According to the U.S. Environmental Protection Agency (EPA), municipal solid waste (MSW), commonly known as trash or garbage, consists of everyday items from households and businesses that are deposited in landfills. Some landfills, however, do accept such non-MSW as construction by-products, wastewater sludge, or other hazardous materials.
Per capita solid waste generation in 2007 was 4.62 pounds per person per day, a slight decline from 4.65 pounds in 2000. 1 While per capita waste production has been fairly constant, MSW continues to increase with population growth. In 2007, the U.S. produced 254 million tons of municipal solid waste of all types—an increase from 239 million tons in 2000, according to the EPA. This included MSW that was generated by households, businesses, construction sites and other sources. 1
In 1986, there were 7,683 municipal solid waste landfills in the U.S. In October 1991, the EPA adopted stringent new federal regulations for landfill design and operation to reduce groundwater contamination from hazardous materials disposed of in landfills. By 1992 the number of U.S. landfills had dropped to 5,345. By 1995 the EPA landfill census recorded only 3,581 facilities. In 2007, the agency counted 1,754 landfills—a decline of 79% within two decades. 1 According to the EPA, the nation’s disposal capacity has remained relatively constant because new landfills are much larger than in the past. In 2006, the National Solid Wastes Management Association estimated that states have disposal capacity for another 20 years. 2
Of the 254 million tons of solid waste generated in 2007, 85 million tons, or 33%, were recycled or composted compared to 30.1% in 2000; 32 million tons, or 13%, were burned in waste-to-energy (WTE) plants; and 137 million tons, or 54%, went into landfills compared to 55.3% in 2000. 1
While the improvement in recycling rates is encouraging news, such issues as the improper disposal of electronic equipment and the emission of greenhouse gasses from landfills pose continued challenges.
The EPA estimates that in 2005 waste electrical and electronic equipment (WEEE) amounted to approximately two million tons, most of which was discarded in landfills. Only between 345,000 and 379,000 tons were recycled. 3 End-of-life electronics may contain such materials as lead that are hazardous to the environment when not handled and disposed of properly. No national standard on the recycling of WEEE exists, and uncoordinated state regulations can discourage consumers from recycling. 4
In 2006, 23% of human-related methane gas emissions came from MSW landfills, making landfills the second largest producer of methane. 5 The methane gas emitted from landfills can be captured and transformed into usable energy. Despite this opportunity, at the end of 2007 only 457 landfill gas (LFG) energy projects were operational. These LFG programs produce approximately 11 billion kilowatt hours of electricity per year and deliver 236 million cubic feet per day of gas to direct-use applications. The EPA estimates that more than 500 additional sites are good candidates for energy conversion projects, but high start-up costs inhibit expansion of this process. 5
Although landfills are dependent on energy and road infrastructure, as a system, solid waste disposal facilities remain resilient. However, the impacts of such landfill failures as air and groundwater pollution on surrounding neighborhoods are apparent but not well quantified, and the time required for restoration is often lengthy and costly. Additionally, landfills can play an important role during recovery operations, but without adequate disposal options cleanup and recovery efforts may be hindered.
Future investments must consider new technologies and behavioral changes focused on energy conversion, recycling, waste reduction, and increased efficiency.
Innovative technologies and recycling efforts have been successful in improving the safety, sustainability, and efficiency of the nation’s waste disposal systems. The lack of long term strategies to deal with increased amounts of electronic waste and under-use of waste to energy practices, however, indicates the need for continued research and development of new policies and management practices.
- U.S. Environmental Protection Agency, Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Facts and Figures for 2006, November 2008.
- National Solid Wastes Management Association, What is a Solid Waste Landfill, November 2006.