In which conditions will ELFM be profitable? I will try to answer this as I pursue my research. In its entirety, I am doing a two-fold research. The first part is about the development of a techno-economic assessment model for the quantification and identification of critical economic factors. It should be a flexible model in a way that it is applicable to many cases, accounts a multi-stakeholder perspective, and internalizes monetized externalities (from Paul, see below). The second part is about the development of a multi-criteria assessment method for the identification of both economic (this study) and environmental (from Giovanna) performance trade-offs, which will aid on the selection and further improvement of various landfill mining and landfill management concepts and technologies, including ELFM.
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Problem statement & objectives
The current knowledge about the economics of landfill mining (LFM) is limited and incoherent. Most of the previous studies have focused on case study-specific assessments, which generate case study-specific knowledge. Acknowledging that LFM is still an emerging concept, with sporadic and often pilot-scale projects, it is imperative to guide its future development. This study aims to generate a generic knowledge about the overall economic potential of LFM and to provide guidance for its cost-efficient development.
Methods
Three journal articles are selected to present a coherent summary of research (Table 2).
Table 2: List of papers that are covered in this summary of research.
| Paper | Title | Status |
| 1 | Esguerra, J.L., Krook, J., Svensson, N., Van Passel, S. 2019. Assessing the economic potential of landfill mining: Review and recommendations. In Detritus | published |
| 2 | Laner, D., Esguerra, J.L., Krook, J., Horttanainen, M., Kriipsalu, M., Rosendal, R.M., Stanisavljević, N., 2019. Systematic assessment of critical factors for the economic performance of landfill mining in Europe: What drives the economy of landfill mining? In Waste Management | published |
| 3 | Esguerra, J.L., Laner, D., Krook, Svensson, N. 20XX. Exploring strategies for an improved economic performance of landfill mining in Europe. | draft |
To address the aim, two main methods were used and compared with a systematic literature review and a newly developed method, called the factor-based method (Figure 39).
Systematic literature review was done to determine the current knowledge about the economics of LFM based on previous assessments (Paper 1). A detailed empirical and methodological review was performed, wherein input data and results were collected, knowledge gaps were identified, and important method features were noted. These motivated the development of the factor-based method (Paper 2), which is designed for a generic assessment. It is divided into three parts such as exploratory scenario development to account for multiple LFM project possibilities, physical flow and economic modelling to present the net economic potential, and global sensitivity analysis to determine the constituent critical economic factors. Paper 2 covers the European context as most of the previous studies involved European cases. Additional data was collected by taking advantage of the affiliation with the working group on LFM within the European Cooperation for Science and Technology - Mining the European Anthroposphere (COST-Action MINEA, Action No CA15115). Economic data on processes and price levels of relevance for LFM and landfill management in different European countries (i.e., Austria, Denmark, Estonia, Finland, Serbia, Sweden) were collected. In terms of technological scope, only conventional technologies were considered so far, which are different from the innovative technologies in NEW-MINE, but with readily available data. It was the only way to go forward, as no immediate primary data was expected within the NEW-MINE consortium because our respective researches started at the same time. With the identified economic potential of LFM in Europe as well as the understanding of the generic critical factors that drive the net results, Paper 3 was conceptualized. The same model from Paper 2 was extended to explore strategies for improved LFM economics (i.e. internalization of thermal treatment and valorisation of fines residue), showing the practical application and flexibility of the factor-based method.
Results
Across Papers 1-3, it can be generalized that LFM is indeed a challenging business venture. Figure 40 shows some of the reported net economic potential of LFM that covered wider geographical scope such as national and Europe-wide, which are within the reported range of results from simulated scenarios in Papers 2-3. In comparison with the previous studies, the results from the factor-based method offered more information about the extent of economic potential in European context. Instead of a single value or few distinct values, the economic potential using the factor-based method covers more than half a million LFM scenario possibilities. With internal valorisation of RDF and fines residue, profitable scenarios increased from 20% (106,288 scenarios in Paper 2) to 38% (201,947 scenarios in Paper 3).
Extending the analysis towards a granular understanding, constituent critical economic factors are presented in terms of main cost and revenue items. There are notable discrepancies from the main cost and main revenue items as provided by the two methods. From Paper 1, the main cost and revenue items only serve as hints with respect to a more generic understanding. Considering the differences in scope and modelling choices, some studies excluded thermal treatment, avoided aftercare, value of landfill void space, and/or value of land. Moreover, as most studies are case study-specific, site-level (i.e. waste composition, landfill size, etc.), and system-level (i.e. disposal tax, price settings, etc.) variations were commonly unaccounted for, leaving out their possibility of being the main drivers. Consequently, there is insufficient knowledge about the overall economic potential of LFM that can be derived from simple synthesis of the main findings in Paper 1, compared to a systematic generic modelling approach using the factor–based method in Papers 2-3. For instance, avoided aftercare does not show up as an important (indirect) revenue item, but in Paper 2, it shows otherwise. While for the main cost item, it is the treatment and disposal of residual materials. Both of these main cost and revenue items are dependent on the incumbent policy settings in Europe, which are clearly not favourable for doing LFM.
In essence, system-level conditions set the overarching boundary requirements that guide site selection and project development. In tandem with granular information derived from global sensitivity analysis, specific strategies for cost-efficient LFM can be determined. In Figure 41 for example, regional archetype with high income and high waste management standards is simulated, showing that minimization of treatment costs is more important than maximization of material revenues. In addition, focus on landfills with low mass-to-area ratios are preferred for higher revenues accounted for aftercare and land revenue. The opposite is preferred for regional archetype with low income and low waste management standards. In this case, maximization of material revenues is preferred rather than minimization of already low treatment costs. It follows that site selection should focus on large landfills that are rich in valorisable materials.
Conclusion & outlook for further work
LFM is a challenging business venture but still, it can serve as a cost-efficient landfill management alternative in European context. Through the factor-based method, several generic knowledge contributions were systematically derived. In general, LFM should aim for multiple benefits such as materials, land and avoided landfill management. Such could be further maximized with adapted market (i.e. market acceptance, market price) and policy conditions (i.e. processing and disposal tax, subsidies) to increase the revenues from valorised materials and decrease the costs from treatment and disposal of process residues. The importance of policy and market conditions define the LFM project prioritization in terms of site selection and subsequent design of project set-up.
Further research expands the scope in terms of the sustainability perspective by including the environmental aspect, and the emerging character of LFM by including advanced technologies as in the NEW-MINE consortium. In essence, it is anticipated to shed light on relevant LFM queries such as Does the advancement in technologies contribute to better sustainability potential of LFM? and How can we guide further development of these LFM technologies?