Economic and environmental impact assessments are increasingly being adopted in the design and implementation of emerging systems. However, their emerging nature leads to several assessment challenges that need to be addressed to ensure the validity and usefulness of results in understanding their potential performance and supporting their development. There is the need to (i) account for spatial and temporal variability to allow a broader perspective at an early stage of development; (ii) handle uncertainties to systematically identify the critical factors and their interrelations that drive the results; (iii) integrate environmental and economic results to support sound decision-making based on two sustainability aspects. To address these assessment challenges, this study presents an alternative approach with the following corresponding features: (i) multiple scenario development to conduct an exploratory assessment of the systems under varying conditions and settings, (ii) global sensitivity analysis to identify the main critical factors and their interrelations, and (iii) trade-off and eco-efficiency analysis to integrate the economic and environmental results. The integrated approach is applied to a case study on plasma gasification for solid waste management. The results of the study highlight how the approach allows the identification of the dynamic relations between project settings and surrounding conditions. For example, the choice of gasifying agent largely depends on the background energy system, which dictates the impacts of the process energy requirement and the savings from the substituted energy of the syngas output. Based on these findings, the usefulness and validity of the proposed integrated approach are discussed in terms of how the key assessment challenges are addressed and how it can provide guidance for the development of emerging systems.

The single-use function of plastic packaging generates a continuously increasing input to the waste management system leading to sustainability challenges. In response, several management strategies along the plastic value chain are proposed including improvements on product design, source-separation, mechanical and optical sorting, and further downstream material recycling. However, in some countries like Sweden, these strategies are often implemented in isolation without considering their combination effects on the performance of the entire plastic value chain. Moreover, the corresponding assessments of these strategies are often limited to material efficiency (i.e., recycling rate) thus overlooking the potential trade-offs with environmental performance. Hence, this study aims to assess the combination effects of different management strategies for plastic packaging in Sweden in terms of both material and environmental dimensions. Over 700 scenarios involving different combinations of management strategies were modeled and assessed through life cycle assessment. The results show that upstream strategies such us polymer restriction especially for food packaging (i.e., limiting to polyethylene terephthalate and polypropylene) lead to higher recycling rates and better environmental performance. In contrast, further downstream material recycling strategies show more apparent trade-offs, especially between recycling rates and environmental impacts related to toxicity. Recommendations for the combinations of management strategies for plastic packaging, which can increase recycling rates and reduce environmental impacts, are presented and discussed. 

Landfill mining är en strategi som kombinerar sanering och resursutvinning av avfallsdeponier. Detta för att minimera de negativa miljö- och hälsoeffekter som dessa platser orsakar och samtidigt återvinna de värdefulla material och energiresurser som tidigare deponerats. Sådana projekt kan även genomföras för att frigöra mark för mer hållbara användningsområden eller för att skapa nytt utrymme för att deponera framtida avfallsflöden. Även om tidigare forskning har visat att landfill mining kan utgöra en viktig råmaterial- och miljöstrategi saknas fortfarande kunskap och erfarenhet om hur sådana projekt kan genomföras på ett lönsamt och miljömässigt motiverat sätt.  

Den här avhandlingens mål är att analysera den ekonomiska prestandan och miljöpåverkan av landfill mining i ett europeiskt perspektiv och hur utfallet av sådana projekt i sin tur beror på olika plats-, projekt- och systemvillkor. Baserat på dessa studier utvecklas sedan strategier för implementering genom att tillämpa kunskapen om hur valet av deponi och projektupplägg påverkar prestandan av sådana projekt under olika policy- och marknadsvillkor.  

Forskningen innefattar tillämpning av en miljösystemanalytisk metod som utvecklats speciellt för att analysera vilka plats-, projekt- och systemvillkor som tillsammans avgör den ekonomiska och miljömässiga prestandan av landfill mining i olika situationer och sammanhang. För att besvara målet med avhandlingen har ett stort antal scenarier analyserats, vilka täcker in den variation som kan förväntas vad gäller olika plats-, projekt- och systemvillkor för landfill mining i Europa.

Resultaten visar på en övergripande nivå att landfill mining presterar bättre med avseende på miljöprestanda än lönsamhet. Ca 50% av de analyserade scenarierna genererar klimatvinster medan endast 20% är fördelaktiga ur ett ekonomiskt perspektiv. Det finns emellertid en stor potential att förbättra både den ekonomiska och miljömässiga prestandan genom att mer noggrant välja och koordinera valet av deponi och projektupplägg. En central slutsats från dessa analyser är att de omkringliggande, och till stor del regionalt betingade, systemvillkoren har en stor inverkan på utfallet av sådana projekt. I många fall inverkar dessa rådande policy och marknadsvillkor och bakgrundsystem för material och energiproduktion också negativt på den miljömässiga och ekonomiska prestandan. För att skapa bättre förutsättningar för landfill mining är det därför ofta nödvändigt att förändra och anpassa dessa systemvillkor. I avhandlingen analyseras potentialen av flera potentiella styrmedel för att stimulera och förbättra de ekonomiska villkoren för projekt som genererar tydliga klimatvinster. Sammantaget visar denna avhandling på hur miljösystemanalys av nya koncept som landfill mining kan användas som ett lärandeverktyg för att vägleda fortsatt kunskaps- och teknikutveckling inom området och ta fram strategier för implementering.

Previous studies showed that resources recovery through landfill mining (LFM) is generally challenging from an economic perspective and that a large share of project costs is related to the external treatment and disposal of bulk process wastes such as combustibles and fines residue. Building on these analyses, this study aims to explore the potential for improving the economy of LFM in Europe by creating value from these bulk process wastes. Specifically, the combustibles are treated through internal incineration with subsequent energy recovery, while fines residue is utilized as construction aggregates. These explored possibilities are investigated considering other varying factors at the site, project, and system levels that cover possible LFM project settings in Europe. A set-based modelling approach is adapted generate multiple LFM scenarios (531,441) and investigate the underlying critical factors that drive the economy of LFM through global sensitivity analysis. Results show that an additional 16% of LFM sce-narios become net profitable, mainly driven by fines residue utilization. Avoided costs for re-landfilling are higher than the revenues from construction aggregates. By contrast, internal incineration is driven by the revenues from recovered energy rather than the avoided gate fee, which is substituted by the costs for building and operating own plants. Overall, the policy conditions remain critical to further improve the economy of LFM in Europe. Recommendations include an inclusive quality standard that relies on pollutant leachability rather than total concentration for higher-value application of fines residue and incentive rather than taxation for producing renewable energy from the combustibles. (c) 2021 Elsevier Ltd. All rights reserved.

Landfill mining (LFM) is an alternative strategy to manage landfills that integrates remediation with secondary resource recovery. At present, LFM remains as an emerging concept with a few pilot-scale project implementations, which presents challenges when assessing its economic performance. These challenges include large knowledge deficits about the individual processes along the LFM process chain, lack of know-how in terms of project implementation and economic drivers, and limited applicability of results to specific case studies. Based on how these challenges were addressed, this thesis aims to analyze the usefulness and validity of different economic assessments of LFM towards the provision of better support for decision-making and in-depth learning for the development of cost-efficient projects. Different studies were analyzed including the previous studies through a systematic literature review and the factor-based method that is developed in this thesis. Four categories of economic assessment approaches were derived in terms of the study object that is about either an individual LFM project (case-study specific) or multiple LFM projects in a region (generic); and in terms of the extent of analysis that is about either the identification of the net economic potential (decision-oriented) or extended towards an in-depth learning of what builds up such result (learning-oriented). Across the different approaches, most of the previous studies have questionable usefulness and validity. The unaddressed parametric uncertainties exclude the influence of using inherently uncertain input data due to large knowledge deficits. While the narrowly accounted scenario uncertainties limits the fact that LFM can be done in various ways and settings in terms of site selection, project set-up and regulatory and market conditions. In essence, these uncertainties propagate from case-study specific to generic study object. From decision-oriented to learning-oriented studies, the identification of what builds up the result are unsystematically determined that raises issues on their subsequent recommendations for improvement based on superficially derived economic drivers. The factor-based method, with exploratory scenario development and global sensitivity analysis, is presented as an approach to performing generic and learning-oriented studies. As for general recommendations, applied research is needed to aid large knowledge deficits, methodological rigor is needed to account for uncertainties and systematically identify economic drivers, and learningoriented assessment is needed to facilitate future development of LFM. This thesis highlights the important role of economic assessments, which is not only limited for the assessment of economic potential but also for learning and guiding the development of emerging concepts such as LFM.

As landfill mining (LFM) gains public attention, systematic assessment of its economic potential is deemed necessary. The aim of this review is to critically analyze the usefulness and validity of previous economic assessments of LFM. Following the life cycle costing (LCC) framework, (i) the employed methods based on goal and scope, technical parameters and data inventory, and modelling choices were contrasted with respect to (ii) the synthesized main findings based on net profitability and economic performance drivers. Results showed that the selected studies (n=15) are mostly case study-specific and concluded that LFM has a weak economic potential, hinting at the importance of favorable market and regulation settings. However, several method issues are apparent as costs and revenues are accounted at different levels of aggregation, scope and scale-from process to sub-process level, from private to societal economics, and from laboratory to pilot-scale, respectively. Moreover, despite the inherent large uncertainties, more than half of the studies did not perform any uncertainty or sensitivity analyses posing validity issues. Consequently, this also limits the usefulness of results as individual case studies and as a collective, towards a generic understanding of LFM economics. Irrespective of case study-specific or generic aims, this review recommends that future assessments should be learning-oriented. That is, uncovering granular information about what builds up the net profitability of LFM, to be able to systematically determine promising paths for the development of cost-efficient projects.

Europe has somewhere between 150,000 and 500,000 landfill sites, with an estimated 90% of them being “non-sanitary” landfills, predating the EU Landfill Directive of1999/31/EC. These older landfills tend to be filled with municipal solid waste andoften lack any environmental protection technology. “Doing nothing”, state-of-theart aftercare or remediating them depends largely on technical, societal and economic conditions which vary between countries. Beside “doing nothing” and landfill aftercare, there are different scenarios in landfill mining, from re-landfilling thewaste into “sanitary landfills” to seizing the opportunity for a combined resource-recovery and remediation strategy. This review article addresses present and futureissues and potential opportunities for landfill mining as an embedded strategy incurrent waste management systems through a multi-disciplinary approach. In particular, three general landfill mining strategies are addressed with varying extentsof resource recovery. These are discussed in relation to the main targets of landfill mining: (i) reduction of the landfill volume (technical), (ii) reduction of risks andimpacts (environmental) and (iii) increase in resource recovery and overall profitability (economic). Geophysical methods could be used to determine the characteristics of the landfilled waste and subsurface structures without the need of aninvasive exploration, which could greatly reduce exploration costs and time, aswell as be useful to develop a procedure to either discard or select the most appropriate sites for (E)LFM. Material and energy recovery from landfilled waste canbe achieved through mechanical processing coupled with thermochemical valorization technologies and residues upcycling techniques. Gasification could enablethe upcycling of residues after thermal treatment into a new range of eco-friendlyconstruction materials based on inorganic polymers and glass-ceramics. The multi-criteria assessment is directly influenced by waste- and technology related factors, which together with site-specific conditions, market and regulatory aspects,influence the environmental, economic and societal impacts of (E)LFM projects.

Landfill mining (LFM) is a strategy to mitigate environmental impacts associated with landfills, while simultaneously recovering dormant materials, energy carriers, and land resources. Although several case study assessments on the economy of LFM exist, a broader understanding of the driving factors is still lacking. This study aims at identifying generically important factors for the economy of LFM in Europe and understanding their role in developing economically feasible projects in view of different site, project and system-level conditions. Therefore, a set-based modeling approach is used to establish a large number (531,441) of LFM scenarios, evaluate their economic performance in terms of net present value (NPV), and analyze the relationships between input factors and economic outcome via global sensitivity analysis. The scenario results range from -139 Euro to +127 Euro/Mg of excavated waste, with 80% of the scenarios having negative NPVs. Variations in the costs for waste treatment and disposal and the avoided cost of alternative landfill management (i.e. if the landfill was not mined) have the strongest effect on the scenario NPVs, which illustrates the critical role of system level factors for LFM economy and the potential of policy intervention to incentivize LFM. Consequently, system conditions should guide site selection and project development, which is exemplified in the study for two extreme regional archetypes in terms of income and waste management standard. Future work should further explore the developed model to provide decision support on LFM strategies in consideration of alternative purposes, stakeholders, and objectives. (C) 2019 Elsevier Ltd. All rights reserved.

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.