Municipal Solid Waste and Construction & Demolition Debris
Estimation processes for OOS shipments of municipal solid waste (MSW) products and the construction and demolition debris (C&D) are similar. Discussions on data and methods used in estimating volumes of shipments associated with the MSW component are presented in the first part of this Section. Similar discussions on the C&D component are then follows.
7.1 OVERVIEW OF MUNICIPAL SOLID WASTE FLOWS
The MSW products, as defined by the U.S. Environmental Protection Agency (EPA) and generally accepted within industry, are typically disposed in landfills and to a lesser extent processed in incinerators and resource recovery facilities. The MSW data collected by the EPA was specified under the Resource Conservation and Recovery Act (RCRA) “Subtitle D” wastes. It is mostly common trash or garbage that consists of everyday items people dispose. The MSW is generally generated from homes, schools, hospitals, and businesses, it includes:
- Containers and packaging (e.g., soft drink bottles and cardboard boxes);
- Durable goods (e.g., furniture and appliances);
- Nondurable goods (e.g., newspapers, trash bags, and clothing); and
Other wastes (e.g., food scraps and yard trimmings).
According to the EPA, Americans generated about 251 million tons of trash in 2012; which included waste being recycled and composted for almost 87 million tons. This is equivalent to about a 35% recycle-rate. Note that it is common for MSW and C&D to be disposed of in the same landfills. The C&D debris is covered under a separate OOS area and is discussed in the latter part of this section. To avoid double counting, estimates associated with C&D debris were eliminated from the MSW estimates. In addition, hazardous material wastes are not covered under the MSW. It should be pointed out that only the domestic portion of the MSW (as well as C&D) is of concern here, because shipments involving foreign trade are covered in a separate OOS component under the FAF (Section 11).
7.2 DATA SOURCES FOR ESTIMATING MSW FLOWS
7.2.1 State Solid Waste Management Reports
The majority of states reported annual statistics on their solid waste management facilities and activities, including information such as volume of waste and recycling generation, import and export of waste across state borders, and allocation of waste to landfills at the county and state levels. Some examples of these reports include Mississippi’s Status Report on Solid waste Management Facilities and Activities for Calendar Year 201210and South Carolina’s Solid Waste Management Annual Report11.
7.2.2 BioCycle - State of Garbage in America
A 2011 survey conducted by the Columbia University Earth Engineering Center (Shin, 2014) 12 on the MSW data produced information that serves as the continuation of BioCycle’s State of Garbage in America survey. Columbia University took over the State of Garbage in America series and surveyed the waste management agencies in all 50 states on the generation and disposition of MSW. Nine states did not respond, so their data was estimated by Columbia University based on information from earlier studies and their population growth. The state totals provided in that study were converted to per capita estimates for MSW generation by state. The 2011 survey data (occurred a year prior to 2012 CFS) was used to fill in any missing data for states that did not have published reports. This data did include C&D debris within the total tonnage of MSW, therefore, this tonnage was removed to avoid double counting for FAF4 purpose.
7.2.3 EPA Municipal Solid Waste in the United States: 2012 Facts and Figures
The EPA report, entitled Municipal Solid Waste in the United States: 2012 Facts andFigures13, contains data on waste generation, recycling, and disposal. Data obtained from this report were used in estimating total national tonnage and value of MSW shipments for the FAF4 base year.
7.3. ESTIMATION METHODS FOR MSW FLOWS
7.3.1 Estimating the Movement of MSW at State Level
Thirty-four state-reports provided their total amounts of MSW generated at the county and state levels. For the remaining 17 states (including Washington D.C.), data from the 2011 Biocycle survey was used to generate 2012 totals, using their population growth factors. Because Biocycle data includes C&D debris with MSW, to avoid double counting, amounts of C&D debris need to be removed from the estimated 2012 state-level total volumes.
Based on an examination of state-provided C&D debris data (Section 7.6), C&D debris, on average, accounted for about 23% of Biocycle-reported state-level numbers. Using this factor (i.e., 23%), Biocycle-based state-estimates can be adjusted to remove the C&D portion of volumes, i.e., estimates of MSW are produced. Based on this process, FAF4 estimated a total of 309 million tons of MSW was landfilled and recycled in 2012. Note that MSW, as a commodity, was assumed to have no dollar value.
Because MSW can be moved to landfills across state borders, state reports were further used to determine the OD and associated tonnage of the MSW being moved. It was estimated that 23 million tons of MSW were transported by truck across state borders in 2012 and accounted for about 7% of the total 309 million. Clearly, most MSW materials are moved within states (i.e., intra-state movements).
7.3.2 Disaggregation to FAF Regional Level
All of the landfilled waste was assigned to SCTG commodity code “41.” For the MWS shipments that crossed state boundaries, the state-reports provided information on their ODs, which allows for a proper assignment in FAF zones.
For shipments of MSW that moved entirely within a state, county-level data, if available, can be aggregated to produce the estimated volume at the FAF-zone level. When county-level data is not readily available, the state-level MSW tonnage can be disaggregated using population shares to produce associated FAF-zone level estimates. The 2012 population data as published by the Census was used for this process for FAF4.
7.4 OVERVIEW OF CONSTRUCTION AND DEMOLITION DEBRIS FLOWS
Debris generated from C&D activities is recognized as one of the largest components of the U.S. solid waste stream. Shipments originating from activities in this OOS sector include companies or establishments engaged in construction of residential and non-residential buildings, utility systems, roadways and bridges, and from specific trade contractors that are out-of-scope to the CFS. These types of shipment generally consist of often-bulky heavy material, such as concrete, wood, metals, glass, and salvaged building components. The majority of C&D debris is recycled, but the statistical tracking of tonnage has been limited in the past.
A recent white paper from the Construction and Demolition Recycling Association (CDRA), entitled The Benefits of Construction and Demolition Materials Recycling in the United States14, estimated approximately 480 million tons of C&D debris was generated in the United States in 2012. The paper also stated that over 70% of the C&D debris was presumed to be “recovered and recycled” in 2012. The following is a breakdown of the components within the C&D debris stream:
- 100 million tons mixed C&D with a 35% recycling rate,
- 310 million tons bulk aggregate (primarily concrete) with a 85% recycling rate, and
70 million tons of reclaimed asphalt pavements with a 99% recycling rate.
7.5 DATA SOURCES FOR C&D DEBRIS
7.5.1 State Solid Waste Management Reports
Similar to the MSW process, available annual reports from states were used (e.g., the States of Alabama15, South Carolina16 and Florida17) to estimate the amount of debris generated by the C&D industry. While 24 states provided annual reports on their solid waste management facilities and C&D activities, few included the tonnage of C&D debris recycled.
7.5.2 BioCycle - State of Garbage in America
This is the same data source as used in the MSW estimation process discussed in Section 7.2.
7.6 ESTIMATION METHOD FOR C&D DEBRIS FLOWS
7.6.1 Estimating Volume of C&D at State Level
Based on the data from the 24 states providing the amount of landfilled C&D debris and the state-level information from the Biocycle report, it was estimated that, on average, C&D debris accounted for 23% of the Biocycle-reported state totals. Using this rate, estimates of total C&D landfilled waste streams in those “unavailable states” can be produced.
With information obtained from the CDRA paper, which suggests 70% of all C&D debris was recycled, individual state totals of C&D debris can be broken into two parts: where 30% of debris going to landfill and the other 70% recycled. Based on this assumption, it was estimated that a total of 80 million tons of C&D debris was landfilled, while 368 million tons were recycled in 2012. In other words, a total of 448 million tons of C&D debris were generated from all states in 2012. Note that, this total is different from the rough estimate of 480 million cited by the CDRA for the national level. The FAF team believes the estimates produced for FAF4 (i.e., 448 million) which are based on information obtained from state reports and BioCycle are more accurate.
7.6.2 Estimating Volumes of C&D Flows
For states with available county-level information on C&D debris, the data for counties within each FAF region are aggregated to obtain the regional estimates for FAF4. Where county-level data is not available, the state-level tonnage of C&D was disaggregated to the desired FAF zones using population shares calculated from Census population data. The rationale of using population-based shares, instead of economic factors (e.g., sales or employment data), is that the use of economic factors might result in bias toward business locations, rather than locations where the demolition sites are located. It is common for construction companies to work outside the regions where their companies are located. Because of its better association with locations of C&D activities (where debris were generated), population data was applied for the disaggregation process in FAF4.
Since the primary commodity shipped by the construction industry is debris, it was expected that the majority of these OOS shipments are local (i.e., within zone moves). For C&D debris that moved across state borders, state reports typically specified O-D of those shipments, which allows one to identify FAF areas that are involved in these movements.
13 “Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Facts and Figures for 2012, EPA, https://www.epa.gov/sites/production/files/2015-09/documents/2012_msw_fs.pdf.