Mats Eklund

Landfill mining: a critical review of two decades of research.

Landfills have historically been seen as the ultimate solution for storing waste at minimum cost. It is now a well-known fact that such deposits have related implications such as long-term methane emissions, local pollution concerns, settling issues and limitations on urban development. Landfill mining has been suggested as a strategy to address such problems, and in principle means the excavation, processing, treatment and/or recycling of deposited materials. This study involves a literature review on landfill mining covering a meta-analysis of the main trends, objectives, topics and findings in 39 research papers published during the period 1988-2008. The results show that, so far, landfill mining has primarily been seen as a way to solve traditional management issues related to landfills such as lack of landfill space and local pollution concerns. Although most initiatives have involved some recovery of deposited resources, mainly cover soil and in some cases waste fuel, recycling efforts have often been largely secondary. Typically, simple soil excavation and screening equipment have therefore been applied, often demonstrating moderate performance in obtaining marketable recyclables. Several worldwide changes and recent research findings indicate the emergence of a new perspective on landfills as reservoirs for resource extraction. Although the potential of this approach appears significant, it is argued that facilitating implementation involves a number of research challenges in terms of technology innovation, clarifying the conditions for realization and developing standardized frameworks for evaluating economic and environmental performance from a systems perspective. In order to address these challenges, a combination of applied and theoretical research is required.

Environmental evaluation of reuse of by-products as road construction materials in Sweden

Reuse of by-products in road construction is most often environmentally evaluated from the narrow perspective of the material itself, i.e. the material level. In this article, we argue that the current mainstream environmental evaluation of reuse of by-products in road construction should use wider system boundaries. In order to illustrate the importance of system boundaries to the final result, three additional levels that complement the material level, are applied to the environmental evaluation of reuse of by-products. In total these four levels of evaluation are, firstly, the material itself, mainly studied by leaching tests, secondly, the road environment studied by substance flow analysis, furthermore, a narrow life-cycle perspective and, finally, the industrial system level that addresses the reuse of by-products in a broader sense. Methods and tools applied to different levels emphasise different environmental aspects and consequently they are appropriate for addressing different questions. However, especially for the evaluation of environmental aspects on the industrial system level, there is a need to develop the methods. To apply these four levels to the evaluation would broaden the knowledge about the environmental impacts of the reuse of by-products. We argue that current leaching tests have to be complemented by the broader system boundaries used in substance flow studies and in life-cycle assessments in order to discuss the use of resources and environmental impacts from a wider perspective.

Environmental impact assessment—a tool for sustainable development?: A case study of biofuelled energy plants in Sweden

Abstract Properly performed, environmental impact assessment (EIA) is a useful tool for promoting sustainable development because it includes many components that can help facilitate intragenerational and intergenerational equity. In a case study, environmental impact statements (EISs) for Swedish biofuelled energy plants are analysed to see whether they include components vital to meet intra- and intergenerational equity, such as assessing local and global impacts, use of resources, public influence on project development, and alternative project design. The analysis shows that the environmental aspects of sustainable development on a local level are only partly met by EIA. However, global effects and effects on the management of natural resources are not assessed, excluding aspects that may affect future generations. Based on this, and since no concerns for sustainable development on a societal level were found, it is concluded that EIA practice in Sweden may not, to a full extent, serve as a tool to promote sustainable development.

Metal contamination in recovered waste wood used as energy source in Sweden.

Abstract Large amounts of recovered waste wood (RWW) originating from construction and demolition activities (C&DWW) and industrial activities (IWW) are annually generated in Sweden. RWW is also imported for use as an energy source at biofuel boilers. Increased use of biomass is one strategy to decrease environmental impact, in general, and the emissions of green house gases, in particular. This study addresses the environmental and resource implications of metal occurrence in RWW that is used as an energy source at biofuel boilers. RWW contains elevated concentrations of arsenic, chromium, copper, zinc, mercury, nickel, lead and possibly cadmium. The metal composition of Swedish and imported RWW differs in that Swedish RWW contains higher concentrations of arsenic, chromium, zinc, nickel and copper, while imported RWW contains higher concentrations of lead, mercury and cadmium. Ashes from combustion of RWW are nowadays generally disposed in landfills due to their elevated metal concentrations. This practice makes it impossible to use these ashes as filler material thereby replacing extraction of raw materials and decreasing the need for landfill space. Furthermore, landfilling leads to accumulation of hazardous heavy metals that poses a future environmental and health problem. If RWW from construction and demolition should contribute optimally to a sustainable energy system, cleaner waste wood flows are a prerequisite. The elementary measure is to track potential pollution sources in this waste stream and find out which are significant. Furthermore, since most of the RWW is untreated and unpolluted wood, there is a great environmental potential to separate this flow through the waste management system. Such an approach might lead to decreased environmental pollution of heavy metals and an improved resource management.

Environmental integration and policy implementation : competing governance modes in waste management decision making

Research into environmental policy integration (EPI) has focused very much on coordination issues associated with the preparation of policies at national and international levels. We instead examine some challenges in implementing EPI at the local level. We look at legal and policy frameworks relating to environmental governance and actual waste management decision making in five Swedish cities. We observe an implementation gap between the high-level policy ambitions relating to environmental governance of the waste sector, as expressed in national policy frameworks, and the local-level decision-making procedures and outcomes. Several discrepancies are identified: between national waste policy and the local decision premises, between local waste planning and project decision making, between knowledge gathering and project decision making, and between the legal mechanism in the development consent process and the national environmental quality objectives framework. Our study indicates that the governance frameworks at different levels are quite different, and at least partly incompatible, which causes important coordination problems across levels. Sectoral developments towards an industrial marketisation of waste have rendered frameworks such as local waste plans obsolete. We also find that the more traditional and coercive forms of governing the sector, such as consent, bans, and taxes, are the ones that have steering power, whereas new procedures, such as management by objectives, lack sufficient institutional and cognitive support structures to be effective.

Towards cooperation in industrial symbiosis : considering the importance of the human dimension

The objective of this study is to evaluate the human dimensions of improving energy and material-use efficiency of a system through increased integration and exchange between local actors. The resu ...

Improving the layout of recycling centres by use of lean production principles

There has been increased focus on recycling in Sweden during recent years. This focus can be attributed to external environmental factors such as tougher legislation, but also to the potential gains for raw materials suppliers. Recycling centres are important components in the Swedish total recycling system. Recycling centres are manned facilities for waste collection where visitors can bring, sort and discard worn products as well as large-sized, hazardous, and electrical waste. The aim of this paper was to identify and describe the main flows and layout types at Swedish recycling centres. The aim was also to adapt and apply production theory for designing and managing recycling centre operations. More specifically, this means using lean production principles to help develop guidelines for recycling centre design and efficient control. Empirical data for this research was primarily collected through interviews and questionnaires among both visitors and employees at 16 Swedish recycling centres. Furthermore, adapted observation protocols have been used in order to explore visitor activities. There was also close collaboration with a local recycling centre company, which shared their layout experiences with the researchers in this project. The recycling centres studied had a variety of problems such as queues of visitors, overloading of material and improper sorting. The study shows that in order to decrease the problems, the recycling centres should be designed and managed according to lean production principles, i.e. through choosing more suitable layout choices with visible and linear flows, providing better visitor information, and providing suitable technical equipment. Improvements can be achieved through proper planning of the layout and control of the flow of vehicles, with the result of increased efficiency and capacity, shorter visits, and cleaner waste fractions. The benefits of a lean production mindset include increased visitor capacity, waste flexibility, improved sorting quality, shorter time for visits and improved working conditions.

Resource and Climate Implications of Landfill Mining A Case Study of Sweden

This study analyzes the amount of material deposited in Swedish municipal solid waste landfills, how much is extractable and recyclable, and what the resource and climate implications are if landfill mining coupled with resource recovery were to be implemented in Sweden. The analysis is based on two scenarios with different conventional separation technologies, one scenario using a mobile separation plant and the other using a more advanced stationary separation plant. Further, the approach uses Monte Carlo simulation to address the uncertainties attached to each of the different processes in the scenarios. Results show that Swedens several thousand municipal landfills contain more than 350 million tonnes (t) of material. If landfill mining combined with resource recovery is implemented using a contemporary stationary separation plant, it would be possible to extract about 7 million t of ferrous metals and 2 million t of nonferrous metals, enough to meet the demand of Swedish industry for ferrous and nonferrous metals for three and eight years, respectively. This study further shows that landfill mining could potentially lead to the equivalent of a one‐time reduction of about 50 million t of greenhouse gas emissions (carbon‐dioxide equivalents), corresponding to 75% of Swedens annual emissions.

The strategic role of recycling centres for environmental performance of waste management systems

This paper analyses how different actors influence the sorting quality of waste at recycling centres. Users (i.e. citizens) play an essential role since they conduct the actual sorting. They have difficulties sorting many of their discarded products, leading to decreased performance of the entire waste management system of which recycling centres are a part. Several measures addressing this problem are identified such as product design, improved terminology for labelling waste and increased manning at recycling centres. A fundamental task for managers and employees is to further develop information and guidance for users, both at home and at recycling centres. Several obstacles for improvements are also discussed, including working conditions and the economy of recycling centres, as well as the routines for communication and quality assurance among actors in the recycling business.

Developing a monitoring method facilitating continual improvements in the sorting of waste at recycling centres

Beneficial use of waste relies on efficient systems for collection and separation. In Sweden, a bring system involving recycling centres for collection of bulky, electr(on)ic and hazardous waste has been introduced. A significant share of this waste is incorrectly sorted, causing downstream environmental implications. At present, however, there is a lack of affordable and accurate monitoring methods for providing the recycling centres with the necessary facts for improving the sorting of waste. The aim of this study was therefore to evaluate the usability of a simplified and potentially more suitable waste monitoring method for recycling centres. This method is based on standardised observations where the occurrence of incorrect sorting is monitored by taking digital pictures of the waste which then are analysed according to certain guidelines. The results show that the developed monitoring method could offer a resource-efficient and useful tool for proactive quality work at recycling centres, involving continuous efforts in developing and evaluating measures for improved sorting of waste. More research is however needed in order to determine to what extent the obtained results from the monitoring method are reliable.