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Environmental input–output analyses can be a useful decision support tool at the subnational level, because of its ability to capture economic and environmental impacts at other geographical levels. Yet, such analyses are hindered by the lack of subnational IO tables. Furthermore, the lack of physical product and waste flows in what is known as a “hybrid” table prevents a range of consumption-based and circular-economy-type analyses. We demonstrate the development of a multiregional hybrid IOT (MRHIOT) along with environmental extensions at the subnational level and exemplify it for the case of Belgium. The development procedure discloses a novel approach of combining national hybrid tables, subnational monetary tables, and physical survey-based data. Such a combination builds upon a partial-survey approach that includes a range of techniques for initial estimation and reconciliation within a balancing procedure. For the validationof the approaches, we assessed the magnitude of deviations between the initial and final estimates and analyzed the uncertainties inherent to each initial estimation procedure. Subsequently, we conducted a consumption-based analysis where we assessed the carbon footprint (CF) at the subnational level and highlighted the CF inherent to the interregional linkages. This study provides methodological and application-based contributions to the discussion on the relevance of hybrid subnational tables and analyses compared to national ones. The proposed approach could be replicable to some extent for further developing subnational MRHIOT. The study is expected to fostermore research toward the development of further subnational MRHIOT as well as its associated wide-ranging applications., iiTSE, SCOPUS: ar.j, info:eu-repo/semantics/published

iiTSE, info:eu-repo/semantics/published

iiTSE, info:eu-repo/semantics/published

iiTSE, info:eu-repo/semantics/published

We live on a planet with finite natural resources and human activities creating pressures on the environment. The Circular Economy (CE) is gaining momentum as a means to cope with the environmental pressures from human activities. One of the main elements of CE is to maintainproducts and materials at their highest application level as long as possible, while minimising the environmental impact. Hence, a CE implies to minimising the natural resource consumption, reducing waste generation, rethinking waste management (WM), reinforcing the recycling andreuse of products and materials, in tandem with reducing emissions. Measuring is key to take the first steps for a transition towards a CE. This includes the quantification of the environmental pressures of human activities in a CE context as well as the quantification of the degree ofcircularity, i.e. how much materials are recovered from waste. Several tools and methods exist to measure and monitor how circular an economy is, but it is the input-output (IO) model that is of interest in this thesis. The general objective of this thesis is twofold: 1) develop a suitable IO model and 2) demonstrate the applicability and limits of that model. For the second point several applications (or tests) of the model are carried out with different types of analyses. The focus on the subnational level is justified by the Belgian legal and policy context in which WM and CE are mostly regional competences. This thesis has developed the first multiregional hybrid input-output (MRHIO) representing theBelgian subnational level for 2011. This development constitutes the major methodological contribution of this thesis. The critical scientific literature review that was carried out in this thesis showed that the MRHIO model is conceptually the most suitable model for WM and CE analyses at the macro scale. The developed model has been applied to analyse the environmental pressures induced by the regional household demand. Three main applicat, Option Gestion de l’environnement et d’aménagement du territoire du Doctorat en Sciences, iiTSE, info:eu-repo/semantics/nonPublished

2015-PRFB-3a, info:eu-repo/semantics/nonPublished

In this paper, material flows and resource potentials for plastics at a national level inDenmark are mapped using an Environmentally Extended Multiregional Input-Output (EE-MRIO)database. EE-MRIO offers an operative improvement to current and prevalent methods for assessingthe industrial and societal metabolism of resources, including plastics. The Exiobase is applied tomap (1) the major sources, (2) calculate the total supply, (3) uses of plastics and waste generation,and (4) end of life pathways in order to indicate the potentials of plastics in the circular economyin Denmark with a focus on recycling. Furthermore, it elaborates how and why this method forperforming Mass Flow Analysis (MFA) differs from mainstream assessments of material flows andfrom default uses of national statistical data. Overall, the results are that Denmark has a total supplyof ≈551 kilotonnes (Kt) of plastics, out of which ≈522 Kt are used domestically and ≈168 Kt of plasticwaste are generated annually. Out of the yearly amount of plastic waste, ≈50% is incinerated and26% is recycled. These results indicate significant potentials for applying circular economy strategiesand identify relevant sectors for closing the plastic loops. However, other initiatives are necessary,such as improvements in product design strategies, in the collection and sorting systems as well as incross-sectoral collaboration., SCOPUS: ar.j, info:eu-repo/semantics/published

Biomass, biobased materials and food waste are considered priority areas for Europe's transition towards a circular economy (CE). Waste management is a central activity for this transition and offers multiple CE implementation options which should be evaluated from environmental perspective. The purpose of this work was to analyze the environmental consequences when redirecting biowaste flows from conventional to more circular management systems and to identify the CE option with the best environmental performance. We were particularly interested in studying the combined management of green and food waste, analyzing the challenges when introducing separate collection and different treatment processes, and evaluating the substitution potential for by-products. To determine environmental impacts, we performed a life cycle assessment (LCA) based on local data. Following the purpose analyzing a change in the system, we applied a consequential LCA and compared impacts from processes that are replaced with impacts from alternative management options such as co-composting, anaerobic digestion (AD) and decentralized composting. The LCA results show clear advantages for impacts on ecosystems and resource use for the local AD system with separate combined collection. The decentralized system shows reductions in resource use, whereas the industrial co-composting system has higher or similar impacts than the baseline scenario. We conclude that local systems with combined food and green waste management can show benefits if process emissions are properly managed and if by-products are used in applications with high substitution potentials. However, a change towards a CE does not necessarily result in environmental benefits. Our research highlights the complexity of biowaste systems and proposes a novel combination of local data, databases and models to handle this issue. With this research we are further contributing to the understanding of the combined management of food and gr, SCOPUS: ar.j, iiTSE, info:eu-repo/semantics/published

We analyze 78 case studies that applied an input-output (IO) model for waste management analyses. We categorize all IO models into four types (waste extended IO (WEIO), waste IO (WIO), physical IO (PIO) and hybrid IO (HIO)). We then define each model within a waste analysis framework, and carry out a bibliometric analysis. Our comparative analysis is twofold. Firstly, to compare the models conceptually, we analyze and discuss three characteristics of the models – the units of intersectoral flows, the modelling of waste and the relation with mass balance principle. Secondly, we analyze and discuss six criteria pertaining to the functionalities of the models, – the waste generation accounting, the purpose of the modelling, the geographical scale, the temporal dimension, the coupling of the IO models with other methods and the level of details of waste treatment sectors and waste types. Our findings are fourfold. First, there is increasing interest in assessing waste management policies with IO models; WIO models are the most applied ones, followed by WEIO models; PIO models are the least widely applied. Second, WIO models have the most mature analytical framework, and HIO models are conceptually the most powerful. Third, there is no cause-effect link between the conceptual characteristics and the functionalities of IO models. The IO models have been widely used for diverse applications in waste management at economy-wide level, but there is potential for several other applications. Fourth, the main limitation of all models is data related: future efforts should include more effective monitoring and collection of physical IO data and waste data, as well as the development of methods for consistent data mining., SCOPUS: re.j, iiTSE, info:eu-repo/semantics/published

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To enable cities to become more circular, i.e. close material cycles, decision-makers need detailed data about the production and treatment of waste. At city level, conventional statistics on waste are often incomplete or lack detail. Waste input-output accounting offers an alternative, using waste supply and use tables to create detailed inventories of economy-wide flows of waste. In this study we develop such tables for the city-region of Brussels (Belgium) and use them to analyse the urban waste metabolism in terms of waste flows, waste production intensity and waste treatment performance. The waste flow analysis revealed: the amount of collected waste; the proportion contributed by individual sectors; the material composition of waste flows and the location of treatment. Currently, around 50% of the 1.5 million tons of waste collected in Brussels is treated in local facilities. However, less than 1% of the collected waste is used in a way that closes material cycles within city limits. The waste performance analysis reveals that the construction sector had the highest waste production intensity and the household sector the highest incineration intensity. In terms of waste prevention and local valorisation potential, we identified flows and sectors for future targeting, one of the most promising being food waste. We conclude that the urban context can restrict the local valorisation of waste flows, thus we see the role of cities such as Brussels in a circular economy as mainly contributing to the closing of material cycles at national or even global level., SCOPUS: ar.j, iiTSE, info:eu-repo/semantics/published

The development of material flow accounting and environmental impact assessment models to evaluate production and consumption activities is a challenge at the regional level due to the restricted availability of regional data, especially waste data. However, the regional context is often required, for example for the development and evaluation of regional circular economy programs for which waste generation and valorization plays a key role. In this research, we present an approach to develop regional waste supply and use tables based on regional waste statistics and national input-output tables. The results show that this method is well suited to quantify waste generation from households, but it is more difficult to implement for waste generation from urban economic activities where production and waste intensities deviate from the national average. The comparison between regional statistics and calculated waste extensions indicates that regional statistics could underestimate certain waste flows which are important for the circular economy context, such as metal, glass and inert waste. Such uncertainties can be reduced by developing more complete and reliable bottom-up waste data and physical/hybrid tables where full mass balance checks can be carried out. However, the results demonstrate that it is possible to develop a coherent framework at city-regional scale that integrates material/waste flow accounting and impact assessment of production and consumption., SCOPUS: cp.p, iiTSE, info:eu-repo/semantics/published

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