Landfill mining has been proclaimed as an alternative strategy to address unwanted impacts of waste deposits. In real-life projects, such excavation and processing of deposited waste has mainly been used to facilitate traditional objectives such as remediation, land reclamation or creation of landfill airspace. A key target of recent landfill mining research is, however, to go beyond this type of local motives and enhance the recovery of materials and energy resources by developing advanced processing technologies. Although such an ambitiousapproach clearly displays a wider societal potential, it also adds complexity to the implementation and assessment of pros and cons of landfill mining.

Shredder fines is a residue of the shredding industry and is currently landfilled or used as landfill cover in Sweden. Throughout the time, the heterogeneity and small particle size have rendered resource recovery and recycling of it challenging. In spite of that, European policies envisioning circular economy, in concomitance with stringent resource recovery requirements and increased landfill taxes are challenging the current disposal practices of the shredding industry. As an attempt to address this issue, the present study has developed a systematic approach for performing an initial assessment of the feasibility of several selected mainstream applications for valorisation of shredder fines.

First, sampling of shredder fines from a major shredding plant was obtained twice a week over a 10 weeks period. The main focus of the sampling program was to encompass the variation in the material’s physical and chemical composition. The two samples from each week were then mixed and divided into six subsamples. That is, one original fraction and five size fractions; ZA (7.10-5.00 mm), ZB (5.00-3.35 mm), ZC (3.35-2.00 mm), ZD (2.00-0.25 mm), and ZE (0.25-0.063 mm). These sub-samples were subsequently sent for laboratory analysis for characterisation of contaminants, potentially valuable metals and energy recovery related properties. Second, three potential main stream applications for shredder fines were identified based on existing research on similar industrial residues (e.g. municipal waste incineration bottom ash) and current practices of the Swedish shredding industry. The selected applications are; Smelting for copper, Energy recovery in cement kilns and municipal solid waste incinerators, and Substitution of aggregates in concrete making and road construction. Third, the gate requirements of potential users and legislative requirements with regards to the identified applications were established, and the characteristics of shredder fines were benchmarked against them.

As far as copper smelting is concerned, the presence of high concentrations of lead and chromium is the biggest challenge. Otherwise, the fractions; ZA, ZB, and ZD show some potential due to manageable concentrations of arsenic, cadmium, and mercury. Concerning energy recovery, the calorific value apparently narrows down the options to municipal waste incinerators. There, the chlorine concentration only allows utilisation of the ZC fraction whereas heavy metal concentrations are too high with regards to all the fractions. With regards to the use as substitute material in construction, legislative requirements in Sweden for total content and leachate content of metals are too strict for shredder fines.

In conclusion, the benchmarking reveals the need for prior upgrading of shredder fines with respect to the different applications. Thus, integrated upgrading processes that could handle the complexity of the material in terms of contaminants and valuable recoverables is needed in order to achieve holistic valorisation of the material.

The shift from linear to circular economy has steered the change in perception about landfills. From final to temporary waste storage, landfills are considered as technospheric stocks of resources that can be recovered through innovative technologies in the concept of enhanced landfill mining (ELFM). At present, most ELFM projects are in pilot-scale and it remains as a proof of concept. Economic feasibility is one of the primary considerations that must be satisfied prior to its full-scale realization. Several economic assessments were conducted in recent years but there is no systematic synthesis of these studies to date. The aim of this review is to compile various empirical insights of previous economic assessments of ELFM in relation to the employed methodological choices. With pre-defined exclusion criteria, 15 studies were selected in this review. For the empirical part, the identified main economic drivers for costs are separation and sorting, thermal treatment and transportation, while for benefits are material sales, recovered land and energy sales. In more than half of the studies, the costs exceeded the benefits concluding that ELFM is not profitable.  The few potentially profitable cases mainly depend on varying the system conditions defined by market prices and regulations. These require changes that are more radical, if not impossible. For the method part, costs and benefits are accounted at different levels of aggregation, scope and scale—that is from process to sub-process level, from private to societal economics, and from laboratory to pilot scale, respectively. As most studies are based on pilot scale, if not purely conceptual, data estimation mainly depends on extrapolation from these pilot projects or on direct adoption of secondary data. In spite of the expected uncertainties in model, scenario and parameter, less than half of the studies employed sensitivity and uncertainty analyses. With it being neglected, their results can be considered to have a weak reliability for practical use in a full-scale ELFM project implementation. A need for systematic framework for early-stage assessment is highlighted to capture both stochastic and epistemic uncertainties. Process and system upscaling with exploratory scenario development, and participatory data collection in ranges rather than in absolute terms are some of the suggested approaches to generate results with a certain level of confidence. In this way, the future economic assessments of ELFM can veer away from simple profitability assessments. Instead, it focuses on knowledge development despite the limited information that is inherent to emerging concepts. Most importantly, it provides reliable information that can be used as a decision-support for various stakeholders such as project managers, technology developers, and policy makers towards the advancement of ELFM.

The EU Commission’s circular economy strategy pushes for a higher recycling rate and a more long-term waste management practice.1 Enhanced Landfill Mining (ELFM) can contribute to this agenda as a better landfill management option, by shifting the landfill paradigm from dumping or as end-storage of waste to resource recovery or as temporary storage of resources.2-4 Through ELFM, landfills becomes a secondary source of both material (Waste-to-Material, WtM) and energy (Waste-to-Energy, WtE) with the use of innovative technologies.3,4

Several studies explored the environmental and/or economic aspects of ELFM having different scopes and objectives. Some cover the entire process value chain while others additionally focused on comparing technological choices for WtE,5–7 WtM,8,9 and even ELFM waste valorisation.10 Furthermore, for the economic assessment, regulation-related costs and benefits as landfill taxes, gate fees and green certificates5,11,12 are also accounted for. Regarding the identification of economic hotspots, many of these studies concluded similar processes to be important. However, most of these studies were based on either hypothetical cases, or real cases but with small-scale excavation and separation using non-sophisticated set-ups, which are not likely to be used for large-scale processing. Hence, more uncertainty is expected from the lack of actual ELFM demonstration projects.

The aim of this study is to analyse the main contributing factors that influence environmental and economic performance of ELFM, considering the landfill owner’s viewpoint. The study is based on a real case of excavation and subsequent separation in an existing stationary facility. Specifically, the influence of the prevailing system conditions is investigated as defined by the current legislation and the market situation.

This paper examines the market potential of disposed shredder waste, a resource that is increasingly emphasized as a future mine. A framework with gate requirements of various outlets was developed and contrasted with a pilot project focusing on excavated waste from a shredder landfill, sorted in an advanced recycling facility. Only the smallest fraction by percentage had an outlet, the metals (8%), which were sold according to a lower quality class. The other fractions (92%) were not accepted for incineration, as construction materials or even for re-deposition. Previous studies have shown similar lack of marketability. This means that even if one fraction can be recovered, the outlet of the other material is often unpredictable, resulting in a waste disposal problem, which easily prevents a landfill mining project altogether. This calls for marketability and usability of deposited waste to become a central issue for landfill mining research. The paper concludes by discussing how concerned actors can enhance the marketability, for example by pre-treating the disposed waste to acclimatize it to existing sorting methods. However, for concerned actors to become interested in approaching unconventional resources such as deposited waste, greater regulatory flexibility is needed in which, for example, re-deposition could be allowed as long as the environmental benefits of the projects outweigh the disadvantages.

Residue products often pose a huge challenge to material recycling industry. Especially heterogenic and fine granular residues. It increases the cost and reduces the efficiency of material separation and recovery. Currently, the most common practice is to landfill such residue products. However, decreasing availability of landfills, increasing landfill costs, and new policy instruments require higher rates of resource recovery. In spite of that, business initiatives for recovering secondary raw material from residue products are often deterred by stringent environmental legislation emphasizing human toxicity concerns. Shredding industry plays a huge role in the context of circular economy via recycling important waste streams such as end-oflife vehicles (ELVs), municipal white goods, construction and demolition waste, and different industrial wastes. The core business model of industrial shredding is driven by recovering different metals while a variety of residue products including plastics, rubber, foam, wood, glass, and sand are generated. Shredder fine residue (also called shredder fines) is a fine granular residue product with intrinsic heterogeneity, which is produced by the shredding industry. A share of 15-20% of the input would end up as shredder fines in a typical plant.

The overall aim of this study is to draw technical, market and regulatory boundary conditions for improved material recovery from shredder fines. Thereby to build a framework of principal guidelines to support systematic identification, development, and evaluation of different valorization options for shredder fines. The outcome of this study is also envisioned to provide generic conclusions to the valorization of heterogenic residue products in general.

The study is performed in collaboration with a major shredding company in Sweden. The methodology reflects the Swedish context and consists of two phases. During the initial phase, firstly, the overall shredding industry structure of Sweden is studied to understand the governing regulatory framework, level of competition, and the scale of operation. Secondly, the collaborating company is studied to gain knowledge on technical feasibility of implementing recovery processes, economic, business and market aspects, and implications of national and local legislation, from the shredding company perspective. Empirical methods such as interviews and study of documentation are used in this phase.

During the second phase, detailed material and elemental characterization tests are performed on shredder fine samples. Thereby the distribution of basic elements, metals, heating value, and ash, in shredder fines as well as across different size fractions of shredder fines is established. The results are compared and contrasted against literature values. An extensive survey is also carried out to identify potential users for different materials which are possibly recoverable from shredder fines. Such potential users are then mapped against materials. Leaching tests are also performed to assess the mobility of heavy metals and thereby the potential environmental risk and human toxicity.

As the main contribution of this study, knowledge is developed and synthesized, boundary conditions are set, and principal guidelines of general relevance are drawn in order to facilitate improved valorization of fine granular residue products.

Residue products often pose a huge challenge to material recycling industry. Especially heterogenic and fine granular residues. It increases the cost and reduces the efficiency of material separation and recovery. Currently, the most common practice is to landfill such residue products. However, decreasing availability of landfills, increasing landfill costs, and new policy instruments require higher rates of resource recovery. In spite of that, business initiatives for recovering secondary raw material from residue products are often deterred by stringent environmental legislation emphasizing human toxicity concerns. Shredding industry plays a huge role in the context of circular economy via recycling important waste streams such as end-oflife vehicles (ELVs), municipal white goods, construction and demolition waste, and different industrial wastes. The core business model of industrial shredding is driven by recovering different metals while a variety of residue products including plastics, rubber, foam, wood, glass, and sand are generated. Shredder fine residue (also called shredder fines) is a fine granular residue product with intrinsic heterogeneity, which is produced by the shredding industry. A share of 15-20% of the input would end up as shredder fines in a typical plant.

The overall aim of this study is to draw technical, market and regulatory boundary conditions for improved material recovery from shredder fines. Thereby to build a framework of principal guidelines to support systematic identification, development, and evaluation of different valorization options for shredder fines. The outcome of this study is also envisioned to provide generic conclusions to the valorization of heterogenic residue products in general.

The study is performed in collaboration with a major shredding company in Sweden. The methodology reflects the Swedish context and consists of two phases. During the initial phase, firstly, the overall shredding industry structure of Sweden is studied to understand the governing regulatory framework, level of competition, and the scale of operation. Secondly, the collaborating company is studied to gain knowledge on technical feasibility of implementing recovery processes, economic, business and market aspects, and implications of national and local legislation, from the shredding company perspective. Empirical methods such as interviews and study of documentation are used in this phase.

During the second phase, detailed material and elemental characterization tests are performed on shredder fine samples. Thereby the distribution of basic elements, metals, heating value, and ash, in shredder fines as well as across different size fractions of shredder fines is established. The results are compared and contrasted against literature values. An extensive survey is also carried out to identify potential users for different materials which are possibly recoverable from shredder fines. Such potential users are then mapped against materials. Leaching tests are also performed to assess the mobility of heavy metals and thereby the potential environmental risk and human toxicity.

As the main contribution of this study, knowledge is developed and synthesized, boundary conditions are set, and principal guidelines of general relevance are drawn in order to facilitate improved valorization of fine granular residue products.

The overall aim of this paper is to draw combined, all-embracing conclusions based on a long-term multidisciplinary research programme on recycling centres in Sweden, focussing on working conditions, environment and system performance. A second aim is to give recommendations for their development of new and existing recycling centres and to discuss implications for the future design and organisation. Several opportunities for improvement of recycling centres were identified, such as design, layout, ease with which users could sort their waste, the work environment, conflicting needs and goals within the industry, and industrialisation. Combining all results from the research, which consisted of different disciplinary aspects, made it possible to analyse and elucidate their interrelations. Waste sorting quality was recognized as the most prominent improvement field in the recycling centre system. The research identified the importance of involving stakeholders with different perspectives when planning a recycling centre in order to get functionality and high performance. Practical proposals of how to plan and build recycling centres are given in a detailed checklist. (C) 2016 Elsevier Ltd. All rights reserved.

Landfill mining has been proposed as an innovative strategy to mitigate environmental risks associated with landfills, to recover secondary raw materials and energy from the deposited waste, and to enable high-valued land uses at the site. The present study quantitatively assesses the importance of specific factors and conditions for the net contribution of landfill mining to global warming using a novel, set-based modeling approach and provides policy recommendations for facilitating the development of projects contributing to global warming mitigation. Building on life-cycle assessment, scenario modeling and sensitivity analysis methods are used to identify critical factors for the climate impact of landfill mining. The net contributions to global warming of the scenarios range from -1550 (saving) to 640 (burden) kg CO(2)e per Mg of excavated waste. Nearly 90% of the results total variation can be explained by changes in four factors, namely the landfill gas management in the reference case (i.e., alternative to mining the landfill), the background energy system, the composition of the excavated waste, and the applied waste-to-energy technology. Based on the analyses, circumstances under which landfill mining should be prioritized or not are identified and sensitive parameters for the climate impact assessment of landfill mining are highlighted.

This article investigates “urks”, i.e., disconnected parts of urban infrastructure that remain in their subsurface location. The reason for engaging in this topic is resource scarcity concerns, as urks contain large amounts of copper and aluminum that could be “mined” for the benefit of the environment.

Our starting point is that there is a certain non–stagnant capacity of waste–like entities such as urks and that their resistance to categorization is crucial to encapsulate their political potential (cf. Hawkins, 2006; Moore, 2012; Hird, 2013). We investigate how this indeterminate capacity has implications in terms of where future trajectories for urk recovery are conceivable.

The study is based on interviews with respondents from the infrastructure and waste sectors in Sweden. By stressing the relationship between urks and their geo–social subsurface surroundings, we use the respondents’ exploratory interpretations of urks to outline a spectrum of issues that should be further discussed for urks to become a matter of concern. The negotiation of these issues, we suggest, can be conceived of as a form of navigation along the perceived fault lines between actors and priorities, and they must be resolved for increased urk recovery to occur.