Chapter 7
Life-Cycle Assessment for Paper Products

Richard A. Denison

Environmental Defense Fund

The Environmental Defense Fund (EDF), in conjunction with a group of major U.S. paper purchasers, recently conducted a life-cycle-based study of various grades of paper. This 28-month effort, called the Paper Task Force, whose members were from Duke University, Johnson & Johnson, McDonald' s, The Prudential Insurance Company of America, and Time, Inc., released its final report in December 1995 (Environmental Defense Fund, 1995). The primary intent of the document is to educate an audience of paper purchasers about the environmental (and related economic and performance) consequences of their paper purchasing decisions and to provide them with steps they can take to increase their purchase and use of environmentally preferable paper.

The technical basis for the environmental preferences identified in the Paper Task Force recommendations is an analysis of environmental impacts associated with the entire life-cycle of several major grades of paper, reaching literally from the forest to the landfill. This chapter, which draws heavily on the final report, describes some of the conceptual and methodologic bases of the analysis. It also serves as an illustration of the approach adopted by one of the country's major environmental advocacy organizations to assess the environmental impacts associated with the use of paper and paper products.

Why Adopt a Life-Cycle View?

In identifying environmental preferences, the task force adopted a broad, systematic view of the issues involved rather than considering just one or a few attributes of paper—its recycled content, for example, or how it is bleached. The task force constructed a set of analytical tools that allow different types of paper



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Chapter 7 Life-Cycle Assessment for Paper Products Richard A. Denison Environmental Defense Fund The Environmental Defense Fund (EDF), in conjunction with a group of major U.S. paper purchasers, recently conducted a life-cycle-based study of various grades of paper. This 28-month effort, called the Paper Task Force, whose members were from Duke University, Johnson & Johnson, McDonald' s, The Prudential Insurance Company of America, and Time, Inc., released its final report in December 1995 (Environmental Defense Fund, 1995). The primary intent of the document is to educate an audience of paper purchasers about the environmental (and related economic and performance) consequences of their paper purchasing decisions and to provide them with steps they can take to increase their purchase and use of environmentally preferable paper. The technical basis for the environmental preferences identified in the Paper Task Force recommendations is an analysis of environmental impacts associated with the entire life-cycle of several major grades of paper, reaching literally from the forest to the landfill. This chapter, which draws heavily on the final report, describes some of the conceptual and methodologic bases of the analysis. It also serves as an illustration of the approach adopted by one of the country's major environmental advocacy organizations to assess the environmental impacts associated with the use of paper and paper products. Why Adopt a Life-Cycle View? In identifying environmental preferences, the task force adopted a broad, systematic view of the issues involved rather than considering just one or a few attributes of paper—its recycled content, for example, or how it is bleached. The task force constructed a set of analytical tools that allow different types of paper

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to be compared on an environmental basis across their full life-cycles, including how the fiber used to make paper is acquired, whether from a forest or from a recycling collection program; how that fiber is manufactured into a range of paper products; and how those products are managed after use, whether in landfills or incinerators or through collection for recycling. In using this approach, the task force has provided a way for purchasers to address all of the major environmental impacts of their paper use. This approach to developing a decision framework for buying paper reflects the facts that impacts associated with the use of paper arise from all of the activities indicated above and that a credible environmental comparison of different types of paper must consider all of them—not just a subset. Equally important, a life-cycle approach elucidates steps to reduce environmental impacts at each stage and acknowledges that actions that affect only one or two stages will not produce optimal environmental results. For example, reducing the use of paper can generally provide major environmental benefits, but even after aggressive use reduction, businesses still use significant quantities. Our analysis documents that using paper with recycled content also provides comparative environmental benefits in the areas of forest management, pulp and paper manufacturing, and solid-waste processing and disposal. However, there are ultimately functional and economic limits to the amount of recycled material that can be used in paper on an aggregate basis. It is important, therefore, to examine opportunities to reduce the environmental impacts associated with the acquisition of virgin fiber through forest management and with the manufacturing of virgin pulp and paper. Considering all Aspects of Fiber Acquisition Obtaining the fiber to make paper products—whether derived from used paper collected for recycling or from trees—entails a range of environmental impacts. Collection and processing of recovered paper—activities that are typically extensively analyzed in life-cycle studies of paper products—requires energy and can release pollutants to the environment. These consequences must be viewed from a larger perspective, however, one that is typically ignored in life-cycle analyses. By displacing some of the need for virgin fiber and extending the overall fiber supply, recycling can offset the environmental impacts of acquiring virgin fiber as well as those from making virgin paper and disposing of paper after use. To explain the environmental differences between virgin and recycled-paper production, use, and postuse management, it is necessary to assemble a complete picture. This means not just examining differences in recycled and virgin manufacturing processes and in waste disposal versus material recovery systems, but also considering the "upstream" impacts associated with acquiring virgin fiber from forests. Most studies of paper products, including virtually all life-cycle inventories, draw the upstream boundary of their analyses after the forest: In

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essence, they assume a given quantity of wood as an input into the product system being studied, without considering the environmental consequences of activities required to produce that wood. To be sure, the biologic and ecologic character of many of the impacts of forest management activities do not allow a direct or quantitative comparison to other measures of environmental impact—for example, energy use or releases of air emissions from a manufacturing facility. Indeed, the omission of forest management issues is usually explained by invoking the difficulty of integrating into the analysis the admittedly more qualitative nature of many such impacts. To omit those impacts entirely from an assessment of paper products, however, produces a greatly distorted picture—one that is systematically biased against paper products that incorporate recovered fiber. The Environmental Defense Fund chose instead to include a full assessment and description of forest management impacts, and through these recommendations, we have directly integrated the information as a paper purchasing consideration. Significantly, such information is not only relevant in assessing the relative merits of recycled versus virgin fiber content, but also in identifying environmental preferences among different management practices used to produce virgin fiber. A critical need in the area of life-cycle assessment methodology as applied to wood as a raw material, therefore, is to develop means for explicitly considering the range of potential and actual environmental impacts associated with forest management practices. These impacts can include damage to forest soils and productivity, water quality and aquatic habitat, plant and animal habitat and diversity, and the preservation of important natural forest communities and ecosystems. The potential consequences of most concern are the cumulative impacts of forest management activities over time and on a scale larger than that of a particular activity conducted in a particular stand of trees—environmental concerns that are particularly far removed from traditional life-cycle analysis methods. Because an increase in the use of recovered fiber by paper mills means a lower requirement for pulpwood, recycling extends the fiber base and can help to conserve forest resources. Moreover, the reduced demand for virgin fiber achieved through recycling will generally reduce the intensity of forest management required to meet a given demand for paper. In so doing, it can help foster changes in forest management practices that are environmentally beneficial. For example, pressure could be reduced to convert natural forests and sensitive areas, such as wetlands, into intensively managed pine plantations, and more trees could be managed on longer rotations to meet demand for solid wood products rather than fiber. Life-Cycle Inventory Methodology The task force compared energy requirements and environmental releases from 100 percent recycled-fiber-based and 100 percent virgin-fiber-based sys-

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tems. Each system includes analogous activities in the acquisition of fiber, pulp, and paper manufacturing and disposal of residuals. The systems approach allows an assessment of the full range of environmental consequences that follow from the choice to produce recycled-content paper and recover and recycle used paper, as opposed to producing virgin paper, disposing of it and replacing it with new virgin paper. We recognized that paper often has less than 100 percent recycled content. By comparing 100 percent virgin and 100 percent recycled papers, we sought to assess the relative energy use and environmental releases of each type of fiber arising from its acquisition, manufacture, use, and postuse management by various means. Environmental attributes of paper that contain intermediate quantities of recycled fiber would fall between the estimates provided in this study. Scope of Comparison For the recycled-fiber-based system, the task force examined used paper collection, transport of the recovered paper to a material recovery facility (MRF), processing of the material at the MRF, transport of processed recovered material to the manufacturing site, manufacturing of pulp and paper using recovered fiber, and disposal of residuals from MRF operations and paper manufacturing. For the virgin-fiber-based system, we included harvesting of trees and transport of logs (or chips) to the mill, debarking and chipping, manufacture of pulp and paper using virgin fiber, collection of the paper after its use as part of municipal solid waste (MSW), transport of the waste to MSW landfills and waste-to-energy incinerators, and disposal or processing of the waste at such facilities. In the United States, landfilling is used for about 80 percent of the MSW that is not recycled, while waste-to-energy incineration accounts for virtually all of the rest (Franklin Associates, 1994). This 4-to-1 ratio was applied to the landfill- and incinerator-specific data developed in our analysis to estimate energy use and environmental releases associated with aggregate disposal of used paper as part of MSW. The environmental data gathered by the task force on the recycled and virgin-fiber-based systems included energy use and environmental releases in the form of solid-waste output, releases in several categories of air emissions and waterborne wastes, and water use-effluent flow in manufacturing (Table 7-1). Our methodology for two specific categories of environmental parameters—energy use and emissions of greenhouse gases—merits further elaboration. In examining energy use, we considered total energy, that generated from combustion of all types of fuels, including fuels derived from wood byproducts (bark and pulping liquors at pulp mills and paper in incinerators). We also examined the subset of energy purchased from electric utilities and from combustion of purchased fossil fuels (that is, excluding combustion of wood-derived materials). The analysis incorporates environmental releases and solid-waste generation as-

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TABLE 7-1 Environmental parameters examined for the recycled- and virgin-fiber-based systems Solid Waste Energy Usage Air Emissions Waterborne Wastes Total Total Purchased Fossil fuel derived Total greenhouse gases Net greenhouse gases Nitrogen oxides Particulates Sulfur oxides Adsorbable organic halogensa Biochemical oxygen demand Chemical oxygen demand Suspended solids     Hazardous air pollutantsa Volatile organic chemicalsa Total reduced sulfura Effluent quantity—water usea a For manufacturing processes only. sociated with the operation of power plants that produce electricity used in recycled and virgin manufacturing processes. Purchased electricity can be generated from a variety of sources, including fossil fuels (coal, oil, natural gas), nuclear power, and hydropower—each of which has its own set of associated environmental impacts. Nationally, about 68 percent of electricity is produced from combustion of fossil fuels (U.S. Environmental Protection Agency, 1992). In our analysis, therefore, we also indicate the fraction of purchased energy used in the virgin and recycled systems that is derived from fossil fuels. The relative consumption of fossil fuels by the different systems is important. Consumption of fossil fuels contributes to the depletion of a natural resource, and fossil fuel extraction and transportation can damage natural resources through mining activities (for example, strip-mining for coal) and accidental releases of raw fuels or other pollutants to the environment (for example, oil spills, refinery explosions, leaks from natural gas pipelines). Fossil fuel extraction, refinement, and combustion also require energy and entail releases to the environment; estimates of these factors are incorporated directly into our quantitative analysis. The difference between total and purchased energy used by a system represents the amount of energy generated from wood-derived fuels (bark, pulping liquors, and used paper). For several paper grades we examined, the virgin-fiber-based system uses more total, but less purchased, energy than does the recycled-fiber-based system. Such a system consumes less fossil fuel and hence entails fewer of the environmental impacts just described, but it also consumes more wood resources, and this has the environmental implications with respect to forest management discussed earlier. Our accounting for greenhouse gases—specifically, CO2 and methane emissions—also requires some elaboration. The environmental concern associated with such emissions is their association with the greenhouse effect, linked to

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global climate change. In assessing these emissions, we compared the virgin and recycled systems with respect to both total and net greenhouse gas emissions. (We did not include emissions of nitrous oxide in our estimate of greenhouse gas emissions, because of a lack of data for most of the activities involved in the paper systems we examined. We also made a judgment that, despite the high potency of nitrous oxide, actual emissions would be so small as to make their contribution to the total minor.) Carbon dioxide and methane emissions are accounted for somewhat differently. Emissions of CO2 derived from burning wood-derived materials (bark and pulping liquors in pulp and paper mills, and paper in incinerators) do not result in a net increase in such emissions, because the trees from which these materials were derived absorbed the equivalent amount of CO2 in the process of growing. (Other activities involved in growing trees that could result in net emissions of CO2 are not included here. Examples are soil disturbance associated with preparing a site for tree planting and energy or materials used in the production of fertilizers and other chemicals used in forests.) In contrast, emissions of CO2 derived from the combustion of fossil fuels do result in a net increase. Hence, wood-derived CO2 emissions are counted in total, but not net, greenhouse gas emissions; fossil-fuel-derived CO2 emissions are counted in both total and net greenhouse gas emissions. Landfills are the only significant source of methane emissions in our systems comparison. (Methane emissions also are generated in the production and transport of petroleum and natural gas. Our examination of the magnitude of these releases indicates they are minor in comparison to landfill methane.) Decomposition of paper-based materials in landfills results in emissions of both CO2 and methane. The CO2 emissions are accounted for as just described. They contribute to total but not to net greenhouse gas emissions, because they are offset by an equivalent amount of CO2 originally absorbed by the trees from which the paper is made. However, emissions of methane must be accounted for differently. Methane is a much more potent greenhouse gas than is CO2, with one pound of methane emissions representing the equivalent of 69 pounds of CO2. The 69-to-1 ratio is a mass-based comparison, and corresponds to the more commonly reported 25-to-1 ratio as measured on a molecule-to-molecule basis; the difference in the two ratios is due to the higher molecular weight of CO2 relative to methane (Franklin Associates, 1994). Each pound of methane contributes 69 pounds of greenhouse gas emissions when expressed as CO2 equivalents. Only one pound of these emissions was derived from CO2 originally absorbed by the trees used to make the paper; hence, all 69 pounds are counted in total greenhouse gas emissions; 68 pounds are counted as net greenhouse gas emissions. Both total and net greenhouse gas emissions are expressed in terms of CO2 equivalents. Except for energy use in harvesting trees and transporting logs, the environmental effects associated with obtaining virgin fiber from trees are not considered in this life-cycle inventory (or in others), because of their largely qualitative

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nature. As discussed earlier, intensive management of forests for fiber and wood production can have significant consequences, such as effects on biodiversity, wildlife habitat, and natural ecosystems. Such consequences are an important difference between recycled-fiberand virgin-fiber-based systems. Illustrative Results The task force compiled data for several grades of paper and paperboard products: newsprint made using either virgin thermomechanical pulp (TMP) or recovered deinked newspapers; corrugated boxes made using either virgin unbleached kraft linerboard and semichemical medium or recovered corrugated boxes; office papers made using either virgin uncoated freesheet or recovered deinked office paper; and paperboard used in folding cartons made using either virgin pulp (coated unbleached kraft or solid bleached sulfate) or nondeinked recovered paper. As an example to illustrate both the scope and the results of our analysis, Figures 7-1 and 7-2 and Table 7-2 present the data for newsprint. Figure 7-1 shows the energy use associated with each component activity within the recycled- and virgin-fiber-based systems. Figure 7-2 summarizes the data for all of the environmental parameters we examined, summing them across all of the activities within a given system, and then comparing the totals for the recycled production plus recycling system to those for a composite virgin production plus waste management system that incorporates data from the two virgin systems involving landfilling and waste-to-energy incineration. This comparison of the recycling-based system to the composite waste-management-based system is ultimately the most useful environmental comparison, for two reasons. First, in contrast to their ability to assist directly in the recycling of paper they use, users of paper have no ability to determine how their paper is managed after discard if it enters the waste stream. Whether such paper is destined for disposal in a landfill or for processing at an incinerator is a function of many factors outside the control of the paper user: the local availability of the two options, their relative economics, the nature of the collection system, and so on—all factors that can change over time. Second, we are most interested in assessing the most typical or representative case associated with management of discarded paper. On average across the nation, about 80 percent of used paper that is not recycled will be landfilled, and about 20 percent will be incinerated. Using this 4-to-1 ratio to calculate a weighted average of the landfill- and incinerator-specific data developed in our analysis allows us to estimate the average energy use and environmental releases associated with management of used paper that is not recycled and becomes part of the waste stream. Table 7-2 gives the detailed data for each parameter and each component activity of the recycled and the two virgin-fiber-based systems. The task force's analysis showed clear and substantial environmental advan-

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Figure 7-1 Total, purchased, and fossil fuel energy use for component activities of paper production and management,

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Figure 7-2 Average energy use and environmental releases for managing newsprint by recycled production + recycling vs. virgin production + waste management (landfilling and incineration).

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tages from recycling all of the grades of paper we examined. For each grade, and for most of the parameters examined, a system based on recycled paper production plus recycling results in comparable or smaller energy use and environmental releases than does a system based on virgin production plus waste management. There are several exceptions to this general finding. Among the most interesting is that, although all of the recycled-fiber-based systems require smaller amounts of total energy than do the virgin-fiber-based systems, for three of the five grades examined here (office papers, corrugated boxes, and coated unbleached kraft paperboard used in folding cartons) the virgin-fiber-based system requires less purchased (and fossil-fuel-derived) energy. Hence, recycling of these grades poses a trade-off between greater use of fossil fuels and greater use of forest resources. The strong environmental advantages attributable to recycling hold true despite the exclusion from the model, because of a lack of data, of several types of energy use and environmental releases associated only with the virgin system. These include, for example, the energy and environmental releases associated with forest management other than harvesting; releases to the air and water from landfills other than CO2 and methane emissions; releases to the air from incinerators other than CO2, sulfur oxides, nitrogen oxides, and particulates; and releases from ash landfills. Our analysis did not include releases from disposal facilities used for residuals from either the virgin-or the recycled-fiber-based systems. In addition, assumptions were made in the model that overestimate energy use and environmental releases for the recycling system. Because of greater availability of data, our quantitative comparison is based on collection of recovered paper through residential curbside collection programs. We recognize that other systems (drop-off centers and collection from commercial sources) constitute most of total paper recovery. This assumption of curbside collection overstates the energy use and associated environmental releases associated with collection of paper, especially for grades such as corrugated containers and office paper that are collected largely from commercial sources through more efficient systems. Similarly, our analysis includes processing of recovered paper at material recovery facilities. Because some recovered paper, especially that from commercial sources, bypasses such intermediate processing and can be delivered directly to the mill, this assumption, too, probably overstates energy use associated with the recycling option. Several other specific results from the comparison are worth noting, because they run somewhat counter to commonly-held perceptions about recycling. Energy Use in Transportation Versus Manufacturing It is often noted that collection and transport of materials for recycling requires more energy and hence generates larger releases of pollutants from vehicles than does collection of municipal solid waste for disposal in landfills or

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TABLE 7-2 Energy, air emissions, solid waste outputs, waterborne wastes, and water use associated with component activities of three methods for managing newsprint   Virgin Production, Landfilling         a b c d e f   Tree harvesting/ transport Virgin mfctr'ing energy/ releases Utility energy/ releases Collection vehicle & landfill equipment MSW landfill Total (per ton ONP landfilled) [Notes]     [7]   [1]   Energy usage (000 Btus/ton)             Total 1,150.0 36,300.0   527.4   37,977.4 Purchased 1,150.0 33,000.0   527.4   34,677.4 Fossil fuel-derived 1,150.0 24,624.6   527.4   26,302.0 Environmental releases (lbs/ton)             Atmospheric emissions             Total greenhouse gases (CO2 equivalents) [9] 183.8 5,946.0   84.1 11,626.7 17,8410.5 Net greenhouse gases (CO2 equivalents) [10] 183.8 5,300.0   84.1 11,152.0 16,719.9 Nitrogen oxides 2.2 21.1   1.0   24.3 Particulates 0.49 13.1   0.23   13.8 Sulfur oxides 0.31 41.4   0.14   41.9 Hazardous air pollutants[8]   0.43       0.43 Volatile organic chemicals [8]   3.9       3.9 Solid wastes 0.6 362.0 444.2 0.26 2,000.0 2,807.0 Waterborne wastes             Biochemical oxygen demand 0.0008 2.5 0.0024 0.0003   2.5 Chemical oxygen demand 0.0031 36.3 0.0073 0.0016   36.3 Suspended solids 0.0008 4.8 0.0048 0.0003   4.8 Effluent flow (gals/ton) [8]   14,172       14,172 NOTES: (1) Landfill gas collected for energy recovery not included. Only CO2 and CH4 in landfill gas are included in atmospheric emissions; CH4 has been converted to CO2 equivalents using a molecular ratio of 25:1 and a weight ratio of 69:1. Waterborne wastes caused by leachate from landfills not included. (2) Air emissions based on new source performance standards (NSPS) for combustors >250 tpd. (3) Values in parentheses represent energy and environmental releases from a utility avoided due to energy generation by incineration. Assumes 670 kWh of electricity generated by a utility is avoided by combusting 1 ton of ONP. Avoided releases based on fuel mix for national electricity energy grid. (4) Waterborne wastes caused by leachate from ash landfills not included. Assumes burning ONP yields 9% ash residue by dry weight, 25% moisture content as disposed. (5) Assumes curbside collection of ONP.

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  Virgin Production, Incineration             a b c d e f g h   Tree harvesting/ transport Virgin mfctr'ing energy/ releases Utility energy/ releases MSW collection W-T-E combustion process Avoided utility energy/ releases Ash landfill disposal Total (per ton ONP combusted) [Notes]     [7]   [2] [3] [4]   Energy usage (000 Btus/ton) 1,150.0 36,300.0   296.6 782.8 (8,202.0) 35.6 30,363.0 Total 1,150.0 33,000.0   296.6 33.0 (8,202.0) 35.6 26,313.2 Purchased 1,150.0 24,624.6   296.6 33.0 (8,202.0) 35.6 17,937.8 Fossil fuel-derived                 Environmental releases (lbs/ton)                 Atmospheric emissions                 Total greenhouse gases (CO2 equivalents) [9] 183.8 5,946.0   47.3 2,207.1 (1,024.8) 5.7 7,365.0 Net greenhouse gases (CO2 equivalents) [10] 183.8 5,300.0   47.3 5.3 (1,024.8) 5.7 4,517.2 Nitrogen oxides 2.2 21.1   0.57 1.8 (4.7) 0.07 21.1 Particulates 0.49 13.1   0.13 0.27 (3.4) 0.02 10.7 Sulfur oxides 0.31 41.4   0.08 0.39 (8.8) 0.01 33.4 Hazardous air pollutants[8]   0.43           0.43 Volatile organic chemicals [8]   3.9           3.9 Solid wastes 0.6 362.0 444.2 0.15 180.0 (122.6) 0.02 864.3 Waterborne wastes                 Biochemical oxygen demand 0.0008 2.5 0.0024 0.0002   (0.0007) 0.0000 2.5 Chemical oxygen demand 0.0031 36.3 0.0073 0.0008   (0.0019) 0.0001 36.3 Suspended solids 0.0008 4.8 0.0048 0.0002   (0.0014) 0.0000 4.8 Effluent flow (gals/ton) [8]   14,172           14,172 (6) Assumes ONP is processed at a material recovery facility (MRF); values based on average of low-tech and high-tech MRF. (7) Values represent the solid waste and waterborne wastes associated with utility generation of electricity purchased by the virgin or recycled pulp and paper mill; energy and air emissions have been incorporated into the adjacent manufacturing energy/releases column. Releases incurred are based on fuel mix for national electricity energy grid. (8) Values for this parameter are reported by the cited sources only for the virgin and recycled manufacturing processes. (9) Total greenhouse gases include CO2 emissions from combustion of both wood-derived materials (including paper) and fossil fuels, as well as CO2 and CH4 emissions from landfills. (10) Net greenhouse gases include CO2 emissions from combustion of fossil fuels and CH4 emissions from landfills.

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  Virgin Production, Recycling           a b c d e f g   ONP collection MRF process Residue landfill disposal Transportation to market Utility energy/ releases Recycled mfctr'ing energy/ releases Total (per ton ONP recycled) [Notes] [5] [6]     [7]     Energy usage (000 Btus/ton)               Total 989.0 282.7 42.2 205.2   19,300.0 20,819.1 Purchased 989.0 282.7 42.2 205.2   19,300.0 20.819.1 Fossil fuel-derived 989.0 282.0 42.2   205.2 15,088.1 16,606.5 Environmental releases (lbs/ton)               Atmospheric emissions               Total greenhouse gases (CO2 equivalents) [9] 157.7 31.7 6.7 33.0   3.232.0 3.461.1 Net greenhouse gases (CO2 equivalents) [10] 157.7 31.7 6.7 33.0   3,232.0 3,461.1 Nitrogen oxides 1.9 0.17 0.08 0.28   12.4 14.9 Particulates 0.43 0.11 0.02 0.05   6.6 7.2 Sulfur oxides 0.27 0.29 0.01 0.06   24.1 24.7 Hazardous air pollutants[8]           0.15 0.15 Volatile organic chemicals [8]           1.7 1.7 Solid wastes 0.49 163.8 0.02 0.10 223.4 530.0 917.8 Waterborne wastes               Biochemical oxygen demand 0.0006 0.0002 0.0000 0.0002 0.0012 6.1 6.1 Chemical oxygen demand 0.0030 0.0005 0.0001 0.0006 0.0037 27.5 27.5 Suspended solids 0.0006 0.0000 0.0000 0.0002 0.0024 6.9 6.9 Effluent flow (gals/ton)[8]           19,304 19.304 incinerators. Our analysis is consistent with this finding, but it also shows that both of these energy uses (and their contribution to environmental releases) are quite small compared with the energy used in manufacturing (see Figure 7-1 for the case of newsprint). Indeed, for all grades of paper and for virgin- and recycled-fiber systems, manufacturing energy is the predominant use of energy, by a large margin. Materials and residuals collection, processing, and transport are all relatively small by comparison. Moreover, the reduction in total manufacturing energy consumption resulting from using recovered paper rather than virgin materials is much larger than the increase in energy required for collection and transport of recovered materials relative to municipal solid waste. Tree Harvest, Transport Energy Versus Recycling Collection Another factor often neglected in assessing virgin-fiber-based systems in-

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volves the amount of wood in the form of trees that must be harvested and transported to serve as a source of raw material. Wood in harvested trees contains approximately 50 percent moisture. In addition, wood pulping processes have yields that are considerably less than 100 percent; bleached kraft pulping yields are about 45 percent, unbleached kraft yields are about 57 percent and mechanical pulp yields are 80–95 percent. The combination of these factors means that from 2 tons to as many as 3.5 tons of trees must be harvested to produce 1 ton of pulp. The harvesting and transport energy per ton of pulp, therefore, is relatively high even compared with recovered paper collection and transport (see Figure 7-1 for newsprint). Greenhouse Gas Emissions Despite the greater use of fossil-fuel-derived energy by several of the recycled-fiber-based systems relative to their virgin counterparts, all of the recycled-fiber-based systems generate far lower emissions of both total and net greenhouse gases. This is because the primary means of managing waste paper is through landfilling. Incineration of waste paper does not generate net greenhouse gas emissions, because the carbon present in the paper that is released as CO2 upon combustion represents CO2 that was originally absorbed by growing trees. Indeed, energy generation from such incineration offsets net greenhouse gas emissions from electric utilities. However, much of the carbon present in landfilled waste paper decomposes anaerobically to produce methane, which is a far more potent greenhouse gas (69-fold, on a mass basis) than is the CO2 that was originally absorbed. In essence, a decision not to recycle paper means that most of it will be landfilled, and much of that paper will anaerobically decompose to produce methane—thereby greatly amplifying the virgin-fiber-based system's contribution to greenhouse gases. Important Caveats All details of the task force' s model, data and assumptions are included in the full report. Some important caveats should be kept in mind when considering the findings just presented. In general, the data cited and presented represent average (mean) values, or estimates, intended to be representative of the facilities and activities being characterized, and the comparisons will be valid only for ''typical'' activities or facilities. Because of the timeand site-specific variation in much of the data presented, caution should be exercised in applying these average data to characterize the environmental attributes of individual facilities or activities. The environmental characteristics of the activities and facilities examined in this type of analysis will virtually always show considerable variation. Average data can therefore overstate or understate the magnitude of a given environmental parameter for a specific activity or facility. Although the data presented are useful in

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indicating general or likely attributes, they should be subjected to further examination and confirmation if they are to be used in a more specific manner or setting than intended. No attempt was made to assess the magnitude of actual environmental impacts that arise from the energy use and environmental releases; only their quantity was reported. Actual impacts depend on site-specific and highly variable factors, such as rate and location of releases, local climatic conditions, population densities, and so on, which together determine exposure to substances released to the environment. Such an assessment would require a detailed analysis of all sites where releases occur, which was well beyond the scope of this project (and indeed virtually any analysis of this sort). Our comparison was of necessity limited to a quantitative comparison of data on the magnitude of energy use and environmental releases associated with the systems examined. References Environmental Defense Fund. 1995. Paper Task Force. Final report is available through EDF, both in hard copy and in electronic form via our Worldwide Web site, at www.edf.org Franklin Associates. 1994. Franklin Associates, Characterization of Municipal Solid Waste in the United States, 1994 Update, prepared for U.S. Environmental Protection Agency, Municipal and Industrial Solid Waste Division, Washington, DC, Report No. EPA/530-S-94-042, November 1994. Franklin Associates, Ltd. September 1994. The Role of Recycling in Integrated Waste Management to the Year 2000, prepared for Keep America Beautiful, Inc. Appendix I, p. 8. U.S. Environmental Protection Agency. 1992. Life-cycle Assessment: Inventory Guidelines and Principles, Vigon, B.W. et al., Report No. EPA/600/R-92/036, Risk Reduction Engineering Laboratory, Office of Research and Development, Cincinnati OH, November 1992, p. 48, citing: U.S. Department of Energy, Energy Information Administration, "Monthly Power Plant Report," EIA-759, 1992; Canadian Electric Utilities and Natural Energy Board, 1991.