Source: Franklin Associates, Ltd., Prairie Village, KS,Characterization of Municipal Solid Waste in the United States: 1998; and earlier reports.Prepared for the U.S. Environmental Protection Agency.

http://www.epa.gov/epaoswer/non-hw/muncpl/

*MATERIAL FLOWS METHODOLOGY

The material flows methodology is utilized to generate the estimates above. Thecrucial first step is making estimates of the generation of the materials andproducts in MSW.

DOMESTIC PRODUCTIONData on domestic production of materials and products were compiledusing published data series. U.S. Department of Commerce sources were usedwhere available, but in several instances more detailed information onproduction of goods by end use is available from trade associations. The goal is toobtain a consistent historical data series for each product and/or material.

CONVERTING SCRAPThe domestic production numbers were then adjusted for converting orfabrication scrap generated in the production processes. Examples of these kindsof scrap would be clippings from plants that make boxes from paperboard, glassscrap (cullet) generated in a glass bottle plant, or plastic scrap from a fabricator ofplastic consumer products. This scrap typically has a high value because it isclean and readily identifiable, and it is almost always recovered and recycledwithin the industry that generated it. Thus, converting/fabrication scrap is notcounted as part of the postconsumer recovery of waste.

ADJUSTMENTS FOR IMPORTS/EXPORTSIn some instances imports and exports of products are a significant part ofMSW, and adjustments were made to account for this.

DIVERSIONVarious adjustments were made to account for diversions from MSW.Some consumer products are permanently diverted from the municipal wastestream because of the way they are used. For example, some paperboard is usedin building materials, which are not counted as MSW. Another example ofdiversion is toilet tissue, which is disposed in sewer systems rather thanbecoming MSW.

In other instances, products are temporarily diverted from the municipalwaste stream. For example, textiles reused as rags are assumed to enter the wastestream the same year the textiles are initially discarded.

ADJUSTMENTS FOR PRODUCT LIFETIMESome products (e.g., newspapers and packaging) normally have a veryshort lifetime; these products are assumed to be discarded in the same year theyare produced. In other instances (e.g., furniture and appliances), products haverelatively long lifetimes. Data on average product lifetimes are used to adjust thedata series to account for this.

MUNICIPAL SOLID WASTE GENERATION AND DISCARDSThe result of these estimates and calculations is a material-by-material andproduct-by-product estimate of MSW generation, recovery, and discards.*TERMS

Municipal solid waste ( MSW) includes wastes such as durable goods, nondurable goods,containers and packaging, food scraps, yard trimmings, and miscellaneous inorganic wastes fromresidential, commercial, institutional, and industrial sources. Examples of waste from thesecategories include appliances, automobile tires, newspapers, clothing, boxes, disposabletableware, office and classroom paper, wood pallets, and cafeteria wastes. MSW does not includewastes from other sources, such as construction and demolition debris, automobile bodies,municipal sludges, combustion ash, and industrial process wastes that might also be disposed inmunicipal waste landfills or incinerators.

Source reduction activities reduce the amount or toxicity of wastes before they enter themunicipal solid waste management system (see Generation). Reuse is a source reduction activityinvolving the recovery or reapplication of a package, used product, or material in a manner thatretains its original form or identity. Reuse of products such as refillable glass bottles, reusableplastic food storage containers, or refurbished wood pallets are examples of source reduction.Generation refers to the amount (weight or volume) of materials and products that enter thewaste stream before recycling (including composting), landfilling, or combustion takes place.

Recovery of materials means removing MSW from the waste stream for the purpose of recycling(including composting). Recovery for recycling as defined for this report includes purchases ofpostconsumer recovered materials plus net exports of the materials. Recovery of yard trimmingsincludes diverting yard trimmings from disposal to a composting facility. For some materials,recovery for uses such as highway construction or insulation is considered recovery along withmaterials used in remanufacturing processes.

Combustion includes combustion of mixed MSW, fuel prepared from MSW, or a separatedcomponent of MSW (such as rubber tires), with or without energy recovery.

Discards include the municipal solid waste remaining after recycling (including composting).These discards are usually combusted or disposed of in landfills, although some MSW is littered,stored, or disposed on site, particularly in rural areas.

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