Search

Waste paper disposed in landfills notably contributes to greenhouse gas (GHG) emissions and impedes more sustainable, circular alternatives, such as recycling. In Hong Kong, this unsustainable approach is currently dominant as 68% of waste paper products are treated in landfills in 2020. To contextualize the impact of local waste paper management and explore mitigation potentials of circular alternatives, this paper develops a quantitative assessment framework around GHG emissions development trajectories. Combining guidelines of the Intergovernmental Panel on Climate Change (IPCC), national GHG inventories, and local parameters from life cycle analysis, five GHG emissions projections were simulated along the Shared Socioeconomic Pathways (SSPs) until 2060. Most recent baselines indicate that Hong Kong's current waste paper treatment generated 638,360 tons CO 2 -eq in 2020, comprising 1,821,040 tons CO 2 -eq from landfill and 671,320 tons CO 2 -eq from recycling, and −1,854,000 tons CO 2 -eq from primary material replacement. Proceeding along a Business-as-Usual scenario under SSP5, GHG emissions will dramatically increase to a net 1,072,270 tons CO 2 -eq by 2060, whereas a recycling-intensive scenario will lead to a net saving of −4,323,190 tons CO 2 -eq. To complement the quantitative evidence on the benefits of waste paper recycling, field research was conducted to explore the feasibility of circular policy innovation from the perspective of recycling stakeholders. These empirical qualitative and quantitative findings from stakeholders' business routines and material transactions provide crucial indications for policy and institutional innovation: Essentially, for Hong Kong to improve waste paper recycling capacities and facilitate a circular economy (CE), local stakeholders require support via fiscal policy measures (financial subsidies or tax reductions) and infrastructure improvements (delivery access and material storage). In sum, this study employs a novel analytical framework combining original qualitative and quantitative evidence to provide policy innovation towards circular, GHG emission-saving waste paper management. [Display omitted] • A new framework assessing greenhouse gas emissions from waste paper treatment. • Exploring long-term carbon neutrality pathways for managing waste paper. • Using empirical evidence from recycling stakeholders for circular policy innovation. [ABSTRACT FROM AUTHOR]

Pulp and paper industry produces massive amounts of sludge from wastewater treatment, which constitute an enormous environmental challenge. A possible management option is the conversion of sludge into carbon-based adsorbents to be applied in water remediation. For such utilization it is important to investigate if sludge is a consistent raw material originating reproducible final materials (either over time or from different manufacturing processes), which is the main goal of this work. For that purpose, different primary (PS) and biological sludge (BS) batches from two factories with different operation modes were sampled and subjected to pyrolysis (P materials) and to pyrolysis followed by acid washing (PW materials). All the materials were characterized by proximate analysis, total organic carbon (TOC) and inorganic carbon (IC), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and N 2 adsorption isotherms (specific surface area ( S BET )and porosity determination). Sludge from the two factories proved to have distinct physicochemical properties, mainly in what concerns IC. After pyrolysis, the washing step was essential to reduce IC and to considerably increase S BET , yet with high impact in the final production yield. Among the materials here produced, PW materials from PS were those having the highest S BET values (387–488 m 2 g −1 ). Overall, it was found that precursors from different factories might originate final materials with distinct characteristics, being essential to take into account this source of variability when considering paper mill sludge as a raw material. Nevertheless, for PS, low variability was found between batches, which points out to the reliability of such residues to be used as precursors of carbon adsorbents. [ABSTRACT FROM AUTHOR]

Household food waste is increasingly recognised as a global wicked problem for its greenhouse gas emissions, economic damage, and resource loss. Although targeted in the UN's Sustainable Development Goals, countries can only respond according to their capacity. For Australia, national policy has put the pressure on states and territories to divert food waste away from landfill into a nascent circular economy. For councils, this increasingly means implementing a FOGO (Food Organics/Garden Organics) kerbside collection. Despite funding and infrastructure development, many are resisting. Framed by the tenets of policy diffusion, this paper presents the results of a nationwide exploratory survey aimed at identifying how and why council-based waste services staff resist, emulate or lead FOGO implementation. By assessing participants current kerbside systems and their attitudes towards household food waste management, the survey found costs, contamination, and capacity and were key concerns. However, responses to these varied considerably despite similarities of situation, often relating more to collaborative attitudes across waste services, council, and councillors. This paper recognises that a conducive environment for change is urgently needed for Australia to achieve organics diversion targets and shift household food towards a circular economy. It provides a starting point for further research into the complex and nuanced dynamics between council waste services and FOGO implementations, from external drivers and council paradigms to individual attitudes and perceptions. • Policy push alone is not enough to achieve Australia's food waste diversion targets. • Achieving uncontaminated household food waste requires strong national legislation and policy. • Regional collaborations between councils are beneficial yet under-used. • Inter-council emulation enhances infectious inaction where policy and support is lacking. • National food waste awareness-raising reduces community confusion. [ABSTRACT FROM AUTHOR]

An insightful attempt has been made in this review and the primary objective was to meticulously provide an update on the sustainabilities, advances and challenges pertaining the removal of ammonia from water and wastewater. Specifically, ammonia is a versatile compound that prevails in various spheres of the environment, and if not properly managed, this chemical species could pose severe ecological pressure and toxicity to different receiving environments and its biota. The notorious footprints of ammonia could be traced to anoxic conditions, an infestation of aquatic ecosystems, hyperactivity, convulsion, and methaemoglobin, popularly known as the "blue baby syndrome". In this review, latest updates regarding the sustainabilities, advancements and challenges for the removal of ammonia from aqueous solutions, i.e., river and waste waters, are briefly elucidated in light of future perspectives. Viable routes and ideal hotspots, i.e., wastewater and drinking water, for ammonia removal under the cost-effective options have been unpacked. Key mechanisms for the removal of ammonia were grossly bioremediation, oxidation, adsorption, filtration, precipitation, and ion exchange. Finally, this review denoted biological nutrient removal, struvite precipitation, and breakpoint chlorination as the most effective and promising technologies for the removal of ammonia from aquatic environments, although at the expense of energy and operational cost. Lastly, the future perspective, avenues of exploitation, and technical facets that deserve in-depth exploration are duly underscored. [Display omitted] • This paper successfully reviewed potential avenues for ammonia valorization. • Gaps in knowledge and challenges related to ammonia treatment were highlighted. • Challenges related to removal and recovery were duly explained. • Future research outlooks and needs were also emphasized in this paper. • Feasibilities of practicing circular economy in ammonia treatment were identified. [ABSTRACT FROM AUTHOR]

This paper reviews the current problems and prospects to overcome circular water economy management challenges in European countries. The geopolitical paradigm of water, the water economy, water innovation, water management and regulation in Europe, environmental and safety concerns at water reuse, and technological solutions for water recovery are all covered in this review, which has been prepared in the frame of the COST ACTION (CA, 20133) FULLRECO4US, Working Group (WG) 4. With a Circular Economy approach to water recycling and recovery based on this COST Action, this review paper aims to develop novel, futuristic solutions to overcome the difficulties that the European Union (EU) is currently facing. The detailed review of the current environmental barriers and upcoming difficulties for water reuse in Europe with a Circular Economy vision is another distinctive aspect of this study. It is observed that the biggest challenge in using and recycling water from wastewater treatment plants is dealing with technical, social, political, and economic issues. For instance, geographical differences significantly affect technological problems, and it is effective in terms of social acceptance of the reuse of treated water. Local governmental organizations should support and encourage initiatives to expand water reuse, particularly for agricultural and industrial uses across all of Europe. It should not also be disregarded that the latest hydro politics approach to water management will actively contribute to addressing the issues associated with water scarcity. • We concentrated on new future perspectives for addressing current resource recovery strategy challenges. • We revealed a snapshot for future needs for a fully circular European economy. • We built a discussion platform in holistic water recovery by COST Action. [ABSTRACT FROM AUTHOR]

The circular economy (CE) has been gaining traction in recent years as it promises a change for good, in terms of environmental, social, and economic benefits. The major changes required to implement circular economy business models (CEBMs), can prove to be especially difficult for organisations. This study provides a holistic analysis of the effect of CE institutional policies on the development of CEBMs in organisations, by exploring not only production-oriented policies, which have been the focus of previous research, but also consumption policies. Consumption policies, in the form of regulatory and information policies, are oriented towards consumers and have the potential to affect the demand for CE products, which in turn affects the development of CEBMs in organisations. The paper is framed within the institutional theory and the context of the European Union. Our results reveal that consumption policies have a positive, albeit diminishing, effect on the CEBMs. Our paper finds that regulation is the most impactful policy, having a larger impact than production policies. Our results highlight the important role of institutional policies in fostering consumers' demand for CE products and of consumption policies as tools to be employed by governments in fostering CEBMs and achieving sustainability. • Consumption policies have a positive, albeit diminishing, effect on the CEBMs. • Regulation for consumption is more impactful than production policies. • Institutional policies are crucial in fostering consumers' demand for CE products. • Consumption policies are an essential tool for governments to foster CEBMs. [ABSTRACT FROM AUTHOR]

Contaminated recyclables, which are frequently discarded as waste, pose a significant challenge to the implementation of a circular economy. These contaminated recyclables impede the circulation of resources, resulting in higher processing costs at material recovery facilities (MRFs). Over the past few decades, machine learning (ML) models such as linear regression (LR), support vector machine (SVM), and random forest (RF) have evolved to provide new methods for predicting inbound contamination rates in addition to traditional statistical models. In this study, we applied ML models to predict inbound contamination rates using demographic features from 15 counties in the U.S. with different curbside collection strategies. In general, we found that ML models outperformed linear mixed models. Specifically, SVM models had the highest performance (R2 = 0.75; mean absolute error (MAE) = 0.06), which may be due to their ability to model nonlinear relationships between features and inbound contamination rates. The key predictor was population, with poverty rate being positively correlated and median age negatively correlated with inbound contamination rates. To improve the management of contamination and enhance the implementation of a circular economy, better models are needed to understand and estimate inbound contamination rates as well as identify critical factors in the present and future. • We examine the factors influencing inbound paper contamination in MRFs. • Importance of the factors are determined by three machine learning models. • The contamination levels in single stream were found to be higher than that of commingled. • SVM regressor obtained the best performance. • Population size is determined to be the most significant factor by all three ML methods. [ABSTRACT FROM AUTHOR]

This research paper delves into the intricate interplay between decarbonisation and sustainability, focusing on adopting chemical looping technologies. Deep decarbonisation scenarios necessitate a profound transformation in various sectors to mitigate climate change, and oil refineries, as pivotal players, must adapt to these changes. Employing the BLUES integrated assessment model, we evaluate the evolution of the refining sector in decarbonisation pathways, emphasising its potential for sustainability through repurposing and emissions mitigation. Additionally, we delve into chemical looping technologies, including Solar Thermal Chemical Looping (STCL), Reverse Water Gas Shift Chemical Looping (RWGS-CL), Chemical Looping Reforming (CLR), and Super Dry Reforming (SDR), elucidating their principles and contributions to carbon dioxide (CO 2) conversion. These technologies offer promising routes for CO 2 capture and present opportunities for sustainable carbon loop cycles, potentially revolutionising industries' emissions reduction efforts. In a world of climate change, this research illuminates a sustainable path forward by integrating decarbonisation and innovative CO 2 management strategies. • Chemical looping technologies offer innovative routes for sustainable carbon capture and utilisation. • Oil refineries can play a pivotal role in reducing emissions through asset repurposing. • Integration of the BLUES model provides insights into refining sector evolution for decarbonisation. • Solar Thermal Chemical Looping (STCL) utilises solar energy for CO 2 conversion. • Methane-utilising CO 2 CL processes like CLR and SDR offer promising sustainability solutions. [ABSTRACT FROM AUTHOR]

The escalating threat of plastic pollution necessitates urgent and immediate action, particularly within the food and beverage (F&B) industry, a significant contributor to single-use plastic waste (SUP). As the global population surges, so does the consumption of single-use plastics in the F&B sector, perpetuating a linear economy model characterized by a 'take, make, use, dispose' approach. This model significantly exacerbates plastic waste issues, with projections indicating an alarming increase in plastic outputs by 2050 if current practices continue. Against this backdrop, the circular economy presents a viable alternative, with its emphasis on resource retention, recovery, and the extension of product lifecycles. This study delves into the problems posed by single-use plastics, introduces the circular economy as a sustainable model, and explores effective strategies for the recycling and reuse of plastic waste within this framework. By examining the environmental impact of SUP in the F&B sector and advocating for the adoption of circular economy principles, this paper underscores a critical pathway towards sustainable solutions in the battle against plastic pollution. In conclusion, the transition to a circular economy, underpinned by global collaboration and the proactive implementation of supportive policies, is imperative for reducing the environmental footprint of single-use plastics and fostering a sustainable future. • Urgent need to address single-use plastic (SUP) waste in food & beverage industry due to escalating threat. • Growing global population drives linear 'take, make, use, dispose' model, exacerbating plastic waste. • Alarming predictions for SUP output by 2050 necessitate shift to circular economy approach. • Circular economy emphasises resource retention, recovery, and extended product lifecycles as a solution. • Study advocates for circular economy principles in F&B sector to combat plastic pollution crisis. [ABSTRACT FROM AUTHOR]

Abstract This paper discusses the economic rationale of recycling exhaustible raw materials and assesses how a circular economy perspective can improve the sustainable use of critical raw materials (CRMs). We use the case study of yttrium, a rare-earth element (REE) on the EU list of CRMs, given its widespread use in the electronics industry and the geopolitical concentration of its supply. Even if recycling REEs from waste electric and electronic equipment is a valid alternative to extraction from mines, as proposed by the circular economy paradigm, less than 1% of REEs used today are recycled. Nevertheless, studies on the economic benefits of recovery REEs are very limited. In this paper, we present the business case of an Italian recycling company, Relight Ltd., and its HydroWEEE project, to recycle REEs such as yttrium, from spent lamps. In environmental terms, recycling REEs has a much lower impact than their extraction from virgin source. In economic terms, it is profitable to recycle yttrium if its market price is above 14€/kg, and above 9.54€/kg taking in consideration the external costs of mining. Therefore, in 2012 and 2013, recycling was profitable thanks to the high price of yttrium, while between 2014 and 2016 recycling was not cost effective. In these cases, policymakers must incentivize recovery and recycling solutions with appropriate policies. Highlights • In this case study, recycling yttrium is convenient if its market price is above 14 €/kg. • If external costs of mining are considered, recycled yttrium is advantageous above 9.54 €/kg. • In 2012 and 2013 the price of yttrium covered the collection and the treatment costs. • Policymakers should incentivize recycling when market conditions are disadvantageous like in 2014–2016. • To prevent supply risk, it is crucial to sustain the European rare-earth recycling industry. [ABSTRACT FROM AUTHOR]

Abstract "Smart Food Waste Recycling Bin" (S-FRB) systems have recently been developed to facilitate the transformation of food waste into an end-product suitable for use as an energy resource following circular economy principles. This decentralized waste decomposition system utilizes fermentative microorganisms for the treatment of organic food waste and has emerged as a possible solution for coping with both landfill capacity and greenhouse gas emissions issues. This paper utilizes Life Cycle Assessment (LCA) to determine the environmental impacts associated with this S-FRB technology and identify environmental hotspots to reduce these impacts. In this paper, we have conducted an on-site pilot-scale study for 2 months at a canteen located at the City University of Hong Kong, which resulted in a 90% reduction in the mass of food waste treated in the S-FRB system. Based on this pilot-scale study hypothetical scenarios were developed to determine potential environmental impacts potential scaled-up deployments of the S-FRB instrument based on varied assumptions. Examination of the LCAs of these different scenarios demonstrated the potential for further reduction in CO 2 equivalent emissions during food waste treatment. Cumulative Energy Demand (CED) and Energy Return on Investment (EROI) were also investigated to understand the energy balance energy of the S-FRB technology. Finally, using current waste treatment methods in Hong Kong as a benchmark, the environmental impacts of the S-FRB are compared with the conventional food waste treatment approaches such as landfilling and organic waste treatment facilities (OWTF). Graphical abstract Image 1 Highlights • S-FRB technology illustrates lower GHG emission comparing with existing facilities. • Energy return on investment of S-FRB depicts the possibility of food waste circulation. • Optimized scenarios show the improvements in both of GHG emission and EROI. [ABSTRACT FROM AUTHOR]

Abstract A large stream of research has studied the performance of waste plastics impregnated concrete, reporting multiple benefits and advocating its use in construction works. But no study has reported the merits of bricks impregnated with waste plastics. The present paper reports the results of experiments done on bricks made up of varying percentages of waste thermoplastics (0 – 10% by weight) and sand (60 – 70% by weight), holding percentages of fly ash and ordinary Portland cement constant at 15% (by weight) each. Three types of waste thermoplastics were used, forming three separate batches of bricks. The plastics were polycarbonates, polystyrenes, and mixed plastics. The bricks were cured under water for 28 days. Some of the batches were baked at temperatures ranging from 90 °C to 110 °C for 2 hours in order to melt the plastics to form voids. The bricks made with the above-stated compositions were found to possess low thermal conductivity and adequately high compressive strength. The compressive strength of these bricks is observed to be more than 17 MPa, which lies within the upper half of the range of strengths specified for bricks in the IS 1077:1992 standard. The waste plastics impregnated bricks display high thermal resistance, a feature that can add economic value to the brick manufacturers, motivating them to establish the necessary logistics for collection and use of all types of waste thermoplastics. The paper also presents a regression model to predict the compressive strength of bricks at varying plastic contents. The study, thus, introduces a new strand of research on sustainable recycling of waste thermoplastics in the context of the circular economy. Graphical abstract Image 1 Highlights • Review of the present state of waste plastics and recycling process are presented. • Making bricks out of waste plastics is explored. • Mechanical properties are satisfactory up to 10% of plastic content. • Recycling waste thermoplastics in construction materials is recommended. [ABSTRACT FROM AUTHOR]

Holistically considering the current situation of the commercial synthetic fertilizer (CSF) market, recent global developments, and future projection studies, dependency on CSFs in agricultural production born significant risks, especially to the food security of foreign-dependent countries. The foreign dependency of countries in terms of CSFs can be reduced by the concepts such as the circular economy and resource recovery. Recently, waste streams are considered as a source in order to produce recovery-based fertilizers (RBF). RBFs produced from different waste streams can be substituted with CSFs as input for agricultural applications. Municipal solid waste leachate (MSWL) is one of the waste streams that have a high potential for RBF production. Distribution of the published papers over the years shows that this potential was noticed by more researchers in the millennium. MSWL contains a remarkable amount of nitrogen and phosphorus which are the main nutrients required for agricultural production. These nutrients can be recovered with many different methods such as microalgae cultivation, chemical precipitation, ammonia stripping, membrane separation, etc. MSWL can be generated within the different phases of municipal solid waste (MSW) management. Although it is mainly composed of landfill leachate (LL), composting plant leachate (CPL), incineration plant leachate (IPL), and transfer station leachate (TSL) should be considered as potential sources to produce RBF. This study compiles studies conducted on MSWL from the perspective of nitrogen and phosphorus recovery. Moreover, recent developments and limitations of the subject were extensively discussed and future perspectives were introduced by considering the entire MSW management. Investigated studies in this review showed that the potential of MSWL to produce RBF is significant. The outcomes of this paper will serve the countries for ensuring their food security by implementing the resource recovery concept to produce RBF. Thus, the risks born with the recent global developments could be overcome in this way besides the positive environmental outcomes of resource recovery. • Municipal solid waste leachate should be considered a source of nutrients. • The number of studies based on nutrient recovery from leachate tends to escalate. • Nutrient recovery from leachate contributes to global food security. • The composition of recovery-derived fertilizer should be further investigated. [ABSTRACT FROM AUTHOR]

Current research in Circular Economy (CE) fails to address the occurrence of Rebound Effects (RE), which are systemic and behavioural responses to the implementation of interventions hindering the potential sustainability benefits. This paper aims to advance the academic discussion and the practical consideration of RE by exploring the potential of using System Dynamics (SD) to enable the ex-ante identification of potential RE of CE initiatives. A five-stage simulation-based approach for the identification and mitigation of potential rebound effects (AIMRE) is proposed. Its application is demonstrated in a use-oriented product/service system (PSS) case focused on a high-end dress rental service. The AIMRE enables the representation of the magnitude and reasons for RE occurrence through 14 scenarios. The finding highlights the importance of considering the interplay between consumers' and companies' decision-making processes in quantifying, understanding, and mitigating RE occurrence. • Simulation-based approach to investigate rebound effects (RE). • Helps identify potential RE in Circular Economy (CE) initiatives. • Relies on relevant consumers' and companies' decision-making structures. • Enables quantification through a valid RE magnitude quantification structure. • Scenarios of CE adoption provide insight into the reason for RE occurrence. [ABSTRACT FROM AUTHOR]

This paper studies the effect of Green Public Procurement (GPP) on competition, bids, and winning bids under two different regulation periods where the latter include more explicitly expressed GPP ambitions. Based on detailed data from Swedish internal cleaning service procurements, our results imply that environmental considerations might not influence the bids as required for GPP to be considered an effective environmental policy instrument. Over time, lower degree of competition and increased bids are found. This phenomenon can be attributed, at least in part, to regulatory influences, signifying an escalating complexity in the process of submitting bids. • Contract characteristics other than green demands impact bids and winning bids. • Environmental criteria alone do not influence bids and winning bids. • The number of criteria has a influence on bids and winnings bids. • Findings indicate increased complexity in public procurement bid submission. • In this market, criteria maintain standards rather than driving greener practices. [ABSTRACT FROM AUTHOR]

An increasing number of countries and regions consider the bioeconomy transition a strategic policy priority. When approached through the lens of a circular economy perspective, investments in bioeconomy have the potential to enhance resource utilisation efficiency, preserve biodiversity and ecosystems, and foster sustainable development with low emissions. At the same time, if requirements and contextual factors of bioeconomy strategies are not formally analysed, bioeconomic investments might lead to unintended negative consequences. This paper proposes a decision support procedure to design, assess, prioritise, and monitor bioeconomy investments and policies. The flexibility and scalability of our decision support procedure is tested in Colombia to foster a regional and local transition to bioeconomy initiatives that consider the local capital assets and the stakeholders' views. The heterogeneous character of the Colombian environment, economy, society and culture represents an ideal condition to test the strength of the decision support procedure to promote bioeconomy in low and middle-income countries. Our empirical results highlight the benefit of adopting a formal assessment framework that includes strategic national indicators, regional features and stakeholders' views. In terms of the Colombian regional bioeconomy ambitions, we highlight the need for expanding knowledge hubs and participatory stakeholder networks and buttressing appropriate financial mechanisms. • Bioeconomy transition needs to be framed in an extended circular economy framework. • Bioeconomy strategies need to consider local context and stakeholders' engagement. • Scalable and replicable decision support procedures should guide bioeconomy implementations. • Balance sheet approach inform all stages of bioeconomy policies and projects. • Application of the balance sheet approach in Colombia highlights diverse local priorities. [ABSTRACT FROM AUTHOR]

Reverse Logistics (RL) of end-of-use/end-of-life products has become a vital part of circular economy practices for manufacturers. However, significant quantities of resources are still landfilled instead of being recovered. With mounting pressure on businesses to address the sustainability crises (resources, climate change, waste, toxicity) on account of the take-make-dispose-based linear economy, companies today realise the importance of RL but face several barriers to implementing it, including a lack of knowledge. Although several studies have investigated different aspects of RL in various industries in different country settings, less attention has been devoted to developing a systematic and holistic approach for designing and implementing RL. To address these gaps, this paper reviews 116 scholarly articles published between 2011 and 2021 to identify attributes related to the design and implementation of RL systems. Based on a systematic literature review, a conceptual framework is presented covering the key activities, drivers and barriers, stakeholder engagement and performance management in RL. Such a framework can support companies evaluate different approaches and strategies, as well as the opportunities and challenges of designing and implementing RL and transitioning towards a Circular Economy. [Display omitted] • Companies often face challenges in designing & implementing Reverse Logistics (RL). • This paper reviews 116 papers to synthesize the state-of-the-art in RL research. • It covers activities, drivers, barriers, stakeholders, metrics and incentives in RL. • It also investigates industry 4.0 and role of digital technologies in RL systems. • The framework for RL helps businesses plan and implement RL for a circular economy. [ABSTRACT FROM AUTHOR]

How far has the transition process to a circular economy progressed? How can this transition process be promoted? So far, the indicators used to analyse such questions have mostly been based on aggregate recycling rates or waste volumes. However, circular economy is much more than that. This paper develops a concept for empirically measuring the transition process along a company's value chain. The concept distinguishes 27 business activities that are relevant for the circular economy and thus enables detailed statements about the transition to the circular economy along the entire value chain and the three dimensions of the circular economy, i.e. efficiency, closing the resource loop and extending product life. Based on this concept, a representative survey of 8,000 Swiss companies was conducted. The data allow – for the first time and for a representative sample – the analysis of the determinants of the transition process to a circular economy using econometric estimations. The results suggest that the transition process has just started; most companies involved in circular economy activities focus on efficiency enhancing measures rather than on extending the life of products/services or closing the loop. In addition, the results show that circular economy pioneers are characterized by a willingness to invest a significant amount of available capital in the breadth of circular activities, have greater financial flexibility, and in some cases face greater non-price competition. Ultimately, the results suggest that the transition to a circular economy can only be successful if the necessary framework conditions are set in such a way that it is profitable for the company to significantly increase the degree of circularity. • Existing data inadequately reflect the transition to a circular economy at the company level. • This paper presents an initial concept for empirically measuring circular economy activities at the company level. • Based on this concept, a representative survey of 8,000 Swiss companies was conducted. • The results indicate that the transition process has just started. • Economic regressions allow to characterize the pioneers of the circular economy. [ABSTRACT FROM AUTHOR]

With global climate change becoming increasingly serious, carbon neutrality, a key strategy to mitigate climate change, has attracted widespread attention. However, due to the multidisciplinary and complexity of carbon neutrality studies, as well as the diversification of research content, a comprehensive review and systematic synthesis of which is quite limited. In this paper, a bibliometric analysis on the topic of carbon neutrality is conducted to reveal the research progress from a quantitative and visual perspective and describe the evolution of research hotspots. The results show that carbon neutrality research is abundant at both the macro and micro levels. Low carbon development is the premise of carbon neutrality, and emission reduction and carbon sinks are the basis of carbon neutrality. The degree of research varies significantly in different countries, with China dominating in the number of publications, followed by the USA and the UK. The realization of carbon neutrality cannot be fully achieved by one single perspective and requires a comprehensive and systematic analysis of technology, economy, and society. Carbon neutrality is a technology-driven process guided by policy. Economically, carbon taxes and carbon markets are two important market mechanisms for reducing carbon emissions. Technically, researches of negative carbon technologies and renewable energy are growing rapidly. Carbon market, carbon negative technology, circular economy, and green energy will become the focus of future research. This paper helps scholars to understand the overall state of carbon neutrality research and provides a historical reference for future research. • The evolution of carbon neutrality research is identified by a bibliometric method. • Visualizes research status and outlines research foci, frontiers and prospects. • Retrieve 5271 articles published over 25 years in SCIE and SSCI databases. • Carbon neutrality is a technology-driven process guided by policy. • Circular economy and carbon markets are new areas of carbon neutrality research. [ABSTRACT FROM AUTHOR]

The lack of proper management of medical waste leads to environmental pollution and threatens the lives of communities. Good medical waste management means appropriate planning and monitoring at all stages, including collection, separation, treatment, recycling, and disposal which promotes a circular approach. This paper presents a multi-item, multi-period, and bi-objective mixed-integer linear programming circular economy transition model for medical waste management considering the uncertainty in the amount of waste generated to design a green reverse network. In this paper, for the first time, the concept of queuing theory is applied to manage the waiting time of trucks carrying infectious waste in treatment centers. In addition, the proposed model simultaneously addresses the centers' location and heterogeneous vehicles routing, and uses a stochastic scenario-based approach to deal with uncertainty of the waste generated. The purpose of the proposed model is to minimize total cost and population risk, and for this end, to employ an improved augmented epsilon-constraint method (AUGMECON2). Finally, the efficiency of the proposed model and solution approach is examined using the data of a case study in Alborz province that includes six hospitals, three potential collection centers, three potential treatment centers, four potential recycling centers, and three potential disposal centers. • Designing a green reverse logistic network to manage medical waste using an MILP model and the queuing theory. • Using a scenario-based approach to deal with uncertainty in amount of waste generated by hospitals. • Applying AUGMECON2 method for solving the proposed bi-objective MILP model. • Validating the proposed model using the real-world data. [ABSTRACT FROM AUTHOR]

One of the many waste components that end up in landfills is sludge, an organic waste that Black Soldier Flies (BSF) may be capable of reducing or removing along with potential pathogens from the environment. Throughout this review, knowledge gaps were evaluated as well as indications that BSF can positively impact the environment and economy when it comes to reducing sludge. This review first aimed to establish consistency across assessed papers (n = 41). Second, previous research on the efficiency and capability of sludge to be reduced by BSF both in isolation and with other substrates (co-digestion) was assessed. Subsequently, this review also evaluated the resulting safety of both the BSF and remaining sludge after consumption. Through this review, reduction difficulties and gaps in research and industry were evaluated. Unfortunately, complications come from the lack of policy for industry status as well as the need for further research. Therefore, further research is required on the consumption of different sludges. In particular, sludge should be tested with co-substrates to decrease waste removal problems. Sludge lacks crucial nutrients and contains extracellular polymeric substances preventing BSFL consumption. This review could potentially be helpful in future research to formulate a methodology for better BSFL consumption and production of insect biomass by sludge pre-treatment. This could lead to the implementation of the new policy in sludge management. • Black soldier fly larvae can reduce different sludges that may contain pathogens. • There are discrepancies with defining sludge and sludge consumption safety. • Sludge research is primarily focused on fecal sludge, leaving gaps in other sludges. • Sludge consumption by larvae and safety research can aid in waste management policy. [ABSTRACT FROM AUTHOR]

The metal resource crisis and the inherent need for a low-carbon circular economy have driven the rapid development of e-waste recycling technology. High-value waste printed circuit boards (WPCBs) are an essential component of e-waste. However, WPCBs are considered hazardous to the ecosystem due to the presence of heavy metals and brominated organic polymers. Therefore, achieving the recycling of metals in WPCBs is not only a strategic requirement for building a green ecological civilization but also an essential guarantee for achieving a safe supply of mineral resources. This review systematically analyzes the hydrometallurgical technology of metals in WPCBs in recent years. Firstly, the different unit operations of pretreatment in the hydrometallurgical process, which contain disassembly, crushing, and pre-enrichment, were analyzed. Secondly, environmentally friendly hydrometallurgical leaching systems and high-value product regeneration technologies used in recent years to recover metals from WPCBs were evaluated. The leaching techniques, including cyanidation, halide, thiourea, and thiosulfate for precious metals, and inorganic acid, organic acid, and other leaching methods for base metals such as copper and nickel in WPCBs, were outlined, and the leaching performance and greenness of each leaching system were summarized and analyzed. Eventually, based on the advantages of each leaching system and the differences in chemical properties of metals in WPCBs, an integrated and multi-gradient green process for the recovery of WPCBs was proposed, which provides a sustainable pathway for the recovery of metals in WPCBs. This paper provides a reference for realizing the gradient hydrometallurgical recovery of metals from WPCBs to promote the recycling metal resources. • Gentle hydrometallurgy of metals in WPCBs is summarized and analyzed. • Leaching methods for gold, copper and other metals are systematically compared. • A process for clean gradient recovery of multi-metals from WPCBs is proposed. [ABSTRACT FROM AUTHOR]

The circular bio-based economy offers great untapped potential for the food industry as possible valuable products and energy can be recovered from food waste. This can promote more sustainable and resilient food systems in Europe in follow-up of the European Commission's Farm to Fork strategy and support the global transition to more sustainable agri-food systems with the common agricultural and fisheries policies. With its high nutrient content, waste and by-products originating from fish and seafood industry (including aquaculture) are one of the most promising candidates to produce alternative fertilising products which can play a crucial role to replace synthetic mineral fertilisers. Whereas several studies highlighted the opportunities to recover valuable compounds from fishery waste, study towards their potential for the production of fertilising products is still scarce. This study presents an extensive overview of the characteristics of fishery waste and by-products (i.e., fish processing waste, fish sludge, seafood waste/by-products), the state-of-the-art nutrient recovery technologies and recovered nutrients as fertilising products from these waste streams. The European Commission has already adopted a revised Fertilising Products Regulation (EU) 2019/1009 providing opportunities for fertilising products from various bio-based origins. In frame of this opportunity, we address the quality and safety aspects of the fishery waste-derived fertilising products under these criteria and highlight possible obstacles on their way to the market in the future. Considering its high nutrient content and vast abundance, fish sludge has a great potential but should be treated/refined before being applied to soil. In addition to the parameters currently regulated, it is crucial to consider the salinity levels of such fertilising products as well as the possible presence of other micropollutants especially microplastics to warrant their safe use in agriculture. The agronomic performance of fishery waste-derived fertilisers is also compiled and reported in the last section of this review paper, which in most cases perform equally to that of conventional synthetic fertilisers. • Fish processing waste/wastewater/sludge has high protein and lipid contents. • The choice of technology depends on the raw material and desired end-product. • Salinity and microplastics are potential critical parameters. • Fish sludge has a great potential but should be treated/refined before application. • Fishery waste-based fertilisers perform equally to commercial synthetic fertilisers. [ABSTRACT FROM AUTHOR]

The incessant population has increased the production and consumption of plastics, paper, metals, and organic materials, which are discarded as solid waste after their end of life. The accumulation of these wastes has created growing concerns all over the world. However, conventional methods of solid waste management i.e., direct combustion and landfilling have caused several negative impacts on the environment (releasing toxic chemicals and greenhouse gases, huge land use) besides affecting human health. Therefore, it is requisite to determine sustainable alternative technologies that not only help in mitigating environmental issues but also increase the economic value of the discarded solid wastes. This process is known as urban mining where waste is converted into secondary resources and thereby conserves the natural primary resources. Thus, this review highlights the technological advancements in the valorization process of discarded wastes and their sustainable utilization. We also discussed several limitations of the existing urban mining processes and further the feasibility of valorization techniques was critically analyzed from a techno-economical perspective. This paper recommends a novel sustainable model based on the circular economy concept, where waste is urban mined and recovered as a secondary resource to support the united nations sustainable development goals (SDGs). The implementation of this model will ultimately help the developing countries to achieve the target of SDGs 11, 12, and 14. [Display omitted] • The wastes are a reservoir of precious and heavy metals, organics, and plastics. • Urban mining of various types of solid wastes helps in mitigating environmental issues. • A sustainable recovery model for waste to wealth has been recommended. • Implementing a circular economy in solid waste can directly achieve SDGs 11, 12 & 14. [ABSTRACT FROM AUTHOR]

Due to lower-cost energy supplies elsewhere, Europe needs resource efficient technologies to safeguard the competitiveness of its energy-intensive industries. The technical feasibility of the CCU value chain components (carbon capture, transportation and utilization) has been widely studied in literature. However infrastructural, regulatory and business strategic issues have received less attention. A review of the relevant policies (e.g. European Emissions Trading Scheme, Renewable Fuels and Waste Directives) has been performed. Stakeholder engagement and the stakeholder influence mapping was used to examine potential climate change, circular economy, renewable energy and regional industrial development policies that can support CO 2 utilization value chains. The main contribution of the paper is to outline potential benefits of policies to foster the production and uptake of CO 2 -derived products such as methanol, polyurethane and mineral construction aggregates. Another outcome is to illustrate the role of key policy-making stakeholders in assessing the suitability of current statutes and the impact of potential changes. An important finding was that the development of connectivity infrastructure is a key missing enabler and more attention to policy on infrastructure is required. Finally, the work examines the justification for a CO 2 Utilization Directive, comparable to the Carbon Capture and Storage Directive, but considering the current complexity of the European Union (EU) policy landscape. • Analysis of all European policies relevant to the development of CO2 utilization. • Stakeholder influence analysis for the future development of CCU policy. • Recommendation to consider CO2 as a material for the circular economy. • Stakeholder engagement with industry participants and European institutions. • Rationale for regional burden sharing of risk in developing CCU infrastructure. [ABSTRACT FROM AUTHOR]

Material flow analysis (MFA) is one of the most widely accepted and utilized tools in the industrial-ecology discipline, that measures the input-output materials and examines the pathways and flux of each material flow within the whole system. The application of MFA in e-waste management has recently increased and quite a few academic articles have been published on this issue providing decision support at the policy level. However, there is a need to understand the dynamics of MFA methodology, the data requirements (as well as the data sources used in the previous studies) and the lessons learnt from the studies, so that countries where such an E-waste-MFA study has not yet been performed can apply the international experience of such an emerging research technique. This comprehensive review article presents the recent applications, trends, characteristics, research gaps and challenges of the MFA method that may help e-waste management with an overview of the need for a such tool to be applied. A country-wise analysis is presented and MFA models complemented by various associated methods are summarized with national-level, regional-level, product-level, and element-level assessment. The highlighted future research perspectives discussed in this study will help to analyze e-waste management systems more critically, including the hidden and known flows of waste products and associated materials, economic assessment of material recovery and the role of responsible authorities. This invaluable contribution will help future researchers, particularly from the data collection techniques and previously applied MFA models complemented by various associated methods. • 55 papers on e-waste related material flow analysis (MFA) were analyzed and reviewed. • E-waste generation estimation was the most popular while e-waste characterization was the least research topic. • 20 different research gaps and future research opportunities were highlighted. • Use of state-of-the-art technologies and implementation of software in E-waste-MFA studies are essential. [ABSTRACT FROM AUTHOR]

Boosting the coordination and symbiosis of urbanization and forest ecological security is notably critical for promoting regional green and sustainable development and achieving emission peak and carbon neutrality goals. However, there was still a lack of in-depth analysis of the coupling coordination relationship between urbanization and forest ecological security and its impact mechanism. On the basis of the data from 844 counties in the Yangtze River Economic Belt, this paper explored the spatial differences and influencing factors of the coupling coordination degree of urbanization and forest ecological security. The results manifested that: i) There were apparent spatial disparities in the urbanization index, forest ecological security index, comprehensive index, coupling degree and coupling coordination degree of the Yangtze River Economic Belt. Among them, the spatial pattern of coupling coordination degree had a strong consistency with urbanization index, that is, areas with higher urbanization index also had higher coupling coordination degree. ii) Based on coupling feature identification, it was found that 249 'problem areas' were mainly located in Yunnan Province, southeastern Guizhou Province, central Anhui Province, and central and eastern Jiangsu Province. The main factor for the formation was due to the lag of urbanization in coordinated development. iii) Among the socioeconomic indicators, population structure (0.136), per capita year-end financial institutions loan balance (0.409) and per capita fixed asset investment (0.202) all had a positive impact on coupling coordination degree, while location conditions (−0.126) had a negative impact. Among the natural indicators, soil organic matter (−0.212) and temperature (−0.094) had a negative impact on coupling coordination degree. iv) During the process of coordinated development, it was necessary to increase financial investment and financial support, actively formulate policies to attract talents, enhance the education and publicity of ecological civilization, and develop a green circular economy. The above measures can promote the harmonious development of urbanization and forest ecological security in the Yangtze River Economic Belt. • Exploring the coupling relationship between urbanization and forest eco-security. • Areas with higher urbanization index have higher coupling coordination degree. • Coordinated development is deeply influenced by socioeconomic and natural factors. • Targeted policies for problem areas promote their coordinated development. [ABSTRACT FROM AUTHOR]

Globally, there is increasing interest in recovering resources from sanitation systems. However, the process of planning and implementing circular sanitation is complex and can necessitate software-based tools to support decision-making. In this paper, we review 24 decision support software tools used for sanitation planning, to generate insights into how they address resource recovery across the sanitation chain. The findings reveal that the tools can address many planning issues around resource recovery in sanitation including analysis of material flows, integrating resource recovery technologies and products in the design of sanitation systems, and assessing the sustainability implications of resource recovery. The results and recommendations presented here can guide users in the choice of different tools depending on, for example, what kind of tool features and functions the user is interested in as well as the elements of the planning process and the sanitation service chain that are in focus. However, some issues are not adequately covered and need improvements in the available tools including quantifying the demand for and value of resource recovery products, addressing retrofitting of existing sanitation infrastructure for resource recovery and assessing social impacts of resource recovery from a life cycle perspective. While there is scope to develop new tools or to modify existing ones to cover these gaps, communication efforts are needed to create awareness about existing tools, their functions and how they address resource recovery. It is also important to further integrate the available tools into infrastructure planning and programming processes by e.g. customizing to relevant planning regimes and procedures, to move them beyond research and pilots into practice, and hopefully contribute towards more circular sanitation systems. • We review 24 decision support software tools used for sanitation planning. • We characterize how they address resource recovery aspects. • Several tools analyse material flows and integrate resource recovery technologies and products in sanitation system design. • Many tools have features to assess sustainability aspects of resource recovery. • Recommendations are made for which tools best address each aspect of resource recovery planning. [ABSTRACT FROM AUTHOR]

Process-related carbon emissions, which cannot be completely eliminated by the improvement of processes and energy structure, are recognized as an enormous challenge for in-depth decarbonization. To accelerate the achievement of carbon neutrality, the concept of 'artificial carbon cycle' is proposed based on the integrated system of process-related carbon emissions from high-emitting industries and CCU technology as a potential pathway towards a sustainable future. This paper conducts a systematic review on the integrated system with the case of China, which is the largest carbon-emitting and manufacturing country, to provide a clearer and more meaningful analysis. Multi-index assessment was used to organize the literature and draw the useful conclusion. Based on literature review, the high-quality carbon sources, reasonable carbon capture approaches and promising chemical products were identified and analyzed. Then the potential and practicability of the integrated system was further summarized and analyzed. Finally, key factors of future development including technology improvement, green hydrogen, clean energy and industrial cooperation were stressed to provide a theoretical reference for future researchers and policy makers. • Demonstration on the rationality and importance of applying CCU technology on process-based carbon emissions. • Multi-index assessment on adoptable carbon sources, possible pathways of carbon capture and carbon conversion. • Analysis on the potential and practicability of the integrated system to accelerate carbon neutrality. [ABSTRACT FROM AUTHOR]

Circular Economy Model (CEM) holds the promise to provide an economic benefit while not compromising environmental balance, growth, and competitiveness. The paper presents the proposal of Circular Economy Competitiveness Index (CECI) which measure the development of CEM implementation on country level in areas of social behaviours, business operations, resource management, and innovativeness. CECI combines a catastrophe progression method based on catastrophe theory and principial component analysis into composite index. The paper presents analysis of CECI state and dynamics in EU countries. The model supported with Eurostat data allow to classify the EU countries into four groups based on CEMI dynamic as well as analyse EU traditional regions' competitiveness in context of CE implementation. Additionally, correlation to Global Competitiveness Index (GCI) has been analysed. The paper presents a quantitative reference for evaluating CE competitiveness and offers relevant implications for EU countries' policymakers in relation to the factors determining that competitiveness. • The paper explores impact of Circular Economy implementation on countries' competitiveness. • Circular Economy Competitiveness Index (CECI) based on catastrophe progression method is proposed. • UK, Italy, Sweden, Netherlands are leading EU countries according to CECI, because they balanced energy and material consumption. • CECI can be useful indicator for government to stimulate economy transformation while not losing competitiveness. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoate (PHA) is a type of polyesters produced in the form of accumulated intracellular granules by many microorganisms. It is viewed as an environmentally friendly bioproduct due to its biodegradability and biocompatibility. The production of the PHA using oil substrates such as waste oil and plant oil, has gained considerable attention due to the high product yield and lower substrate cost. Nevertheless, the PHA fermentation using oil substrate is complicated due to the heterogenous fatty acid composition, varied bio-accessibility and possible inhibitory effect on the bacterial culture. This review presents the current state-of-the-art of PHA production from oil-based substrates. This paper firstly discusses the technical details, such as the choice of bacteria strain and fermentation conditions, characteristic of the oil substrate as well as the PHA composition and application. Finally, the paper discusses the challenges and prospects for up-scaling towards a cleaner and effective bioprocess. From the literature review, depending on the cell culture and the type of PHA produced, the oil platform can have a PHA yield of 0.2–0.8 g PHA/g oil substrate, with PHA content mostly from 40 to 90% of the cell dry weight. There is an on-going search for more effective oil-utilising PHA producers and lower cost substrate for effective PHA production. The final application of the PHA polymer influences the treatment needed during downstream processing and its economic performance. PHA with different compositions exhibits varied decomposition behaviour under different conditions, requiring further insight towards its management towards a sustainable circular economy. [Display omitted] • The review focuses on the use of lipid waste for polyhydroxyalkanoate (PHA) production. • The PHA yield with lipid substrate is around 0.4–0.6 g PHA/g oil substrate. • The effect of fatty acids composition on the polymer makeup requires more insight. • Strategies were identified to improve the economic performance of PHA fermentation. • The decomposition behaviours differ among polymers and under different environments. [ABSTRACT FROM AUTHOR]

Abstract Remediation of polluted soils using phytoremediation techniques is an effective strategy. However, the use of the biomass from these soils for energy purposes may raise efficiency and pollution emission problems and there is currently little research on this issue. In this work, the main results of a fluidized-bed gasification treatment conducted on poplar biomass pruning residues from a multi-contaminated area are presented. The samples were collected from an experimental site in which a plant-assisted bioremediation (PABR) technology has been applied since 2013 to reduce the soil heavy metal (HM) and polychlorinated biphenyl (PCB) contents. The main goal of this study was to identify the specific treatment necessary, in addition to conventional tar reforming, for trapping possible residues of HMs and PCBs in ashes during the gasification process. In our study, we demonstrate that gasification of contaminated biomass coming from PABR (where contaminant residues are concentrated mainly in the roots and are insignificant in the shoots) produces syngas whose characteristics are similar to those obtained using non-contaminated biomass. The results showed that contaminant concentrations in the prunings were negligible; the total amount of PCBs was 1.63 ng/g, while HMs ranged from 0.01 to 0.70 mg/kg, except for Cu and Zn (∼20 mg/kg). Furthermore, the presence in the biomass of Ca and traces of other metals showed a possible catalytic effect with an improvement in the tar conversion in the gasifier leading to a reduction of 5–10% in tar content. The overall results suggest that a specific treatment for pollutant capture is necessary only when the roots, the part of the plants where these contaminants are concentrated, are sampled and used for the gasification process. Although energy from biomass produced on a contaminated site is currently considered waste and involves disposal costs, this paper shows that the poplar biomass grown on a multi-contaminated soil can be used for energy purposes without any impact on the environment. Graphical abstract Image 1 Highlights • Biomass quality assessment is necessary for evaluating gasification capabilities. • Poplar from PABR accumulate contaminants mainly in the roots. • Trace PCB concentrations in biomass not affect the gasification treatment. • The soil characteristics affect the yield and quality of syngas. • Ca occurrence in soil and biomass has a catalytic effect in tar cracking increase. [ABSTRACT FROM AUTHOR]

Abstract The introduction of effective solid waste management strategies in developing countries should be considered for improving sustainability at global level. Many barriers should be overcome, concerning the introduction of environmental policies, effective investments, social inclusion and public awareness, which are significant issues in low-middle income countries. The Circular Economy could represent the answer for improving current solid waste management activities worldwide, since denote the principle of waste valorization and recycling for boosting developing economies. This paper is focused on this theme, analyzing main opportunities for improving the current state of solid waste management in developing big cities. The solid waste management of two countries are reviewed: Romania is the emerging country where Circular Economy is becoming a future objective due to economic aids and strength regulations which the European Union (EU) established for the nations forming parts the alliance; as a comparison, Bolivia is reported for evaluating main differences founded for developing recycling systems in a no-EU country. These two case studies could be of interest for highlighting main pros and cons of the participation into a wide organization like the EU for introducing in short terms Circular Economy principles. Moreover, a theoretical Circular Economy model for developing big cities in low-middle income countries is described within the study for effectively comparing which chances can spread for these countries as regard municipal solid waste exploitation. Despite the economic level, Romania and Bolivia are both facing with many solid waste management issues although in different magnitude. For the Romanian case study, it is visible how it cannot achieve the European goals for 2020 due the need of change in public recycling behavior. Bolivia, instead, represents the case where international aids and new investments are required, considering the informal sector into the formal management system as a real opportunity for improving local recycling rate. In conclusion, the comparison suggests how external supports led to implement the principles of the Circular Economy within a developing region. The model of Circular Economy proposed is recommended for developing big cities in order to advance a new form of safe employment, encouraging the activities that are still in action (i.e. informal sector) and boosting the principles of sustainable development. Highlights • A circular economy model for developing countries was presented. • Solid waste management of Romania and Bolivia can be compared. • Municipal and "special" solid waste should be managed in an integrated manner. • Integrated regulations about solid waste are essential for developing countries. • The informal sector plays a key role on sustainable solid waste management. [ABSTRACT FROM AUTHOR]

Abstract This study presents a methodology that allows the analysis of how an existing product design meets the design guidelines required from the circular economy perspective, and which are the design guidelines that would need to be incorporated into its design to become a better circular design product. For that, as a starting point, the design guidelines required for the circular product design have been identified from an extensive literature review. Then, criteria have been defined to measure the margin of improvement of a product design based on the level of compliance of each circular design guideline, and the relevance of each circular design guideline for the specific product category to which it belongs. Finally, the methodology has been applied to a representative sample of 127 appliances belonging to different categories of small household electrical and electronic equipment. The circular design guidelines related to extending life span and to product/components reuse have been identified as those that more urgently need to be incorporated, while the urgency of those related to connectors or product structure is moderate. Graphical abstract Image Highlights • This research reviews design guidelines from the perspective of circular economy. • A methodology is proposed for evaluating the level of circularity of products. • The paper introduces a case study on 127 small electrical and electronic equipment. [ABSTRACT FROM AUTHOR]

The paper provides a systematic literature review to investigate whether circular economy (CE) performance in the technical cycle will contribute to the sustainable development. Two academic databases, namely Scopus and Web of Science were used to retrieve research papers which span over the period 2000–2019. The research articles were classified according to the Sustainable Development Goals (SDG's) addressed, industries involved, key areas of CE, pillars of sustainability, CE principles (R-Imperatives and Systems perspective), type of cycle in CE, and transversality (generic, product-specific and sector-specific). The review highlights various research gaps concerning the proposed classification. The research gaps will provide new emerging areas to the CE and will help to align the CE performance with the SDGs. • Indicators can evaluate the Circular Economy (CE) performance of studies. • CE performance can lead to sustainable development. • Major contribution of CE performance is to SDG12, SDG7, SDG9, SDG6, SDG8 and SDG11. [ABSTRACT FROM AUTHOR]

Resource depletion and environmental pollution are increasingly a matter of concern for their adverse effects on ecosystems, human health, and the economy. Circular Economy (CE) practices can help us address these challenges. This paper proposes a composite circularity index (CI) to assess the level of implementation of CE practices. The main advantage of the proposed index is its ability to combine multiple indicators of circularity for different units operating in a given sector (given as inputs), using a 'Benefit of the Doubt' model. This new model is innovative in the manner it deals with ordinal scales and also by considering both relative and absolute performance indices. These indices are computed using mathematical programming tools, building on ideas from Data Envelopment Analysis models. Although the model can be applied to any sector, this work addresses the hotel industry in particular. The selection of indicators for this CI was based on seven blocks of the Circular Economy Action Plan and a literature review of circular practices. An application of the proposed index is performed by using data from Portuguese and Spanish hotels. The proposed CI allows the identification of the organizations with the best and worst performance in implementing the CE practices and clarifying the benchmarks they could follow to improve their level of circularity. Moreover, the index analysis also provides specific targets for improvement, indicating which circular practices should be improved for the lower performers to reach the implementation levels of the best performers. • A circularity index based on DEA and the Circular Economy Action Plan is developed. • The circularity index is customized and applied to 51 hotels in Portugal and Spain. • Targets and priorities aimed at reducing hotels' footprint are discussed. • The method proposed offers potential for application in many other sectors. • 19 hotels are efficient, and the average efficiency is 85.26% in a relative assessment. [ABSTRACT FROM AUTHOR]

In recent years, circular business models (CBM) have become an inevitable requirement to foster improvements in environmental performance. However, the current literature rarely discusses the link between Internet of Things (IoT) and CBM. This paper first identifies four IoT capabilities including monitoring, tracking, optimization and design evolution for improving CBM performance based on the ReSOLVE framework. In a second step, a systematic literature review using the PRISMA approach analyzes how these capabilities contribute to 6 R and CBM through the CBM-6R and CBM-IoT cross-section heatmaps and relationship frameworks, followed by assessing the quantitative impacts of IoT on potential energy saving in CBM. Finally, challenges are analyzed for the realization of IoT-enabled CBM. The results show that the assessments of Loop and Optimize business models dominate current studies. IoT plays a significant role in these business models respectively through tracking, monitoring and optimization capabilities. While (quantitative) case studies for Virtualize , Exchange and Regenerate CBM are substantially needed. IoT holds the potential to reduce energy consumption by around 20–30% for referenced applications in the literature. However, the IoT hardware, software and protocol energy consumption, interoperability, security and financial investment might become main obstacles for the wider use of IoT in CBM. • A mapping framework is built connecting ReSOLVE with 4 IoT capabilities and 6Rs. • IoT-enabled tracking and monitoring capabilities dominates Loop model. • Optimize model is related to 'Reduce' by monitoring and optimization of IoT. • IoT provides virtual and dematerialized solutions, supporting 'Redesign' strategy. • IoT reduces the energy use of the Optimize and Loop business model with 20–30%. [ABSTRACT FROM AUTHOR]

Wastewater management is included in one of the 17 Sustainable Development Goals (SDGs): SDG 6 is dedicated to water and sanitation and sets out to “ensure availability and sustainable management of water and sanitation for all”. SDG 6 expands the Millennium Development Goals (MDGs) focus on drinking water and basic sanitation to now cover the entire water cycle, including the management of water, wastewater and ecosystem resources. A UN report in 2017 states that likely over 80% of the wastewater worldwide is still discharged without adequate treatment. In several countries the wastewater management is nowadays a norm, but still there are open discussions about the kind of approach to be adopted, i.e. centralisation vs. decentralisation. The choice of the adopted technologies is strictly linked to environmental performances and economical aspects; one of the possible causes for the still enormous amount of untreated wastewater discharged into the environment can be the low “willingness to pay” for this kind of service and therefore a great focus should be given to all the technologies that are able to lower the treatment costs still maintaining reliable and robust performances in the long term. When considering wastewater as a carrier of valuable primary chemicals that can be easily converted to marketable products (fertilisers, bio-plastics, soil conditioners, biofuels, etc.), and as well as a relevant source of “new water” to be used for specific purposes, wastewater and runoff management can be highlighted as one of the most exciting challenges and occasions for a sustainable development in the near future. The paper aims to clarify the future role of CWs in circular economy, resource-oriented, and ecosystem services approaches, which want to respond to sanitation worldwide and the future research needs. We give an overview on how the conventional wastewater treatment scheme (what we call “waste paradigm”) should move towards more sustainable water and biogeochemical cycles following the new resource-oriented, circular economy and ecosystem service views. On this basis, we review the potential application of CWs within this new, and needed, paradigm. Finally, a meta-analysis shows that the scientific community involved in CWs should put more effort in making CWs more suitable for these new tasks. [ABSTRACT FROM AUTHOR]

This paper assesses the economic viability of the production process of an innovative form of digestate known as "microfiltered digestate", suitable for use as a fertilizer in driplines for permanent crops. A Break-Even Analysis was performed to determine the Break-Even Point which identifies the minimum quantity of products necessary to cover production costs at a certain selling price. Our results show that the production of microfiltered digestate provides positive economic viability for anaerobic digestion managers, providing them with an attractive market outlet and, at the same time, a new form of income. The experimental study was stated in Sicily, but it is replicable in any territorial context with anaerobic digestion plants. The results are in line with the principles of circular economy and are very current with reference to the use of organic fertilizers instead of chemical ones. • Innovative micro-filtered digestate (MFD) is a new source of income. • A stategy to decrease the degree of dependence on public subsidies. • Break-Even Analysis was made to determine lower convenient level of production. • Break-Even Point was estimated for three different selling price. • MFD guarantee high economic profitability for the companies that produce it. [ABSTRACT FROM AUTHOR]

Implementation of green roofs requires a large amount of primary material, especially for constructing the growing media layer. In addition, irrigation of green roofs with potable water is uneconomical and unsustainable. The novel hybrid green roof system proposed in this paper is in line with the principles of circular economy as it incorporates recycled materials into green roof growing media and greywater for irrigation. Two experimental beds were built to evaluate the concept of treating greywater in a constructed wetland prior to using it to irrigate a dual-layer extensive green roof. The growing media in both two extensive green roof beds contained ca. 37.5% by volume of recycled crushed building rubble containing a large proportion of brick. One of the two beds additionally contained 9.5% by volume of sewage sludge-based biochar. The concept of the hybrid roof and novel growing media was evaluated based on laboratory analysis of the growing media and on onsite measurements of hydraulic and thermal performance. The growing media amended with recycled materials developed in this study had hydrophysical properties comparable to commercially available growing media without recycled materials. Observations made during one vegetation season from June to October and a ten day-intensive water quality monitoring campaign during September 2020 showed that the constructed wetland significantly reduced total nitrogen and orthophosphate concentrations in pre-treated greywater. Due to the irrigation method employed, in which water flowed predominantly through drainage mats below the growing media, nutrient-leaching by the irrigation water was avoided. Concentrations of nutrients in the effluent were observed to increase only in response to precipitation. The temperature peak of the bottom green roof layer was shifted by almost 9 h from the peak in air temperature, and temperature fluctuations were significantly reduced. Vegetation on the bed amended with biochar demonstrated more vigorous growth due to available nutrients in the biochar which increased the rate of temperature-reducing evapotranspiration. More water evapotranspirated more water, which provided more water retention capacity confirmed by a lower runoff coefficient. Simple storage routing hydraulic modeling of hybrid green roof runoff using a nonlinear reservoir was performed. [Display omitted] • Hybrid constructed wetland - green roof concept was developed. • Performance of the concept was successfully tested on experimental beds. • Biochar and recycled crushed brick were used in newly developed growing media. • Ability of CW to reduce nutrient concentration was confirmed. • Runoff was successfully simulated by non-linear reservoir model. [ABSTRACT FROM AUTHOR]

With the ongoing urbanization in developing regions, integrating regional waste disposal capability is challenging due to unbalanced economic development and rising environmental issues. This research proposed a multi-dimensional symbiotic integration of waste disposal capability. Applying data from the Yangtze River Delta (YRD) in China, we first explore the waste flows and interactions between cities to identify the possibility of inter-municipal collaboration based on the augmented gravity model. We then employ social network analysis to categorize the cities in the collaborative network of waste disposal into subgroups by functionalities. Finally, we proposed the top-down framework of symbiotic networks for waste disposal. Our findings indicate that YRD cities can be classified into four types according to their waste density and disposal efficiency: High-High, Low-High, Low-Low, and High-Low. We also identify three types of inter-municipal collaborative relationships: between high-density and high-efficiency cities, between high-density cities, and between high-efficiency cities. The city subgroups can be categorized into "high-efficiency clusters," "high-density clusters," and "hub clusters," which pave the way for a shared or complementary urban symbiosis in the waste recycling industry. The division of roles among subgroups enables symbiotic activities within the city cluster. This paper extends the spatial scope of industrial symbiosis literature and has practical implications for transitioning to a circular economy in waste management of developing countries. [Display omitted] • Inter-municipal collaboration based on spatial heterogeneity is discussed. • DEA model, the gravity model, and social network analysis is employed. • Complementary or shared symbiotic cooperation between cities is emerging. • Cities are clustered into different functional subgroups. • We proposed a symbiotic waste disposal network. [ABSTRACT FROM AUTHOR]

This paper aims to explore critical elements for eco-retrofitting a conventional industrial park, based on a survey of companies and institutions located in Brazil. The study investigates social barriers to be overcome in promotion of opportunities for waste exchange. Our results indicate that values, trust behaviour, waste cognitive domain and environment engagement are necessary for the creation of an eco-industrial park. Similar values of benevolence and universalism are essential for company engagement to eco-retrofit. Low levels of trust behaviour combining with limited waste cognitive domain prevent firms from establishing agreement on waste exchange initiatives. The findings lend support to the view that social barriers are pre-requisites to engagement among firms in establishing technological and logistical solutions. Serious attention needs to be given to these social barriers because they are not easily overcome in the social and economic context of developing countries. [ABSTRACT FROM AUTHOR]

Significant loss of valuable resources and increasing burdens on landfills are often associated with a lack of proper planning in waste management and resource recovery strategy. A sustainable waste management model is thus urgently needed to improve resource efficiency and divert more waste from landfills. This paper proposes a comprehensive system model using stock-and-flow diagram to examine the current waste management performance and project the future waste generation, treatment and disposal scenarios, using England as a case study. The model comprises three integrated modules to represent household waste generation and collection; waste treatment and disposal; and energy recovery. A detailed mass and energy balance has been established and waste management performance has been evaluated using six upstream and downstream indicators. The base case scenario that assumes constant waste composition shows that waste to landfills can be reduced to less than 10% of the total amount, by 2035. However, it entails greater diversion of waste to energy-from-waste facilities, which is not sustainable and would incur higher capital investment and gate fees. Alternative case scenarios that promote recycling instead of energy recovery result in lower capital investment and gate fees. Complete elimination of the food and organic fraction from the residual waste stream will help meet the 65% recycling target by 2035. In light of the need for achieving a more circular economy in England, enhancing material recovery through reuse and recycling, reducing reliance on energy-from-waste and deploying more advanced waste valorisation technologies should be considered in future policy and planning for waste management. • A stock-and-flow model for waste management in England has been developed. • Resource recovery potential has been proposed as a more robust indicator. • Material recovery and valorisation should be promoted in lieu of energy-from-waste. • Diversion of waste to incineration incurs higher capital investment and gate fees. [ABSTRACT FROM AUTHOR]

A circular economy can help reduce the impact of plastic waste using reaction, resilient, and digital approaches. In addition, it can facilitate reducing plastic consumption. In this regard, consumer behaviour and digitalization are deemed to be two main factors that play major roles in the implementation of a circular economy of plastic waste. The idea of this paper is to understand the relevance of consumer behaviour and digital ecosystem efficiency on plastic waste at the country level. Hence, the efficiency of eight European countries in the generation of plastic waste was analysed using international databases and the statistical method of receiver operation characteristic (ROC). For this purpose, the dependent actual state variables were defined as plastic waste generations, and the independent test variables were defined as digital ecosystem and consumer behaviour factors. ROC plots for the determination of the area under the curve (AUC) indices were produced between the mentioned state and test variables. The results revealed that consumer behaviour increases the higher generation of plastic waste (AUC >0.6), indicating that consumer behaviours have high effectiveness on the generation of plastic waste in European countries. Furthermore, the results indicated that the digital ecosystem has a controlling role in the generation of plastic waste in the study area (AUC <0.5), indicating the digital ecosystem factors associated with the low generation of plastic waste. The overall consumer behaviour in the selected European countries showed an unskilled role regarding the higher generation of plastic waste, while the digital ecosystem context showed a mitigating role in decreasing plastic pollution. The confirmation of the research hypotheses leads to some managerial propositions for the circular economy of plastic waste in the area of consumer behaviour and digitalization. The results propose an elaborated framework, including a reduction in waste generation, recycling in waste circulation, recovery in waste valorization, and efficiency in resource consumption by the digitalization of design technology and education in consumer behaviour for the circular management of plastic waste. • The circular economy can help reduce the impact of plastic wastes. • Consumer behaviour is an unskilled role in generation of plastic wastes. • Digital ecosystem for stakeholders can create new social values in the environment. • Improving consumption behaviour enhances recycling rates of the plastic wastes. • At the country level, digital technology can help the circular economy procedures. [ABSTRACT FROM AUTHOR]

Sustainability reports may play an important role as a supporting tool in the transition of organisations towards more circular economy models, since their content can help to measure, monitor and communicate the organisations' transition and to establish goals in the short/medium term. The aim of this study is to determine whether it is possible to calculate indicators capable of measuring the transition of organisations towards circularity from the information that they are currently communicating in their Corporate Sustainability Reports (CSRs), and what information would need to be incorporated in these reports to successfully carry out this procedure. To this end, by applying a three-step methodology, 34 indicators grouped into 10 categories were proposed to measure the level of circularity of organisations. This was completed with a detailed proposal of units/metrics to measure the indicators, based on those that organisations commonly use in their CSRs. For this purpose, information from 8 international programmes/frameworks that measure circularity at the territorial level was combined with circularity information that organisations are currently communicating in their CSRs. Finally, the proposed set of indicators and metrics were applied to a Spanish organisation dedicated to the forestry and paper sector with a CSR based on GRI-Standards. The results demonstrated that 25 of the 34 proposed indicators (74%) can be measured directly using the information included in the CSRs. • Which indicators measure the advance of organisations towards circularity? • Which information organisations communicate in their Sustainability Reports (CSR)? • Can be circular indicators calculated using data from CSR? • Case study: 74% of the circular indicators can be calculated using data from CSR. [ABSTRACT FROM AUTHOR]

In this paper we conducted a life cycle assessment to evaluate the environmental performance of the valorization of spent pickling acid (SPA) generated in the hot-dip galvanizing (HDG) process. We analyzed the environmental impacts of treating one m3 of SPA, comparing the reference treatment consisting of neutralization, precipitation, stabilization, and landfilling of the metallic sludge (scenario #1), with the innovative LIFE2ACID technology (scenario #2) that produces secondary zinc and iron chloride in solution through non-dispersive solvent extraction (NDSX) and electrowinning (EW). The results showed that the materials credits achieved by the implementation of LIFE2ACID technology turned most of the impact categories evaluated (toxicity, acidification, eutrophication, ozone depletion, etc.) into environmental benefits. Scenario #2 was adapted to achieve either zinc-only recovery (#2.1) or simultaneous iron and zinc recovery (#2.2). The abiotic depletion potential (ADP) of fossil fuels increased slightly from scenario #1 to scenario #2.1 because of the higher energy demand and NaOH consumption of EW, and because only zinc was recovered. However, the valorization of both zinc and iron chloride in scenario #2.2 reduced the ADP-fossil by 27%, compared to the reference treatment. Furthermore, the global warming impact was reduced by 20% and 97% in scenarios #2.1 and #2.2, respectively. With the focus on promoting the circular economy concept, we conclude that the LIFE2ACID technology significantly improves the environmental performance of SPA management. Next steps should consider the life-cycle costs analysis in specific scenarios to find out the trade-off between environmental and economic objectives. [Display omitted] • Life cycle assessment of alternatives to manage HDG spent pickling acids. • NDSX/EW technology reduces the environmental impacts compared to the reference treatment. • ADP-fossil and GWP are reduced by 27% and 97% with the NDSX/EW technology. • Energy demand of zinc electrodeposition is the main environmental impact of NDSX/EW. • Recovery and valorization of zinc and iron chloride overcomes the environmental loads of NDSX/EW. [ABSTRACT FROM AUTHOR]

The European Green Deal along with directives promoting Circular Economy support sustainability transition and foster green growth through developing appropriate funding. However, information on how to access such funding affects firms' decision to expand their business strategy. This paper investigates the effect of information about financing tools on the adoption of Circular Economy business activities by exploring whether the better-informed firms are 'greener' and what influences such decision through a switching endogenous regressor model to account for endogeneity and selectivity bias. Data on European SMEs is combined with country-specific characteristics and econometric results indicate that better informed firms are by 65 percentage points more likely to adopt an activity promoting Circular Economy, highlighting that awareness about funding tools is crucial for sustainability transition. Evidence advocates for mainstreaming information regarding funding sources to pave the way towards green growth. A rebound effect regarding the use of renewables is observed whilst evidence points towards the rejection of Porter Hypothesis. Policy makers should target in fostering a greener business environment for the firms that engage in Circular Economy practices through increased information on funding options. Findings are also pertinent to the ongoing discussion and policy agenda around acceleration of the transition to a greener European Economy. • We explore whether better informed firms are greener and what drives that decision. • Firms with information on funding tools are by 65% more likely to be greener. • Mainstreaming information about funding paves the way towards green growth. • Better informed firms are not deterred by the complexity of funding procedures. • Funders should reward trailblazing firms by simplifying funding acquisition. [ABSTRACT FROM AUTHOR]

Recognition of construction waste compositions using computer vision (CV) is increasingly explored to enable its subsequent management, e.g., determining chargeable levy at disposal facilities or waste sorting using robot arms. However, the applicability of existing CV-enabled construction waste recognition in real-life scenarios is limited by their relatively low accuracy, characterized by a failure to distinguish boundaries among different waste materials. This paper aims to propose a novel boundary-aware Transformer (BAT) model for fine-grained composition recognition of construction waste mixtures. First, a pre-processing workflow is devised to separate the hard-to-recognize edges from the background. Second, a Transformer structure with a self-designed cascade decoder is developed to segment different waste materials from construction waste mixtures. Finally, a learning-enabled edge refinement scheme is used to fine-tune the ignored boundaries, further boosting the segmentation precision. The performance of the BAT model was evaluated on a benchmark dataset comprising nine types of materials in a cluttered and mixture state. It recorded a 5.48% improvement of MIoU (mean intersection over union) and 3.65% of MAcc (Mean Accuracy) against the baseline. The research contributes to the body of interdisciplinary knowledge by presenting a novel deep learning model for construction waste material semantic segmentation. It can also expedite the applications of CV in construction waste management to achieve a circular economy. • A boundary-aware transformer (BAT) model is proposed for CW composition recognition. • The BAT model innovatively integrates Transformer with a cascade decoder. • An edge refinement network is trained to finetune the ignored boundaries. • BAT outperforms the baseline by 5.48% for mean intersection over union (MIoU). [ABSTRACT FROM AUTHOR]

Technological interventions and eco-innovative solutions are necessary to cope with the adverse environmental impacts of waste accumulation. The notion to consider "waste as a resource and recycling of the same for getting the value of the waste" has truly transformed the approach towards solid waste management (SWM). Technological eco-innovations rely on the automation of waste segregation, collection, route optimization, digital apps for creating communication (enhanced efficiency by 40–85%) and treatment technologies. The regulatory framework with amendments in rules, new policies, schemes, smart city missions are responsible for the implementation of "Tech-innovations" at the ground level and has shown societal benefits. India has significantly shown progress in sustainable development goals (SDGs) score from 50.93 to 60.23 (year 2000–2019). The innovative and sustainable waste management practices in India have increased contribution to renewable energy (approx. 2554 MW/annum), 15-billion-USD business opportunity by the circular economy, 25–30% resale profit from processed E-waste, increased co-operative collaborations, trailblazing start-ups, improved SDG 3,7,8,9,11,12,13, improved market for green products and services, brilliant institutional and regional innovations addressing the issue of climate change. The present article critically reviews the exemplary eco-innovations (technological and non-technological) including resource recovery and viable technologies for SWM in India. The review also illustrates the lacunae (in awareness, bioproducts adoption and advanced technologies), recommendations based on findings and future research areas. The paper can also assist researchers, entrepreneurs and the policy makers for improving the status of SWM in India as well as other developing countries with the same societal and economic status. [Display omitted] • Collated details of technological advancements for SWM in India. • Summarized eco-innovations in SWM and its impacts on societal economy and SDG. • Deliberated effects of digitization and collaborations in waste Management. • Trailblazing start-ups of India are also deeply elaborated with examples. [ABSTRACT FROM AUTHOR]

This paper focuses on the association between the probability and the number of green jobs at the firm level and the circular economy (CE) strategies related to the 4Rs approach (reduce, reuse, recycle and redesign) implemented by companies located in the European Union. Factors related to resources and technological and organizational capabilities are also considered. Using a zero-inflated negative binomial model (ZINB), results confirm that firms involved in CE have a higher probability to generate green jobs. Reusing, redesign and reducing practices are positively related to the number of green jobs. When we consider separately different CE actions, energy efficiency and minimising waste have a positive relationship with the number of green jobs, while recycling practices are not relevant. Reusing materials and redesign are both positively associated with the probability to have green employment and with the number of green jobs. Concerning firm resources and capabilities, larger firms have a higher probability to be in the group of firms with green jobs. As well, firms' technological capabilities, openness to external sources of knowledge and green products and services specialization are crucial not only for the probability but also for having a greater number of green jobs. • CE strategies influence on probability and number of green jobs at firm-level. • Reusing material and redesign linked to probability and number of green jobs. • Reducing water/material and recycling linked to probability of having green jobs. • Reducing energy and waste minimization linked to higher number of green jobs. • Effects of CE strategies on green jobs must be assessed at macro and meso-level. [ABSTRACT FROM AUTHOR]