas.
  • Build to design specifications, which includes composite liners (flexible membranes) overlaying two feet of compacted clay soil lining the bottom and sides of the landfill.
  • Ensure leachate collection and removal systems are working properly.
  • Follow mandated operating practices, including compacting and covering waste frequently with several inches of soil.
  • Follow groundwater monitoring requirements, including testing groundwater wells to determine whether waste materials have leaked.
  • At the end of the active life of the landfill, follow prescribed closure and post-closure care requirements. These include covering landfills and providing long-term monitoring and maintenance.
  • Control and clean-up any landfill releases and achieve groundwater protection standards.
  • Maintain proof of finances for environmental protection during and after landfill closure.
• Hazardous waste landfills
  • Follow design standards to minimize the chance of releases into the environment. These include:
    • Double liner,
    • Double leachate collection and removal systems,
    • Leak detection system,
    • Run on, runoff, and wind dispersal controls, and
    • Construction quality assurance program.
  • Comply with inspection, monitoring, and release response requirements.
  • Comply with closure and post-closure care requirements, including:
    • Installing and maintaining a final cover, and
    • Continuing to operate the leachate collection and removal system until leachate is no longer detected.
  • Maintain and monitor the leak detection system.
  • Maintain groundwater monitoring.
  • Prevent stormwater run on and runoff.
  • Install and protect surveyed benchmarks.