Per- and poly-fluoroalkyl substances (PFAS) are a class of synthetic chemicals known for their widespread presence and environmental persistence. Carbon-fluorine (C-F) bonds are major components among PFAS and among the strongest organic bonds, thus destroying PFAS may present significant challenge. Thermal treatment such as incineration is an effective and approved method for destroying many halogenated organic chemicals. Here, we present the results of existing studies and testing at combustion-based thermal treatment facilities and summarize what is known regarding PFAS destruction and mineralization at such units. Available results suggest the temperature and residence times reached by some thermal treatment systems are generally favorable to the destruction of PFAS, but the possibility for PFAS or fluorinated organic byproducts to escape destruction and adequate mineralization and be released into the air cannot be ruled out. Few studies have been conducted at full-scale operating facilities, and none to date have attempted to characterize possible fluorinated organic products of incomplete combustion (PICs). Further, the ability of existing air pollution control (APC) systems, designed primarily for particulate and acid gas control, to reduce PFAS air emissions has not been determined. These data gaps remain primarily due to the previous lack of available methods to characterize PFAS destruction and PIC concentrations in facility air emissions. However, newly developed stack testing methods offer an improved understanding of the extent to which thermal waste treatment technologies successfully destroy and mineralize PFAS in these waste streams.

Landfills manage materials containing per-and polyfluoroalkyl substances (PFAS) from municipal solid waste (MSW) and other waste streams. This manuscript summarizes state and federal initiatives and critically reviews peer-reviewed literature to define best practices for managing these wastes and identify data gaps to guide future research. The objective is to inform stakeholders about waste-derived PFAS disposed of in landfills, PFAS emissions, and the potential for related environmental impacts. Furthermore, this document highlights data gaps and uncertainties concerning the fate of PFAS during landfill disposal. Most studies on this topic measured PFAS in liquid landfill effluent (leachate); comparatively fewer have attempted to estimate PFAS loading in landfills or other effluent streams such as landfill gas (LFG). In all media, the reported total PFAS heavily depends on waste types and the number of PFAS included in the analytical method. Early studies which only measured a small number of PFAS, predominantly perfluoroalkyl acids (PFAAs), likely report a significant underestimation of total PFAS. Major findings include relationships between PFAS effluent and landfill conditions - biodegradable waste increases PFAS transformation and leaching. Based on the results of multiple studies, it is estimated that 84% of PFAS loading to MSW landfills (7.2 T total) remains in the waste mass, while 5% leaves via LFG and 11% via leachate on an annual basis. The environmental impact of landfill-derived PFAS has been well-documented. Additional research is needed on PFAS in landfilled construction and demolition debris, hazardous, and indus-trial waste in the US.

Reducing food loss and waste (FLW) is widely recognized as an important lever for lowering the environmental impacts of food systems. The United Nations Sustainable Development Agenda includes a goal to reduce FLW by 50% by 2030. Given differences in resource inputs along the food supply chain (FSC), the environmental benefits of FLW reduction will vary by stage of the FSC. Here, we identify the points along the supply chain where a 50% FLW reduction could yield the largest potential environmental benefits, assuming that decreases in consumption propagate back up the supply chain to reduce production. We use an environmentally extended input-output (EEIO) model combined with data on rates of FLW to calculate the scale of the total environmental impacts of the U.S. food system resulting from lost or wasted food. We evaluate the maximum potential environmental benefit resulting from 50% FLW reduction at all possible combinations of six supply chain stages (agricultural production, food processing, distribution/retail, restaurant foodservice, institutional foodservice, and households). We find that FLW reduction efforts should target the foodservice (restaurant) sector, food processing sector, and household consumption. Halving FLW in the foodservice sector has the highest potential to reduce greenhouse gas output and energy use. Halving FLW in the food processing sector could reduce the most land use and eutrophication potential, and reducing household consumption waste could avert the most water consumption. In contrast, FLW reduction at the retail, institutional foodservice, and farm level averts less environmental impact. Our findings may help determine optimal investment in FLW reduction strategies.

Reducing food loss and waste (FLW) is critical for achieving healthy diets from sustainable food systems. Within the United States, 30% to 50% of food produced is lost or wasted. These losses occur throughout multiple stages of the food supply chain from production to consumption. Reducing FLW prevents the waste of land, water, energy, and other resources embedded in food and is therefore essential to improving the sustainability of food systems. Despite the increasing number of studies identifying FLW reduction as a societal imperative, we lack the information needed to assess fully the effectiveness of interventions along the supply chain. In this paper, we synthesize the available literature, data, and methods for estimating the volume of FLW and assessing the full environmental and economic effects of interventions to prevent or reduce FLW in the United States. We describe potential FLW interventions in detail, including policy changes, technological solutions, and changes in practices and behaviors at all stages of the food system from farms to consumers and approaches to conducting economic analyses of the effects of interventions. In summary, this paper comprehensively reviews available information on the causes and consequences of FLW in the United States and lays the groundwork for prioritizing FLW interventions to benefit the environment and stakeholders in the food system.

Cities often have limited financial resources for sustainability planning, including sustainable solutions for municipal solid waste management. In this paper, we investigate municipal solid waste management strategies designed to meet two common environmental goals: reducing greenhouse gas emissions and achieving zero waste by maximizing materials recovery. We analyzed strategies using data collected from a range of low- to high-income cities around the world. We inputted these data into RTI’s Municipal Solid Waste Decision Support Tool and used the tool to identify the waste management strategies for each city that best met these two environmental goals. We compared results among the cities and strategies and then highlighted the limitations of designing sustainable programs based on a single goal. Strategies for minimizing greenhouse gas emissions and for maximizing materials recovery can have significantly different environmental impacts in the same city, ranging from net savings under one strategy to net emissions under another. We were able to explain many of these differences by considering the regional differences in waste composition—in particular, the amount of recyclable commodity materials—and the energy and emissions savings associated with displacing conventional fuels in waste-to-energy processes for the strategies that included these processes.

Summary A life cycle assessment (LCA) of various end‐of‐life management options for construction and demolition (C&D) debris was conducted using the U.S. Environmental Protection Agency's Municipal Solid Waste Decision Support Tool. A comparative LCA evaluated seven different management scenarios using the annual production of C&D debris in New Hampshire as the functional unit. Each scenario encompassed C&D debris transport, processing, separation, and recycling, as well as varying end‐of‐life management options for the C&D debris (e.g., combustion to generate electricity versus landfilling for the wood debris stream and recycling versus landfilling for the nonwood debris stream) and different bases for the electricity generation offsets (e.g., the northeastern U.S. power grid versus coal‐fired power generation). A sensitivity analysis was also conducted by varying the energy content of the C&D wood debris and by examining the impact of basing the energy offsets on electricity generated from various fossil fuels. The results include impacts for greenhouse gas (GHG) emissions, criteria air pollutants, ancillary solid waste production, and organic and inorganic constituents in water emissions. Scenarios with nonwood C&D debris recycling coupled with combustion of C&D wood debris to generate electricity had lower impacts than other scenarios. The nonwood C&D debris recycling scenarios where C&D wood debris was landfilled resulted in less overall impact than the scenarios where all C&D debris was landfilled. The lowest impact scenario included nonwood C&D debris recycling with local combustion of the C&D wood debris to generate electricity, providing a net gain in energy production of more than 7 trillion British thermal units (BTU) per year and a 130,000 tons per year reduction in GHG emissions. The sensitivity analysis revealed that for energy consumption, the model is sensitive to the energy content of the C&D wood debris but insensitive to the basis for the energy offset, and the opposite is true for GHG emissions.

This paper compares life-cycle greenhouse gas (GHG) emissions from two municipal solid waste (MSW) management options, municipal waste combustion, and landfilling, using a U.S. EPA life-cycle assessment (LCA) model, the MSW Decision Support Tool. Unlike previously reported LCAs, key combustion model inputs—total MSW carbon content and its biogenic/fossil split—are determined not from MSW composition studies, but from measurements taken at operating municipal waste combustors (MWCs). MWC measurement data show U.S. MSW carbon content averages of 30% with a biogenic/fossil split of 66%/34%. The LCA also considers a range of landfilling scenarios which account not only for alternative landfill gas (LFG) management techniques, but also for the variability of landfill methane generation and capture. The LCA found that for the range of inputs and scenarios considered, municipal waste combustion outperforms landfilling in terms of GHG emissions, regardless of the LFG management technique.

There has been increasing recognition of the important role that aerosols such as black carbon (BC) play in influencing net climate forcing, in particular the high rates of warming in the Arctic, and there is significant interest in reducing BC emissions. In order to assess mitigation options, there is a need for a better understanding of how current air quality policies designed for particulate matter reductions affect BC emissions and for the development of improved BC specific marginal abatement cost (MAC) curves. Using data from the United States (US), we assess the effects of existing air quality regulations on projected BC emissions (diesel fuel regulations in particular are already having significant effects). We also identify key US-specific abatement strategies and present MAC curves for further reducing BC emissions from two key US sources. This analysis may serve to inform similar research on BC mitigation in other regions and sectors.

The U.S. Environmental Protection Agency’s Office of Research and Development (US EPA ORD) has developed a “Municipal Solid Waste Decision Support Tool”, or MSW-DST, for local government solid waste managers to use for the life cycle evaluation of integrated solid waste management options. The MSW-DST was developed over a five year period (1994–1999) with the assistance of numerous outside contractors and organizations, including the Research Triangle Institute, North Carolina State University, the University of Wisconsin-Madison, the Environmental Research and Education Foundation, Franklin Associates and Roy F. Weston. The MSW-DST can be used to quantify and evaluate the following impacts for each integrated solid waste management alternative: • Energy consumption, • Air emissions, • Water pollutant discharges, • Solid Waste disposal impacts. Recently, the MSW-DST was used by the U.S. EPA to identify solid waste management strategies that would help to meet the goal of the EPA’s “Resource Conservation Challenge.” In this effort, ten solid waste management strategies were evaluated for a hypothetical, medium-sized U.S. community, with a population of 750,000 and a waste generation rate of approximately 3.5 pounds per person per day. (Table 1). The assumed waste composition was based on national averages. A peer-reviewed paper on this research was published in 2008 by the American Society of Mechanical Engineers (ASME).

Municipal solid waste (MSW) management is internationally recognized for its potential to be both a source and mitigation technology for greenhouse gas (GHG) emissions. Historically, GHG emission estimates have relied upon quantitative knowledge of various MSW components and their carbon contents, information normally presented in waste characterization studies. Aside from errors associated with such studies, existing data do not reflect changes over time or from location to location and are therefore limited in their utility for estimating GHG emissions and mitigation due to proposed projects. This paper presents an alternative approach to estimate GHG emissions and mitigation using the concept of a carbon balance, where key carbon quantities are determined from operational measurements at modern municipal waste combustors (MWCs).

Chromated copper arsenate (CCA)-treated wood is a preservative treated wood construction product that grew in use in the 1970s for both residential and industrial applications. Although some countries have banned the use of the product for some applications, others have not, and the product continues to enter the waste stream from construction, demolition and remodeling projects. CCA-treated wood as a solid waste is managed in various ways throughout the world. In the US, CCA-treated wood is disposed primarily within landfills; however some of the wood is combusted in waste-to-energy (WTE) facilities. In other countries, the predominant disposal option for wood, sometimes including CCA-treated wood, is combustion for the production of energy. This paper presents an estimate of the quantity of CCA-treated wood entering the disposal stream in the US, as well as an examination of the trade-offs between landfilling and WTE combustion of CCA-treated wood through a life-cycle assessment and decision support tool (MSW DST). Based upon production statistics, the estimated life span and the phaseout of CCA-treated wood, recent disposal projections estimate the peak US disposal rate to occur in 2008, at 9.7millionm3. CCA-treated wood, when disposed with construction and demolition (C&D) debris and municipal solid waste (MSW), has been found to increase arsenic and chromium concentrations in leachate. For this reason, and because MSW landfills are lined, MSW landfills have been recommended as a preferred disposal option over unlined C&D debris landfills. Between landfilling and WTE for the same mass of CCA-treated wood, WTE is more expensive (nearly twice the cost), but when operated in accordance with US Environmental Protection Agency (US EPA) regulations, it produces energy and does not emit fossil carbon emissions. If the wood is managed via WTE, less landfill area is required, which could be an influential trade-off in some countries. Although metals are concentrated in the ash in the WTE scenario, the MSW landfill scenario releases a greater amount of arsenic from leachate in a more dilute form. The WTE scenario releases more chromium from the ash on an annual basis. The WTE facility and subsequent ash disposal greatly concentrates the chromium, often oxidizing it to the more toxic and mobile Cr(VI) form. Elevated arsenic and chromium concentrations in the ash leachate may increase leachate management costs.

Black carbon (BC) and organic carbon (OC) aerosols have been identified as having potentially significant impacts on climate change, particularly at regional scales. However, the appropriate role for BC and OC emissions in any climate change mitigation strategy remains uncertain. We present emission inventories and projections for BC and OC in the United States circa 2000, and projections for the years 2015 and 2020. The projected U.S. emission inventories for 2015 and 2020 take into account recently promulgated regulations that target PM2.5 (of which BC and OC are essentially subcomponents), such as the Clean Air Highway Diesel Rule (or 2007 Highway Rule), the Clean Air Nonroad Diesel Rule, the Clean Air Interstate Rule, and others. BC emissions in the United States are projected to decline by 42 percent from 2001 to 2020, primarily as a result of diesel vehicle regulations. In contrast, OC emissions are projected to decline by only 9 percent, because open biomass burning emissions are assumed to be largely unaffected by these air quality regulations. We also briefly present the results of global assessments of 1996 and 2030 emissions of BC and OC, and contrast these results with the inventory results for the United States. INTRODUCTION AND CLIMATE CHANGE BACKGROUND Purpose The purpose of this research is to report and assess different black carbon (BC) and organic carbon (OC) primary emission inventories in the United States, to report and characterize the effects of air quality regulations that target PM2.5 on BC and OC emissions, and to identify and evaluate emission mitigation measures that can lower emissions beyond levels achieved by full implementation of existing and forthcoming regulations. Background BC and OC are particulate aerosols formed by incomplete combustion. The co-emission ratio of BC to OC varies by fuel type, combustion efficiency, and the extent of emissions control. When fossil fuels, such as oil and coal, are incompletely combusted (i.e., not completely oxidized to carbon dioxide [CO2]), BC tends to be formed in much larger amounts than OC. Diesel engines, for example, are estimated to be the largest source of BC in the United States. When biomass fuels, such as wood, are incompletely combusted, OC is formed in greater amounts than BC.

The US Environmental Protection Agency (US EPA) launched the Resource Conservation Challenge (RCC) in 2002 to help reduce waste and move towards more sustainable resource consumption. The objective of the RCC is to help communities, industries, and the public think in terms of materials management rather than waste disposal. Reducing cost, finding more efficient and effective strategies to manage municipal waste, and thinking in terms of materials management requires a holistic approach that considers life-cycle environmental tradeoffs. The US EPA’s National Risk Management Research Laboratory has led the development of a municipal solid waste decision support tool (MSW-DST). The computer software can be used to calculate life-cycle environmental tradeoffs and full costs of different waste management or materials recovery programs. The environmental methodology is based on the use of life-cycle assessment and the cost methodology is based on the use of full-cost accounting. Life-cycle inventory (LCI) environmental impacts and costs are calculated from the point of collection, handling, transport, treatment, and disposal. For any materials that are recovered for recycling, offsets are calculated to reflect potential emissions savings from use of virgin materials. The use of the MSW-DST provides a standardized format and consistent basis to compare alternatives. This paper provides an illustration of how the MSW-DST can be used by evaluating ten management strategies for a hypothetical medium-sized community to compare the life-cycle environmental and cost tradeoffs. The LCI results from the MSW-DST are then used as inputs into another US EPA tool, the Tool for the reduction and assessment of chemical and other environmental impacts, to convert the LCI results into impact indicators. The goal of this paper is to demonstrate how the MSW-DST can be used to identify and balance multiple criteria (costs and environmental impacts) when evaluating options for materials and waste management. This type of approach is needed in identifying strategies that lead to reduced waste and more sustainable resource consumption. This helps to meet the goals established in the US EPA’s Resource Conservation Challenge.

SUMMARY: The desire for less waste and more sustainable use of resources has resulted in the U.S. EPA’s Resource Conservation Challenge. This initiative is directed towards helping the U.S. transition from waste disposal towards materials management. Understanding the potential environmental and economic tradeoffs requires the use of life-cycle analysis and full cost accounting. Using the Municipal Solid Waste Decision Support Tool (MSW-DST), nine scenarios were evaluated to compare the life-cycle environmental tradeoffs and costs for a range of technologies for a medium-size U.S. community. The MSW-DST can be used to identify more sustainable use of resources, which helps meet goals set forth in the Resource Conservation Challenge.

SUMMARY: The recently completed municipal solid waste decision support tool (MSW-DST) is being used in communities across the United States. The methodology that the tool is based on incorporates both life-cycle inventory (LCI) analysis and full-cost accounting. The results of this tool are helping communities to make decisions that will result in more efficient environmental management. This paper provides an overview of some of the case studies that the tool has been used for to help illustrate the variety of potential applications.