Although its growth rate is slowing, the total amount of municipal solid waste MSW) in the United States continues to rise, according to a report released by the U.S. En-vironmental Protection Agency (EPA).
Based on an analysis of data collected from 1960 to 1994, EPA re-ports that although the waste stream's products and packaging components continue to increase, efforts to restrict yard trimmings from the system are beginning to have an effect. Therefore, per capita generation is expected to remain constant at 4.4 pounds per person per day through the year 2000.
Recycling and composting recovery rates also continue to grow, and this year, for the first time, composting food scraps has reach-ed measurable proportions - an estimated 3.4 percent was composted (500,000 tons out of 14.1 million tons generated). As MSW generation rises and recycling ma-tures, however, source reduction will be increasingly important, said EPA.
Recycling and composting recovered 24 percent of MSW in 1994, reducing the discard rate to 3.4 pounds per person per day, as compared with 3.5 pounds in 1993. The report concluded that, as a nation, during 1994, we quickly approached the goal of 25 percent MSW recovery.
Nonferrous metals have the highest recovery rate (66 percent), due to high lead recovery rates from lead-acid batteries. On the other hand, only 38 percent of aluminum reportedly was recovered, in spite of aluminum can recovery rates ex-ceeding 65 percent.
Meanwhile, paper and paperboard recovery accounted for more than half (nearly 29 million tons) of total MSW recovery. Composting of yard trimmings contributed to the next largest recovery fraction at 7 million tons (see chart on page 14), said EPA.
Landfills managed 61 percent of the MSW generated (127 million tons) and combustion facilities managed another 15 percent (32.5 million tons). Although the percentage of MSW being landfilled is de-creasing, the actual tonnage is ex-pected to increase until the year 2000. According to the report, landfilling will continue to be the future's single most predominant MSW management method. Com-bustion rates, however, will remain relatively unchanged through the end of the century.
MSW sources, as characterized in this report, include both residential and commercial locations such as schools, industrial sites where packaging is generated and businesses. Identifying generation sources is important to developing management techniques, including collection for disposal, recycling or composting, EPA said. Residential wastes, including refuse from multi-family dwellings, are estimated to be be-tween 55 and 65 percent of total MSW generation; meanwhile commercial wastes constitute between 35 and 45 percent.
MSW's effect on changes in global climate also is ad-dressed in the re-port. Product manufacturing, distri- bution and the subsequent solid waste generated contri-butes to the formation of excess "greenhouse gases." These gases regulate the earth's temperature by trapping the sun's heat.
Greenhouse gas emissions can be generated throughout a product's life cycle. Source reduction and recycling can help reduce these atmospheric gases by reducing the need to harvest or extract new raw materials and to manufacture new products; by reducing the amount of energy required in manufacturing (through the use of recycled as opposed to virgin materials); and by diverting waste from disposal, according to the report.
Source reduction and recycling initiatives, as outlined in President Clinton's 1993 Climate Change Ac-tion Plan, reportedly will make a significant contribution to reducing these emissions.
For more information or to order Characterization of Municipal Solid Waste in The United States: 1995 Update (EPA530-R-96-001 PB96-152 160), contact the U.S. EPA Solid Waste and Emergency Re-sponse Office, 401 M St. (5305W), Washington, D.C. 20460.