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.

No abstract

Environmental input-output analyses (EIOA) can be a useful decision support tool at the subnational level, due to 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 validation of the approaches, we assessed the magnitude of deviations between the initial and final estimates and analysed 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

No abstract

In this paper, material flows and resource potentials for plastics at a national level in Denmark are mapped using an Environmentally Extended Multiregional Input-Output (EE-MRIO) database. EE-MRIO offers an operative improvement to current and prevalent methods for assessing the industrial and societal metabolism of resources, including plastics. The Exiobase is applied to map (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 economy in Denmark with a focus on recycling. Furthermore, it elaborates how and why this method for performing Mass Flow Analysis (MFA) differs from mainstream assessments of material flows and from default uses of national statistical data. Overall, the results are that Denmark has a total supply of ≈551 kilotonnes (Kt) of plastics, out of which ≈522 Kt are used domestically and ≈168 Kt of plastic waste are generated annually. Out of the yearly amount of plastic waste, ≈50% is incinerated and 26% is recycled. These results indicate significant potentials for applying circular economy strategies and 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 in cross-sectoral collaboration.