Survey of MSW Generation and Disposition in the US

In 2014 EEC-Columbia carried out its last state-by-state US survey of waste management

MSW Management

by Nickolas J. Themelis & Dolly Shin

Oct. 2, 2015

The Columbia 2013 Survey of Waste Generation and Disposition in the US is a continuation of Journal’s State of Garbage in America (SOG) surveys, initiated by BioCycle in 1989. From 2002 to 2010, BioCycle conducted the State of Garbage in America survey and report with the Earth Engineering Center (EEC) of Columbia University. The Columbia 2013 Survey of Waste Generation and Disposition in the US compiled and analyzed 2011 data provided by the waste management agencies of the 50 States of the Union. The Survey questionnaire was first reviewed by EPA’s Office of Resource Conservation and Recovery, and their comments were incorporated in the final edition submitted to the states. The Survey showed that in 2011 the US generated a total of 389 million short tons of municipal solid wastes (MSW), corresponding to a per capita generation of 1.3 short tons. Of the total MSW generated, 22.6% was recycled, 6.3% composted, 7.6% used as fuel in waste-to-energy (WTE) power plants, and 63.5% was landfilled.

An interesting finding was that, in comparison to 2008, landfilling decreased by about 20 million tons, while recycling increased by nearly the same amount. An estimated 247 million tons of solid wastes were landfilled in MSW landfills, i.e., 113 million higher than EPA estimate. This ­difference is believed to be due to several wastestreams that are deposited in MSW landfills but are not included in the EPA definition of MSW, such as packaging of imported goods, automobile shredder residue, ash residues, paper residues from wastewater treatment plants, and some construction and demolition debris. The Columbia Survey considers that all recyclable, compostable, or combustible materials that are discarded in MSW landfills represent a loss of valuable resources and an unnecessary use of land; therefore, they should be included in the national account of waste management.
All states and municipalities provide waste collection and disposal services to their citizens. However, an accurate account of how much of the MSW is directed to materials or energy recovery facilities is essential for planning and policy decisions. All tonnages in this paper are in short tons (1 metric ton = 1.1 short ton). In the hierarchy of waste management (Figure 1), the highest priority is to reduce the waste generation per person. However, this metric depends on economic development and culture, as witnessed by the fact that the per capita generation of MSW in the US is substantially higher than in countries with nearly the same GDP per capita, such as Austria, Switzerland, and the Netherlands. Waste reduction is not within the control of MSW managers who have at their disposal four broad methods: Recycling, composting, thermal treatment with energy recovery, and landfilling. Landfills range from the preferred sanitary landfills to the non-regulated waste dumps that are still used in many parts of the developing world (Figure 1).

Several states have adopted various source reduction programs. For example, Minnesota has an exchange service that connects organizations with unwanted goods to others who may need them (iWasteNot Systems Inc.). Some cities in California, Iowa, Massachusetts, New York, Washington, and Wisconsin have instituted pay-as-you-throw (PAYT; USEPA 2012). Some of these systems are also called Volume-Based-Waste-Fee (VBWF) programs. For example, the town of Sandwich, MA, has implemented a program whereby citizens have to purchase labeled trash bags at local stores at prices of 24 cents to $1.20 for 8- to 30-gallon bags. This measure resulted in a 42% reduction of MSW to the WTE plant and a 74% increase in the collection of recyclable streams (Abrashkin 2015).

There are four methods of collecting recyclable materials in the US: Curbside collection, drop off, buy-back, and deposit/refund. The collected materials include paper fiber (office paper, newsprints, and cardboards), metals (aluminum cans, ferrous and non-ferrous metals), plastic containers, consumer electronics, and tires. In general, the collected recyclables are transported to material recovery facilities (MRF) or to transfer stations and then to MRF. At the MRF, the recyclables are sorted to marketable streams and a residue that is sent to a WTE, a cement plant, or is landfilled. Reporting of materials treated and marketed by MRF to the state agencies is not uniform. Also, some homogeneous streams—such as paper, cardboard, and aluminum cans—may go directly to recycling companies to be used as part of their feedstock.

Organic wastes can be broadly divided into two categories: Yard or green wastes (grass clippings, leaves, etc.) and food wastes. Source-separated yard wastes are usually processed in open-air windrows to produce a soil conditioning compost. Food wastes are not usually composted in open-air windrows because they emit unpleasant odors. Therefore, the preferred method is "anaerobic digestion” in dedicated chemical plants or in biodigesters of wastewater treatment plants. A detailed analysis of the present state of composting in the US was published recently in BioCycle (Themelis and Arsova 2015); about 50% of the US yard/green wastes are processed, mostly in open air windrows, while collection and anaerobic digestion of food wastes is less than 10% of the US food wastes.

The 2014 Survey Questionnaire

From 2002 to 2010, the EEC of Columbia University conducted, in collaboration with BioCycle journal, BioCycle’s biannual survey of national waste statistics called "State of Garbage in America”. The 2014 EEC survey was based on 2011 data provided by the waste management agency of each state (Shin 2013). The excel-format survey included questions on all means of waste management in the state. The sum of reported MSW recycling, composting, combusting, and landfilling is equal to the total MSW generated.

The recycling section of the survey asked for tonnages of recyclables going to single-stream and dual-stream MRFs, as well as those sent directly to recycling plants. Estimated tonnages of individual recycled commodities were separate questions. Additional questions were on existing PAYT and VBWF programs. The composting section asked for municipalities and populations provided with curbside collection of yard and food wastes and number of composting facilities in the state. In the energy recovery section, the survey requested the number of municipalities served by WTE facilities, MSW tonnage processed and gate fee paid, electricity and heat supplied, and tons of metals recovered. The landfill questions were on number of landfills, tons landfilled, gate fee, volume of landfill gas (LFG) generated, and tons of MSW exported to or imported from other states.

State Responses to Survey

Nine states, representing 13% of the US population, were not able to participate in the 2013 Columbia survey. For these states, their 2008 Survey data (Themelis and Musche 2014) were used, after adjusting for population growth between 2008 and 2011. The most accurate data reported in the Survey were for MSW disposed in landfills or combusted with energy recovery in WTE plants because trucks in and out of these facilities are weighed and the data are reported to the state. Since there is no reporting requirement for recycling facilities, 10 states could not provide recycling data (AL, GA, IA, ID, IL, IN, MS, NE, TX, and WI). Twenty-six states provided complete data on recycled tonnages of individual commodities. Eight states could not provide information on the number of municipalities providing curbside collection or the number of MRFs in the state. For the few states which did not provide recycling data, the 2008 Survey data were used, adjusted for population growth.

Composting facilities are also not required by states to report processed tonnages. Six states only provided combined total tonnages of yard and food wastes. Most of 21 states reporting composting tonnages provided tons of yard ("green”) waste composted. Eleven states provided tons of food waste composted while and eight states (AR, DE, KS, KY, NC, ND, RI, and WY), and Washington DC reported that they only compost yard waste. The composting results of the Survey are discussed in a recent BioCycle article (Themelis and Arsova 2015).

Only some states provided the average gate fee for landfills. Table 1 compares the landfill gate fees of 11 states (2011 data) with the WTE gate fees for the same states in the 2010 BioCycle-Columbia survey (2008 data). It can be seen that, on average, WTE gate fees were a few dollars higher than landfill fees. Thirty-four states reported the number of biogas collecting landfills, and 17 of them provided the total amount of LFG collected.

Results of the Columbia 2014 Survey of 2011 Data National Overview
The Survey showed that in 2011, the United States generated a total of 389 million tons of MSW, and that the per capita generation of MSW was 1.3 tons (1.19 metric tons). Of the MSW generated, 22.7% was recycled, 6.3% composted, 7.6% was combusted with energy recovery at WTE facilities, and 63.5% was landfilled. The amounts of MSW recycled, composted, combusted, and landfilled in each state are shown in Tables 2 and 3.
 Figure 2. Methods of managing MSW in the 10 EPA Regions in 2011

Figure 2 shows the percent disposition of MSW generated with the states divided into the 10 EPA regions. Combustion with energy recovery (WTE) is most prevalent in the East Coast (Regions 1–4), with Region 1 having the highest fraction of MSW disposed by WTE (41%). In the other regions, less than 4%, or none, of the MSW is disposed at WTE facilities. The mid-western regions (Regions 5–8) are still very reliant on landfilling and have the lowest recycling rates. The West Coast states (Regions 9 and 10), lead in recycling with over 30% rates. Composting activity is highest in Region 6, with Regions 8–10 following closely.

This Survey was based on 2011 data and showed that the principal changes from 2008 were that landfilling decreased by about 20 million tons while recycling increased by nearly the same amount. In contrast to the most advanced nations in Europe and Asia, the US continues to landfill about 63% of its MSW while recycling and composting about 30%. The state of Connecticut is at the top of the waste management "ladder” by landfilling only 7.7% of its MSW.

The survey showed that it has become increasingly difficult for the states to collect and compile reliable recycling and composting data, especially since the economic downturn of 2008 has reduced state budgets and resources. For states to sustainably manage waste and plan ahead to accommodate for increasing waste generation, timely collection and accurate analysis of recycling and composting data are essential. The environmental agencies of some states need to develop a systematic data reporting process for all types of waste managing facilities.

This study identified, semi-quantitatively, several types of wastes that, according to the EPA definition, are not considered to be MSW and yet, for lack of other alternatives, are disposed in MSW landfills. Further study is required to quantify the annual generation of these wastes and use this information to devise strategies for reducing landfilling and increasing the recovery of materials and energy from MSW.

The authors are grateful to the USEPA Office of Resource Conservation and Recovery for reviewing the Survey questionnaire and making valuable suggestions for improvement. Support of this study by the American Chemistry Council and the SEGUE program of the National Science Foundation is gratefully acknowledged.
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