Circular Economy Model Research Articles

Biobased Strategies for E-Waste Metal Recovery: A Critical Overview of Recent Advances

The increasing e-waste volumes represent a great challenge in the current waste management landscape, primarily due to the massive production and turnover of electronic devices and the complexity of their components and constituents. Traditional strategies for e-waste treatment focus on metal recovery through costly, energetically intensive, and environmentally hazardous processes, such as pyrometallurgical and hydrometallurgical approaches, often neglecting other e-waste constituents. As efforts are directed towards creating a more sustainable and circular economic model, biobased alternative approaches to these traditional techniques have been increasingly investigated. This critical review focuses on recent advances towards sustainable e-waste treatment, exclusively considering studies using e-waste sources. It addresses, from a critical perspective, approaches using inactive biomass, live biomass, and biogenic compounds, showcasing the diversity of strategies and discussing reaction parameters, advantages and disadvantages, challenges, and potential for valorization of generated by-products. While ongoing research focuses on optimizing operational times and metal recovery efficiencies, bioprocessing approaches still offer significant potential for metal recovery from e-waste. These approaches include lower environmental impact by reducing energy consumption and effluent treatments and the ability to recover metals from complex e-waste streams, paving the way for a more circular economy in the electronics industry.

Delivering Extraordinary Adventure Experiences During the “Chthulucene”: Circular Economy Challenges and Digital Solutions for the Environmentally Conscious Visitor

Adventure tourism offers unique experiences while presenting environmental concerns related to resource consumption and waste generation. Studies integrating circular economy (CE) principles in adventure tourism, particularly in South Africa, are limited. This research investigates the perspectives of managers and owners of adventure Small, Micro, and Medium Enterprises (SMMEs) on challenges hindering the implementation of a CE model and explores how digital technologies can be leveraged to overcome these challenges. The purpose is to gain a deeper understanding of the specific barriers faced by adventure companies in adopting CE principles. The study is rooted in an interpretivist epistemological stance. This study adopts qualitative methodology whereby netnographic tools were used for data collection through 12 online interviews with owners and managers in Mpumalanga. The results present the solutions provided by digital technologies towards advancing resource efficiency in a sustainable and resilient pathway in the adventure tourism industry. By focusing on the perspectives of stakeholders within adventure tourism SMMEs, this research provides valuable insights for a more sustainable and resource-efficient industry in South Africa. The Mpumalanga case study of successful CE implementation and investigation of the environmental impact reduction potential of CE practices in adventure tourism could be beneficial to practitioners and researchers.

Cross-Mediterranean Insights: Governance in Action for Circular Economy and Sustainable Waste Management Solutions in Tunisia’s Tourism

The current research work emphasizes the urgent need for a paradigm shift in Mediterranean tourism, advocating for the adoption of a comprehensive framework centered on sustainability in Tunisia. The establishment of an Inter-Ministerial Task Force is proposed to facilitate collaboration across governmental sectors, thereby enhancing governance and addressing the complexities of waste management within the tourism industry. Results reveal significant waste management inefficiencies and underscore the potential of integrated approaches that can lead to substantial environmental improvements. By fostering inter-ministerial collaboration, a strategic roadmap is provided that promotes effective resource recovery and sustainable waste management practices. Furthermore, the integration of the informal sector, exemplified by local recyclers, into formal waste management systems is anticipated to enhance social equity and bolster environmental stewardship. A comprehensive SWOT analysis identifies Tunisia’s intrinsic strengths, including its rich cultural heritage and significant eco-tourism potential, while simultaneously exposing shortcomings such as fragmented governance structures and insufficient infrastructure. It is posited that the creation of a centralized coordination body, coupled with the enhancement of public–private partnerships, could catalyze innovation in sustainable tourism practices, leading to increased investment opportunities and the successful implementation of circular economy principles. Drawing inspiration from Spain’s successful circular economy model, actionable recommendations for policymakers are offered, including the introduction of eco-certification programs aimed at incentivizing environmentally responsible practices within the tourism sector. Ultimately, the proposed framework aspires to position Tunisia as a regional leader in sustainable tourism, delivering long-term benefits to local communities through enhanced environmental protection and economic resilience.

Factors Affecting Sustainable Consumption in the Era of Consumerism: An Empirical Study in the Context of Circular Economy

Sustainable consumption is one of the best ways to address global environmental challenges in an era dominated by consumerism. The circular economy model emphasizes reducing waste, maximizing resource use, and promoting environmentally friendly production and consumption patterns. At the same time, consumers play an equally important role in this change by making responsible choices that prioritize durability, repairability, and recyclability. But despite growing awareness, challenges such as the intention-behaviour gap and infrastructural barriers still exist, limiting the widespread adoption of sustainable practices. Bridging these gaps requires collaborative efforts across sectors and a cultural shift toward mindful consumption. This paper explores the importance of consumer behaviour, business strategies, and policy interventions in promoting sustainable consumption within the circular economy framework. Greater awareness and encouragement of responsible actions can help society transition towards a more sustainable future, ensuring both environmental preservation and economic resilience. A sample of 209 consumers were surveyed to know the factors that affects sustainable consumption in the era of consumerism and found that Consumer Environmental Awareness, Economic factors, Corporate Practices and Policy Implementation are the factors that affects the sustainable consumption.

Harnessing Biochar for Sustainable Horticulture: Strategies to Cope with Abiotic Stress

Biochar, an important by-product of the waste biomass pyrolysis process, shows great potential to reduce the environmental impact of and address the serious problems related to climate change as well as to define an efficient circular economy model. Its use as a soil conditioner has increased the interest in biochar in agriculture over time. This review investigates how critical aspects such as starting material, temperature, and the presence or absence of oxygen during the pyrolysis process influence the yield and quality of this valuable soil conditioner. Considering the horticultural sector, this review also provides a comprehensive and detailed overview of how biochar positively influences growth, development, and yield by explaining the mechanisms and modes of action under both optimal growth conditions and unfavorable contexts (salt and water stress and the presence of heavy metals). The main mechanisms highlighted by this literature review are improvement in soil aeration and water-holding capacity, microbial activity, and nutritional status of soil and plants, as well as alterations in some important soil chemical properties. This in-depth review of the literature highlights how the interaction between biochar types, dose, crop species, and growing conditions (optimal or nonoptimal) result in nonunique responses. The heterogeneity of the results reported in the literature confirms how many of the topics discussed deserve further investigation, with particular attention to identifying the right dose of biochar in relation to the different preharvest factors considered.

Circular Economic Model of Waste Bank Based on Technological Innovation: A Comprehensive Bibliometric Insight

Circular Economic Model of Waste Bank Based on Technological Innovation: A Comprehensive Bibliometric Insight

Biological silage from tambaqui (Colossoma macropomum) by-products on the productive performance, hematological parameters and egg quality of older commercial hens.

This study evaluated the effects of incorporating biological silage from tambaqui (Colossoma macropomum) by-products (BST) on the performance, hematological and plasma biochemical parameters, and egg quality (physical, proximate composition and sensory characteristics) of older commercial hens. The BST was prepared by ensiling tambaqui by-products with lactic acid bacteria, cassava trimmings, and preservatives, producing a nutrient-rich, high-protein feed ingredient. One hundred and twenty Hisex Brown hens (83weeks old) were divided into five treatment groups, each receiving diets with 0, 1, 2, 3, or 4% BST. Performance metrics, egg quality parameters, and blood samples were collected over 63days. The results showed that diets with 1 to 2% BST improved egg weight, eggshell quality, and feed efficiency without adverse effects on hen health. However, higher BST inclusion levels led to declines in feed intake, egg production, and mineral content in eggs, possibly due to the sensory properties of the tambaqui-based diets. Hematological analysis indicated an increase in MCV and MCH values with higher BST levels, while triglycerides increased and cholesterol decreased, suggesting potential benefits for lipid metabolism at moderate inclusion levels. Sensory analysis of eggs showed greater acceptance in diets with 3% to 4% BST due to yolk color enhancement, although higher levels were not optimal for hen productivity. These findings support BST as a viable alternative feed in poultry diets, promoting waste utilization in a sustainable, circular economy model for the agribusiness sector.

Circular economy model and sustainable development nexus in Bangladesh

Circular economy model and sustainable development nexus in Bangladesh

WASTE MANAGEMENT AS AN ELEMENT OF REVERSE LOGISTICS IN THE CIRCULAR ECONOMY

This article examines waste management and recycling as an element of reverse logistics in a circular economy. The concept of circular economy can be found very often in scientific and social environment. The aim of the article is to analyze the trends of waste management and recycling as a reverse logistics element in the conditions of circular economy in Europe and Lithuania. To achieve the goal were done: an analysis of theoretical sources to reveal the essence and connections of reverse logistics and circular economy, analysis of LR and EU legislation, development strategies of the environmental protection and waste management sector, analysis of EUROSTAT statistical data, monitoring, situation assessment and questionnaire survey. The main goals of the circular economy model are less raw materials, less waste, less emissions, managing such elements as raw materials, sustainable design, production, distribution, consumption, reuse, repair, collection, waste management, and residual waste. Direct logistics processes and reverse logistics play really important role in this concept. Logistics examines the movement of material, financial and information flows from the source of raw materials to the end user, reverse logistics examines the same flows, only in the opposite direction. Reuse, repair, collection, waste management are on responsibility of reverse logistics. For this reason, waste management in the terms of a circular economy cannot be seen only as the responsibility of the government and the end user (the resident sorting the waste). All participants in the supply chain, who were interested in bringing the material flow to the end user, and who created added value in the supply chain, according to the "polluter pays" principle, should take responsibility for the waste generated in the country, waste management and sorting, recycling. Because, for example, prevention of waste generation is a priority, and the cheapest solution is to avoid waste management and recycling. Thus, all participants in the supply chain must be interested and cooperate in the implementation of the circular economy. The general trends in the collection of the main sorted waste in Europe and Lithuania are not unambiguous, since waste management is regulated by different local laws of the countries. A general increase in the amount of sorted and collected waste is recorded, but not all countries demonstrate an increase, this may be related to the elements of the circular economy that have already been implemented, public awareness, declining consumerism, the economic situation in the country and other factors that lead to a generally more responsible approach to ecological aspects. EU newcomer countries are characterized by large increase in waste collection, regardless of waste types. Consumer opinion is quite favorable to the implementation of circular economy principles, but the main idea is that most of the responsibility for waste collection and management must be transferred to commercial participants in the supply chain.

Circular Water and Wastewater Management in State College, Pennsylvania

In recent years, great attention has been paid to activities aimed at implementing a circular economy (CE) in the management of water resources around the world. One of the possibilities for the practical implementation of CE, based on the sustainable management of primary and secondary resources (waste), is the circular management of water and wastewater generated in urban wastewater treatment plants (WWTPs). This work presents examples of good practices in the implementation of CE in the college town of State College, Pennsylvania (United States of America). There are two WWTPs here – one belonging to Penn State University (Water Reclamation Facility) and another operated by the municipality (University Area Joint Authority). Both facilities implement CE goals through various initiatives dedicated to water, raw materials and energy recovery. The scope of these activities include using reclaimed water for irrigation of green areas, production of renewable energy, as well as recovery of biogenic components by processing sewage sludge in compost. This approach, where the university and municipality propose solutions in the environmental and social areas, is consistent with the idea of building social responsibility of units, which is a path to sustainability. Further actions to implement the CE model are expected to counteract ongoing climate change in various regions.

Advances in circular economy models for sustainable energy supply chains

The transition to sustainable energy systems has placed increasing importance on the adoption of circular economy (CE) models, particularly within energy supply chains. Circular economy practices emphasize the efficient use of resources, waste minimization, and the reuse, recycling, or repurposing of materials, promoting long-term sustainability. In energy supply chains, this model aims to reduce environmental impact, enhance resource efficiency, and improve overall economic performance. Recent advancements in circular economy models have facilitated the integration of renewable energy sources such as solar, wind, and hydropower into energy supply chains, significantly lowering carbon emissions. Energy producers are now focusing on maximizing the lifecycle of resources and optimizing energy generation and distribution processes. One of the core components of CE in energy is the shift toward closed-loop systems, where waste from one process becomes the input for another, minimizing environmental degradation and resource depletion. Furthermore, waste-to-energy technologies and energy storage systems are becoming crucial in reducing energy wastage and improving grid reliability. Key innovations include the development of energy-efficient technologies, such as smart grids, and advances in digital tools that enable real-time monitoring of energy consumption and emissions. These technologies allow energy companies to optimize their operations, reduce inefficiencies, and enhance supply chain resilience. Additionally, digitalization and data analytics are supporting the tracking of resource flows, carbon footprints, and waste streams, driving transparency and accountability across the supply chain. However, the widespread implementation of circular economy models in energy supply chains still faces significant challenges, including technological limitations, financial constraints, and regulatory barriers. Governments and industries must collaborate to create frameworks that support circular practices and incentivize investment in sustainable solutions. Despite these challenges, the potential of CE models to drive the transformation toward low-carbon, resource-efficient energy systems is undeniable. By advancing these models, energy supply chains can contribute significantly to global sustainability goals, reducing the carbon footprint and fostering long-term resilience in the energy sector. Keywords: Circular Economy, Sustainable Energy, Energy Supply Chains, Renewable Energy, Resource Efficiency, Carbon Emissions, Waste-To-Energy, Smart Grids, Digitalization.

Reducing greenhouse gas emissions in China’s automobile manufacturing with circular economy strategies

Circular economy strategies encompass a wide range of approaches and initiatives designed to foster sustainable resource utilization and minimize waste, particularly in the context of complex products such as automobiles. These strategies encompass, among others, material recycling and reuse, energy recovery, efficiency enhancements, and circular-focused product design. To evaluate the potential of different circular economy strategies to reduce greenhouse gas emissions in China’s automobile manufacturing, this research employs the input-output subsystems approach to analyze three distinct scenarios based on the interconnections between various components: the low-carbon transition of the energy structure, closed-loop material recycling, and the transition to shared mobility. The findings reveal that spillover component emissions account for over 98% of the total emissions of the automobile manufacturing sector. The circular economy model, through material recycling, can significantly cut down emissions from these spillover components, thereby aiding the automobile manufacturing industry in meeting its emission reduction targets. Notably, compared to relying solely on the low-carbon transition of the energy structure, the closed-loop material recycling scenario can reduce greenhouse gas emissions by approximately 10% through the recycling of steel and plastics alone. Moreover, the transition to shared mobility has the potential to achieve an additional 4%-18% reduction in greenhouse gas emissions by diminishing the final demand for automotive products.

Запровадження циркулярної та зеленої економіки в контексті досягнення Цілей сталого розвитку та забезпечення економічної безпеки держави: огляд сучасних концепцій

Introduction. The modern world faces numerous challenges related to climate change, limited natural resources, degradation of natural ecosystems, and increasing wastes. The answer to these challenges is the transition from a traditional linear economy to a circular model and green transformation aimed at conserving resources and mitigating the impact of environmental problems. Problem Statement. The introduction of the circular and green economy involves the application of a systematic approach both in the context of achieving the Sustainable Development Goals and ensuring the state's economic security. This makes it expedient to study the theoretical foundations and institutional environment for implementing the principles of circular economy and green transformation, which will allow to form a scientific basis for disseminating these concepts in Ukraine in the context of European integration processes and achieving sustainability. The purpose is to analyze the modern concepts of circular and green economy in the context of achieving the Sustainable Development Goals and ensuring the state's economic security. Methods. The following methods were used:comparative analysis; synthesis and generalization of the data obtained; graphical and tabular methods (to ensure the clarity of the data presentation). Results. The central categories of the concept of sustainable development are the rational use of resources and responsible consumption, which also form the basis for the formation of institutional support for the integration of circular economy principles into the economic life of society. This requires cooperation between the state, businesses, and civil society and finding innovative solutions to ensure economic security. This necessitates a scientific rethinking of existing traditional economic models in the context of sustainability. Conclusions. An important element of the transition mechanism from a linear to a circular economy model in Ukraine in the context of European integration processes is the creation of appropriate institutional support. Adapting the mechanism for implementing the principles of the circular economy and the EU's green transformation in Ukraine requires proper scientific substantiation, which is a promising area for further research.

Bioconversion of Poultry Litter into Insect Meal and Organic Frasstilizer Using Black Soldier Fly Larvae as a Circular Economy Model for the Poultry Industry: A Review

Poultry litter waste management poses a significant global challenge, attributed to its characteristics (odorous, organic, pathogenic, attracting flies). Conventional approaches to managing poultry litter involve composting, biogas generation, or direct field application. Recently, there has been a surge of interest in a novel technology that involves the bioconversion of organic waste utilizing insects (known as entomoremediation), particularly focusing on black soldier fly larvae (BSFL), and has demonstrated successful transformation of various organic waste materials into insect meal and frass (referred to as organic frasstilizer). Black soldier flies have the capacity to consume any organic waste material (ranging from livestock litter, food scraps, fruit and vegetable residues, sewage, sludge, municipal solid waste, carcasses, and defatted seed meal) and convert it into valuable BSFL insect meal (suitable for animal feed) and frass (serving as an organic fertilizer). The bioconversion of poultry litter by black soldier flies offers numerous advantages over traditional methods, notably in terms of reduced land and water requirements, lower emissions, cost-effectiveness, swift processing, and the production of both animal feeds and organic fertilizers. This review focuses on the existing knowledge of BSFL, their potential in bioconverting poultry litter into BSFL meal and frass, and the utilization of BSFL in poultry nutrition, emphasizing the necessity for further innovation to enhance this sustainable circular economy approach.

A Proposed Circular Economy Model for Hospital Bio-Waste Management in Municipal Settings

This paper presents a proposed circular economy (CE) model for hospital bio-waste management, using Athens as a case study to demonstrate its applicability in urban environments. The model incorporates waste segregation at the source, resource recovery methods such as composting and anaerobic digestion, and data-driven tools to enhance the efficiency and sustainability of healthcare waste management. The study investigates the transition from linear to CE practices, focusing on structured collection strategies, collaborative efforts between hospitals and municipal authorities, and continuous tracking of waste flows. A comprehensive analysis of bio-waste volumes from participating hospitals over a three-year period is conducted, utilizing multi-criteria decision-making (MCDM) tools such as TOPSIS to evaluate the system’s effectiveness. The results indicate a significant increase in hospital participation, improved waste separation, and optimized resource recovery, offering a scalable framework for other municipalities seeking to implement CE-based waste management practices in healthcare settings.

Assessing the Circular Economy in Regions of Chile by Using Multiple-Criteria Decision-Making (MCDM)

The circular economy has gained significant global attention, particularly in developed countries, as a novel economic model to reduce waste and optimize resource utilization. This study assesses the capacity of Chilean regions to adopt the circular economy model. Six Chilean regions were selected for this purpose. The research process is carried out and employs a descriptive–analytical approach, conducting a comparative analysis of the six regions based on nine waste-related indicators. The Rank Alternative by Fractional Separation of Ideal Solutions (RAFSI) method, a multi-criteria decision-making (MCDM) technique, was used with trapezoidal fuzzy numbers for data analysis. A sensitivity analysis was employed to ensure the robustness of the results and determine the range of variation and flexibility of the model. The findings indicate that the Antofagasta region ranked first based on the research indicators, followed by Coquimbo, Arica y Parinacota, Valparaíso, Atacama, and Tarapacá. These results highlight significant disparities in the performance of Chile’s northern regions, emphasizing the key factors influencing circular economy adoption. This underscores the crucial need for region-specific strategies to enhance sustainability and waste management, as one size does not fit all in this context.

Sustainable branding and innovation in the craft beer sector

PurposeThe study aims to analyse whether the selected craft beers carry out sustainable practices, not only in production but also in promotion and distribution, highlighting territoriality and shared pride with their audience.Design/methodology/approachThis article examines sustainable practices in craft beers through a qualitative analysis of 42 breweries in Spain. Territorial marketing and circular economy strategies are identified. The results show an increasing integration of sustainable practices and their impact on brand perception. This research contributes to the literature on sustainability in local industries and offers recommendations for small breweries seeking to differentiate themselves in competitive markets.FindingsKey results show the integration of territoriality and sustainability elements in their marketing. Diverse sustainable practices are observed such as the installation of solar panels and the use of gas-powered vehicles. As for the advertising, and public relations strategy, it is noted that all the beers studied use these tools to be present at fairs, festivals, and events in their territories.Originality/valueThis study investigates the integration of sustainable practices in the craft beer industry in Spain, analysing a sample of 42 breweries. Qualitative methods are used to identify sustainability practices and the promotion of territorial branding strategies. Results indicate a correlation between brand identity and sustainability, with implications for the expansion of the circular economy model. It is suggested that small artisanal producers adopt territorial branding models to strengthen their sustainability and competitiveness.

Driving Circular Innovation: From Business Model to Industrial Ecosystems

The problems related to environmental sustainability have led to the redefinition of economic processes, in particular from the previous linear model (take-make-dispose) to circular economic models. This implies changing the way and approach to industrial production particularly through innovation. This paper focuses on the question if and in which terms today we can talk about innovative ecosystems as an evolution of the industrial districts and clusters, and in which terms they can be capable of pursuing circularity issues by leveraging the innovation process. The paper aims at tackling the issue by means of a literature review of theories: circularity and business model innovation, spatial diffusion and clusters, innovation ecosystems. From the literature review, we derived an overview of the evolutionary path taken by local production systems from industrial districts and clusters that can lead to circular innovation ecosystems, conceptualizing the possible relationship between local industrial development, innovation and circularity.

Simulation of Heavy Metal Removal in Irrigation Water Using a Shell-Derived Biochar-Integrated Ecological Recycled Concrete

Water pollution intensifies water scarcity and poses a significant threat to ecosystems and human health. Construction waste generated by rapid urbanization also imposes a considerable burden on the environment. Fortunately, a large portion of this waste can be efficiently converted into recycled aggregates and reused in various fields including environmental remediation. In this study, three types of eco-recycled concretes (ERC) (Control-ERC, Biochar-ERC-1, and Biochar-ERC-2) were formulated by integrating shell-derived biochar with recycled aggregates. The porosity and water permeability of these concretes were characterized, and their efficacy evaluated in treating polluted water with six primary heavy metals (HMs), i.e., cadmium (Cd), chromium (Cr), arsenic (As), manganese (Mn), lead (Pb), and copper (Cu). Biochar addition significantly enhanced the continuous porosity and water permeability of the concrete, and substantially enhanced its adsorption capacity of HMs. Specifically, Biochar-ERCs removed over 90% of As, Cd, and Mn, and achieved a removal rate exceeding 60% for other HMs, surpassing the performance of Control-ERC. This study not only lays a solid foundation for the wide application of Biochar-ERCs in the field of environmental protection and remediation, but also provides strong technical support and practical examples for advancing the circular economy model of converting waste into resources while addressing the challenge of global water scarcity.

An Overview on Nettle Studies, Compounds, Processing and the Relation with Circular Bioeconomy.

This paper provides an interdisciplinary overview of nettle bioactive compounds and processing, and ir also explores its role in the circular bioeconomy. Urtica dioica L. is sometimes referred to as a multipurpose herbaceous species that has been used historically in food, textiles, and medicine owing its rich profile of biological compounds. This study synthesizes the recent literature to examine nettle's applications across various industries, from nutritional supplements to eco-friendly fiber materials. In addition, it highlights nettle's potential in sustainable production chains, aligning with the EU's bioeconomy directives. The methods involve a comprehensive literature review and data analysis, with a focus on bioactive compounds and eco-sustainable applications. The results of this review underscore the plant's unique adaptability to low-input farming and its contributions to reducing resource dependency. The findings position nettle as a valuable resource for sustainable innovation, emphasizing its relevance within circular economic models.