Hello everyone! I am the ESR responsible for the environmental impact assessment of all Enhanced Landfill Mining solutions and processes involved. More practically speaking, with specific data from all ESRs their projects, I will assess the environmental impact of different scenarios to identify the weak points of the solutions and find the optimal and most sustainable one to apply to our case studies. My aim is to do so by integrating two methodologies for the impact assessment, namely Risk Assessment and Life Cycle Assessment, in order not to underestimate time and spatial- dependent data that can affect results.
I am working in Leuven, a beautiful University-city in Belgium. If you have any questions don’t hesitate to contact me via email!
If you are interested in our research and want to get more information, get in touch with us!
Problem Statement & Objectives
Europe is characterized by around 150 000 – 500 000 landfills, of which 90% are non-sanitary landfills pre-dating the landfill directive 1999/31/EC (Jones et al., 2013). Moreover, in Europe and globally, landfills are still widely used as waste disposal sites, with 23% of MSW still disposed in landfills in 2017 (Eurostat, 2019). The mentioned landfill directive, the waste directive 2008/98/EC and the related amendments 2018/851, 2018/850, and the Circular Economy Action Plan of 2018, have set specific requirements for landfill design and management, landfill closure and aftercare, and waste acceptance criteria. The aim of the directives is to reduce the risks to human health and the environment (HHE) that derive from soil, surface- and ground- water contamination. They also define new waste management targets, to increase waste recycling and promote a shift to circular solutions. In particular, aim of these directives is to increase resource recovery from existing waste streams, minimizing disposal and maximizing the closure of material loops.
In this context, the concepts landfill mining (LFM) and enhanced landfill mining (ELFM) are receiving increasing interest as their goals are fully in line with the abovementioned waste management requirements and targets. In fact, most LFM projects around the world have been conducted for environmental protection, to recover resources from landfilled waste, to recover land and landfill void space, for urbanization purposes, or to comply with closure and aftercare requirements (Calderón Márquez et al., 2019). Consequently, the drivers and objectives of these projects reflect the objectives of the landfill and waste directives. ELFM projects further develop from LFM projects, with the aim of maximizing the resource recovery potential from landfills and to minimize the amount of waste re-landfilled, in compliance with the need to close material loops and reduce the need for primary raw materials.
Multi-criteria assessments are adopted in (E)LFM projects to support stakeholders in the decision making process. Aim of these multi-criteria assessments is to define the feasibility of (E)LFM projects from an environmental, economic and societal perspective. In particular, focus of this research is the assessment of the feasibility of ELFM from an environmental perspective, taking into account the impacts of landfills and the environmental performance of potential waste valorisation routes. However, the environmental impact assessment of waste management systems and, in particular, of landfills and enhanced landfill mining solutions, is often challenging due to the influence of site-specific and time-dependent parameters. This research aims at integrating spatial and temporal information in the environmental assessment of the different scenarios, new waste management technologies and concepts, in the context of ELFM. To achieve the objective, the research is divided in two milestones defined in the NEW MINE project: (i) the development and application of an integrated LCA and RA methodology for the environmental impact assessment of ELFM; (ii) an integrated environmental and techno-economic assessment of ELFM. This second part of the research (milestone 2) was conducted together with ESR 14 from the NEW MINE project.
Methods & Results
The integrated LCA and RA methodology for the environmental impact assessment of ELFM
As environmental protection is one of the main drivers for (E)LFM, the reference scenario (or “business as usual” scenario), which represents the alternative of leaving the landfill as it is, is of great importance in the comparative assessment of ELFM (Danthurebandara, 2015; Laner et al., 2016). However, the definition and environmental impact assessment of landfill impacts is a challenging matter, due to the short- and long- term emission potential, the lack of data, and the influence of site- and time- dependent factors, which make the assessments case specific and highly uncertain. The studies on the environmental performance of disposal sites should therefore consider the influence of the variation of landfill conditions in the estimation of the emission potential and impacts.
Life cycle assessment (LCA) is a commonly used tool for the environmental impact assessment of products and systems, and has extensively been used globally to assess the environmental performance of waste management systems. Indeed, LCA has gained increasing importance to support policy- and decision-making processes. The tool aims at a broad estimation of impacts of products/systems throughout their life cycle. However, emissions are aggregated over space and time, and therefore spatial and temporal information is lost. This leads to high uncertainties related to the potential variation of specific characteristics of the system assessed. To overcome the limitations of LCA for the environmental assessment of ELFM projects, other tools can be integrated in the assessment. In particular, risk assessment includes site- and time- specific information in the estimation of the potential effects of a hazard source on an environmental target and in a specific scenario. It therefore evaluates the exposure to a hazard and the magnitude of the potential effect under specific conditions. The need to include spatial and temporal information in the environmental assessment of ELFM, has encouraged the integration of the tools.
The main factors influencing the environmental performance of landfills were first identified following an extensive literature review and related case study. Multiple scenarios were then built to address the influence of the variation of factors such as waste composition, climatic conditions (flooding or heavy rainfalls) and landfill stability (degradation/failure of containment systems), on the impacts of disposal sites (Sauve & Van Acker, 2020). However, in a comparative LCA, the results of the scenarios can only be compared or used individually to represent the reference scenario. They do not give any information on the probability of occurrence of each scenario, or how they could vary over time, and which of them is most representative of a specific case. These considerations were at the basis of the development of the further integrated LCA and RA approach with the aim to include the probability of occurrence of the scenarios (or events) in the assessment of the landfill impacts and in the definition of the reference case. The overall aim of this novel approach was to address model uncertainties in the assessment of the reference landfill scenario.
The integrated environmental and techno-economic assessment
Site- and time- specific factors are crucial also in the assessment of new waste management concepts and technologies. In fact, processes and technologies need often to be assessed at different levels of technology development. Moreover, other critical performance factors can affect the ELFM scenarios. For example, waste composition of the landfill affects the landfill impacts, as well as the resource recovery potential, and the design of the valorization routes. A summary of the critical performance factors in ELFM projects can be found in (Hernández Parrodi et al., 2019). To be able to address both emerging technologies and emerging design concepts, while considering the variation of the critical factors, a new approach is required that can focus on different types of uncertainties. The ex-ante LCA approach focuses on the assessment of those technologies which are under development or which have been tested at lab and/or pilot scale. Ex-ante LCA uses scenarios to simulate alternative performances of the technologies, and estimating possible ranges of performances depending on the developed scenarios.
For the integrated environmental and economic assessment of ELFM scenarios, conducted in collaboration with ESR 14, the factor based approach introduced by Laner et al. (2016) was used. For each critical factor different datasets are considered depending on the possible ranges of values. Scenarios are built as unique combinations of datasets of all factors. The developed framework further integrated the approach from Laner et al. (2016) to estimate the combined environmental and economic performance of the scenarios and support decision making.
The framework was first applied to plasma gasification. This technology has gained increasing interest in the past years for the combined material and energy recovery potential. However, plasma gasification has always been studied at pilot scale, as very few industrial scale implementations exist. This brings to increased uncertainties when comparing plasma gasification to other commercial thermal valorization technologies, such as incineration. Different types of uncertainties need to be considered, from the lack of commercial data, to the choice of the technology set-up, to the variability of the feedstock and the output products. Therefore, the integrated ex-ante environmental and economic assessment aimed at assessing different technology set-ups, input factors (i.e. variation in feed quality), and output valorization routes in plasma gasification of excavated landfill waste. 7 factors, with 3 datasets each were defined, for a total of 2187 scenarios. For each impact category, results for all scenarios were analyzed as a function of the four main factors influencing the impacts.
Conclusions & Outlook for further work
Overall, both integrated approaches aim at increasing the understanding of landfill impacts and the potential for resource recovery through enhanced landfill mining. The ranges of results obtained by varying critical factors in the studies performed, confirmed the importance of addressing and including spatial and temporal information in the environmental, but also multi-criteria, assessment of waste management concepts and technologies. A further integrated environmental and economic assessment is currently being conducted to assess the influence of technology choices, and other factors, on the performance and feasibility of the whole ELFM process chain. The study integrates the research results of WP1 of the NEW MINE project.
The two integrated methodologies presented in the research could also be used in a same assessment. In fact, the factor-based approach can also be carried out with ranges of values and probability distributions for each parameter. The Monte Carlo simulation would then enable to better address parameter uncertainties,. Therefore, the ranges of values, with the probability distribution and expected value, estimated with the integrated LCA and RA approach for the reference case, could be introduced in the integrated assessment of ELFM.
Additionally, given the different possibilities for the integration of LCA and RA, a further study could also be conducted in conclusion of the research and depending on the time available. A life cycle risk assessment (LCRA) could in fact be performed to assess the potential shift of impacts from the landfill to the ELFM processes.
References
Calderón Márquez, A. J., Cassettari Filho, P. C., Rutkowski, E. W., & de Lima Isaac, R. (2019). Landfill mining as a strategic tool towards global sustainable development. Journal of Cleaner Production, 226, 1102–1115. https://doi.org/10.1016/j.jclepro.2019.04.057
Danthurebandara, M. (2015). Environmental And Economic Performance of Enhanced Landfill Mining.
Hernández Parrodi, J. C., Lucas, H., Gigantino, M., Sauve, G., Esguerra, J. L., Einhäupl, P., … Van Passel, S. (2019). Integration of resource recovery into current waste management through ( enhanced ) landfill mining, 08, 141–156.
Jones, P. T., Geysen, D., Tielemans, Y., Passel, S. Van, Pontikes, Y., Blanpain, B., … Hoekstra, N. (2013). Enhanced Landfill Mining in view of multiple resource recovery: a critical review. Journal of Cleaner Production, 55, 45–55. https://doi.org/10.1016/j.jclepro.2012.05.021
Laner, D., Cencic, O., Svensson, N., & Krook, J. (2016). Quantitative analysis of critical factors for the climate impact of landfill mining. Environmental Science & Technology, 50, 6882–6891. https://doi.org/10.1021/acs.est.6b01275
Sauve, G., & Van Acker, K. (2020). The environmental impacts of municipal solid waste landfills in Europe: A life cycle assessment of proper reference cases to support decision making. Journal of Environmental Management, 261. https://doi.org/10.1016/j.jenvman.2020.110216