Systematic assessment of critical factors for the economic performance of landfill mining in Europe: What drives the economy of landfill mining?

doi:10.1016/j.wasman.2019.07.007

Waste Management

Volume 95, 15 July 2019, Pages 674-686

https://doi.org/10.1016/j.wasman.2019.07.007 Get rights and content

Highlights

•
80% (439,276) of the generated landfill mining scenarios show negative results.
•
System-level factors are critical for the economic feasibility of landfill mining.
•
Main costs are related to treatment and disposal of excavated and processed materials.
•
Main revenues account to avoided landfill management costs – an indirect revenue.
•
Site selection is of key importance from a practical perspective.

Abstract

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.

Introduction

Recent estimates state that Europe hosts several hundred thousands of landfills, of which the majority are old municipal solid waste (MSW) deposits lacking up-to-date sanitary technology (Van Vossen and Prent, 2011, Jones et al., 2018). Although these sites are associated with local to global environmental impacts, land-use restrictions and needs for aftercare and remediation (Johansson et al., 2012, Laner et al., 2012), Europe does not yet have any coherent strategy for their future management (Krook et la., 2018a). In several recent policy initiatives, including European Parliament seminars, policy briefs, and proposals to the amendment of the Landfill Directive, Landfill mining has been suggested as an alternative strategy to address unwanted implications of landfills while simultaneously recovering deposited materials, energy carriers and land resources (Jones et al., 2018). Although such an ambitious approach to landfill management displays a broader societal potential (Damigos et al., 2016, Krook et al., 2012, Jones et al., 2013) visions of a circular economy (European Commission, 2018), it also adds complexity to the implementation and evaluation of such projects (Van Passel et al., 2013, Burlakovs et al., 2017, Johansson et al., 2017). This complexity is further advocated by a general lack of real-life projects validating the feasibility of landfill mining as a mean to facilitate aftercare, reclaim valuable land or landfill void space and bring significant amounts of metals, minerals and energy carriers back to use in society (Krook et al., 2015). In this study, we focus on the essential issue of economic feasibility as the further development of the landfill mining area suffers from a deficit in knowledge about if, and if so, how, such projects could be executed cost-efficiently (Krook et al., 2015, Jones et al., 2018). In essence, our current understanding is restricted to a few case studies assessing the economic feasibility of mining a specific deposit by considering one or a limited number of possible project settings (Frändegård et al., 2013, Zhou et al., 2015, Wagner and Raymond, 2015, Wolfsberger et al., 2016, Winterstetter et al., 2018). Although these assessments provide valuable insights on some current challenges, they fail to address the importance of local landfill settings (Krook et al., 2018b) and only offer limited and case-specific guidance on how different technical set-ups (e.g. Danthurebandara et al., 2015, Kieckhäfer et al., 2017, Winterstetter et al., 2015) and policy and market conditions (Ford et al., 2013, Van Passel et al., 2013, Rosendal, 2015) influence economic performance. In order to facilitate selection of suitable landfills for mining and development of profitable projects, there is thus a need for more generic knowledge that goes beyond individual cases and develops a systemic understanding of the landfill mining economy (Krook et al., 2018b, Laner et al., 2016). This is especially so because the characteristics and importance of different site (e.g. landfill compositions, land values and obligations for aftercare), project (e.g. technologies for sorting, treatment and resource recovery) and system (e.g. policy instruments, regulatory frameworks and market structures) conditions could vary widely between projects and regions (Hogland et al., 2018, Hölzle, 2019).

Apart from a limited applicability of the findings, most previous assessments only provide superficial knowledge of what builds up the economy in the studied projects (Krook et al., 2018b). Typically, the provided results are limited to the net profitability and some main cost and revenue items, while the contributions and interrelations of the underlying conditions and settings that actually build up this performance remain unknown, or at least not reported (Esguerra et al. 2018). In particular, little emphasis has so far been laid upon the interactions of various conditions occurring on the site, project and system levels and how such interaction effects influence the landfill mining economy (cf. Saltelli et al., 2019, Ferretti et al., 2016, Saltelli and Annoni, 2010). Without such fine-grained knowledge, it is difficult to develop a sound understanding about the principles and critical factors of the landfill mining economy.

This study aims to enhance both the applicability and depth of current knowledge regarding what builds up the economic performance of landfill mining in different situations and settings. In doing so, we combine capital budgeting metrics, scenario modeling and global sensitivity analysis to perform a fine-grained assessment of how different site, project and system conditions interplay and jointly contribute to the net present value (NPV) of a large number of landfill mining scenarios. Altogether, these scenarios represent a wide range of possible landfill mining conditions and settings that could be encountered within Europe. In order to illustrate the usefulness of such generic and fine-grained knowledge on the economic principles of landfill mining, we apply it on two specific regional settings as a mean to facilitate selection of suitable landfills for mining and corresponding project set-ups. The spatial and temporal scope of the study involves MSW landfills in Europe with current regional variations in policy and regulatory frameworks, markets conditions and price settings as well as waste management and treatment practices.

In the following section, the selected factors and the methods used to analyze the results are described. In Section 3 results are presented with respect to the NPVs of the whole LFM projects as well as with regard to the present values of selected cost and revenue items. Critical factors are identified and discussed in general, for specific cost and revenue items, and also with respect to two specific regional settings (=archetypes). Finally, in Section 4, major findings on economically favorable and unfavorable conditions for landfill mining are highlighted and recommendations on how to improve the economic feasibility of landfill mining are provided.

Section snippets

Modeling approach

The modeling approach to investigate the importance of different factors for the economy of landfill mining builds on (i) the combination of generic factor datasets to develop a large number of possible landfill mining scenarios, (ii) the economic assessment of each established scenario, and (iii) the analysis of relationships between factor variation and model results using global sensitivity analysis (see Fig. 1). The use of mathematically rigorous procedures to investigate the effect of

Net present value of the whole landfill mining project

The results for the 531,441 landfill mining scenarios show a mean net deficit of −27 Euro/Mg and a large variation of possible outcomes, ranging from −139 to +127 Euro/Mg (Fig. 3). This implies that landfill mining is a challenging business venture with only 19% or 99,821 scenarios resulting in net profits. Most of these profitable scenarios (i.e., 92% or 92,165 scenarios) range within >0 to 50 Euro/Mg, while only few of the scenarios (i.e., 0.1% or 89 scenarios) have profits that are over 100

Conclusions

Through a set-based modeling approach, this study contributes with a systematic understanding of what builds up the economic performance of landfill mining in general and in a wide range of different European situations and settings. In contrast to previous case studies, the present analysis also generates knowledge on how different site, project and system conditions interplay and jointly contribute to the economic performance of landfill mining projects.

In general, landfill mining is a

Acknowledgements

This study has received funding from the European Cooperation for Science and Technology - Mining the European Anthroposphere (COST-Action MINEA, Action No CA15115), the Christian Doppler Laboratory for Anthropogenic Resources, and the European Training Network for Resource Recovery Through Enhanced Landfill Mining (NEW-MINE, Grant Agreement No 721185).

The authors declare no competing financial interests.

References (38)

J. Burlakovs et al.
Paradigms on landfill mining: from dump site scavenging to ecosystem services revitalization
Resour. Conserv. Recycl.
(2017)
M. Danthurebandara et al.
Assessment of environmental and economic feasibility of Enhanced Landfill Mining
Waste Manage.
(2015)
D. Damigos et al.
Monetizing the social benefits of landfill mining: evidence from a Contingent Valuation survey in a rural area in Greece
Waste Manage.
(2016)
F. Ferretti et al.
Trends in sensitivity analysis practice in the last decade
Sci. Total Environ.
(2016)
P. Frändegård et al.
Integrating remediation and resource recovery: on the economic conditions of landfill mining
Waste Manage.
(2015)
I. Hölzle
Analysing material flows of landfill mining in a regional context
J. Clean. Prod.
(2019)
N. Johansson et al.
The institutional capacity for a resource transition—a critical review of Swedish governmental commissions on landfill mining
Environ. Sci. Pol.
(2017)
N. Johansson et al.
Transforming dumps into gold mines. Experiences from Swedish case studies
Environ. Innov. Soc. Transit.
(2012)
P.T. Jones et al.
Enhanced landfill mining in view of multiple resource recovery: a critical review
J. Clean Prod.
(2013)
K. Kieckhäfer et al.
Material flow-based economic assessment of landfill mining processes
Waste Manage.
(2017)

J. Krook et al.

Landfill mining: a critical review of two decades of research

Waste Manage.

(2012)

D. Laner et al.

A review of approaches for the long-term management of municipal solid waste landfills

Waste Manage.

(2012)

A. Saltelli et al.

Why so many published sensitivity analyses are false: a systematic review of sensitivity analysis practices

Environ. Model Softw.

(2019)

A. Saltelli et al.

How to avoid a perfunctory sensitivity analysis

Environ. Model Softw.

(2010)

S. Van Passel et al.

The economics of enhanced landfill mining: Private and societal performance drivers

J. Clean. Prod.

(2013)

T.P. Wagner et al.

Landfill mining: case study of a successful metals recovery project

Waste Manage.

(2015)

A. Winterstetter et al.

Framework for the evaluation of anthropogenic resources: a landfill mining case study – resource or reserve?

Resour. Conserv. Recycl.

(2015)

A. Winterstetter et al.

Decision making guidelines for mining historic landfill sites in Flanders

Waste Manage.

(2018)

C. Zhou et al.

A cost-benefit analysis of landfill mining and material recycling in China

Waste Manage.

(2015)

Cited by (27)

Integrated early-stage environmental and economic assessment of emerging technologies and its applicability to the case of plasma gasification
2023, Journal of Cleaner Production
Citation Excerpt :
The hotspot analysis allows for the partitioning of the total scenario results, both environmental and economic, in terms of the main contributing processes. GSA, specifically variance-based sensitivity analysis in which the choice of alternative data sets of a factor is addressed, is instead used to investigate the criticality, or relative importance, of each factor to the variance of the scenario results (Laner et al., 2016, 2019; Saltelli et al., 2019). This addresses the assessment challenge of systematically handling the uncertainties and identifying the critical factors and their interrelations to understand the wide variations of the results.
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.
Influence of dissolved organic matter and heavy metals on the utilization of soil-like material mined from different types of MSW landfills
2022, Waste Management
Soil-like material (SLM) mined from municipal solid waste (MSW) landfills can be used as nursery cultivation soil, landfill cover, and as a building material. However, SLM utilization is restrained by heavy metal (HM) contents whose speciation and migration are influenced by their dissolved organic matter (DOM) content. Therefore, the properties of aged refuse and the correlation between DOM and HM forms were studied using samples from different types of MSW landfills. The dominant components of aged refuse were SLM (18.80%–83.51%) and plastics (11.17%–65.51%). The moisture, organic matter, and pH ranged from 29.55% to 57.92%, 15.70%–57.68%, and 7.84–8.51, respectively. The Zn content was highest (455.48–1379.27 mg/kg) in the SLM, followed by Cu (96.29–428.90 mg/kg), Cr (49.10–236.21 mg/kg), Pb (53.52–222.71 mg/kg), and Ni (20.92–39.10 mg/kg). The SLM cannot be used for agriculture because the HM contamination exceeds the multiple of 0.07–7.99. Zinc in the acid-soluble state and reducible state had the highest mobility in SLM. However, Cu and Pb, mainly in the oxidizable state, and Cr and Ni, in the oxidizable and residual states, were relatively stable. In the sanitary and simple MSW landfills, the average proportion of protein-like materials decreased from 84.44% to 82.61% and from 65.58% to 55.94%, respectively, as the landfill depth increased. Both the acid-soluble and oxidizable HM states and all forms of Zn in the SLM were significantly positively correlated with tyrosine-like materials (r = 0.58*–0.87**). Protein-like materials may enhance the mobility of HMs.
Pyrolysis and in-line catalytic decomposition of excavated landfill waste to produce carbon nanotubes and hydrogen over Fe- and Ni-based catalysts – Investigation of the catalyst type and process temperature
2022, Chemical Engineering Journal
Undeniably, non-sanitary landfills existing worldwide pose considerable environmental risks related to air, water and soil pollution. Despite that, the landfill mining concept does not spread swiftly around the world. To prevent its fading into oblivion, it is necessary to transform the perception of landfills as waste to seeing them as stocks of valuable materials. Guided by this idea, this novel study investigates the possibility of producing carbon nanotubes (CNTs) and hydrogen-rich gas, materials crucial for our transition towards a more sustainable future, from excavated waste as these. To the best of our knowledge, this is the first study on catalytic pyrolysis of excavated waste. For this purpose, excavated waste was subjected to pyrolysis followed by in-line catalytic decomposition of the produced pyrovapours. The impact of the catalyst type and catalyst bed temperature on the process performance was analysed. Six types of monometallic and bimetallic Ni- and Fe- based catalysts, synthesised using two methods (the sol–gel and the impregnation method), were considered. Three catalyst bed temperatures were taken into account, namely 700 °C, 800 °C, and 900 °C. The results showed that the bimetallic catalyst prepared by using the sol–gel method (FeNi/Al_Sg) outperformed the other analysed catalysts, yielding 9 mmol/g_{sample_daf} of H₂ and 76 mg/g_{sample_daf} of CNTs at 800 °C. The product yields and quality were comparable to those reported in the open literature for homogeneous plastic waste pyrolysis. Eventually, the future research directions were discussed.
Pyrolysis characteristics of excavated waste and generation mechanism of gas products
2022, Journal of Cleaner Production
Citation Excerpt :
Meanwhile, with the development of other disposal technologies, such as incineration and composting, landfills are beginning to seek alternative outlets. However, the challenge needs to seek more land for landfills is not only in China (Zhou et al., 2014), but also in other countries, including the EU (Laner et al., 2019), South Korea (Yi, 2019) and Indonesia (Lokahita et al., 2019). Landfill mining has attracted the interest of researchers as a way to mitigate this challenge.
The mining of landfills provides an important opportunity for waste resource recovery, and the excavated waste with potential useable value has attracted widely attention. In this work, the pyrolysis technique was used to analyze the properties of excavated waste, including the thermal characteristics and kinetics analysis, the distribution of pyrolysis products and the composition of pyrolysis gas. The pyrolysis of excavated waste was performed in a lab-scale reactor in the temperature range of 500–900 °C. The results show that the pyrolysis activation energy of wood and textile was lower than that of plastics and rubber, and it was easier for the pyrolysis reaction to proceed. With the increase of temperature, the pyrolysis gas yield increased and the tar showed a decreasing trend. The plastic has the highest yield of tar with 74.9% and the textile has the highest yield of gas with 61.8% at 900 °C. Wood and rubber tend to produce high yield char with 28.5% and 40.6%, respectively. The pyrolysis gas composition was determined by Micro GC, and the release pattern during pyrolysis was also monitored. High temperature favors the production of H₂/CO, and hinders the CO₂/CH₄. Plastics and rubber were more likely to produce C₂∼C₃ gases than wood and textiles. In addition, the pyrolysis properties of excavated waste and raw waste was compared.
The conceptualization of societal impacts of landfill mining – A system dynamics approach
2021, Journal of Cleaner Production
Citation Excerpt :
The visualizations identified trade-offs as well as dynamic processes that can enable policy- and decision-makers to reinforce positive and avoid negative change, or, if necessary, find the right balance of effects. To do so we recommend a factorial approach based on Laner et al. (2019, 2016). The identified variables have to be combined into sensible factors and filled with data.
Landfill mining (LFM) refers to the excavation and processing of formerly buried waste streams. It offers significant environmental and societal benefits through the mitigation of greenhouse gas emissions or the reduction of long-term waste management costs. LFM’s profitability, however, is still in question and public investment support might be necessary to fully exploit its potential. To enable decision-makers to identify the best solutions for a landfill site, societal impacts of LFM still have to be investigated. Throughout relevant literature, societal impacts of LFM projects have only selectively been studied and it remains unclear if and which benefits justify policy interventions. This paper firstly provides a comprehensive conceptualization of the societal impact of an LFM project and dives into the underlying societal context of this emerging industry. It disentangles formerly identified burdens and benefits by applying a system dynamics approach to LFM research. Based on this approach, four causal loop diagrams are presented showing how LFM is embedded into its societal context, analyzing the composition of the net societal impact of an LFM project, the mechanisms influencing LFM’s public acceptance, and the dynamics of the market acceptance of LFM products. Key variables and leverage points have been identified, such as (i) technology choices influencing avoided impacts from the mitigations of primary resource consumption, since many societal impacts are closely related to environmental impacts, (ii) a timely and broad stakeholder involvement to prevent project opposition, and (iii) the after-use of the mined landfill, generating a major part of the local and regional societal benefits but also creating potential conflicts between stakeholder interests. Key intradimensional trade-offs and potential conflicts were identified in (i) spatial and (ii) temporal risk distribution, (iii) conflicting societal goals of the after-use such as job creations and recreation, as well as (iv) material and energy recuperation. These findings provide important insights for LFM decision-makers and can help to implement this emerging industry in a sustainable way.
Landfill mining in Europe: Assessing the economic potential of value creation from generated combustibles and fines residue
2021, Waste Management
Citation Excerpt :
In addition to the net economic performance, the important underlying factors that build up the economy in different scenarios were systematically identified, which served as the basis to guide the development of strategies towards an improved economy of LFM in Europe. Based on the reference model used by Laner et al. (2019), two modified versions were derived (Modified Models 1 and 2) to account for the different management options for RDF and fines residue. All of the models are described with corresponding economic implications in Table 1.
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 to 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 scenarios 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.

View all citing articles on Scopus

View full text

Systematic assessment of critical factors for the economic performance of landfill mining in Europe: What drives the economy of landfill mining?

Highlights

Abstract

Introduction

Section snippets

Modeling approach

Net present value of the whole landfill mining project

Conclusions

Acknowledgements

Resour. Conserv. Recycl.

Waste Manage.

Waste Manage.

Sci. Total Environ.

Waste Manage.

J. Clean. Prod.

Environ. Sci. Pol.

Environ. Innov. Soc. Transit.

J. Clean Prod.

Waste Manage.

Waste Manage.

Waste Manage.

Environ. Model Softw.

Environ. Model Softw.

J. Clean. Prod.

Waste Manage.

Resour. Conserv. Recycl.

Waste Manage.

Waste Manage.