- Email: [email protected]
Introduction to the special issue: “Environmental Assessments and Waste Management”
Journal of Cleaner Production 13 (2005) 209–211 www.elsevier.com/locate/jclepro
Introduction to the special issue: ‘‘Environmental Assessments and Waste Management’’ Cleaner production is a concept that goes beyond simple pollution control. It involves the development of new processes, materials and products which are more resource and energy efficient. The prevention of waste streams through waste minimisation is an attractive strategy in this context. Waste prevention is also at the top of the so-called waste hierarchy, followed by reuse of products, recycling of materials, incineration with energy recovery, and disposal at landfills or through incineration without energy recovery. Why, then, publish a special issue on the management of waste in the Journal of Cleaner Production? In my mind, there are at least three valid and partly overlapping arguments for this effort: – The service of waste management is, in itself, a product, and cleaner production of waste management services is increasingly important because the quantities of wastes continue to rise in spite of waste prevention and other cleaner production efforts; – Waste management is often not only an issue of disposal, but a question of utilising valuable resources through the reuse of products, recycling of materials or recovery of the energy in the waste streams; – When a new process, material or product is evaluated through a life cycle assessment (LCA), this study is bound to include an environmental assessment also of the management of waste from the life cycle. These arguments point to the fact that we need knowledge on the environmental aspects of existing and potential future processes and systems for waste management. We also need to understand how the systems for waste management can be improved to reduce their environmental impacts and to enhance the utilisation of waste flows as resources. Additionally, we need methodological knowledge on how to carry through environmental assessments of waste management systems. Tools for cleaner production such as LCA have been widely applied on waste management systems since the beginning of the 1990s [1]. The goal of these studies was typically to investigate system-wide consequences 0959-6526/$ - see front matter # 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.jclepro.2004.02.017
of different options for waste management. A series of international, scientific workshops on environmental systems analysis of waste management have been held [2–4], which indicates that this has become an established research area. An international expert group on LCA for integrated waste management (IWM) was established in 1998 to support the development of LCA techniques specifically for IWM systems. Thomas and McDougall describe the goal and activities of the expert group later in this special issue. Most research papers presented in this issue are developed from conference papers presented at the Workshop on Systems Studies of Integrated Solid Waste Management in Stockholm, Sweden, in 2001 [4]. Finnveden et al. and Moberg et al. contribute with two connected papers, presenting a comparative LCA of different strategies for waste management. The aim of their study was to identify advantages and disadvantages of different methods for treatment of solid waste in Sweden, and to identify critical factors in the systems, including the background systems, which may significantly influence the results. Part of the aim was also to test the validity of the part of the waste hierarchy that states the environmental preference of material recycling over energy recovery over landfilling. Finnveden et al. present the methodology and an overview of the results. Moberg et al. present a specific comparison of newsprint paper and PET plastics. Their results suggest that the waste hierarchy is valid as a rule of thumb. There are, however, assumptions and value choices that can be made which make landfilling more preferable. This is, for example, the case for the contribution to climate change of plastic waste management when only emissions during a limited time period are considered. When transportation of waste by passenger car from the households is assumed for the other treatment options but not for landfilling, landfilling also gains in preference in some cases. The authors conclude that assumptions made, including value choices with ethical aspects, are important when ranking waste treatment options. Three of the papers in this special issue—papers by Eriksson et al., Carlsson Reich, and Assefa et al.— present case studies derived from the usage of the mod-
210
Editorial / Journal of Cleaner Production 13 (2005) 209–211
elling tool ORWARE (organic waste research). This tool, which was originally developed to evaluate options for treatment of organic wastes, has been expanded to describe municipal waste management in general. It also includes other systems that are affected by the choice of waste management options: systems for the production of electricity, district heating, materials, etc. [5]. Eriksson et al. present case studies performed in three Swedish municipalities (Uppsala, Stockholm, and ¨ lvdalen) to estimate the energy turnover, environmenA tal impact and economy of different management systems for municipal solid waste. Different combinations of incineration, recycling of separated plastic and cardboard containers, and biological treatment (anaerobic digestion and composting) of biodegradable wastes, were studied and compared to landfilling. Similar to the results of Finnveden et al. and Moberg et al., this study indicates that reduced landfilling to the benefit of increased energy recovery and materials recycling is positive with respect to environmental impacts, energy turnover, and economic aspects. This is mainly due to the fact that the choice of waste management method affects processes outside the waste management system, such as generation of district heating, electricity, vehicle fuel, plastic, cardboard, and fertiliser. Thus, the authors recommend that landfilling of energy-rich waste should be avoided, as far as possible, partly because of the environmental impacts from landfilling, but mainly because of the low recovery of resources in landfills. Carlsson Reich examines the possibilities and limitations of using ORWARE to link economic information to an LCA of municipal waste management systems. A terminology and methodology for economic assessment of municipal waste management systems is proposed and tested through a case study. The methodology consists of a financial life cycle costing (LCC), which is used in parallel with an LCA, and a consecutive, environmental LCC that integrates results from the two parallel methods. In the case study, the financial LCC covers all the costs incurred by the extended waste management system, as if the LCA system was a single economic actor. The environmental LCC is based on three different weighting methods to monetarise environmental effects such as emissions and resource use. As both LCCs use the same unit of account, they can easily be added together to a welfare economic tool. This step-by-step aggregation leads, the author argues, to a transparent, reproducible method for systems analysis. Assefa et al. discuss the prospects of using ORWARE as a tool for Environmental Technology Chain Assessment. Conventional technology assessment relied on the judgements and intuition of the assessors. A computer-based tool such as ORWARE provides a structure for the management of input and output data that cover ecological and economic para-
meters. The application of the model as Environmental Technology Chain Assessment tool is illustrated through a study of alternative technical systems linking waste management to vehicle fuel production and use. Lundie and Peters present an LCA of alternative means for managing food waste in Sydney, Australia: a household in-sink food waste processor (FWP), home composting, centralised composting of food and garden waste, and disposal at landfill as part of the mixed municipal waste. The environmental assessment takes into account eight different environmental indicators and impact categories. The results indicate that, if operated aerobically, the home composting has the least environmental impact in all impact categories. The FWP performed well in terms of energy consumption, global warming and acidification potentials, but it made a large contribution to potential eutrophication and toxicity. Centralised composting has a relatively poor environmental performance due to the energy required for collection. The environmental profile of landfilling was relatively low, except with respect to global warming and eutrophication potential. Houillon and Jolliet compare six methods for the treatment of waste water sludge: agricultural spreading, fluidised bed incineration, wet oxidation, pyrolysis, incineration in cement kilns and landfilling. They focus on the energy demand and on emissions contributing to climate change. Parallel to Eriksson et al., the results of Houillon and Jolliet demonstrate the importance of the environmental burdens that can be avoided through utilisation of co-products from the sludge treatment. The energy balance suggests that incineration and agricultural spreading have the lowest nonrenewable primary energy consumption. For global warming, wet oxidation and incineration have the best balance, while landfill and agricultural spreading are the worst options. The authors also discuss the requirements to make the waste water sludge a resource rather than a waste management problem. Last but not least, Hellweg et al. present a new methodology for modelling, in LCA, the emissions of heavy metals to the groundwater from slag landfills. This methodology takes into account time and site-dependent aspects. The environmental impacts of a pollutant often depend strongly on where, when, and how it is emitted. This fact is not taken into account in a traditional LCA; however, as Hellweg et al. indicate, approaches to take site-dependent aspects into account in the modelling of specific environmental impacts have been presented in recent years. Hellweg et al. use a scenario analysis to calculate the future background contamination of the Swiss groundwater with Cd2+ and Cu2+. The environmental impacts of a slag landfill were assessed considering this changing background contamination. The impacts of the Cu2+ emissions from the slag landfill were found to be more important than those of the com-
Editorial / Journal of Cleaner Production 13 (2005) 209–211
plete system waste incineration in previous analysis, where the landfill emissions had been assumed to enter the surface water and where the background contamination was assumed constant. Based on these results the authors argue that a site- and time-dependent impact assessment is crucial for a thorough assessment of the treatment of heavy metal-containing wastes.
References [1] Ekvall T, Finnveden G. The application of life cycle assessment to integrated solid waste management: part 2—perspectives on energy and material recovery from paper. Trans IChemE 2000;78B:288–94. [2] Finnveden G, Huppes G, editors. Life cycle assessment and treatment of solid waste. Proceedings of the International Workshop, September 28–29, 1995, Stockholm, Sweden. AFR-report 98. Stockholm: Swedish Environmental Protection Agency; 1995.
211
˚ , editors. Systems engineering [3] Sundberg J, Nybrandt T, Sivertun A models for waste management. Proceedings from the International Workshop in Gothenburg, AFR-report 229. Stockholm: Swedish Environmental Protection Agency; 1998. [4] Sundquist JO, Finnveden G, Sundberg J, editors. Workshop on System Studies of Integrated Solid Waste Management in Stockholm April 2–3, 2001. B1490. Stockholm: Swedish Environmental Research Institute; 2002. [5] Eriksson O, Frostell B, Bjo¨rklund A, Assefa G, Sundquist JO, Granath J, et al. ORWARE—a simulation tool for waste management. Resources, Conservation and Recycling 2002;36(4): 287–307.
Tomas Ekvall Department of Energy Technology, Chalmers University of Technology, SE-6 Gothenburg, Sweden E-mail address: [email protected]
Introduction to the special issue: ‘‘Environmental Assessments and Waste Management’’ Cleaner production is a concept that goes beyond simple pollution control. It involves the development of new processes, materials and products which are more resource and energy efficient. The prevention of waste streams through waste minimisation is an attractive strategy in this context. Waste prevention is also at the top of the so-called waste hierarchy, followed by reuse of products, recycling of materials, incineration with energy recovery, and disposal at landfills or through incineration without energy recovery. Why, then, publish a special issue on the management of waste in the Journal of Cleaner Production? In my mind, there are at least three valid and partly overlapping arguments for this effort: – The service of waste management is, in itself, a product, and cleaner production of waste management services is increasingly important because the quantities of wastes continue to rise in spite of waste prevention and other cleaner production efforts; – Waste management is often not only an issue of disposal, but a question of utilising valuable resources through the reuse of products, recycling of materials or recovery of the energy in the waste streams; – When a new process, material or product is evaluated through a life cycle assessment (LCA), this study is bound to include an environmental assessment also of the management of waste from the life cycle. These arguments point to the fact that we need knowledge on the environmental aspects of existing and potential future processes and systems for waste management. We also need to understand how the systems for waste management can be improved to reduce their environmental impacts and to enhance the utilisation of waste flows as resources. Additionally, we need methodological knowledge on how to carry through environmental assessments of waste management systems. Tools for cleaner production such as LCA have been widely applied on waste management systems since the beginning of the 1990s [1]. The goal of these studies was typically to investigate system-wide consequences 0959-6526/$ - see front matter # 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.jclepro.2004.02.017
of different options for waste management. A series of international, scientific workshops on environmental systems analysis of waste management have been held [2–4], which indicates that this has become an established research area. An international expert group on LCA for integrated waste management (IWM) was established in 1998 to support the development of LCA techniques specifically for IWM systems. Thomas and McDougall describe the goal and activities of the expert group later in this special issue. Most research papers presented in this issue are developed from conference papers presented at the Workshop on Systems Studies of Integrated Solid Waste Management in Stockholm, Sweden, in 2001 [4]. Finnveden et al. and Moberg et al. contribute with two connected papers, presenting a comparative LCA of different strategies for waste management. The aim of their study was to identify advantages and disadvantages of different methods for treatment of solid waste in Sweden, and to identify critical factors in the systems, including the background systems, which may significantly influence the results. Part of the aim was also to test the validity of the part of the waste hierarchy that states the environmental preference of material recycling over energy recovery over landfilling. Finnveden et al. present the methodology and an overview of the results. Moberg et al. present a specific comparison of newsprint paper and PET plastics. Their results suggest that the waste hierarchy is valid as a rule of thumb. There are, however, assumptions and value choices that can be made which make landfilling more preferable. This is, for example, the case for the contribution to climate change of plastic waste management when only emissions during a limited time period are considered. When transportation of waste by passenger car from the households is assumed for the other treatment options but not for landfilling, landfilling also gains in preference in some cases. The authors conclude that assumptions made, including value choices with ethical aspects, are important when ranking waste treatment options. Three of the papers in this special issue—papers by Eriksson et al., Carlsson Reich, and Assefa et al.— present case studies derived from the usage of the mod-
210
Editorial / Journal of Cleaner Production 13 (2005) 209–211
elling tool ORWARE (organic waste research). This tool, which was originally developed to evaluate options for treatment of organic wastes, has been expanded to describe municipal waste management in general. It also includes other systems that are affected by the choice of waste management options: systems for the production of electricity, district heating, materials, etc. [5]. Eriksson et al. present case studies performed in three Swedish municipalities (Uppsala, Stockholm, and ¨ lvdalen) to estimate the energy turnover, environmenA tal impact and economy of different management systems for municipal solid waste. Different combinations of incineration, recycling of separated plastic and cardboard containers, and biological treatment (anaerobic digestion and composting) of biodegradable wastes, were studied and compared to landfilling. Similar to the results of Finnveden et al. and Moberg et al., this study indicates that reduced landfilling to the benefit of increased energy recovery and materials recycling is positive with respect to environmental impacts, energy turnover, and economic aspects. This is mainly due to the fact that the choice of waste management method affects processes outside the waste management system, such as generation of district heating, electricity, vehicle fuel, plastic, cardboard, and fertiliser. Thus, the authors recommend that landfilling of energy-rich waste should be avoided, as far as possible, partly because of the environmental impacts from landfilling, but mainly because of the low recovery of resources in landfills. Carlsson Reich examines the possibilities and limitations of using ORWARE to link economic information to an LCA of municipal waste management systems. A terminology and methodology for economic assessment of municipal waste management systems is proposed and tested through a case study. The methodology consists of a financial life cycle costing (LCC), which is used in parallel with an LCA, and a consecutive, environmental LCC that integrates results from the two parallel methods. In the case study, the financial LCC covers all the costs incurred by the extended waste management system, as if the LCA system was a single economic actor. The environmental LCC is based on three different weighting methods to monetarise environmental effects such as emissions and resource use. As both LCCs use the same unit of account, they can easily be added together to a welfare economic tool. This step-by-step aggregation leads, the author argues, to a transparent, reproducible method for systems analysis. Assefa et al. discuss the prospects of using ORWARE as a tool for Environmental Technology Chain Assessment. Conventional technology assessment relied on the judgements and intuition of the assessors. A computer-based tool such as ORWARE provides a structure for the management of input and output data that cover ecological and economic para-
meters. The application of the model as Environmental Technology Chain Assessment tool is illustrated through a study of alternative technical systems linking waste management to vehicle fuel production and use. Lundie and Peters present an LCA of alternative means for managing food waste in Sydney, Australia: a household in-sink food waste processor (FWP), home composting, centralised composting of food and garden waste, and disposal at landfill as part of the mixed municipal waste. The environmental assessment takes into account eight different environmental indicators and impact categories. The results indicate that, if operated aerobically, the home composting has the least environmental impact in all impact categories. The FWP performed well in terms of energy consumption, global warming and acidification potentials, but it made a large contribution to potential eutrophication and toxicity. Centralised composting has a relatively poor environmental performance due to the energy required for collection. The environmental profile of landfilling was relatively low, except with respect to global warming and eutrophication potential. Houillon and Jolliet compare six methods for the treatment of waste water sludge: agricultural spreading, fluidised bed incineration, wet oxidation, pyrolysis, incineration in cement kilns and landfilling. They focus on the energy demand and on emissions contributing to climate change. Parallel to Eriksson et al., the results of Houillon and Jolliet demonstrate the importance of the environmental burdens that can be avoided through utilisation of co-products from the sludge treatment. The energy balance suggests that incineration and agricultural spreading have the lowest nonrenewable primary energy consumption. For global warming, wet oxidation and incineration have the best balance, while landfill and agricultural spreading are the worst options. The authors also discuss the requirements to make the waste water sludge a resource rather than a waste management problem. Last but not least, Hellweg et al. present a new methodology for modelling, in LCA, the emissions of heavy metals to the groundwater from slag landfills. This methodology takes into account time and site-dependent aspects. The environmental impacts of a pollutant often depend strongly on where, when, and how it is emitted. This fact is not taken into account in a traditional LCA; however, as Hellweg et al. indicate, approaches to take site-dependent aspects into account in the modelling of specific environmental impacts have been presented in recent years. Hellweg et al. use a scenario analysis to calculate the future background contamination of the Swiss groundwater with Cd2+ and Cu2+. The environmental impacts of a slag landfill were assessed considering this changing background contamination. The impacts of the Cu2+ emissions from the slag landfill were found to be more important than those of the com-
Editorial / Journal of Cleaner Production 13 (2005) 209–211
plete system waste incineration in previous analysis, where the landfill emissions had been assumed to enter the surface water and where the background contamination was assumed constant. Based on these results the authors argue that a site- and time-dependent impact assessment is crucial for a thorough assessment of the treatment of heavy metal-containing wastes.
References [1] Ekvall T, Finnveden G. The application of life cycle assessment to integrated solid waste management: part 2—perspectives on energy and material recovery from paper. Trans IChemE 2000;78B:288–94. [2] Finnveden G, Huppes G, editors. Life cycle assessment and treatment of solid waste. Proceedings of the International Workshop, September 28–29, 1995, Stockholm, Sweden. AFR-report 98. Stockholm: Swedish Environmental Protection Agency; 1995.
211
˚ , editors. Systems engineering [3] Sundberg J, Nybrandt T, Sivertun A models for waste management. Proceedings from the International Workshop in Gothenburg, AFR-report 229. Stockholm: Swedish Environmental Protection Agency; 1998. [4] Sundquist JO, Finnveden G, Sundberg J, editors. Workshop on System Studies of Integrated Solid Waste Management in Stockholm April 2–3, 2001. B1490. Stockholm: Swedish Environmental Research Institute; 2002. [5] Eriksson O, Frostell B, Bjo¨rklund A, Assefa G, Sundquist JO, Granath J, et al. ORWARE—a simulation tool for waste management. Resources, Conservation and Recycling 2002;36(4): 287–307.
Tomas Ekvall Department of Energy Technology, Chalmers University of Technology, SE-6 Gothenburg, Sweden E-mail address: [email protected]