© 2018 The Author(s) Since its development at the end of the previous century, the waste input–output (WIO) model has been extended to wide areas of industrial ecology including material flow analysis (MFA), life-cycle costing (LCC), regional analysis, and linear programming (LP)-based technology selection. To our knowledge, the dynamics of waste generation and recycling is an area of possible conceptual extension that remains least explored. Building upon our recent work on dynamic MFA, in this work, we develop a dynamic WIO (dWIO) model that fully considers the issue of quality in recycling that involves mixing, dissipation, and contamination.

Importance of end-of-life vehicles (ELVs) as an urban mine is expected to grow, as more people in developing countries are experiencing increased standards of living, while the automobiles are increasingly made using high-quality materials to meet stricter environmental and safety requirements. While most materials in ELVs, particularly steel, have been recycled at high rates, quality issues have not been adequately addressed due to the complex use of automobile materials, leading to considerable losses of valuable alloying elements. This study highlights the maximal potential of quality-oriented recycling of ELV steel, by exploring the utilization methods of scrap, sorted by parts, to produce electric-arc-furnace-based crude alloy steel with minimal losses of alloying elements. Using linear programming on the case of Japanese economy in 2005, we found that adoption of parts-based scrap sorting could result in the recovery of around 94-98% of the alloying elements occurring in parts scrap (manganese, chromium, nickel, and molybdenum), which may replace 10% of the virgin sources in electric arc furnace-based crude alloy steel production.

Alloying metals are indispensable ingredients of high quality alloy steel such as austenitic stainless steel, the cyclical use of which is vital for sustainable resource management. Under the current practice of recycling, however, different metals are likely to be mixed in an uncontrolled manner, resulting in function losses and dissipation of metals with distinctive functions, and in the contamination of recycled Steels. The latter could result in dilution loss, if metal scrap needed dilution with virgin iron to reduce the contamination below critical levels. Management of these losses resulting from mixing in repeated recycling of metals requires tracking of metals over multiple life cycles of products with compositional details. A new model (MaTrace-alloy) was developed that tracks the fate of metals embodied in each of products over multiple life cycles of products, involving accumulation, discard, and recycling, with compositional details at the level of both alloys and products. The model was implemented for the flow of Cr and Ni in the Japanese steel cycle involving 27 steel species and 115 final products. It was found that, under a high level of scrap sorting, greater than 70% of the initial functionality of Cr and Ni could be retained over a period of 100 years, whereas under a poor level of sorting, it could plunge to less than 30%, demonstrating the relevance of waste management technology in circular economy policies.

Substantial amounts of post-consumer scrap are exported to other regions or lost during recovery and remelting, and both export and losses pose a constraint to desires for having regionally closed material cycles. To quantify the challenges and trade-offs associated with closed-loop metal recycling, we looked at the material cycles from the perspective of a single material unit and trace a unit of material through several product life cycles. Focusing on steel, we used current process parameters, loss rates, and trade patterns of the steel cycle to study how steel that was originally contained in high quality applications such as machinery or vehicles with stringent purity requirements gets subsequently distributed across different regions and product groups such as building and construction with less stringent purity requirements. We applied MaTrace Global, a supply-driven multiregional model of steel flows coupled to a dynamic stock model of steel use. We found that, depending on region and product group, up to 95% of the steel consumed today will leave the use phase of that region until 2100, and that up to 50% can get lost in obsolete stocks, landfills, or slag piles until 2100. The high losses resulting from business-as-usual scrap recovery and recycling can be reduced, both by diverting postconsumer scrap into long-lived applications such as buildings and by improving the recovery rates in the waste management and remelting industries. Because the lifetimes of high-quality (cold-rolled) steel applications are shorter and remelting occurs more often than for buildings and infrastructure, we found and quantified a tradeoff between low losses and high-quality applications in the steel cycle. Furthermore, we found that with current trade patterns, reduced overall losses will lead to higher fractions of secondary steel being exported to other regions. Current loss rates, product lifetimes, and trade patterns impede the closure of the steel cycle. (C) 2016 Elsevier B.V. All rights reserved.

Cobalt and nickel are high-value commodity metals and are mostly used in the form of highly alloyed materials. The alloying elements used may cause contamination problems during recycling. To ensure maximum resource efficiency, an understanding of the removability of these alloying elements and the controllability of some of the primary alloying elements is essential with respect to the recycling of end-of-life (EoL) nickel- and cobalt-based superalloys by remelting. In this study, the distribution behaviors of approximately 30 elements that are usually present in EoL nickel- and cobalt-based superalloys in the solvent metal (nickel, cobalt, or nickel-cobalt alloy), oxide slag, and gas phases during the remelting were quantitatively evaluated using a thermodynamic approach. The results showed that most of the alloying elements can be removed either in the slag phase or into the gas phase. However, the removal of copper, tin, arsenic, and antimony by remelting is difficult, and they remain as tramp elements during the recycling. On the other hand, the distribution tendencies of iron, molybdenum, and tungsten can be controlled by changing the remelting conditions. To increase the resource efficiency of recycling, preventing contamination by the tramp elements and identifying the alloying compositions of EoL superalloys are significantly essential, which will require the development of efficient prior alloy-sorting systems and advanced separation technologies. (C) The Minerals, Metals & Materials Society and ASM International 2016

The assessment methodology of soil remediation technologies including citizen's opinions about environmental policy was developed to enable direct comparison between the resident health risk reduction by carrying out remediation (decreased primary risk) and the potential impacts of chemicals emitted during the remediation on national health, social assets, and primary production (secondary risk). Both risks were quantified with an unified index, disability-adjusted life years (DALYs), by employing life cycle costing (LCC), economic input-output life cycle assessment (EIO-LCA), and life cycle impact assessment (LCIA) database. Four remediation technologies were considered: excavation-disposal, high temperature thermal desorption (HTTD), biopile, and landfarming. There was almost no difference in the decreased primary risk among the four technologies, apart from landfarming, which had the smallest decreased primary risk. The secondary risk of the biological technologies (biopile, landfarming) was smaller than that of the physical and chemical technologies (excavation-disposal, HTTD). The ratio of the decreased primary risk to the secondary risk was largest in case of landfarming, which indicated that landfarming was most effective. The sum of the residual primary risks and secondary risk was small in the biological technologies, indicating that the biological technologies had smaller environmental impacts. Indexing both of decreased primary risk and secondary risk with DALYs enables non-experts who prioritize resident's health to assess the soil remediation technologies and would facilitate the decision making in the selection of remediation technologies.

Effective strategic planning for industrial waste management requires sound knowledge of the waste streams in an economy. Based on an input output analysis with an extended function to consider the entire life cycle of a product, waste input output (WIO) analysis plays an important role in describing the driving forces behind the generation of industrial waste. In this study, we compile a high-resolution WIO table for Taiwan that traces the flow of waste streams covering almost all types of waste emitted from industries into corresponding wake treatments and that identifies the driving force of waste in the economic system. In addition, we generate a detailed breakdown of the final demand categories into sub-categories to clarify consumption patterns or lifestyles that produce specific waste streams. The results show that export is the main driving force generating industrial waste. This dominance is obvious for "waste acidic etchants" and "copper and copper compounds", of which the electronic parts and components sector is the largest generator. In addition, this study reveals the industries that create the substantial demand for incinerators and landfills. This article illuminates the diagnostic features of the high-resolution WIO table and provides useful insights for linking the WIO and supply chain analysis approaching sustainable consumption and production. (C) 2015 Elsevier Ltd. All rights reserved.

The aim of this article is to propose a method for forecasting future secondary material flows by combining a product lifetime distribution analysis with a waste input-output analysis and present a simple case study of automobiles. The case study demonstrates that the proposed method enables us to estimate replacement demand of new vehicles, number of end-of-life (EOL) vehicles arising from the aging of vehicles, volume of shredder scraps recovered from EOL vehicles, and volume of shredder scraps required to meet final consumption in the future.

The removability of impurities during the aluminum remelting process by oxidation was previously investigated by our research group. In the present work, alternative impurity removal with chlorination has been evaluated by thermodynamic analysis. For 43 different elements, equilibrium distribution ratios among metal, chloride flux and oxide slag phases in the aluminum remelting process were calculated by assuming the binary systems of aluminum and an impurity element. It was found that the removability of impurities isn't significantly affected by process parameters such as chloride partial pressure, temperature and flux composition. It was shown that Ho, Dy, Li, La, Mg, Gd, Ce, Yb, Ca and Sr can be potentially eliminated into flux by chlorination from the remelted aluminum. Chlorination and oxidation are not effective to remove other impurities from the melting aluminum, due to the limited parameters which can be controlled during the remelting process. It follows that a proper management of aluminum scrap such as sorting based on the composition of the products is important for sustainable aluminum recycling.

Even for metals, open-loop recycling is more common than closed-loop recycling due, among other factors, to the degradation of quality in the end-of-life (EoL) phase. Open-loop recycling is subject to loss of functionality of original materials, dissipation in forms that are difficult to recover, and recovered metals might need dilution with primary metals to meet quality requirements. Sustainable management of metal resources calls for the minimization of these losses. Imperative to this is quantitative tracking of the fate of materials across different stages, products, and losses. A new input-output analysis (IO) based model of dynamic material flow analysis (MFA) is presented that can trace the fate of materials over time and across products in open-loop recycling taking explicit consideration of losses and the quality of scrap into account. Application to car steel recovered from EoL vehicles (ELV) showed that after 50 years around 80% of the steel is used in products, mostly buildings and civil engineering (infrastructure), with the rest mostly resided in unrecovered obsolete infrastructure and refinery losses. Sensitivity analysis was conducted to evaluate the effects of changes in product lifespan, and the quality of scrap.

Alloying elements in steel add a wide range of valuable properties to steel materials that are indispensable for the global economy. However, they are likely to be effectively irretrievably blended into the steel when recycled because of (among other issues) the lack of information about the composition of the scrap. This results in the alloying elements dissipating in slag during steelmaking and/or becoming contaminants in secondary steel. We used the waste input-output material flow analysis model to quantify the unintentional flows of alloying elements (i.e., chromium, nickel, and molybdenum) that occur in steel materials and that result from mixing during end-of-life (EOL) processes. The model can be used to predict in detail the flows of ferrous materials in various phases, including the recycling phase by extending steel, alloying element source, and iron and steel scrap sectors. Application of the model to Japanese data indicates the critical importance of the recycling of EOL vehicles (ELVs) in Japan because passenger cars are the final destination of the largest share of these alloying elements. However, the contents of alloying elements are rarely considered in current ELV recycling. Consequently, the present study demonstrates that considerable amounts of alloying elements, which correspond to 7% to 8% of the annual consumption in electric arc furnace (EAF) steelmaking, are unintentionally introduced into EAFs. This result suggests the importance of quality-based scrap recycling for efficient management of alloying elements.

Steel is not elemental iron but rather a group of iron-based alloys containing many elements, especially chromium, nickel, and molybdenum. Steel recycling is expected to promote efficient resource use. However, open-loop recycling of steel could result in quality loss of nickel and molybdenum and/or material loss of chromium. Knowledge about alloying element substance flow is needed to avoid such losses. Material flow analyses (MFAs) indicate the importance of steel recycling to recovery of alloying elements. Flows of nickel, chromium, and molybdenum are interconnected, but MFAs have paid little attention to the interconnected flow of materials/substances in supply chains. This study combined a waste input-output material flow model and physical unit input-output analysis to perform a simultaneous MFA for nickel, chromium, and molybdenum in the Japanese economy in 2000. Results indicated the importance of recovery of these elements in recycling policies for end-of-life (EoL) vehicles and constructions. Improvement in EoL sorting technologies and implementation of designs for recycling/disassembly at the manufacturing phase are needed. Possible solutions include development of sorting processes for steel scrap and introduction of easier methods for identifying the composition of secondary resources. Recovery of steel scrap with a high alloy content will reduce primary inputs of alloying elements and contribute to more efficient resource use. © 2013 American Chemical Society.

Metals can in theory be infinitely recycled in a closed-loop without any degradation in quality. In reality, however, open-loop recycling is more typical for metal scrap recovered from end-of-life (EoL) products because mixing of different metal species results in scrap quality that no longer matches the originals. Further losses occur when meeting the quality requirement of the target product requires dilution of the secondary material by adding high purity materials. Standard LCA usually does not address these losses. This paper presents a novel approach to quantifying quality- and dilution losses, by means of hybrid input-output analysis. We focus on the losses associated with the recycling of ferrous materials from end-of-life vehicle (ELV) due to the mixing of copper, a typical contaminant in steel recycling. Given the quality of scrap in terms of copper density, the model determines the ratio by which scrap needs to be diluted in an electric arc furnace (EAF), and the amount of demand for EAF steel including those quantities needed for dilution. Application to a high-resolution Japanese IO table supplemented with data on ferrous materials including different grades of scrap indicates that a nationwide avoidance of these losses could result in a significant reduction of CO2 emissions.

The separation and control of undesired elements are key to recycling scrap or end-of-life (EoL) metal products, as the quality of regenerated metals is often impaired by contamination from the alloying elements in the scrap. However, little is known of their removability or controllability because they are normally absent in the production of primary metal from natural ore. Here, the distribution ratios of 31 kinds of alloying element among the metal, slag, and gas phases in the re-melting of EoL titanium products were quantitatively discussed. Our results clarified that the typical titanium alloying elements - Al, Fe, and V - are essentially uncontrollable in re-melted titanium by oxidation or evaporation. This suggests that the mixing of commercially pure titanium (CP-Ti) and other titanium alloys should be avoided. Hence, the development of new technologies to separate alloying elements from titanium scraps for sustainable titanium recycling is highly anticipated. (C) 2012 Elsevier B.V. All rights reserved.

軽金属リサイクルにおける合金元素の挙動は物質資源循環の設計において極めて重要であるにも関わらず、一部の元素について実験的な報告がなされているだけで、十分な議論がされていない。本研究ではアルミニウム、マグネシウムおよびチタンのリサイクルプロセスにおける合金元素のスラグ（ドロス）相、ガス相およびメタル相への分配傾向を熱力学的に解析し、各合金元素の除去可能性を検討した。解析の結果、一般的な不純物除去法である酸化や揮発では、軽金属リサイクルにおいてほとんどの不純物が除去不可能な傾向にあることがわかった。この結果は、軽金属リサイクル技術のさらなる発展はもちろん、市中スクラップの組成を重視した選別技術の構築や、社会システムにおけるスクラップ管理が重要であることを示唆している。

The operation of an economy is supported by the stock of materials in the form of durables and infrastructure such as machinery, equipment, buildings, and structures. The amount of durables and infrastructure or "capital stock" in the economy is of great interest in the literature of economics, and is usually measured in monetary terms based on the data on capital expenditure. In spite of its wide use by economists, this measure of "capital stock" is of very limited use for sustainable management of material stock because of its neglect of physical properties such as the mass and material composition. This paper proposes a new method of measuring the stock of long-lived durables and infrastructure in terms of the mass of its materials. This method is based on the WIO-MFA method [S. Nakamura et al. J. Ind. Ecol. 11 (2007) 50-63] and the capital formation matrix that is one of the supplementary tables of the input-output table. The method is applied to the Japanese input-output data with 400 sectors, with 9 types of metals (iron, ferroalloy, copper, zinc, lead, tin, aluminum, silver, and gold) and 8 types of plastics (thermo-setting resins, PE (low), PE (high), PS, PP, PVC, high-performance resins, and other resins) occurring as materials. It was found that substantial variations exist among sectors while fixed capital formation in the year 2000 weighs 518 kg per million Japanese yen on average in metals and plastics.

In this paper, the possibility of removing impurities during magnesium recycling with pyrometallurgical techniques has been evaluated by using a thermodynamic analysis. For 25 different elements that are likely to be contained in industrial magnesium alloys, the equilibrium distribution ratios between the metal, slag and gas phases in the magnesium remelting process were calculated assuming binary systems of magnesium and an impurity element. It was found that calcium, gadolinium, lithium, ytterbium and yttrium can be removed from the remelted end-of-life (EoL) magnesium products by oxidization. Calcium, cerium, gadolinium, lanthanum, lithium, plutonium, sodium, strontium and yttrium can be removed by chlorination with a salt flux. However, the other elements contained in magnesium alloy scrap are scarcely removed and this may contribute toward future contamination problems. The third technological option for the recycling of EoL magnesium products is magnesium recovery by a distillation process. Based on thermodynamic considerations, it is predicted that high-purity magnesium can be recovered through distillation because of its high vapor pressure, yet there is a limit on recoverability that depends on the equilibrium vapor pressure of the alloying elements and the large energy consumption. Therefore, the sustainable recycling of EoL magnesium products should be an important consideration in the design of advanced magnesium alloys or the development of new refining processes.

Identification of the flow of materials and substances associated with a product system provides useful information for Life Cycle Analysis (LCA), and contributes to extending the scope of complementarity between LCA and Materials Flow Analysis/Substances Flow Analysis (MFA/SFA), the two major tools of industrial ecology. This paper proposes a new methodology based on input-output analysis for identifying the physical input-output flow of individual materials that is associated with the production of a unit of given product, the unit physical input-output by materials (UPIOM). While the Sankey diagram has been a standard tool for the visualization of MFA/SFA, with an increase in the complexity of the flows under consideration, which will be the case when economy-wide intersectoral flows of materials are involved, the Sankey diagram may become too complex for effective visualization. An alternative way to visually represent material flows is proposed which makes use of triangulation of the flow matrix based on degrees of fabrication. The proposed methodology is applied to the flow of pig iron and iron and steel scrap that are associated with the production of a passenger car in Japan. Its usefulness to identify a specific MFA pattern from the original 10 table is demonstrated.

Vehicle replacement schemes such as the "cash for clunkers" program in the U.S. and the "scrappage scheme" in the UK have featured prominently in the economic stimulation packages initiated by many governments to cope with the global economic crisis. While these schemes were designed as economic instruments to support the vehicle production industry, governments have also claimed that these programs have environmental benefits such as reducing CO(2) emissions by bringing more fuel-efficient vehicles onto the roads. However, little evidence is available to support this claim as current energy and environmental accounting models are inadequate for comprehensively capturing the economic and environmental trade-offs associated with change's in product life and product use. We therefore developed a new dynamic model to quantify the carbon emissions due to changes in product life and consumer behavior related to product use. Based on a case study of Japanese vehicle use during the 1990-2000 period, we found that extending, not shortening, the lifetime of a vehicle helps to reduce life-cycle CO(2) emissions throughout the supply chain. Empirical results also revealed that even if the fuel economy of less fuel-efficient ordinary passenger vehicles were improved to levels comparable with those of the best available technology, i.e. hybrid passenger cars currently being produced in Japan, total CO(2) emissions would decrease by only 0.2%. On the other hand, we also find that extending the lifetime of a vehicle contributed to a moderate increase in emissions of health-relevant air pollutants (NO(x), HC, and CO) during the use phase. From the results, this study concludes that the effects of global warming and air pollution can be somewhat moderated and that these problems can be addressed through specific policy instruments directed at increasing the market for hybrid cars as well as extending lifetime of automobiles, which is contrary to the current wisdom.

Replacement demand of durable goods such as automobile is not only an important driving force of economic growth but also a key factor in emissions reduction. Considering the future replacement demand largely depend on engineering scrappage reflecting physical wear and tear which increases with products age and/or use (Greenspan and Cohen, 1999), this study proposed a novel method to forecast the replacement demand of durable goods and the life cycle emissions by incorporating product lifetime distributions reflecting the engineering scrappage into the waste input-output analysis (Nakamura and Kondo, 2009).

我が国は鉄鋼合金元素の一次資源のほぼ全量を海外から輸入している。これらの多くは特殊鋼鋼材に含まれ、最終的に様々な製品に組み込まれ、国内で消費及び蓄積されるか、再び海外へと輸出される。 本研究では、廃棄物産業連関分析に基づくマテリアルフロー分析手法(WIO-MFA)と、貿易統計等から得られる貿易量情報を組み合わせることにより、合金元素の海外を含めた最終需要先を明らかにし、資源有効利用の可能性を検討する。

The demand for iron and steel materials has been increasing mainly because of the rapid economic growth of the BRIC countries. The annual worldwide production of crude steel is approximately 2 billion tons. There has been a corresponding increase in the production of crude steel in Japan. As a result, the significance of Japan as a source of iron and steel scraps has also increased.(1))
Scrap recycling, however, is subject to some problems, such as unstable supply conditions and contamination by impurities.(2)) A significant part of these problems can be attributed to the increasing use of electric devices, such as circuit boards, motors, and wiring harnesses, in high-tech products. These electric devices/equipments contain many kinds of metals, such as copper, lead, and zinc, which can become a source of contamination of steel scrap recovered from end-of-life vehicles (ELVs) or home appliances.
Here the contamination of tramp elements was analyzed using a Waste Input Output model, considering the following points: (1) the amount of ferrous scrap usage in iron and steel production process, (2) copper elimination from ELV scraps, and (3) contamination of copper in iron and steel products.
The results of scenario analysis indicated that copper contamination in crude steel production associated with the use of scrap from ELVs could be reduced by 2 % by the use of a more recycle-oriented ELV treatment. The effects of copper elimination on CO2 emission were more significant for ordinary steel production than special steel production.

This study proposes a method of combining a waste input output material flow analysis (WIO-MFA) model with trade statistical data to identify the flows of substances embedded in trade commodities. We focused on the case of Japan as a typical processing and trading country, and we estimated each mass of iron and aluminum embedded in the imports and exports of 300 product items categorized in the WIO-MFA. We found that iron ore imported from Australia, Brazil, and India as a raw material is processed and exported to South Korea, China, and other Asian countries as steel materials and to the United States as steel materials and automobiles. Primary aluminum imported from Russia, Australia, and Brazil as a raw material is processed and exported to Asia as rolled materials and to the United States as rolled materials and automobiles.

In previous studies on the physical chemistry of pyrometallurgical processing of aluminum scrap, only a limited number of thermodynamic parameters, such as the Gibbs free energy change of impurity reactions and the variation of activity of an impurity in molten aluminum, were taken into account In contrast, in this study we thermodynamically evaluated the quantitative removal limit of impurities during the remelting of aluminum scrap; all relevant parameters, such as the total pressure, the activity coefficient of the target impurity, the temperature, the oxygen partial pressure, and the activity coefficient of oxidation product, were considered. For 45 elements that usually occur in aluminum products, the distribution ratios among the metal, slag, and gas phases in the aluminum remelting process were obtained. Our results show that, except for elements such as Mg and Zn, most of the impurities occurred as troublesome tramp elements that are difficult to remove, and our results also indicate that the extent to which the process parameters such as oxygen partial pressure, temperature, and flux composition can be changed in aluminum production is quite limited compared to that for iron and copper production, owing to aluminum's relatively low melting point and strong affinity for oxygen. Therefore, the control of impurities in the disassembly process and the quality of scrap play important roles in suppressing contamination in aluminum recycling.

In the current recycling system of end-of-life (EoL) appliances, which is based on shredding, alloying elements tend to end up in the scrap of base metals. The uncontrolled mixing of alloying elements contaminates secondary metals and calls for dilution with primary metals. Active disassembling fastener (ADF) is a design for disassembly (DfD) technology that is expected to solve this problem by significantly reducing the extent of mixing. This paper deals with a life cycle assessment (LCA) based on the waste input-output (WIO) model of an ADF developed using hydrogen storage alloys. Special attention is paid to the issue of dilution of mixed iron scrap using pig iron in an electric arc furnace (EAF). The results for Japanese electrical and electronic appliances indicate superiority of the recycling system based on the ADF over the current system in terms of reduced emissions of CO2. The superiority of ADF was found to increase with an increase in the requirement for dilution of scrap.

近年、リサイクル資源を含めた資源の需給構造、および国際的な物質バランスを定量化するための手法として、マテリアルフロー分析(MFA)が有益とされている。本稿では、WIO-MFAモデルを応用した国際マテリアルフロー分析に関する研究事例として、鉄やアルミニウムを対象元素として取り上げて日本を中心とした国際マテリアルフローを明らかにする。

The present paper proposes an analytical framework for measuring the spatial pollution repercussion effects of regional waste management. The empirical analysis using the 1995 nine-region waste input-output table reveals that as the regional population size become larger, the intraregional waste treatment level directly and indirectly induced by a person's consumption behaviour tends to be large due to economies of scale. In contrast, we especially find that the indirect household contributions per capita of the Chugoku and Shikoku region were, conversely, about 1.4 times larger than that of the Kanto region, because of the differences in the regional commodity consumption patterns. In comparing the actual economic system in 1995 with the hypothetical complete intraregional waste treatment system, we also find that the latter system increased total waste landfill by 18,103 tonnes, which amounts to 0.03% of the total waste landfill, revealing the location advantage of intermediate inputs for waste treatment activities and regional technological differences. (C) 2006 Elsevier B.V. All rights reserved.

Goal, Scope and Background. This paper is concerned with a life cycle assessment (LCA) and life cycle costing (LCQ by the use of the waste input-output (WIO) quantity- and price model of air conditioners with different energy efficiency at the use phase (high-end, lowend and average models) that were available in Japan as of winter 2002. The functional unit is an air conditioner of the 2.5kW type that is used for 10 years, and then subjected to an end-of-life (EoL) process that is consistent with the Japanese law on the recycling of appliances.
Methods. This is the first simultaneous application of the WIO methodology to an LCA and LCC over the entire life-cycle of a product including the use phase, and represents a methodological extension (in the sense of considering the use phase) and integration (in the sense of a simultaneous application) of previous studies by us (Kondo and Nakamura, Int J LCA 2004, Nakamura and Kondo, Ecol Econ 2006). The main body of data is provided by the WIO table for the year 2000, an update of the previous table for 1995 that was used in the above WIO studies. Compared with the WIO table for 1995 that consisted of only about 80 industry sectors, the current one consists of about 400 industry sectors, and includes air conditioner as a separate sector. The data on the purchase price and efficiency of air conditioners indicate wide variations: the cheapest one (the lowend model) costs half of the most expensive one (the high-end model), but its efficiency is about half of the latter.
Results and Discussion. When the cost in the use and EoL phases is included, the low-end model becomes the most expensive one, and the high-end model with the highest purchase cost the least expensive. This reversal of the relative cost levels is attributed to the difference in the efficiency in the use phase. A sensitivity analysis indicates that a reduction of the electricity price in the use phase by about 40% does not alter the significant superiority of the high-end model over the low-end model. In spite of the largest amount of input in the production phase, the high-end model performs the best in terms of both global warming potential (GWP) and landfill, while the low-end model performs the worst. The use phase generates the largest amount of waste for landfill across the three models, the largest component of which is flyash generated from coal firing power plants. A possible internalization of externality in the form of carbon tax was found to work in favor of the high-end model. The cost advantage of the high-end model, however, is sensitive to the rate of discounting of future costs: discounting at 15% diminishes its advantage over the low-end model.
Recommendation and Perspective. The results indicate the effectiveness of the pricing based on the life cycle cost for achieving sustainability, that is, for promoting the shift of the demand away from appliances with low environmental performance to the one with higher environmental performance. Acceptance by society of pricing based on life cycle costing would require, among other things, an economywide standardization of the LCC concept (in a manner analogous to ISO-LCA) that can be used complementary to ISO-LCA.

However excellent a product may be environmentally, it would not come into wide use in the economy to realize its environmental load reducing potential unless it is also economically affordable. Life-cycle costing (LCC) is a tool to assess the cost of a product over its entire life cycle, and can be regarded as an economic counterpart of LCA. A combined use of LCA and LCC would be imperative for assessing the sustainability of a product or product systems in the economy. This paper presents a new methodology of LCC which gives the cost and price counterpart of the hybrid LCA tool (Waste Input-Output, WIO) that was developed by Nakamura and Kondo (2002) [Nakamura, S., Kondo, Y., 2002. Input-output analysis of waste management. Journal of Industrial Ecology 6 (1), 39-63.1]for LCA of waste management. Building upon the preceding LCA study by Kondo and Nakamura (2004) [Kondo, Y., Nakamura, S., 2004. Evaluating alternative life-cycle strategies for electrical appliances by the waste input-output model. International Journal of Life Cycle Assessment 9 (4), 236-246.], the applicability of the methodology is illustrated by a case study of electric appliances under alternative end-of-life scenarios: landfilling, intensive recycling that is consistent with the Japanese law on the recycling of appliances, and an advanced form of intensive recycling augmented by Design for Disassembly (DfD). Application of the proposed LCC methodology indicates that while the life-cycle cost is the highest under intensive recycling and the lowest under landfilling, the cost of recycling can be reduced by appropriate implementation of MD. The possible introduction of a carbon tax is also found to significantly reduce the cost disadvantage of recycling against landfilling. Given the high level of environmental load associated with landfilling and the possible introduction of carbon taxes, Design for Environment or EcoDesign emerges as a strategy of vital importance to achieve the sustainability of appliances. (c) 2005 Elsevier B.V. All rights reserved.

This paper develops a theoretical model of material flow analysis (MFA) within the framework of the Waste Input-Output model (WIO) (Nakamura and Kondo). The model is developed based on two fundamental ingredients: yield ratios and the degree of fabrication. In manufacturing process, multiplication of physical inputs by the yield ratios gives the portion that enters physical outputs, with the rest being discarded as process waste without entering outputs. In input-output analysis, the degree of fabrication can be visualized as triangularity of the input coefficients matrix (goods of lower degree of fabrication can enter those of higher fabrication, but the reverse does not hold), which is known to emerge through an appropriate reordering of sectors. Application to the Japanese 10 data indicates that the model can provide accurate estimates of the weight as well as the composition of metals (Fe, Cu. Pb, Zn. and At) used in a passenger car. The model is also used to estimate the major final use categories (household consumption, public consumption, capital investment, inventory investment, and export) of metals.

This paper is concerned with a decision analytic extension of the waste input-output model, based on the method of linear programming. The resulting model, which is named the waste input-output linear programming model, allows one to automatically obtain an 'optimal' waste management and recycling strategy from among a given set of alternative feasible strategies. The model can thus explore the extent to which a given measure of eco-efficiency can be maximized by an appropriate combination of existing (technological and resource) potentials. An application to Japanese data is also presented. © 2005 The International Input-Output Association.

Goal, Scope and Background. In 2001, a new law on the recycling of end-of-life electric home appliances (EL-EHA) was put into effect in Japan; it was the first legislation of its sort in the world, and deserves to be called the 'Japan model.' This article is concerned with the LCA of alternative life-cycle strategies for EL-EHA, which consist of recycling as prescribed by the law, 'ecodesign' strategies such as the implementation of design for disassembly (DfD) and the extension of product life (EPL), with and without ex-post functional upgradability, and the once-dominant treatment methods such as landfilling and simple shredding.
Methods. We use the waste input-output (WIO) analysis, a new method of hybrid LCA that was developed by the authors [I]. The WIO extends the conventional input-output analysis to explicitly take into account the interdependence between the flow of goods and the flow of waste in the whole economy, and. hence provides an optimal platform for LCA involving waste treatment and recycling. Furthermore, the WIO enables us to evaluate not only environmental impacts, but also economic: impacts such as sectoral output and employment. Our analysis is based on the WIO table for 1995 and detailed process data. on recycling.
Results and Discussion. Recycling was found to outperform the 'traditional' treatment method strategy with regard to the reduction of CO2 emission, landfill consumption, and the demand for abiotic resources. Thanks to efficient utilization of the existing retail network system, it was also found to be more efficient economically. Additional implementation of DfD and the associated increase in the quality of recovered materials (plastics) were found to augment the positive environmental impacts of recycling. The EPL without upgrading resulted in a significant reduction in the environmental impacts, but also in the level of employment. On the other hand, the EPL with upgrading was found to outperform the recycling strategy in terms of environmental impacts without having significant negative economic impacts.
Conclusion and Recommendation. Recycling of EL-EHA, as prescribed by the Japanese law on the recycling of EL-EHA, was found to be effective in reducing CO, emission, depletion of abiotic resources, generation of waste, and landfill consumption, provided the rate of retrieval remains at a high level. Our results also indicate the possible effectiveness of ecodesign strategy toward the realization of a sustainable economy.

A new scheme of hybrid life-cycle assessment (LCA) termed the waste input-output (WIO) model is presented that explicitly takes into account the interdependence between the flow of goods and waste. The WIO model has two distinguishing features. First, it expands the Leontief environmental input-output (EIO) model with respect to waste flows. It turns out that the EIO model is a special case of the WIO model in which there is a strict one-to-one correspondence between waste types and treatment methods. By relaxing this condition, the WIO model provides a general framework for LCA of waste management. Second, the WIO model takes into account the "dynamics of waste treatment," which refers to the fact that the input-output relationships of waste treatment are significantly affected by the level and composition of waste feedstock, by incorporating an engineering process model of waste treatment. Because waste treatment is expected to accept whatever waste is generated by industry and households, a proper consideration of this feature is vital for LCA of waste management. We estimated a WIO table for Japan and applied it to evaluating effects of alternative waste management policies with regard to regional concentration of incineration and the sorting of waste with regard to flammability. We found that concentrating treatment in a small number of large incinerators combined with an increased degree of sorting could decrease both landfill consumption and the emission of carbon dioxide.

A new non-homothetic globally concave flexible cost function is introduced and applied to a panel of firms in the Japanese paper and pulp industry. This cost function is a mixture of the generalized McFadden form and the generalized Ozaki form due to Nakamura (1990). A generalized index of technical change is used in place of the standard quadratic form of time-trend. The estimated cost function satisfied global concavity, and the symmetry condition of the Slutsky matrix was not rejected. Homotheticity was strongly rejected.

Economic and emission effects of alternative life-cycle strategies for electric home appliances were analyzed by use of Waste Input-Output (WIO). The strategies consist of 1) landfilling, 2) conventional shredding with iron recovery, 3) integrated recycling with the recovery of metals, glass, and plastics, and 4) extension of products lives without and with increased maintenance and updating activities. It was found that strategy 3 outperformed strategies I and 2 in terms of both CO2 emission and landfill consumption. The result was robust to the variation of transport conditions. The overall increase in labor cost under strategy 3 turned out almost neutral. Strategy 4 outperformed strategy 3 in terms of environmental effects. The extent to which the reduced sales of new appliances were compensated by the increased demand for maintenance was found to have significant effects on the level of employment.

環境との調和を図りながら経済発展を実現する手段として, 循環型経済への変換が叫ばれている。循環型経済を設計するためには, 財と廃棄物の循環を巡る動脈と静脈の連関関係を定量的に把握することが極めて重要である。産業連関分析は, 動脈における財の流れを定量的に把握する手法として開発されてきた。これを廃棄物と財の循環をも把握するべく拡張することが出来れば, 上の目的に資する所大であると考えられる。この観点から, 産業連関分析とその廃棄物への応用を解説する。産業連関分析の簡単な解説に続いて, レオンチェフの廃棄物モデルとその派生モデルによる分析 (二酸化炭素分析, 環境統合勘定) を紹介する。続いて, 廃棄物に関する物質収支を踏まえた廃棄物産業連関表・モデルを紹介し, その物質フロー分析, 生態的足跡分析との関連, および国際産業連関表の活用可能性について述べる。

In 1998, the Japanese government passed a law for the recycling of specified kinds of electrical home appliances, which is to be put in full operation in 2001. Under the law, the manufacturers of TV sets, refrigerators, washing machines, and air conditioners, who operate in Japan, are obliged to recycle specified percentage of discarded appliances. While the recycling is said to be technically feasible, uncertainty remains with respect to its overall effects on the environment and economy. Using the Waste Input-Output Model (WIO, [1]) we evaluated these effects, and found that the landfill consumption and carbon dioxide emission could be reduced without reducing the level of employment.

Recycling of waste reduces the demand for virgin materials, the amount of waste to be incinerated and/or landfilled, and also reduces emissions from these sources, however, it generates waste and emissions of its own. This paper presents a static inter-industry model for analyzing economic and environmental effects of the recycling of waste that is capable of accommodating these aspects of recycling. Waste can be classified into two major categories depending on the way it is generated: (1) those generated as 'undesired' by-products in the production process such as wastewater or sludge, and (2) those originally produced as goods but have turned to waste with the passing of time, such as old paper or discarded consumer durables. We are concerned with the second category of waste. This category of waste tends to be distributed over a wide geographical area because it is generated in the place of final use, whereas the first one is generated in the place of production. Since the issue of sorted collection will thus be a non-negligible element of any recycling program involving this category of waste, we treat the collection and recycling of waste as distinct activities, instead of their being put into a black box. In this respect, our model is an extension of Duchin, 1990, Structural Change and Economic Dynamics, 1, 243-262. We regard the amount of waste as a given stock, and do not consider the process of its generation. As an empirical illustration, we construct a numerical example for the recycling of old paper based on the Dutch NAMEA data for 1992, and analyze effects of alternative recycling scenarios on the industrial activity and emission of CO2. Each scenario consists of a set of parameters referring to the proportion of recycled goods in total input, the efficiency of waste collection, and the efficiency of recycling technology.

Recycling of waste reduces the demand for virgin materials, the amount of waste to be incinerated and/or landfilled, and also reduces emissions from these sources, however, it generates waste and emissions of its own. This paper presents a static inter-industry model for analyzing economic and environmental effects of the recycling of waste that is capable of accommodating these aspects of recycling. Waste can be classified into two major categories depending on the way it is generated: (1) those generated as 'undesired' by-products in the production process such as wastewater or sludge, and (2) those originally produced as goods but have turned to waste with the passing of time, such as old paper or discarded consumer durables. We are concerned with the second category of waste. This category of waste tends to be distributed over a wide geographical area because it is generated in the place of final use, whereas the first one is generated in the place of production. Since the issue of sorted collection will thus be a non-negligible element of any recycling program involving this category of waste, we treat the collection and recycling of waste as distinct activities, instead of their being put into a black box. In this respect, our model is an extension of Duchin, 1990, Structural Change and Economic Dynamics, 1, 243-262. We regard the amount of waste as a given stock, and do not consider the process of its generation. As an empirical illustration, we construct a numerical example for the recycling of old paper based on the Dutch NAMEA data for 1992, and analyze effects of alternative recycling scenarios on the industrial activity and emission of CO2. Each scenario consists of a set of parameters referring to the proportion of recycled goods in total input, the efficiency of waste collection, and the efficiency of recycling technology. (C) 1999 Elsevier Science B.V. All rights reserved.

A dynamic factor demand model is presented which pays special attention to the prevalence of a long-term employment relationship in Japan. The model is based on the representation of technology by a variable cost function with adjustment costs for employment and capital stock, where the variable cost consists of the sum of overtime costs and materials costs. With employment being quasi-fixed and scheduled hours institutionally regulated, short-run adjustments are mostly made by overtime hours. Application to a time-series data on the Japanese electrical machinery industry indicates quasi-fixity of capital and employment and reproduces short-run overshooting of overtime hours to compensate for the sluggish adjustment of employment.

This paper analyses total factor productivity growth and trends in relative efficiency levels in the national Two-Digit Manufacturing industries of Japan, Canada, and the United States during the last quarter-century. The well-known slowdown in productivity growth rates in the 1973-80 period was a common phenomenon across the three countries but was felt most strongly in Japan and least in Canada. While the 1980s saw a pick-up in productivity growth over the slowdown period, growth in productivity has not returned to the pre-1973 level. The productivity slowdown and any subsequent increase in productivity growth rates have been correlated across industries in the three countries to a very high degree.

The Japanese input-output tables for 1975, 80, and 85 with 175 endogenous sectors were triangulated using the algorithm of Simpson and Tsukui. The degree of obtained triangularity measured by a linearity index is about 0.9, and indicates the existence of significant hierarchy among 175 industries. Rank correlation coefficients of sectoral orderings are about 0.98, and indicate stability of the hierarchical structure over time.

The introduction of robots leads to a reduction of direct labor, whereas it stimulates the investment activity of firms and thereby brings about a rise in indirect employment. This paper attempts to evaluate relative magnitudes of both effects of robotization on employment. The method of analysis depends on the application of an econometric model. The results of the survey at the individual firm level are also utilized. The forecast for the current five years (1985-1990) is that robotization will result in a net effect of a 23 thousand person decrease in employment. © 1989.

This paper tests symmetry and negativity of the Slutsky matrix for a system of demand functions derived from an aggregate model of multi product technology within a flexible dynamic framework. The model considers three inputs and three outputs, including imports and exports of intermediate goods. We derive a static demand model from a trans log cost function and specify the data generation process by a stationary ARX (1, 1) model. Results based on West German quarterly data indicate that the integrability conditions are not rejected when imposed on the ARX (1, 1) model, whereas they are rejected for all the less general dynamic models considered. Copyright © 1986 John Wiley &amp
Sons, Ltd.

Life cycle assessment (LCA) enables one to compare the environmental impact of alternative product systems, and identify the one with the least impact. However environmentally sound a product system is however, it cannot be widely introduced into the economy unless it is also economically affordable. Without a wide ranging introduction into the economy, its potential to reduce environmental impact remains unexploited. The aspect of cost is thus of great importance for assessing the economic affordability and hence the economic sustainability of a product system which is found environmentally sound by an LCA. The aspect of cost that maters here is not limited to the conventional one referring to that of manufacturing only, but should be a broader one referring to the life cycle cost that encompasses the use and the end-of-life cost as well. Life cycle costing (LCC) is concerned with the comparison of life cycle costs among alternative product systems. This paper presents a new methodology of LCC, WIO-price model, that builds upon the WIO quantity model, a hybrid LCA tool developed by us that is specially designed for application to waste management (Nakamura and Kondo, 2002). The ap