Municipal Solid Waste Landfills
Although greater amounts of municipal solid waste (MSW) have been recycled and composted in the last forty years, the majority of MSW generated in the United States is safely disposed of in landfills. No longer the the "garbage dumps" of years past, today’s modern MSW landfills are well-engineered facilities that are regulated under strict federal and state regulations to ensure protection of human health and the environment. Modern MSW landfills are operated, located, designed, monitored, closed, and cared for after closure to ensure environmental performance. In addition, modern MSW landfills collect and treat the leachate (the water that passes through the waste) and gas (from the decomposition of the waste). Recovered landfill gas can be converted into energy (electricity, steam, heat, vehicle fuel) to reduce America’s dependence on petroleum products.
Cross-Section of a Modern MSW Landfill
A graphic depiction of the major components of a MSW landfill in compliance with federal regulations.
Typical Municipal Solid Waste Landfill Components
||Liner systems can include clay, geotextiles, and/or plastics on the bottom and sides of the landfill to prevent liquids from leaving the landfill and impacting groundwater resources. In the cross-section, the liner system is comprised of a compacted liner overlain by a synthetic liner.
|Leachate Collection System
||Leachate collection system (LCS) is placed on top of the liner to collect and remove water (rainwater or liquids contained in the waste) draining through the waste. The water passing through the waste is typically referred to as leachate. Leachate collected in the LCS is treated on- or off-site.
||A final cap with the same hydraulic conductivity as the liner is placed on top of the landfill when the final height has been reached. On top of the hydraulic barrier, a vegetative layer is installed to grow vegetation. The cap system prevents precipitation from infiltrating into landfill after closure.
|Gas Collection System
||A gas collection system is installed in the landfill using perforated vertical (wells) and horizontal pipes to prevent methane and other trace organic gases from escaping. The gas is extracted under vacuum and pumped to a destruction devise such as a flare or energy utilization facility.
|Surface Water Control System
||A network of storm water drainage channels are installed on and around the landfill to collect precipitation and collect it rainwater retention pond. The storm water collection system controls erosion on the cap and adjacent areas to prevent surface water contamination.
||A comprehensive environmental monitoring system is installed around the landfill to ensure that the liner system and gas collection system is operating properly and human health and the environment are protected.
Federal MSW Landfill Regulations – The federal requirements contain location restrictions, liner requirements, operating practices, groundwater-monitoring requirements, closure and post-closure care requirements, corrective action requirements, and financial assurance requirements for all active MSW landfills.
National Emission Standards for Hazardous Air Pollutants: Municipal Solid Waste Landfills – The NESHAP standards contain federal requirements for controlling the gas emissions from larger MSW landfills as defined in the regulations.
Bioreactor Landfills: A Viable Technology – An NSWMA Research Bulletin that describes the benefits of liquids addition and management in promoting rapid waste decomposition.
NSWMA’s 2005 Tipping Fee Survey – A research bulletin that reports on the “spot market” tip fees for some 800 privately owned MSW landfills and tracks historical trends in tipping fees.
Guide for Industrial Waste Management - An EPA resource that provides state-of-the art tools and practices to enable states, companies and communities to properly manage industrial waste.
Managing Solid Waste Facilities to Prevent Odors - A research paper describing methods to control odors at landfills and transfer stations.
Solid Waste Landfills and Residential Property Values - One common misconception about landfills is that they have a negative effect on property values. While the impact of landfills on adjacent property values cannot be easily generalized, academic research indicates that residential property values are not necessarily adversely affected by close proximity to disposal facilities.
Modern Landfills - A Far Cry from the Past is an NSWMA White Paper on changes in landfill technology.
NSWMA comments on regulatory proposal to ship garbage from Hawaii to the mainland.
NSWMA comments on EPA "Pre-Decisional Draft: Disposal of Domestic Birds Infected by Avian Influenza"
Occasionally, NSWMA files legal briefs in legal cases affecting landfills. The amicus brief in Waste Management v Reheis concerned an attempt to close the Live Oak Landfill, a properly permitted landfill in Georgia, even though the state environmental agency presented no evidence of any threat to the public health or safety.