In recent years, electrical and electronic products (e-products) have been central to the discussion of resource sustainability due to their growing demand, use of critical resources, and challenges in managing the resulting waste stream (e-waste). As such, the concept of circular economy, which seeks to ‘design out’ waste by better products, practices and business models, is deemed to be very relevant for e-products. The nature of circular systems mandates a collective effort of businesses, consumers, and governments. While the techno-economic sides of the circular economy have attracted large attention in recent years, the role of consumer behavior – a critical factor in defining the long-term success of ‘sustainable production and consumption’ initiatives – remains less explored. In this context, this paper explores the potential of integrating lessons from behavioral sciences to facilitate circular economy in e-waste management. It offers a review of prominent behavioral theories and their application in the context of sustainable consumption and pro-environmental behaviors. Finally, the paper identifies opportunities for behavioral interventions in improving e-waste management and in achieving a more circular economy.
The treatment of ideas of repair in circular economy literature is critically reviewed, revealing instrumental understandings of repair as a tool to extend product life-spans and reduce waste. These framings are interpreted as an expression of the dominant technocratic and post-political discourses of circular economy as an intervention to sustain industrial capitalism in the face of sustainability constraints. The review contrasts these understandings of repair derived from a review of circular economy literature with richer and contested interpretations found in sociological, ethnographic and political literatures examining material repair in practice. Drawing on the emerging sociology of repair and applying more distinct concepts of restoration, remediation, reconfiguration and reconciliation derived from these literatures, the paper argues that the understandings of repair in circular economy literature are limited and restrictive, generally supporting a view of repair as sustaining, consumerist and nostalgic; and thereby overlooking potentially transformative, political and future-oriented roles for repair in a circular economy. In the restorative and remedial modes most commonly understood in the circular economy, repair is seen to enable new forms of capitalist commodification, notably of waste and domestic labour. Learning from contestation in other arenas of repair by contrast, understanding repair as encompassing ideas for reconciliation and reconfiguration, and adopting values of integrity, care and legibility, opens up repair in the circular economy to constructive critical discussion and reflection and offers new insights for policy makers.
The existing building stock represents a huge accumulation of physical resources: a material 'reserve' that could be mined in the future to improve resource efficiency. However, in the absence of systematically collected information about materials deposited in the built environment, the ability to manage and exploit them is limited. An approach to quantification of material stocks based on the use of secondary data from external research bodies, national statistics and a housing stock management database is used to estimate the timber stock in residential buildings constructed in the London Borough of Tower Hamlets before 1992. Results show a total timber accumulation of almost 67,000 tonnes across 68,000 dwellings, with a material intensity for timber between 20−34 kg/m2 of building floorspace (6.8–11.2 kg/m3 of gross building volume) for terraced houses and 5.4−11 kg/m2 (1.8–3.6 kg/m3) for flats and maisonettes. Generally, there is more timber in floors and roofs, and in older buildings. This method appears to be robust, as it results in comparable timber intensities to those determined using other methods in previous studies. It can be used for other materials and may be useful in other contexts where data is available (i.e., other scales, building types and materials), and capable of contributing to the growing understand of existing buildings as material banks.
Several independent assessments have identified rare earth elements (REEs) as critical materials, notably neodymium (Nd), praseodymium (Pr), and dysprosium (Dy) used in permanent magnets. Factors affecting their criticality include expected growth in demand arising from their unique performance-enhancing properties in consumer, energy, and military applications and the supply risk associated with China's dominance in their production. We demonstrate the use of Argonne's Global Critical Materials (GCMat) agent-based model to explore the possible consequences to REE market dynamics of different types of regional supply disruptions including a temporary loss of production, shutdown of capacity, and diversion of supply. Results suggest that supply disruptions may foster earlier and more REE mine starts outside of China, although some of these mines may not be able to sustain operations post disruption. Further, price and associated market responses such as production, capacity, and demand tended to extend beyond the disruption period. Such market impacts in the magnet supply chain could affect the costs and availability of a number of emerging clean energy technology applications such as electric vehicles and wind turbines. In the future, GCMat could be used to evaluate the effectiveness of mitigation strategies — including recycling, conservation, product substitution, and diversification of supplies — on reducing the severity of disruptions in REE markets.
To determine the environmental and economic performance of emerging processes for the valorization of red wine pomace, a techno-economic assessment (TEA) and a Life Cycle Assessment (LCA) are combined at an early design stage. A case study of two polyphenol extraction methods at laboratory scale, solvent extraction (SE) and pressurized liquid extraction (PLE), were first analyzed via a carbon footprint (CFP). Subsequently, the laboratory scale design was improved and translated into industrial scale and a TEA was performed on the industrial scale designs. Finally, LCA was applied again with all impact indicators and the information gathered from both the TEA and LCA was combined into concise decision support, using Multiple Criteria Decision Analysis (MCDA). SE performs better than PLE, due to a lower solvent to DW ratio and a less expensive processing setup in both environmental and economic terms. The CFP of at laboratory scale aided in showing potential environmental hotspots and highlighted the need to reduce solvent use. The MCDA showed a shift in decision support depending on how strongly economic or environmental benefits are valued and eases the interpretation of the 19 different indicators derived from the TEA-LCA results. Both SE and PLE with a solvent to dry weight (DW) ratio of 5 and 10, respectively, perform competitively while SE with a solvent to DW ratio of 10 outperforms PLE with a solvent to DW ratio of 25. The case study illustrated how early design calculations (CFP), and combined LCA and TEA may be combined to improve process design.
Large-scale mining of low-grade ores is energy-intensive and generates vast wastes. It has limited suitability for production of specialist metals that are required in relatively small quantities. An approach that limits environmental impact by restricting mining to high-grade deposits requires the investigation of small ore deposits as alternative sources of metals. The return on investment from small deposits is incompatible with the expensive surveys needed to secure investment and the high costs of managing risk. But increasing energy and transport costs may create space in the market for small-deposit mining with highly-competitive technological solutions. It can be argued that small-deposit mining is ethical because it must involve cooperation between mining companies and local residents who share a collective expectation and responsibility for their quality of life. However, small-deposit mining tends to be a limited, short-term initiative, which requires consideration of the extended ‘afterlife’ of mines. This manuscript is the culmination of five years of cross-sector dialogue and stakeholder engagement activities. It debates what constitutes a small deposit and describes the interactions between mining and manufacturing, investment, environment and society. It reaches the conclusion that technological innovations will support the re-emergence of small deposit mining as an important part of a diverse raw materials production sector. We do not suggest a return to past approaches, to mining of small, high-grade deposits, but a consideration of alternative narratives of localised, community-orientated mining processes, thus giving social, economic and environmental context to the needs of the present day.
Sustainable supply chain management (SSCM) has become a popular research topic among scholars as evidence suggests it has significantly contributed to achieve more environmentally conscious and socially responsible supply chains. Operational excellence (OE), on the other hand, can be achieved by incorporating SSCM practices within existing supply chain operations. However, due to human expertise, involvement and commitment towards excelling at sustainable and operational performance, the effective deployment of SSCM practices now depends on various human-based behavioral factors (BFs). Human behavior is dynamic in nature and hence has an effect on the implementation of SSCM practices. Nevertheless, research on BFs in view of SSCM practices is limited. To fill this knowledge gap, this study examines the nature of BFs for SSCM practices towards OE in supply chains, particularly within the context of the footwear industry of Bangladesh. In the first phase, the BFs were identified and determined through a literature review and empirical investigation. In the second phase, the Hesitant Fuzzy DEMATEL method was used to establish the cause-effect relationships among the factors. The influence of group validation by experts and a literature survey, along with managerial implications, was discussed and explained in the third phase of the study. The results suggest that the factor, 'organization culture' is the most influencing behavioral factor, followed by 'commitment from higher authority'. Both theoretical and practical contributions of the study are drawn from its findings, helping footwear industry managers to more effectively adopt SSCM practices in the supply chain operations of their organizations to achieve OE.
A circular biobased economy must be able to sustainably manage multiple resources simultaneously. Nutrient (nitrogen, phosphorus, and potassium) recycling and renewable energy production (biogas) can be compatible practices but require substantial transport of heavy organic waste. We combine a spatial optimization model and Life Cycle Assessment (LCA) to explore how Sweden could maximize its use of excreta resources. We use 10×10 km2 resolution data on the location of animal and human excreta and crop demand and model both optimal biogas plant locations and transport of nutrients to and from these plants. Each type of biogas plant (given 4 realistic mixes of excreta) is then evaluated for global warming potential, primary energy use and financial resource costs. Moving excreta through biogas plants, as opposed to simply reapplying on fields, to meet crop nutrient demands comes at a similar cost but the climate and primary energy savings are substantial. As much as 91% of phosphorus and 44% of nitrogen crop demand could be met via optimally transported excreta and the country would avoid about 1 450 kt of CO2-eq, save 3.6 TWh (13 000 tera-joules) of primary energy, and save 90 million euros per year. Substituting mineral fertilizers with recycled nutrients results in savings across all indicators, but the added energy and avoided greenhouse gas emissions associated with biogas production make a large difference in the attractiveness of nutrient recycling. Although the numeric values are theoretical, our results indicate that carefully coordinated and supported biogas production could help maximize multi-resource benefits.
Aluminum water treatment residuals (Al-WTR), a waste product created during drinking water treatment, is generated in large quantities globally and typically landfilled; alternative, uses are desperately required. Inorganic phosphorus (P) is proven to be quickly and irreversibly sorbed by Al-WTR, rendering P unavailable for subsequent environmental use.However, little work has been done to characterize how Al-WTR interacts with organic P sources (e.g., wastewaters) to both sorb and later release P. Experiments characterized Al-WTR's ability sorb and subsequently desorb swine wastewater organic P, and to ascertain Al-WTR's potential for agricultural wastewater treatment and to return organic P to systems (e.g., soils) for beneficial use. Al-WTRs were shaken with swine wastewater (2.5:1;w/w) and solution total/inorganic/organic P were monitored over 21 days. The Al-WTR sorbed almost 100% (~ 16,500 mg kg−1) of swine wastewater organic P within a 1-h timeframe. X-ray absorption near-edge spectroscopy showed that P was primarily sorbed by Ca phases present in Al-WTR during the initial 1-h sorption phase. In a subsequent study, the newly generated organic P-laden Al-WTR was shaken in 0.01M KCl along with an anion membrane-probe to capture desorbed P. Approximately 17% (~ 3000 mg kg−1) of the organic P sorbed onto Al-WTR was desorbed. Findings suggest that Al-WTR can remove excessive organic P from agricultural waste streams, with the Al-WTR-organic P-containing material potentially having the ability to supplement agricultural soils with P for plant use. By following such an approach, this could provide municipalities with an alternative and beneficial utilization strategy as compared to landfilling.
Using human excreta derived fertiliser (HEDF) in agriculture reduces dependence on diminishing phosphorus rock reserves, improves soil health, and facilitates sustainable nutrient recycling. Such schemes have particular scope for expansion in peri-urban areas of low-income countries, where large quantities of faecal sludge from on-site sanitation systems are available. However, public acceptability is a critical unknown factor. This study used surveys of 534 peri-urban subsistence farmers in Blantyre, Malawi, to investigate the public acceptability of HEDF. Two factors are highlighted as having a particularly strong association with acceptability: showing a sample of composted, granulated faecal sludge to participants at the start of the survey, and having heard of HEDF before. For instance, almost all participants who were shown the composted, granulated sample and had prior knowledge of HEDF were willing to buy maize grown in HEDF (96%). Conversely, less than a third of participants who had not heard of HEDF before and were not shown the composted, granulated sample were willing to do so (30%). Maize was the most widely accepted crop for use with HEDF, as there is perceived to be little contact between the edible parts and the ground. This suggests that HEDF has the potential to be widely accepted by subsistence maize farmers and the general public in Malawi. However, uptake rates could be substantially improved with public engagement campaigns involving demonstrations or samples of a visually appealing product, and by promoting the concept through channels such as farmer radio programmes or agricultural extension workers.
Packaging plays an important role in safely distributing products throughout today's society and supply chains. With a consumption of about 40% of plastics and 50% of paper in Europe, the packaging sector is a large user of materials. Packaging has a lot of environmental impacts, while it also represents a significant cost in the current supply system. Reusable packaging has been suggested as an option to significantly reduce environmental impacts. In this paper, we review the trends in reusable packaging and the literature on reusable packaging to generate insights into the current state-of-the-art knowledge and identify directions for research and development. This can help to better understand the key factors underlying the design and impacts of more sustainable packaging systems.
The principle of cascading, the sequential and consecutive use of resources, is a potential method to create added value in circular economy (CE) practices. Despite conceptual similarities, no research to date has explored how cascading has been operationalised and how to integrate it with CE R-imperatives (Reduce, Reuse etc.) to facilitate implementation practices. CE practices emphasise value creation and retention, yet, there has been little reflexive examination of explicit and intrinsic value considerations; namely, how allocation choices, i.e. the decision-making process, for resource utilization are made. This paper aims to (1) examine how cascading has been operationalised (empirically and theoretically) to understand its normative underpinnings and value considerations; and (2) integrate cascading with the CE practices in a manner that accounts for the complexities of material allocation choices. Through a literature review of 64 articles from three bodies of literature (CE, cascading and up/downcycling), plus additional material on sustainable development, we show the cascading concept is a suitable framework to direct material uses and provides an overarching concept to integrate with CE R-imperatives. From this, we propose a new theoretical framework that considers the socio-organisational necessities for a CE-cascading system, specifically by deconstructing the allocation choices and exchanges of product material combinations between actor groups. This considers a dual perspective of the physical aspects of materials and the social context in which material allocation is made. The framework transcends individual value chain actor configurations to propose an overarching steering/governance framework, based on the triple-P of sustainability (People, Planet, Prosperity), to examine and direct CE-cascading exchanges, between and above individual users/firms.
The sharply increasing solid waste generation has raised the environmental concerns worldwide which currently have been escalated to a worrying level. Intending to eliminate the negative environmental impacts of solid waste and meanwhile promote sustainability on the energy- and resource-intensive construction and building sector, considerable efforts have been devoted to recycling solid waste for the possible use in sustainable construction material products. This paper reviews the existing studies on recycling municipal and construction solid waste for the manufacture of geopolymer composites. Special attention is paid to the predominate performance of these geopolymer composite products. The principal findings of this work reveal that municipal and construction solid waste could be successfully incorporated into geopolymer composites in the forms of precursor, aggregate, additive, reinforcement fiber, or filling material. Additionally, the results indicate that although the inclusion of such waste might depress some of the attributes of geopolymer composites, proper proportion design and suitable treatment technique could alleviate these detrimental effects and further smooth the recycling progress. Finally, a brief discussion is provided to identify the important needs in the future research and development for promoting the utilization of solid waste materials in the forthcoming sustainable geopolymer industry. In summary, this work offers guidance for the better ecological choice to municipal and construction solid waste through developing waste materials into highly environmental-friendly construction materials.
In recent years, electrical and electronic products (e-products) have been central to the discussion of resource sustainability due to their growing demand, use of critical resources, and challenges in managing the resulting waste stream (e-waste). As such, the concept of circular economy, which seeks to ‘design out’ waste by better products, practices and business models, is deemed to be very relevant for e-products. The nature of circular systems mandates a collective effort of businesses, consumers, and governments. While the techno-economic sides of the circular economy have attracted large attention in recent years, the role of consumer behavior – a critical factor in defining the long-term success of ‘sustainable production and consumption’ initiatives – remains less explored. In this context, this paper explores the potential of integrating lessons from behavioral sciences to facilitate circular economy in e-waste management. It offers a review of prominent behavioral theories and their application in the context of sustainable consumption and pro-environmental behaviors. Finally, the paper identifies opportunities for behavioral interventions in improving e-waste management and in achieving a more circular economy.
Cascade use has been identified as a key concept towards the sustainable use of bio-based products aiming at the hierarchical utilization of biomass, first as materials; secondly recycled into new materials; and finally used energetically. This principle is plausible in theory. However, the quantification of economy-wide GHG savings due to the increased cascade use is scarce. Furthermore, another option to reduce GHG emissions – the extension of product lifetime – is not taken into consideration by this concept. This article aims at analyzing the potential of increasing the cascade use of wood products in Germany and contrasting the results with the extension of product lifetime. In doing so, we combine a disaggregated input–output model with a cumulative lifetime model. Results show that increased cascade use of wood products may reduce the current total GHG emissions in Germany at about 0.19% (1.68 ± 0.34 Mt CO2eq.). Lifetime extension seems not to have such a high reduction potential at about 0.04% (0.35 ± 0.06 Mt CO2eq.). Despite limited GHG reduction potentials of increased cascade use and lifetime extension, nevertheless, these concepts should be addressed by policy makers.
The market for solid-state lighting (SSL) systems has expanded 40-fold in installed lamps since 2001. At the same time, systems which preserve materials over time and promote material reuse are getting increasing attention in light of calls for reducing consumption of natural resources. As new lighting technology products are designed and brought to market, consideration must be given to how products will be managed throughout the life-cycle as well as their end-of-life (EOL) fate. Lighting-as-a-service (LaaS) business models have emerged as a potential strategy for preserving the materials embedded in lighting products. In this paper, we examine the cost and environmental implications of technology management decisions in the context of the street lighting industry, employing life-cycle assessment and a Markov Decision Process model. The goal of the research is to determine a policy that minimizes expected costs and emissions for the system over a fixed time horizon thus reducing uncertainty for managers. The model used in the paper evaluates the optimal replacement strategies for street lighting products and additionally connects the result to the optimal EOL product trajectory, taking both costs and carbon emissions into account. In doing so, we are able to more deeply understand the role that LaaS business models might play in enabling closed-loop systems within the street lighting industry.
Rainwater harvesting systems (RWHS) are increasing in popularity because of their ability to alleviate water pressure on centralized systems, minimize or delay rainfall runoff, and fit relatively easily in both the centralized/decentralized infrastructure organization. Adequately sizing RWHS is critical to optimizing their operation because under-sizing results in systems that are unable to provide a sufficient, reliable source of water while oversizing increases the capital costs incurred with limited marginal benefits and poses potential water quality risks. In this paper, we conduct a systematic literature review to assess the state-of-art in the field of optimization of domestic rainwater harvesting systems. Sizing of storage is identified as the most important objective of optimization, yet sizing for cost is the most frequently implemented outcome of optimization. Optimizing for a local maximum is often favored over simulation-based optimization methods that produce global maxima. To derive more realistic sizing estimates, future optimization studies will have to take into account greater variation in water demands as well as various climate change scenarios, especially given that rainfall frequency and quantity are critical design variables of a rainwater harvesting system.
Car electronics form an extensive yet untapped source for secondary critical raw materials. To seize their recycling potentials it is imperative to understand how the number and volumes of car electric and electronic (EE) devices are affected by trends in: i) car typology, ii) penetration and integration of automobile electronic control systems (AECS), and iii) unit mass of EE devices. We used a layered dynamic material flow analysis (MFA) incorporating comprehensive data series to analyze the aforementioned trends and their influence on end-of-life mass flows of two automobile EE devices in Switzerland over the period 1975 to 2015. We found that there has been an increased penetration of the EE devices coinciding with a replacement of unifunctional devices by multifunctional ones (integration) and a decrease in their unit mass (downsizing). Both penetration and unit mass changed most rapidly in the 1990s and have flattened after the year 2000. Penetration outweighed integration and downsizing, so that before stabilizing, it caused a rapid increase in the mass flows of the EE devices. Due to the long lifetime of cars, changes in penetration, integration and downsizing are still evident at the end-of-life flows, but can be expected to slow down considerably between 2015 and 2025. The results demonstrate that monitoring of the trends at the car inflow, in combination with a dynamic MFA, can be used to anticipate changes in end-of-life flows 10–20 years before they occur and to timely inform recycling policies.
Biomass is projected to play a key role in meeting global climate targets. To achieve a resource-efficient biomass use, European bioeconomy strategies increasingly consider the concept of a circular bioeconomy (CBE). We define the term CBE via a literature review and analyze the concept’s role in north-west European bioeconomy clusters through interviews. We identify strategies regarding the clusters’ feedstock and product focus, and investigate what role biorefineries, circular solutions, recycling and cascading play. Finally, we discuss gaps in CBE literature and the potential contributions of the CBE to sustainability. The analyzed bioeconomy clusters move towards a CBE by increasingly considering residues and wastes as a resource, developing integrated biorefineries and focusing more on material and high value applications of biomass. However, there is so far only little focus on the end-of-life of bio-based products, i.e. on circular product design, recycling and cascading. Key challenges for implementing circular strategies are policies and regulations, costs and the current small size of bio-based markets. Amongst the product sectors the interviewees identified as promising for the bioeconomy, plastics and construction & building materials have most recycling and cascading potential. While the CBE could contribute to improving the sustainability of the bioeconomy, the concept is not inherently sustainable and its potential trade-offs need to be addressed. Especially social aspects, cascading, circular product design, and aspects related to product use seem to be underrepresented in CBE literature, while the topics biorefinery, wastes and residues as well as waste management are significantly covered.
