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Abstract Given the complexity of circular economy implementation, the literature is missing a strategic standpoint. This paper investigates the taxonomy of circular economy implementation strategies at the managerial level by linking it to strategy literature. The taxonomy was developed by using standard k-mean clustering method that incorporates 391 Cradle-to-Cradle product scorecards of 187 companies from 10 different industries. The analysis was based on the relative importance assigned to each competitive capability that defines the circular economy; namely, material health, material reutilization, renewable energy, water stewardship, and social fairness. Three distinct clusters of circular economy implementation strategy groups were observed: (i) founding (recyclers), (ii) development (all-decent circulars), and (iii) maturity (toxicity fighters). All clusters have been present in various industries, although there is an industry effect. The results indicate that each cluster has a different strategy. The results obtained contradict the general assumption and expectation of simultaneous improvement at all circular economy dimensions. Our research contributes to the theoretical understanding of circular economy implementation by providing a taxonomy of strategies. It contributes to the strategy literature by suggesting that the maturity degree of a competitive capability may determine the implementation strategy. For practice, the study presents a road-map for managers to reach higher degrees of circularity. Highlights • Links circular economy literature to strategy literature. • Employs hierarchical k-means clustering method to analyze 391 Cradle-to-Cradle products. • Proposes a taxonomy with three degrees of circularity adopting different strategies. • Suggests that the maturity degree of a competitive capability may determine the strategy. • Contributes to the theoretical understanding of circular economy implementation in the manufacturing industry. [ABSTRACT FROM AUTHOR]

Abstract Combining sustainable consumption with the circular economy concept could help tackle challenges, such as resource scarcity and climate change by reducing resource throughput and increasing cycling of products and materials within the economic system, thereby reducing emissions and virgin material use. To achieve sustainable consumption in a circular economy production and consumption practices need to change. Business models can potentially influence both practices as it defines how a company conducts business and shapes the company-consumer relationship. This paper developed future business models for sustainable consumption through two rounds of semi-structured interviews with experts from academia, industry, and policy. During the first interview round, four business model elements that are important for sustainable consumption were identified: Resource strategy, Revenue model, Consumer effort, and Objective to (decrease/increase) consumption level. Based on these elements, we developed a comprehensive business model framework. Using this framework, experts envisioned future business models for sustainable consumption of clothing during the second interview round. The findings of this study suggest that the most promising business models for sustainable consumption are those that reduce overall consumption levels and consumer effort. Further, we found that a diverse range of business models in the market can potentially enable different customer segments to consume sustainably. [ABSTRACT FROM AUTHOR]

Abstract The development of renewable energies was impressive in recent years on a global scale. This produced changes regarding production processes, citizens' habits, industrial investments and consumer decisions. In this context, the policy-maker played a crucial role. The subsidies are able to determine the development of a specific market. Biogas market spread globally, while biomethane market concentrated in some territories. Green gas can be used as vehicle fuel or injected into the gas grid but also burnt for co-generation. The present work proposes a techno-economic analysis for an existing biogas plant. In particular, the analysis was focused on the comparison between two possible strategic plans, in order to establish which one was the best in terms of profitability: the first one is the expansion of the plant to upgrade biogas to biomethane, whereas the second one is to continue the production of biogas as planned when the plant was constructed. The Discounted Cash Flow (DCF) method was proposed in this paper, and the Net Present Value (NPV) is the main index used. One 250 m3/h biomethane plant located in Italy using pressure swing adsorption (PSA) technique is analysed. The results demonstrated the positive environmental impact deriving from the use of zeolites synthesized from spent fly ash and the profitability is verified only in some scenarios. However, they are limited only to the construction of new biomethane plants, while the upgrading of existing biogas plants are always unprofitable. A Break-Even Point (BEP) analysis quantifies the value of subsidies of biogas and biomethane by which the profitability could be reached. Biomethane can contribute to the development of circular economy models, while the sustainability targets are achieved only in some scenarios. [ABSTRACT FROM AUTHOR]

Abstract Considerable efforts are undertaken to make the transition towards a more Circular Economy (CE). At the same time there is no generally accepted monitoring framework. Rather, what exists is a large variety of measurement approaches that aim to assess the progress. The different assessment methodologies cover different and varied aspects of the CE transition and are seemingly unrelated to each other. Therefore, the main contribution of this paper is the provision of a structured picture of the current stock of CE metrics, including the identification of methodology clusters and the related assessment perspectives. The method of Multiple Correspondence Analysis (MCA) was used to assess 63 CE metrics and 24 features relevant to CE, such as recycling efficiency, longevity and stock availability. The MCA was used to assess how the different CE features are associated to each other and how they are related with each of the 63 metrics. Also, it was determined which combinations of CE features are frequently assessed together. The analysis identified three main clusters of metrics, (1) a resource-efficiency cluster, (2) a materials stocks and flows cluster, (3) a product-centric cluster. The results of the analysis show poor integration of resource-efficiency and product-centric perspectives, while the product-centric and system-dynamic perspectives are least frequently assessed. Further, the analysis provides the most prevailing CE perspectives and it is shown that only a few CE metrics assess CE features that are related to the maintenance of value. The MCA provides a guidance for further metrics development, as it identifies areas with a lower metrics density. For a detailed analysis, a standardized visualisation framework for CE metrics is derived, which allows to compare individual metrics in a simple and illustrative way. The goal of the visualisation framework is to provide guidance for (i) the integration of the most complementary CE metrics and (ii) facilitate further metrics development. Highlights • Structuring of 63 circular economy (CE) metrics along 24 identified CE elements. • Identification of three main clusters of CE metrics and their typical CE elements. • Visualisation framework for a detailed assessment and design of CE metrics. • Identification of most prevailing CE perspectives and their associations. • Guidance for case-specific and complementary selection of CE metrics. [ABSTRACT FROM AUTHOR]

Abstract European countries are attempting to promote sustainable development by transitioning from a linear to a circular economy, where waste is to be prevented and recycling activities are promoted. This paper studies the implementation of Extended Producer Responsibility (EPR) policies for the packaging waste in two later European adopter countries of waste management policies: Portugal and Spain. The main goal is to evaluate whether EPR policies in both countries have achieved their basic two goals: 1) reduction of waste, and 2) increase recycling activities. Two case-studies were built based on interviews made to main waste management stakeholders. The analysis shows that the implementation of the EPR policies have had a positive impact throughout the years in both countries. Regarding the waste reduction goal, the systems have still not been completely able to detach packaging waste production from economic growth, but they have been able to promote material usage reduction directly through the Green dot fee model adopted. Regarding the increasing of recycling activities, both countries have been able to increase such rates throughout the years, in the direction of the EU targets. Highlights • EPR policies implemented in Spain and Portugal are evaluated. • EPR policies have contributed to packaging waste reduction and increase recycling activities. • EPR policies are having a positive impact throughout the years in both countries. • Some challenges still need to be faced: eco-design promotion and packaging life-cycle. [ABSTRACT FROM AUTHOR]

Abstract For the widespread establishment of a circular economy, the acceptance of used products among consumers is a prerequisite. This paper investigates the customer experience of product–service systems related to used products (PSSuP), such as renting, remanufacturing, and second-hand models, and aims to point out the offering characteristics that effect customer response and customer engagement. This study was conducted by means of a content analysis-based literature review of 69 empirical PSSuP studies. A frequency analysis of the categories that determine customer experience creation was conducted, as well as a contingency analysis to reveal the interrelationship between these categories. On this basis, the different PSSuP types were compared, and four strategic orientations of customer experience creation in PSSuP are pointed out: price, confidence, convenience, and delight orientation. For each of these strategic orientations, supportive PSSuP offering characteristics are specified. Building on the findings of this study, theoretical and managerial implications for product–service systems marketing are pointed out, and the need for research on the role of information and communication technology as an enabler of customer experience creation in PSSuP is highlighted. [ABSTRACT FROM AUTHOR]

Abstract Improving the eco-efficiency of the circular economy system in mining areas has been recognized as the most effective way to reduce the greenhouse effect and achieve sustainable development. Based on the emergy theory and on data envelopment analysis (DEA), this paper adopts the SBM-Undesirable model to evaluate the eco-efficiency of the circular economy system in China's largest coal mining area, Shanxi Province, during the period 2006–2015. Emergy flow indices are treated as input and output indices. Eco-efficiency is factorized into economic efficiency and environmental efficiency. The potential for improvement of the circular economy system is analyzed based on input redundancy and output deficiency. The results for the period 2006–2015 indicate the following: (1) both the input and the output of the circular system increase during this period; (2) the increased input relies on mostly imported emergy, and the increase in waste emergy is lower than the exported emergy; (3) eco-efficiency is invalid except for 2011 and 2012 and exhibits a decreasing trend beginning in 2013; (4) environmental efficiency is invalid over the entire period, and the eco-efficiency level is positively related to the economic efficiency score; and (5) the circular economy system has a larger energy saving space, and the key to achieving sustainability of the circular economy system is output growth. Highlights • We assess the circular economy system eco-efficiency of coal mining in China using emergy and DEA. • We decompose eco-efficiency as economic efficiency and environmental efficiency. • The circular economy system is an energy-intensive system with high input and output. • The eco-efficiency level is positively related to economic efficiency. • The circular economy system has huge potential to save energy and reduce emissions. [ABSTRACT FROM AUTHOR]

Abstract The environmental benefit from sustainable packaging is not only dependent on the characteristics of the packaging, but also on consumer willingness to purchase sustainably packaged products. Consumer response is likely influenced by the specific design strategies that are used to make packaging more sustainable. Based on the circular economy concept, this paper distinguishes between circular and linear design strategies, and investigates consumer responses to packaging redesigned according to such strategies. Two experiments were conducted to assess to what extent (combinations of) sustainable design strategies affect consumers' purchase intentions. The results show that consumers are more positive toward redesigns following a circular design strategy (e.g., biodegradable materials) compared to linear redesigns (e.g., packaging lightweighting). Additionally, consumers are not more willing to buy packaging redesigns combining multiple sustainable design strategies, relative to those using only a single redesign strategy. Multi-strategy redesigns are perceived only as marginally more sustainable than single strategy redesigns. These diminishing returns can be attributed to a lack of increase in the moral satisfaction consumers achieve from buying product with multi-rather than single-strategy redesigned sustainable packaging. [ABSTRACT FROM AUTHOR]

Abstract The built environment is the most resource intensive sector of the economy, accounting for a significant share of the extracted materials and the total waste generated. Within the built environment the most recurrent replacements of building materials and components take place during fit-outs, which are the process of installing interior fittings, fixtures and finishes. These materials and components are frequently replaced in non-domestic buildings. Non-domestic building fit-outs are therefore responsible for a significant consumption of materials and a large source of waste. However, they tend to be excluded and unmeasured in the research on the built environment. The present work aims to study this research gap and analyse the potential for fit-outs to become more sustainable. The approach of this project ties in closely to the concept of circular economy, where materials are kept at their most useful state for as long as possible. This paper analyses fit-out practices within London, identifying the supply-chain stakeholders, the key materials used and the waste streams generated, while tracing the decision and material flows across the supply chain. A material flow analysis (MFA) is conducted for a fit-out case study, showing the paths and destinations of the waste generated. The mixed methodology includes on-site observations, cross-examination of the corresponding waste reports, MFA, and qualitative analysis of interviews with the involved stakeholders. The aim of this research is to provide a grounded perspective that allows the identification of process and design flaws as well as potential improvements that support the transition towards more "circular" fit-outs. It is concluded that there are potential areas of improvement as fit-out practices show a predominantly linear tendency both for decision making and material flows, in which there is a discontinuity of communication and material-flow information across the supply chain. [ABSTRACT FROM AUTHOR]

Abstract This paper provides a comprehensive review of literature on the properties of sugar industry waste, their varied uses in energy and construction sector, performance and limitations. An efficient upcycling of sugar industry waste in energy production would help the energy sector to reduce its dependency on non-renewable fossil fuels. Literature demonstrates that in the recent years there has been an increased research interest in thermochemical conversion of sugarcane bagasse to produce cleaner energy, rather than its landfilling or combustion. On the other hand, utilisation of secondary by-products from sugar industry in the production of cement, bricks, paver blocks, activated binder and other construction products helps to cut down the carbon footprint of the construction industry, while improving the properties of the final products. From the perspective of the sugar industry, such an arrangement eliminates disposal problems and creates additional revenue. Although independent research studies investigating the use of sugar industry by-products exist, few studies consider these valorisation options together to minimise waste and to create an efficient material flow chain. This study identifies various material and energy recovery pathways from published literature and connects the materials and processes to form a continuous material supply chain with minimum wastage. From the findings, a symbiotic framework has been developed with primary and secondary by-products from the sugar industry serving as source materials for energy production and sustainable construction products. Graphical abstract Image 1 Highlights • Utilisation of sugar industry by-products in various construction products is discussed. • Methods of cleaner energy production from sugar mill by-products are reviewed. • The symbiotic relationship between sugar, construction and energy industries is described. • A circular framework is proposed for sustainable valorisation of sugar industry waste. [ABSTRACT FROM AUTHOR]

This paper shows how to constructively engage with waste and resource management frameworks, by clarifying their role in the societal discourse on waste and resources, providing insight into their step-based structure, and how they draw on different definitions of ‘waste’ and ‘resource.’ Through use of the concepts of ‘frame,’ ‘collective action frame’ and ‘logics,’ a language and conceptual toolbox is made available that facilitates a constructive debate around such frameworks. Ten waste and resource management frameworks are included here, among which are the five frameworks that are part of the synthesis of the Ellen MacArthur Foundation's Circular Economy framework: Cradle-to-Cradle™ by Braungart and McDonough, the Performance Economy by Walter Stahel, the Blue Economy by Gunter Pauli, Regenerative Design by John Lyle and the Industrial Symbiosis framework. A case is made for the careful consideration, creation, use and further development of such frameworks and directions are provided for the further development of the CE concept into a robust concept. [ABSTRACT FROM AUTHOR]

Activities to advance circular economy are accelerating, and ecodesign has been mentioned as a necessary ingredient for their success. These activities might be further accelerated with more shared understanding of the related terminology. Many of these suggested activities take place in companies' product development where employees should implement them, including that of ecodesign. Employees' interpretation of enhancing practices are assumed critical in supporting the implementation. A survey using a judgmental nonprobability sampling is used to assess the perceived level of selected environmental topics in the product development contexts, and how these are associated with perceived ecodesign practices in product development. One focus is on how the perceived durability considerations might be linked with these practices. Furthermore, the paper contributes to the discussion on the soft-side of ecodesign by examining how one human factor - ecological concern - might be associated with these perceived activities. [ABSTRACT FROM AUTHOR]

Currently, design for sustainability is a necessary issue in any product development process. This situation is due to the existing and increasing pressure under industrial activities that follow a linear economy model based on design, manufacture, use and final disposal. As a feasible solution, Circular Economy (CE) model is considered a key strategy to enhance the overall sustainability performance of products, including strategies to improve the useful life of products and close flows of material in a circular path. In the measurement of circularity, existing sustainability indicators are oriented solely to single products and do not consider the product family approach, which involves the use of a common product platform comprised by constructive components or modules able to generate different product variants to satisfy a variety of customer requirements. Consequently, this paper proposes six indicators regarding material flow, reusability, reconfiguration, and functional performance. Such indicators are focused on measuring the circularity of product families respect the circularity of components among their product variants. A case study based on a family of prosthetic fingers is developed to demonstrate the implementation and usefulness of the proposed set of indicators. [ABSTRACT FROM AUTHOR]

Within an envisioned circular bio-based economy, a key component is the valorization of biomass wastes and residues into valuable products. If the commonly used method of life-cycle assessment (LCA) is applied to such products, an update and adaptation of LCA practice is needed regarding potentially outdated assumptions of residual resources as free from environmental impact. This paper therefore presents and discusses LCA approaches to evaluating residual biomass as resources, and implications of different approaches to LCA results and decision-making. Based on an analysis of 31 LCA studies of bio-based products, and on a model for recycling in LCA, we discuss alternatives to zero-burden assumptions for biomass residues. The studied literature shows a variety of approaches to assessing the impacts of residues, including views of relevant characteristics and causality in primary production systems, and intended use and interpretation of LCA results. In general, acknowledging upstream impacts through a simple model of recycling and allocation entails that the environmental characteristics of primary production systems reflect on by-products and residues. We argue that LCA studies of residue valorization must recognize the potential value of residues by considering upstream impacts, and thereby avoid both misconceptions of residues as per default environmentally preferable resources, and unintentional support for high-impact primary production systems. Residues as resources require this adaptation in LCA practice in order to avoid misguided decisions for a low-impact, bio-based and circular economy. [ABSTRACT FROM AUTHOR]

In circular economy, the Green Supply Chain Management (GSCM) provides the resource optimization and it is seen as a solution to solve environmental problems and consumption patterns within the whole supply chain. The GSCM implementation and performance assessment is relatively important for survival in an ever-increasingly competitive environment. Within the circular economy context; companies that aim to improve GSCM must constantly monitor their performance. In order to integrate the circular economy concept into GSCM, it is required to achieve an optimal balance of environmental, economic, logistics, organizational, and marketing performance indicators. However, in the literature, these indicators were investigated separately in terms of GSCM performance assessment, therefore, to achieve this optimal balance, it is necessary to assess these different indicators. Within this context, the aim of this paper is to propose a new holistic conceptual GSCM performance assessment framework which integrates environmental, economic, logistics, operational, organizational and marketing performance. The framework has three-dimensional hierarchy which includes the main criteria, sub-criteria, and the measures for the GSCM performance assessment which have great significance to implement effective GSCM. [ABSTRACT FROM AUTHOR]

Building on the idea that the more general and systemic the policy objectives, the more cooperation and scientific support is needed for sound policy design, this paper explores the potential for knowledge sharing and research-based cooperation in the policymaking process in the field of circular economy. A sample of 1244 research publications on circular economy from the Scopus database was collected to assess: i) how the research on CE is distributed among the main disciplines of scientific research, and how much attention each of them pays to the subject; ii) what potential they exhibit for interdisciplinary communication and knowledge sharing; and iii) the potential for developing a transdisciplinary cooperation under a common conceptual policy framework. The analysis shows that policies for circular economy at the micro/meso level (firm or inter-firm initiatives) can rely on a much more adequate knowledge base and potential scientific support than those at the macro level (circular economy as a model of systemic sustainable development). To improve the results on the macro side, a number of disciplines (including social sciences, economics and some behavioural sciences) should be solicited to devote more space to the study of the subject and to develop the basis for mutual understanding with other traditionally more involved research areas. [ABSTRACT FROM AUTHOR]

Investigating the benefits of sustainable business models for our societies is an important and timely topic. This Special Volume contributes to current research by exploring a variety of sustainable models in use around the world. The accepted articles provide an overview of the various organizational forms, management mechanisms, sustainability solutions, challenges, theoretical lenses and empirical evidence, i.e. fundamental elements in the study of sustainable business models. In this introductory paper, the thirty-seven articles included in this Special Volume are presented, organized in four approaches to sustainable business models: 1/the generalist approach, 2/the technology-based approach, 3/the entrepreneurship and innovation approach and 4/the behavioral approach. In conclusion, avenues for future research are formulated, with a call for solid theory building, more sophisticated research methods, focus on the interplay of sustainable with existing conventional business models, and systemic consideration of the role of governments in advancing sustainable business models. [ABSTRACT FROM AUTHOR]

Food packaging facilitates storage, handling, transport, and preservation of food and is essential for preventing food waste. Besides these beneficial properties, food packaging causes rising concern for the environment due to its high production volume, often short usage time, and problems related to waste management and littering. Reduction, reuse, and recycling, but also redesign support the aims of the circular economy. These tools also have the potential to decrease the environmental impact of food packaging. In this article, we focus on chemical safety aspects of recycled food packaging, as recycling is currently seen as an important measure to manage packaging waste. However, recycling may increase the levels of potentially hazardous chemicals in the packaging and -after migration- in the food. Since exposure to certain chemicals migrating from food packaging has been associated with chronic diseases, it is of high importance to assess the safety of recycled packaging. Therefore, we describe recycling processes of commonly used food packaging materials, including plastics, paper and board, aluminum, steel, and multimaterial multilayers (e.g., beverage cartons). Further, we give an overview of typical migrants from all types of recycled food packaging materials, and summarize approaches to reduce chemical contamination. We discuss the role of food packaging in the circular economy, where recycling is only one of many complementary tools for providing environmentally-friendly and safe food packaging. [ABSTRACT FROM AUTHOR]

An Eco-Industrial Park (EIP) is composed of a number of Industrial Symbiosis (IS) instances, which allow energy/material exchanges among the different industrial enterprises (Individual Actors, IA) therein. By so doing, IA's economic and environmental performances can be improved. Despite recent methodological advancements, the existing approaches to EIP design optimization are still suffering from several major problems: (i) dominance of the global EIP optimum over the local IA optimum, (ii) limited number of optimization objectives falling into the categories of economic and environmental objectives and (iii) EIP optimization performed without considering possible operational uncertainties. In addition, the adoption of the bio-inspired concept of IS makes EIP evolve from classical engineered systems towards complex engineered systems, with associated static and dynamic complexity characteristics. To highlight and understand the complexity features of EIP, in this paper we present them as intelligent networks for multiple energy and material exchanges, drawing a parallel with another typical complex system, that of the electric power network, in its modern Smart Grid (SG) concept, conceived to improve and optimize the distribution and use of electrical energy. Then, the modelling and optimization framework proposed in this paper adopts a more systematic methodology for accounting of the EIP complexity characteristics and addressing the associated optimization challenges. The proposed approach allows ensuring a sustainable and robust EIP design, thanks to the due account given to the related uncertainties and risks, e.g., due to major changes in the regulatory context and IA operational strategies, failures of interconnections among IA, interruption or shutdown of IA operation. [ABSTRACT FROM AUTHOR]

Cement manufacturing is a high volume process, with large quantities of substances turned into commercial products, in the process consuming non-renewable resources and energy. It is one of the most material and energy-intensive industrial processes, as well as being CO 2 emissions-intensive. The latter is due in large part to the production of clinker, the key component in cement. Over the last decades, the European cement industry has applied a variety of solutions for improving environmental performance and cost competitiveness. The co-processing of alternative raw materials and fuels, in particular, has played a pivotal role, producing a triple win: emissions reductions, decreases in the extraction of natural resources and fossil fuels, and enhancement of waste management operations. This paper outlines characteristics of the European cement industry, in order to pinpoint trends and performance improvements, and to assess the suitability of sustainability routes adopted and programmes launched. Finally, the paper compares the experiences of the industry in Italy and Germany, the two most important European manufacturers of cement, evaluating their different industrial approaches with regard to the use of alternative raw materials and fuels and improvements in resource efficiency. Results indicate the need for a collaborative approach between the business community, policy makers, and institutions, in order to embrace sustainability as a business imperative, adopting models that facilitate systemic change towards circular economy goals. [ABSTRACT FROM AUTHOR]

This paper analyses household behaviour as response to changes in waste management systems. The paper discusses the results of a case study from Vellinge municipality (Sweden), where the introduction of separate food waste collection is thought to have a role in reducing the total amount of household waste and improving the sorting of packaging waste. The study relies on data from official waste statistics and a survey of 117 municipal residents focusing on households' perceptions, attitudes and self-reflected changes in waste sorting behaviour. The respondents mentioned the increased environmental awareness and the convenience of food waste sorting among the primary reasons for the perceived changes in personal waste sorting routines. The study also tested the significance of other variables, such as income, employment, economic activity, socio-demographics, infrastructure, waste tariffs, illegal dumping, and awareness raising campaigns. Most of the variables were static and none showed sufficient correlation to the observed reduction of waste collection rates and the improvements in sorting other waste fractions. The analysed case had particularly high income levels, which were the main dynamic variable under study. The analysis suggests that we may be observing an example of a decoupling between economic growth and waste generation rates. This observation is explained by the Kuznets phenomena and it is being discussed in this paper. [ABSTRACT FROM AUTHOR]

To fully contribute to sustainable development, circular economy has to devote more attention to social inclusion. This paper thoroughly analyzed the literature, answering the research question: how is circular economy embracing social inclusion? The research design applied quantitative and qualitative strategies. Bibliometric quantitative analysis with the aid of VosViewer, the RStudio software, and Bibliometrix Package were employed. An inductive content analysis was undertaken to analyze the themes of circular economy and social inclusion, applying NVivo software. The results brought out six clusters: (i) reverse logistics and recycling, (ii) circular economy and innovation, (iii) social innovation, (iv) sustainable supply chains, (v) bioeconomy, and (vi) closed-loop supply chain. Our findings showed that the circular strategies of reuse and reduce were the focus of the surveyed literature, while consumers and communities were the key stakeholders addressed. Recycling was directly linked to waste management and the inclusion of waste pickers in developing countries. As future research themes, it highlighted more theoretical and empirical research about community and consumer engagement in circular practices, besides the importance of entrepreneurship and social innovation to intensify circular practices embracing social inclusion. • The literature focused on reuse and reduce as circular strategies. • The key stakeholders addressed were consumers and communities. • Recycling was linked to waste management and the inclusion of waste pickers. [ABSTRACT FROM AUTHOR]

While firms' investment in Industry 4.0 and adoption of circular economy practices are seen as indispensable to a sustainable economy, synergies from the interaction of these two received less systematic empirical treatment. These synergies are particularly important in Europe, given that both the digital and the green transitions are Europe's strategic political priorities, and the "twin" transitions are expected to reinforce each other. By investigating the link between Industry 4.0 technologies and circular economy practices for European SMEs, which have an important place in the European economy and are responsible for a significant amount of waste, this study aims to uncover the potential of digital transition in supporting green transition. Using the ReSOLVE framework as the conceptual background, this paper examines the effect of Industry 4.0 technologies on SMEs' circular economy applications among EU countries using firm-level data from SMEs, Start-ups, Scale-ups, and Entrepreneurship (Flash Eurobarometer 486) Survey in 2020. The results of econometric analyses provide evidence of a statistically significant positive effect of Industry 4.0 technologies on circular economy practices. These findings imply that a key policy priority should be to plan to spread Industry 4.0 components to improve and enhance SMEs' circular economy practices. Overall, the results indicate that Industry 4.0 technologies serve not only Europe's digital and industrial strategies but also its environmental strategies. [ABSTRACT FROM AUTHOR]

Aside from potential environmental benefits, the implementation of circular economy principles in businesses can have merits for the labour market. The current unemployment in several regions of Europe and the qualitative mismatch between supply and demand could be countered by reskilling the labour force to adjust supply and demand to one another for increased reuse, repair, or recycling, among others. This study uses interviews to increase the focus of the research question and uses survey data to perform an ordered probit regression analysis to sketch the current and future landscape of startups' skills in Flanders (Belgium), and to analyse the relationship between circular strategies and different types of skills. The results show that design to lower material use increases the need for transport and logistics skills, digitalisation increases the need for R&D and IT skills, and the recuperation of waste requires technical knowledge. Furthermore, gender, age, and experience of the entrepreneur influence the needed skills. The paper probed for policy recommendations for the uptake of circular strategies and recommendations for future research. The most asked policy measures by the respondents are innovation and collaboration support (subsidies), fiscal measures that support circular goods and services, and public procurement for circular goods and services. This research is of relevance for several stakeholders, such as startup ecosystems, sector organisations, policy makers in innovation policy and labour market policy, and educational institutions. [ABSTRACT FROM AUTHOR]

In Spain, due to its important mining past, there are many abandoned mine waste facilities. This study evaluates the potential of Spanish mine wastes for the recovery of critical and strategic raw materials and other elements of economic relevance. For this purpose, 20 mine waste facilities have been selected in different parts of Spain based on criteria such as tonnage, element content or metal market price. Surface samples were taken at the facilities, considered representative of these, for subsequent granulometric, mineralogical and chemical analysis. The grain size data were obtained by standard sieving (ASTM 5000), while the mineralogy was obtained by X-ray Diffraction (XRD). For chemical characterization, Wavelength Dispersion X-ray Fluorescence Spectrometry (WDXRF) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) were used to analyze 38 chemical elements (Be, Sc, V, Cr, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Y, Zr, Nb, Mo, Ag, Cd, Sn, Sb, I, Cs, Ba, La, Ce, Nd, Sm, Hf, Ta, W, Tl, Pb, Bi, Th and U), many of them included in the European Union's list of Critical Raw Materials (CRMs). In addition, leachate data from mine wastes in the Iberian Pyritic Belt were analyzed to assess their bioleaching potential. The calculated enrichment factors (EF) indicate that some critical elements, as well as others with strategic and economic interest, are highly enriched in the wastes, including Sb, Bi, As, Pb, Cu, Ag, Zn, Cd, Sn, Se and Th. The most promising facilities with the highest recovery potential are located in the historic Riotinto and Tharsis mines (both in Huelva, Iberian Pyrite Belt) and the Rubiais mine in Lugo, whose tailings could contribute up to 3.2 billion dollars gross, according to the current market metal prices. This paper aims to provide a first step to promote mine waste recycling and circular mining in Spain, an initiative that would also help to mitigate the environmental damage derived from abandoned mine wastes. • First national-scale assessment of Critical Raw Materials from mine waste facilities in Spain. • Mine waste facilities enriched with critical and strategic metals in terms of enrichment factors. • Most promising facilities evaluated in terms of metal tonnages and estimated gross benefit. [ABSTRACT FROM AUTHOR]

A critical issue that has dominated the field of Lithium-ion Batteries (LIBs) and Battery Electric Vehicles (BEVs) is their usefulness to climate change, their second life, and their recyclability. With recent developments in the discipline of circular economy, Life Cycle Assessment (LCA) of LIBs becomes important. There are numerous studies on LCA of LIBs and this paper investigates the existing LCA results to quantify the different parameters that could affect the decisions of a battery pack design engineer. Global Warming Potential (GWP) and Abiotic Depletion Potential (ADP) are the two most discussed environmental impacts among the previously executed LCA studies. GWP gives information on the carbon footprint associated with the usage of LIB whereas the ADP is associated with the depletion of resources, both environmental factors important to consider for a sustainable design process. This study also takes into account the Cumulative Energy Demand (CED) component, which provides a designer with a sense of the amount of energy used over the course of a LIB's lifetime. The authors of this work suggest a design process model for a LIB pack design based on these considerations, which aids a design engineer in making the right choices. Consequently, this helps the designer to achieve more utility of raw materials, making sparing use of resources and find potentials to reduce waste in different life stages of a LIB pack. • State of Art - Life Cycle Assessment studies for Lithium-ion Batteries (LIBs). • Quantifying relevant parameters for design decisions within battery pack engineering. • Cumulative Energy Demand (CED) component for energy used in whole lifetime. • Decision-based design process model for a battery pack design. [ABSTRACT FROM AUTHOR]

In this paper, we describe and analyze the novel type of circular economy business model that we define herein as "open circular economy business model." Unlike a typical circular business model based on six R-imperatives (reuse, recycling, redesign, regenerate, reduce, and recover), the analyzed business model leads to greater flexibility as it allows the incorporation of raw materials from the external organizational context into the internal sustainable production cycle. Hence, the societal benefits of adopting an open circular economy business model are potentially more significant than in the case of a conventional circular economy business model because it allows greater distribution of the benefits among heterogeneous external actors that interact with the organization. The study is based on the single case study of the Italian manufacturing company, which obtained significant market success by applying an open circular economy business model in the first few years since its incorporation. By examining in-depth interviews with principal organizational decision-makers triangulated with internal and external secondary data analysis, we describe the model's main characteristics while highlighting its strengths and weaknesses. The commercial success of the studied organization can be an incentive for direct and indirect competitors to implement similar business models resulting in the activation of system-level circularity-oriented behaviors. [ABSTRACT FROM AUTHOR]

Contemporary concepts of economic development in the European Union (EU) progressively focus on environmental protection. At the stage of their implementation by the EU countries, some of the policies include sustainable development, green growth, green economy, and circular economy. The leading concept in this regard is the European Green Deal. It should be noted, that a multitude of means exists within EU countries, by which plastic waste is managed, with a significant share of countries largely landfilling it or placing it in waste storage facilities. The aim of this paper is to introduce a proposal meant to propel the prospects related to managing plastic waste through chemical recycling. This recommendation would contribute to the fulfillment of the circular economy model implemented by EU countries. By means of chemical recycling, it is possible to transform plastic waste into a full-value market product which can be used, for example, in the fuel industry, constituting an alternative to the agricultural products used (biocomponents). Thereby, it may result in the production of, for example, engine fuel components that can replace plant-based components or other added-value chemicals. The findings demonstrated on four levels: environmental, technical, economic, and managerial, confirm the technological possibilities of chemical recycling of plastics and the legitimacy of the implementation of the presented concept. [ABSTRACT FROM AUTHOR]

Climate change poses significant challenges in terms of water scarcity, environmental crisis, and economic uncertainty. This situation drives an increasing need to pursue more sustainable futures and to conserve and maximise the use of resources whenever possible. The EU-funded H2020 NextGen project aimed to boost sustainability using new and novel technologies and approaches implemented within the water cycle, and to maximise the efficient use of water and water-embedded resources. To facilitate and communicate the potential benefits of such technologies, NextGen developed Serious Games (SGs), enabled by underlying System Dynamic Models (SDMs), for demonstrating how interactions between water, energy, and materials/embedded resources within the urban water cycle can be utilised in the context of the Circular Economy of water. As part of a fast-track development process, a testbed dubbed "Toy Town" was developed that encompasses a range of technologies and options that provides a demonstrable framework that can later be refined and modified accordingly for other case studies. The underlying SDM driving the SG is built using the Julia programming language. The testbed incorporates a range of components, including water-saving and water-reuse technologies, stormwater management, and wastewater treatment systems. The SDM acts fundamentally as a mass-balance model tracking over time volumetric flows of water/wastewater and the concentrations/dilution of pollutants/material within the urban water cycle. A variety of water use, water reuse and wastewater treatment components can be tested within this model to maximise the resource potential of the water and material moving through the cycle. The paper focuses on an extreme drought scenario and highlights the benefits of a modelling testbed for exploring potential technological solutions for managing the urban water cycle and how such solutions can be employed in the context of the circular economy of water. The NextGen SG thus has the potential to improve stakeholders' understanding of the implementation of novel technologies in the water cycle and the benefits that could be accrued by such stakeholder groups. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the valorisation opportunities for the secondary metallurgy slag (SMS) as a by-product of electric arc furnace (EAF) steel production. The key stakeholders, their aim and possible configurations of the SMS value chain are identified considering the treatment unit owners and locations, pre-treatment and treatment processes, and collaboration aspects. A multi-criteria Analytic Hierarchy Process (AHP) model has been developed to evaluate value chain configurations according to criteria such as technology, legislation, economic and environmental sustainability, and supply chain. This approach helps analyse the impact of circular economy practices and the opportunities for industrial symbiosis in the European steelmaking areas. The AHP model was tested on the case of Lombardy region that is one of the major European hubs for EAF steel production. Knowledge was collected and formalized from interviews with several experts. The results show economic sustainability has the highest impact on the SMS value chain, followed by CO 2 emission and water consumption. The ranking of SMS value chain configurations shows that a pre-treatment phase is essential since it facilitates SMS logistics management and has environmental advantages. A collaborative approach among steel producers or with external recyclers is preferred when there is the readiness of the ecosystem, hardware infrastructure, and legislation about product certificates and operations. In a collaborative system, a value chain consisting of a third-party industry for SMS recycling is preferred to a consortium of producers due to the broader market coverage, environmental sustainability, and higher profits for the recycler. The multi-criteria combined with the multi-expert modelling approach helps balance the importance of different criteria from the actors' points of view, such as steel producers and technology providers. From the theoretical point of view, the analysis shows how an SMS collaborative ecosystem integrated with two recycling facilities reinforces the steelmaking business profitability, market potential, and environmental-friendly solutions. This study can help steel producers decide on the feasibility and profitability of treatment units, collaborating with other producers, or selling SMS to recyclers. In addition, policymakers can analyse the regional perspective, identify potential industrial sectors, and explore new business models. [ABSTRACT FROM AUTHOR]

The current macroeconomic models of the circular economy rely on the unrealistic assumption that materials can be recycled infinitely, often ignoring price and demand adjustments. In reality, most virgin materials are recycled only a few times, while the proliferation of cheap products made from recycled materials is likely to affect final demand. In this paper, we address both of these shortcomings. We propose a novel climate-economy agent-based model of the circular economy combined with the climate cycle and opinion dynamics. Consumers and producers are embedded in co-evolving networks, with preferences of consumers influencing the direction of technological progress and the diffusion of goods made from recycled materials. The main novelty of our study is that we compare the macroeconomic consequences of inputs being recycled once, twice and infinitely. We find that the more times materials are recycled, the more global temperature and resource depletion decrease. In addition, our study shows that the transition to renewable energy leads to the material rebound effect, where more raw materials are used in the manufacturing sector compared to an economy dependent on fossil fuels. Whether the circular economy can mitigate this effect depends on how many times inputs are recycled. • We study inputs being recycled once, twice or infinitely in the circular economy. • The more times materials are recycled, the more global temperature decreases. • A combination of low-carbon and circularity goals can cause the material rebound. [ABSTRACT FROM AUTHOR]

Wastage from electrical and electronic hardware includes a huge range of unsafe and complex materials, which can cause major natural and health issues. A promising approach that can bring about change and help in addressing this wastage is the circular economy (CE). However, understanding how this approach can be successfully implemented when it comes to waste electrical and electronic equipment (WEEE), has remained surprisingly nascent to date. Therefore, this paper contributes to a better understanding of CE implementation in the WEEE sector by exploring its critical success factors (CSFs) and identifying their causal relationships and hierarchy of importance. To achieve this, a systematic literature review (SLR) was conducted to identify and understand the CSFs that influence the implementation of CE that were subsequently refined based on industry practitioners' inputs in Bangladesh via a structured survey. Then, the decision-making trial and evaluation laboratory approach integrated with intuitionistic fuzzy sets (IF-DEMATEL) was employed to understand their causal relationship and hierarchy of importance. A wide range of CSFs were identified, of which "Market Contenders" and "Formation of Cross-functional Teams" were found to be more prominent for the successful implementation of CE to address WEEE, and that "Global Standard" influences the majority of other CSFs, including "Skilled Manpower", "Financial Sustainability", "Consumer Awareness", etc. The results of this study will help professionals and policymakers implement better e-waste management systems, which can lead to the development of eco-friendly businesses and innovative and flexible production systems. [ABSTRACT FROM AUTHOR]

This paper reports the development of green bio-composite mortars, obtained reusing spent coffee ground (SCG), an agri-food residue, in the light of the Circular Economy approach. This process can boost the sustainability in Construction and proposes an alternative to SCG disposal in landfill, potentially dangerous to humans and the environment. For the first time, specimens were produced and compared using different blends of conventional hydraulic binders (ordinary Portland cement and natural hydraulic lime); SCG partially substituted sand (up to 15 wt%, with a 2.5% increment) for the aggregate mix. The manufacturing process was performed at ambient conditions (20 °C, 65% RH) resulting highly sustainable, and consisted of simple operative steps reproducible in a real building site. The prepared mixes were fully characterised to assess their technological potentials in construction. Morphology analysis, performed by Scanning Electron Microscopy (SEM), showed SCG addition led to a more compact structure. Considering the functional properties, results widely range on binder blend base, offering various concrete applications; it was observed that with SCG addition, despite a decrease in the bulk density (up to 26%), the mechanical performance still remained suitable for proper masonry applications, according to the relevant standards (class of resistance M2.5-M10). A light water imbibition increase was registered (about 5%) while a significant decrease of the capillarity index was seen. Moreover, a robust thermal conductivity reduction was observed (up to 72%), making the mortars highly suitable for energy-saving uses in building. Finally, a reduction in the manufacturing cost (up to 8%) was calculated, granting significant financial saving in light of the industrial symbiosis. These encouraging results showed that reusing SCG not only provides numerous benefits to the overall building performance and management but it is also a valid alternative to usual SCG disposal. The high amount of reused bio-waste significantly widens the knowledge of greener and more efficient building sector, making the prepared mortars promising candidates for the Minimum Environmental Criteria certification, in light of the recent EU regulations, and in line with the principles of the Circular Economy. [Display omitted] • Spent coffee ground can effectively substitute silica sand in mortars manufacture. • Spent coffee ground reuse makes the preparation much cleaner and more sustainable. • Spent coffee ground based-mortars show superior energy saving behaviour. • The cost associated with mortars manufacture is lower to traditional ones. • Novel produced mortars are suitable for innovative architectural applications. [ABSTRACT FROM AUTHOR]

This paper investigates how institutional pressures affect the development of Circular Economy (CE) in firms. Using Institutional Entrepreneurship as a theoretical framework, this paper considers three different levels of institutional pressures (coercive, normative, and mimetic) to examine the effect of each pressure and their interactions on the development of CE. Seeking to clarify the debate on the effect of institutional pressures, this paper considers that the main limitation arises from the fact that previous research has analysed the relationship between institutional pressures without considering the interaction between them and the non-linearity of the processes. Deviating from previous papers, our analysis combines regression methods with Machine learning (i.e. Artificial Neural Networks), and employs data from the EU survey on Public Consultation on the Circular Economy. This research finds that while coercive pressures have a compulsory effect on the development of CE, mimetic and normative pressures do not have an effect by themselves, but only in interaction with coercive pressures. Moreover, this paper shows that the application of machine learning tools has an important contribution in solving interaction problems. From the perspective of environmental policy, this means that a comprehensive policy is required, which implies the coexistence or interaction of the three types of pressures. [Display omitted] • Discrepancies on the effect of institutional pressures are due to methodology. • Coercive pressure has a compulsory effect on the development of Circular Economy. • Mimetic & Normative pressures only have effect in interaction with coercive pressure. • Artificial Neural Networks contribute to solving interaction problems. • Comprehensive environmental policy that considers these interactions is required. [ABSTRACT FROM AUTHOR]

Clothing consumption continues to increase worldwide, with many fashion brands facing criticism for producing poor quality garments which have short lifetimes, adding to already unsustainable levels of post-consumer waste. This paper aims to identify the causes of failure for different types of garments and discusses solutions through which to increase their durability. Recent literature has highlighted the need for companies in the clothing industry to progress to a circular fashion model and the important role of consumer attitudes and expectations in determining clothing lifetimes. Garment failure due to inadequate technical durability is acknowledged but has not attracted significant attention from academic researchers. This paper reports on a survey which identified different types of garment failure by assessing discarded items at end of life, explains the causes of such failure and reveals potential solutions, drawing upon data from a series of research projects commissioned by WRAP and Defra. The survey revealed that the most common causes of garment failure are pilling and colour fading. Other causes included fabric breakdown, accidental damage, loss of dimensional stability, logo failure, discolouration, and holes in seams. Increased garment durability is achievable by following best practice technical guidance but also requires effective management of product development and manufacturing processes. Implementation of technical solutions requires appropriate testing, improved technical skills and knowledge, collaboration to promote better design practices, and new business models that support garment longevity. • Clothing consumption continues to increase and is unsustainable. • The lifetime of many garments is unduly short due to inadequate technical quality. • A garment condition survey identified the most common causes of failure as pilling and colour fading. • Causes of failure and potential solutions were explored through a multi-methods research approach. • Solutions include better testing, improved technical expertise, collaboration on design, and sustainable business models. [ABSTRACT FROM AUTHOR]

Papermaking is regarded as an industry that consumes a great amount of energy and produces serious pollution. The papermaking industry in China, which has a large population and rapid economic development, is indispensable and presents a trend of rapid development. China and the rest of the world pay considerable attention to resource conservation and environmental protection. Therefore, determining how the papermaking industry can realize cleaner production and sustainable development is an urgent issue that should be addressed. This paper introduces Guangdong Silver Island Lake (GSIL) Papermaking Park, which realizes cleaner production and sustainable development by developing circular economy (CE). This park constructs a CE industrial mode by recycling energy, water, and materials. After 10 years of implementation, the CE plan of GSIL Papermaking Park has integrated the resources of the papermaking and power industries horizontally, thus forming the unique development mode of its CE. The resource consumption, resource comprehensive utilization, and pollutant emission indexes of the park have reached the advanced level in the papermaking industry of China. [ABSTRACT FROM AUTHOR]

The Circular Economy is increasingly seen as a possible solution to address sustainable development. An economic system that minimises resource input into and waste, emission, and energy leakage out of the system is hoped to mitigate negative impacts without jeopardising growth and prosperity. This paper discusses the sustainability performance of the circular business models (CBM) and circular supply chains necessary to implement the concept on an organisational level and proposes a framework to integrate circular business models and circular supply chain management towards sustainable development. It was developed based on literature analysis and four case studies. The proposed framework shows how different circular business models are driving circular supply chain in different loops: closing loops, slowing loops, intensifying loops, narrowing loops, and dematerialising loops. The identified circular business models vary in complexity of the circular supply chain and in the value proposition. Our research indicates circular business and circular supply chain help in realising sustainability ambitions. [ABSTRACT FROM AUTHOR]

This paper examines the role of small entrepreneurial companies and their partnerships with large corporations to advance the circular economy (CE). The authors provide insights from a U.S.-based empirical study that involved 12 companies and examined the emerging drivers, current challenges and future opportunities for advancing waste repurposing and product reuse. Many large companies fail to incorporate CE principles into their business strategy due to lack of mandates, costs, logistical hurdles and inertia. This presents an opportunity for entrepreneurial companies with innovative business models to fill the gap and provide critical links for corporations in reverse supply chains while creating new business opportunities with social benefits. The study found that despite the lack of federal regulations in the U.S. a growing number of corporations are partnering with entrepreneurs to reduce waste and advance product reuse. Key drivers for such trends include sustainability commitments and zero waste goals by companies and municipalities, European Union and U.S. state mandates, reputation and the growing focus on local sourcing. Technology, knowledge, and strategic partnerships between entrepreneurs and corporations play a critical role in reducing financial costs, time, energy, environmental impacts and resources, thus helping establish viable business models. The authors propose a new framework for corporate-entrepreneur collaborations to advance a CE. The study contributes to the research on the relationship between entrepreneurial innovation and the development of CE principles within corporate supply chains, a field that is still in its infant stage. [ABSTRACT FROM AUTHOR]

Existing schemes of solid waste handling have been improved implementing advanced systems for recovery and reuse of various materials. Nowadays, the ‘zero waste’ concept is becoming more topical through the reduction of disposed waste. Recovery of metals, nutrients and other materials that can be returned to the material cycles still remain as a challenge for future. Landfill mining (LFM) is one of the approaches that can deal with former dumpsites, and derived materials may become important for circular economy within the concept ‘beyond the zero waste’. Perspectives of material recovery can include recycling of critical industrial metals, including rare earth elements (REEs). The LFM projects performed in the Baltic Region along with a conventional source separation of iron-scrap, plastics etc. have shown that the potential of fine-grained fractions (including clay and colloidal matter) of excavated waste have considerably large amounts of potentially valuable metals and distinct REEs. In this paper analytical screening studies are discussed extending the understanding of element content in fine fraction of waste derived from excavated, separated and screened waste in a perspective of circular economy. Technological feasibility was evaluated by using modified sequential extraction technique where easy extractable amount of metals can be estimated. Results revealed that considerable concentrations of Mn (418–823 mg/kg), Ni (41–84 mg/kg), Co (10.7–19.3 mg/kg) and Cd (1.0–3.0 mg/kg) were detected in fine fraction (<10 mm) of waste sampled from Högbytorp landfill, while Cr (49–518 mg/kg) and Pb (30–264 mg/kg) were found in fine fraction (<10 mm) of waste from Torma landfill revealing wide heterogeneity of tested samples. Waste should become a utilizable resource closing the loop of anthropogenic material cycle as the hidden potential of valuable materials in dumps is considerable. [ABSTRACT FROM AUTHOR]

The concept of circularity has been widely discussed in the literature, but the implementation of the circular economy at the micro-level remains unexplored. It is still not clear what are the antecedents for circular economy implementation at the industry level, instead of cleaner production principles and practices have been discussed as essential for circular economy adoption from the bottom up, but more empirical studies are still necessary to better understand the adoption and effects of cleaner production in promoting circular economy. Thus, this paper aims to explore the cleaner production principles and practices adopted by a manufacturing company located in an emerging economy in order to understand how these were valuable in foster circular economy implementation. A case-based research approach was adopted in this investigation. The circular economy practices introduced by the company were analyzed by considering their connections with the requirements when transitioning to a circular economy paradigm, within company-related processes in addition to circular economy areas at the micro-level. An inductive approach was adopted for data analysis to develop some propositions regarding circular economy interactions. The main findings revealed that cleaner production practices for product optimization are valuable to circular economy implementation regarding circular product design strategies. The cleaner production principle of input substitution is valuable for reducing input and use of natural resources as well as increasing the share of renewable and recyclable resources. Technological optimization can contribute to reducing emissions levels. In addition, field data showed that cleaner production practices at the production area enable circular economy practices to be implemented at the micro-level, as well as there is a connection with other circular economy areas (i.e. waste management, consumption, and support). Moreover, the findings confirmed that all cleaner production practices and principles implemented by the organization are connected to each other and across the processes. Further studies may focus on testing the propositions developed in this study in other manufacturing contexts, as well as on the investigation of possible cause-effect relationships that may exist between cleaner production and circular economy transition pathways. [ABSTRACT FROM AUTHOR]

Anaerobic digestion of food waste within urban areas can generate decentralised renewable energy and support community enterprise activities, thereby contributing to closing the waste-energy-food loop. However, widespread uptake of small-scale, urban anaerobic digestion networks is limited by economic costs and the safe disposal of surplus digestate. This paper uses an interdisciplinary approach to assess the feasibility of anaerobic digestate management through the installation of hydroponics or algae cultivation systems, based on a case study of a micro anaerobic digestion system in London, England. Results show that installing a dewatering sifter together with a hydroponics system is a technically and economically feasible option for digestate enhancement in the urban environment. Its installation is, however, not currently justified for the system under consideration due to cost, regulatory, spatial, and contextual constraints identified using actor-network analysis. Nevertheless, if regulatory and wider contextual issues are accommodated, and more than 30 L of digestate are produced daily, a dewatering and vertical hydroponic system could result in a profit of approximately £100,000 over 10 years. While the microalgal system was also able to upgrade digestate, at present productivity is too low and the capital cost of photobioreactor technology is prohibitively expensive. This underlines the need for technical improvements and low-cost enhancement options to achieve justifiable paybacks until regulatory reforms and the wider economic situation are more favourable to anaerobic digestion treatment within cities. [ABSTRACT FROM AUTHOR]

This paper reviews studies of the environmental impact of textile reuse and recycling, to provide a summary of the current knowledge and point out areas for further research. Forty-one studies were reviewed, whereof 85% deal with recycling and 41% with reuse (27% cover both reuse and recycling). Fibre recycling is the most studied recycling type (57%), followed by polymer/oligomer recycling (37%), monomer recycling (29%), and fabric recycling (14%). Cotton (76%) and polyester (63%) are the most studied materials. The reviewed publications provide strong support for claims that textile reuse and recycling in general reduce environmental impact compared to incineration and landfilling, and that reuse is more beneficial than recycling. The studies do, however, expose scenarios under which reuse and recycling are not beneficial for certain environmental impacts. For example, as benefits mainly arise due to the avoided production of new products, benefits may not occur in cases with low replacement rates or if the avoided production processes are relatively clean. Also, for reuse, induced customer transport may cause environmental impact that exceeds the benefits of avoided production, unless the use phase is sufficiently extended. In terms of critical methodological assumptions, authors most often assume that textiles sent to recycling are wastes free of environmental burden, and that reused products and products made from recycled materials replace products made from virgin fibres. Examples of other content mapped in the review are: trends of publications over time, common aims and geographical scopes, commonly included and omitted impact categories, available sources of primary inventory data, knowledge gaps and future research needs. The latter include the need to study cascade systems, to explore the potential of combining various reuse and recycling routes. [ABSTRACT FROM AUTHOR]

The need for circularity assessment tools to prevent undesirable effects (e.g. recycling processes requiring more energy) is gaining recognition. Preserving resources and relieving pollution reservoirs are both necessary conditions to achieve a sustainable circular economy (CE), and the corresponding assessment tools should be selected accordingly. We chose life cycle assessment (LCA) and the Material Circularity Indicator (MCI). In this paper, we tested the tools through two case studies from the tire industry. The Brazilian case proposes three scenarios to process used tires: baseline, retreading and regrooving. The European case suggests collecting secondary material from end-of-life (EoL) tires to produce recycled content (RC) at 4% and 10% rates. These rates were chosen to illustrate the change in tire performance in the use phase. We propose an approach to discuss MCI and LCA results that identifies four pathways toward or away from the CE goal: coupling, decoupling, trade-off on resources or trade-off on reservoirs. The case studies reveal that extending lifetime through retreading and introducing recycled material improves the MCI of a tire but do not necessarily improve impacts on human health and ecosystems. Also, discrepancies in the results between the MCI and the LCA's resource indicator highlight relevant issues for new CE experts seeking to design assessment tools. Even though LCA provides a broader scope than the MCI, it still reflects a relative contribution to environmental sustainability while the MCI focuses on micro-scale improvements in resource use efficiency. [ABSTRACT FROM AUTHOR]

The city is an important component in the construction of circular economy (CE), and after years of development, assessment of urban CE and calculation of an urban circular development index (UCDI) is an important task that the Chinese government has faced. However, existing research into the indicator system and evaluation methods is not enough to support calculation and subsequent publishing of UCDI. Building off current research into CE, its index systems and its evaluation, this paper puts forward an evaluation index system for urban CE development (UCDI) that uses an improved entropy methodology combining expert and entropy weightings. The index was calculated for 40 cities that were part of China's pilot CE cities program for alternating years in the five year period between 2012 and 2016 (that is, the index was calculated for 2012, 2014 and 2016). The study found that the level of urban CE increased significantly over the five year period, with that in the CE pilot cities growing at a faster rate than the national average. Results show that a certain relationship exists between UCDI, urban types and economic development, but has little relationship with industrial structure. Finally, recommendations for the promotion of urban CE are proposed. [ABSTRACT FROM AUTHOR]

The growing importance of the concept of the circular economy as a way to attain sustainable development has encouraged scholars to propose different ways to understand it. Given the large number of studies done on the circular economy, their differing approaches and their multiple applications, this paper attempts to propose a consensus view of the basic notions of the circular economy framework and highlight its relationship with eco-innovation. To that end, this study carried out a systematic literature review that resulted in four main outputs: a knowledge map of the circular economy, an analysis of the main notions of the concept, principles, and determinants of a circular economy. Finally, this study brings to light some remarkable examples of eco-innovations developed for implementation in the circular economy. [ABSTRACT FROM AUTHOR]

Circular Economy (CE) aims to overcome the take-make-dispose linear pattern of production and consumption, proposing a circular system in which the value of products, materials and resources is maintained in the economy as long as possible. In recent years there has been a proliferation of scholars' publications on the topic. This study presents the results of a systematic literature review exploring the state-of-the-art of academic research on CE. The paper examines the CE body of literature with a systematic approach, to provide an exhaustive analysis of the phenomenon with rigorous and reproducible research criteria. The revisited material consists of 565 articles collected through the Web of Science and Scopus databases, and has been evaluated using specific structural dimensions to group literature into analytical categories. Starting from being a concept studied in connection with industrial ecology, CE has slowly acquired its independent role in academic research, framed mainly into environmental sustainability related studies. As a result of policies implementation, academic production is mainly concentrated in China and Europe, employing tools and methods for modelling processes and supporting decision-making for CE implementation (e.g. Life Cycle Assessment and Material Flow Analysis). CE studies follow three main lines of action: the first aims to change the social and economic dynamics at macro and administrative level; the second to support firms in circular processes implementation at micro level to spread new forms of consumption and product design; the third, developed at meso level, discusses industrial symbiosis experiences. CE is associated with a variety of concepts, and waste management emerges as the most relevant sub-sector. CE is also strongly connected with the concept of sustainability, proposing ways to operationalize its implementation at the environmental and economic level, while scholars only marginally consider social and institutional implications. The most explored practices are those related to cleaner production, aiming at reducing environmental impact and waste production along the life cycle of a product, and optimizing the performance and efficiency of processes. Conversely, studies on CE may devote greater attention to strategies for social and institutional changes, able to transform the upstream process of production and consumption. Considering business model strategies, scholars mainly focus on studying closing material loops strategy, while slowing the loops, which requires a radical change of consumption and production patterns, is only marginally included with respect to CE implementation. This study's findings highlight CE as an evolving concept that still requires development to consolidate its definition, boundaries, principles and associated practices. [ABSTRACT FROM AUTHOR]

The transformation of the energy systems encompasses technological, societal, cultural, economic, and environmental aspects and calls for a more important role for citizens and communities. Bioenergy systems are subjects to legal, technical, environmental, economic, and social settings. At the regional level, bioenergy can incorporate agricultural traditions and offer waste-management solutions. Many are the stakeholders, with different perceptions and sometimes, conflictual interests. This study is a multidisciplinary, comprehensive review of recently published papers, on legal, technical, economic, and environmental layers of the bioenergy. It highlights the role of bioenergy in the transition to a Circular waste-based Bioeconomy. Three dimensions of sustainability (environmental, economic, and social) were discussed and some thermodynamic (energy, exergy, emergy) and environmental indicators applied to bioenergy systems, were cited. Findings conclude that in the context of Circular Bioeconomy, global bioenergy sector may face challenges, due to the new demand for biomaterials from the same sources. Bioenergy sustainable pathways should be selected at the base of high efficiency, towards closing loops and in the concept of cascade and integrated biorefineries. At the regional level, bioenergy systems may be integrated with the cascade biorefinery models or can offer waste management solutions by stand-alone, tailor-made decentralized systems. In redesigning the bioenergy sector, local knowledge, public health, and community's resilience should not be neglected, while social-environmental benefits should be considered in addressing the viability of bioenergy plants. Social acceptance can be improved by a better understanding of the scientific and technical issues and by developing a broader consciousness of the planet and life. [ABSTRACT FROM AUTHOR]

Among scholars, politicians and practitioners, the term “circular economy” (CE) has become increasingly familiar, but the concept comes from different epistemological fields and there is still a lack of consensus and convergence in the literature. This paper investigates the trends and gaps on the pathways convergence of the circular economy literature. The research method is a combination of semantic analysis, bibliometrics, networks and content analysis in a systematic literature review. The sample is composed of 327 articles extracted from the Web of Science and Scopus database. The results point out the lack of consensus on terminologies and definitions, thus, based on semantic analysis, a definition is proposed. In addition, the literature shows two main clusters, with different backgrounds, of different leading research groups in distinctive geographic regions. One cluster focuses on ecoparks and industrial symbiosis, mostly in the context of China. The second cluster is concerned with supply chains, material closed loops and business models. [ABSTRACT FROM AUTHOR]

The global consumption of metals is tremendously high and growing, a problem that calls for immediate action. This paper presents a comprehensive investigation on the anthropogenic use of 55 metallic elements in two main parts: life cycle quantification and assessment. Firstly, a dynamic life cycle model is constructed to quantify annual flows, losses, and stocks during their technical use periods, that is mainly from 1900 to 2013. The results show that the global demand for 55 metals has increased from 224 Mt/yr in 1953 to 1543 Mt/yr in 2013. Meanwhile, emerging applications have created a tremendous demand for 32 metals rarely used prior to the 1980s. Furthermore, the in-use stock of all metals, except Hg, has been increasing. The results further reveal many diverse patterns in the per capita trends of these metals (i.e. increasing (27 elements), saturating (25 elements) and decreasing (2 elements)). Based on the material flow results, this study confirms that metals are used in an extremely inefficient manner. This was found by studying three indicators (total resource efficiency, circularity, and total losses) which exist on the anthropogenic cycle level. This study not only helps to highlight the necessity of closing the loop, but also urges that more attention be paid to the leakages along the metal cycle due to the significant losses (e.g. for every unit of metal use, around 4 units have been lost on average). Furthermore, the losses at each life stage are also assessed for each metal. The anthropogenic use of metals needs to be more efficient and metal-specific solutions from the manufacturing industry are needed. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to assess, theoretically and empirically, the governance approach associated with the formation of the circular value ecosystem (CVES) within the Sustainable Wealth creation based on Innovation and enabling Technologies (SWIT) framework. The SWIT framework is designed to interlink economic models, policies and strategies so as to introduce and convert residue, waste and by-product chains into multiple increasing returns cycles. Unlike regional circular economy cases in Germany, Japan and China where governments or industry have taken the lead on such initiatives - a top-down governance approach, the SWIT framework was developed for regions where government support for eco-initiatives is weak and where the participation of community stakeholders is critical – a bottom-up governance approach. The ecological, social and economic dimensions of the system are explored so as to ascertain the key stakeholders critical to the governance of the circular value ecosystem (CVES). We seek to answer: What stakeholders must be incorporated in a bottom-up CVES governance approach for the SWIT framework to be able to restore environmental resilience while creating economic returns and social benefits in rural communities? We report the results of an action research case – both successes and challenges – which sought to test this community-driven bottom-up governance approach on a rural community in Mexico. Our findings suggest that a bottom-up governance approach requires a deep understanding of the social, political, environmental and economic characteristics of the community as well as civic collaboration. [ABSTRACT FROM AUTHOR]