Circular Economy Research Articles

Deep Learning for Sustainable E-Waste Management: Leveraging Transfer Learning for Classification

The rapid rise of electronic waste (commonly referred to as "e-waste") has become a world's growing challenge which should be managed by creative approaches. The number of e-waste produced is estimated to be 53.6 million metric tons in 2019. From this we can see that the seriousness of the issue direly calls upon taking the measures to prevent the environmental and public health risks associated with this expanding crisis [1]. Since a lot of the e-waste may contain hazardous materials such as mercury, lead and cadmium, which can impact the health and the environment if not treated properly, the mismanagement of it increases the problem [2]. In the case of e-waste, there is wide assortment of the electronic devices and components hence, it becomes difficult to classify them into their product categories properly. Sorting processes can't keep up with the pace of production waste as a result of being tedious, error-prone, and slow. This research employs deep learning approaches to segregate E-waste items using images for automated category. Utilizing contemporary models like VGG16, DenseNet121, InceptionV3, MobileNetV3, and ResNet50, the research designs classification systems that have these great attributes. Dataset building (training and assessment) become easy when an extensive dataset of 3000 images from 10 different types of equipment is developed. This research study helps to offer useful implications for managing current methods of electronic waste disposal and developing sustainable circular economies with quantitative analyzing of model performance factors that include accuracy, precision, F1- score, mean squared error (MSE), and mean absolute error (MAE).

Ulva species from the Romanian Black Sea Coast – between green blooms and nature’s contribution to people

Ulva species have a worldwide distribution and remarkable ability to develop under various conditions, being considered an important natural resource that is under-exploited along the Romanian Black Sea coast. These green algae, involved in green tides observed worldwide, have also a remarkable potential as prolific sources of bioactive compounds with potential health benefits and a wide range of applications in food, feed, pharmaceutical, nutraceutical, cosmetic, or biofuel industries. The study aims to analyze the quantitative variability of Ulva spp. during 2019 - 2023, in order to highlight the areas with algal agglomerations. These are also areas where potential algal deposits can develop during summer season. This fresh biomass can be selectively collected and valorized, thus supporting the circular economy. The sampling method was the classic one (square method/20x20 cm) from 14 stations along Pescarie towards Vama Veche, at depths between 0 to 3 m deep. Among all Ulva spp., Ulva rigida and Ulva intestinalis quantitatively distinguished during the study period, being also the main components of algal deposits. The highest mean wet biomasses were recorded in the southern part, as follows: U. rigida – a maximum value of 2200 g/m2 at 2 Mai; U. intestinalis – max. value of 700 g/m2 at Eforie South. Furthermore, a review of species’ main bioactive compounds, emphasizing their potential health benefits, will also be provided.

European waste management regulations in Spanish local administrations: Compliance assessment and integration Frontiers

AbstractThis research analyzes the impact of European directives, particularly the Waste Framework Directive, on municipal waste management in Spain, with a focus on Law 7/2022 promoting circular economy principles. Through an assessment of waste management ordinances in 980 municipalities, the study found that over 60% of local ordinances have not yet fully incorporated the latest regulatory requirements, indicating significant delays in adapting to European regulations. The findings reveal notable disparities in compliance, with larger municipalities showing higher adaptation rates compared to smaller ones. Additionally, regions like Catalonia and the Balearic Islands have adopted innovative approaches, including ‘pay‐as‐you‐throw’ schemes and community composting. The study underscores the critical need for better integration of circular economy principles, enhanced monitoring, and increased public awareness to promote sustainable waste management practices. By identifying regulatory gaps, this research aims to provide practical insights for improving local waste management policies and fostering greater compliance with EU mandates.

On-Farm Production of Renewable Energy in 2014–2022

The main purpose of this study is to present family farms as consumers and producers of renewable energies which provide them with an opportunity to reduce operating costs. The time scope of the study is 2014–2022, and the Farm Accountancy Data Network is used as the data source. The following research methods were employed: comparative and descriptive analysis, intensity indicators, ranking assignment and panel regression. Based on the values of energy output and energy costs, the rankings revealed a strong position of the Netherlands and Germany. As demonstrated by the study, energy production and consumption volumes depend on the farms’ economic size, but are not impacted by production type. Another finding is that energy production covers only one-third of its costs. Also, both production volumes and costs were on a growth path on a year-over-year basis, with similar growth ratios. The European Union’s leaders in energy consumption and production are the Netherlands, Germany, Belgium, Denmark, Czech Republic, Hungary, Luxembourg, Slovakia and Sweden. The study included the structuring of panel models for energy output and costs and identified their determinants. Energy output depends on total inputs and grows as they grow. Energy costs, in turn, are related to utilized agricultural area, total output and family farm income. An important limitation of this study is that FADN is a provider of high-level data. Hence, it is impossible to tell what specific sources of renewable energy are used by farms, and how they are affected by such exogenous factors as climate, earmarked subsidies or energy policy. The findings from this study are discussed in the context of the European Commission’s recommendations laid down in the Bioeconomy Strategy of the EU (2013), the Seventh Environment Action Program, the New Innovation Agenda of the European Union, the Report “Transforming Our World: the United Nations 2030 Agenda for Sustainable Development” and the Circular Economy Action Plan.

RETRACTION: Exploring antecedents for the circular economy capability of micro, small and medium enterprises: An empirical study

RETRACTION: Exploring antecedents for the circular economy capability of micro, small and medium enterprises: An empirical study

Sustainable bioconversion of rice straw into indole-3-acetic acid by Streptomyces coelicoflavus using response surface methodology

AbstractRice straw is an abundant agricultural waste that poses environmental disposal challenges and can be utilized for biotechnological applications. This study investigates the potential of actinobacteria to enhance rice straw biodegradation and sustainable indole-3-acetic acid (IAA) production, addressing the need for sustainable agricultural practices. Certain actinobacteria strains can effectively degrade rice straw while optimizing IAA production under controlled fermentation conditions. Twenty actinobacteria isolates were screened for lignocellulolytic enzyme activity, and ten were selected for rice straw biodegradation. IAA production was further optimized using response surface methodology based on temperature, pH, and agitation speed (RPM). Isolate S16 achieved a degradation rate of 68.75%, while S18 produced the highest IAA concentration (1040.625 μg/mL) under optimized conditions (25 °C, pH 9, 160 RPM). The purified IAA significantly improved Medicago sativa L. growth. Furthermore, the 16S rRNA gene sequence of isolate S18 was identified it as Streptomyces coelicoflavus strain NSH24 with accession number PP 320383.1. These findings underscore the potential of actinobacteria to efficiently convert agricultural waste into valuable bioproducts and promote sustainable farming practices. By transforming rice straw into high-value products like IAA, this approach contributes to a circular economy, offering an environmentally friendly solution for biomass utilization and agricultural sustainability.

Evaluation of Greenhouse Gas Emission Assessment Resulting from Processing Municipal Organic Waste into Bahan Bakar Jumputan Padat for Co-firing in Power Plants; Case Study: Bagendung Landfill Cilegon City

One type of biomass that can be used as fuel for co-firing in power plants is Bahan Bakar Jumputan Padat (BBJP)/Solid Waste Fuel. BBJP is a non-hazardous waste derivative that cannot be recycled. The production process of BBJP is strictly regulated by the Indonesian national standard (SNI) 8966:2021. The definition, characteristics and specifications of BBJP are much closer to Solid Recovered Fuel (SRF) than Refuse Derived Fuel (RDF). The utilization of BBJP reflects the dedication to reducing waste in landfills with a circular economy concept approach as well as the transition of the energy mix in Indonesia. To the present day, the production capacity of BBJP at Bagendung landfill in Cilegon City, Banten Province, has successfully produced 30 tons/day of organic municipal waste with an average BBJP product yield ranging between 11-15 tons/day. This research is intended to assess the Greenhouse Gas emissions (GHG) generated from the processing of municipal waste into BBJP. There are three main processes that produce GHG emissions, namely during bio drying processing, the use of machinery that produces emissions from electricity and the transportation process that produces combustion emissions in diesel fuel. As a result, direct GHG emissions arising from all waste processing activities into BBJP consist of 10 pollutants, namely CH4, N2O, CO, NH3, CO2, NOX, SO2, NVMOC, PM2.5 and ID(1,2,3,c,d)P. CO2 emission is the largest pollutant, accounting for 96.70% of the entire BBJP process.

Adaptive business policies for the energy transition: Balancing short-term profitability with long-term sustainability in oil and gas companies

This review examines the challenges and opportunities faced by oil and gas companies as they navigate the global energy transition, focusing on the delicate balance between maintaining short-term profitability and ensuring long-term sustainability. As the world shifts towards cleaner energy sources, traditional fossil fuel companies are under increasing pressure to adapt their business models and strategies. This study synthesizes current literature on adaptive business policies, sustainability initiatives, and their impacts on the oil and gas industry's future. Through a comprehensive analysis of case studies and empirical research, we identify several key mechanisms through which companies can effectively balance short-term financial objectives with long-term sustainability goals. These include diversification into renewable energy, investment in carbon capture and storage technologies, and the adoption of circular economy principles. Our findings suggest that successful adaptation requires a nuanced understanding of market trends, strong leadership commitment, and strategic use of technology and innovation. The review also highlights the potential of partnerships and collaborations in accelerating the transition process. By identifying key factors contributing to successful adaptive strategies and their subsequent impacts on both profitability and sustainability, this study provides valuable insights for industry leaders, policymakers, and researchers working towards a more sustainable energy future. Future research directions are proposed to further explore the long-term viability and scalability of these adaptive business policies across different market contexts.

Uranium Mill Tailings Generation and Management Challenges

Uranium mining has been ongoing for the past 200 years, yet managing uranium waste remains a significant challenge. This difficulty arises due to strict regulations imposed on uranium-related industries, driven by the assumed health risks associated with radiation. As a result, much of the waste generated by nuclear industries is currently stored. In India, uranium mining and milling waste is stored that require large tracts of land and continuous monitoring. Given the high value of land in India and the potential expansion of uranium mining to meet net-zero emission targets, an effective solution for managing uranium mill tailings is urgently needed. Meanwhile, India's construction sector is rapidly growing that require a huge quantity of materials. This paper reviewed the history of uranium mining and mill tailings generation and propose that the construction industry could effectively utilize these tailings. This approach not only addresses resource scarcity but also promotes environmental sustainability by conserving natural resources, reducing ecological imbalances, and advancing a circular economy.

An Overview of Fly-ash Geopolymer Composites in Sustainable Advance Construction Materials

Fly-ash geopolymer composites are an exciting advancement in eco-friendly construction materials. Fly-ash has become a sustainable alternative to regular cement because the approach addresses critical concerns in construction, such as high energy use, excessive carbon emissions and the challenge of managing industrial waste. In this review, a brief discussion on how fly-ash geopolymer composites could transform construction practices and reduce their impact on the environment. The construction industry is a major contributor to climate change, whereas industrial byproducts like fly-ash can also be an environmental challenge. Thus, the fly-ash geopolymer composites offer an innovative solution by reusing this waste to create environmentally friendly binding materials. Fly-ash can effectively replace traditional cement in construction, improving the durability and sustainability of buildings. By reducing our reliance on regular cement, these composites could revolutionise construction practices across various industries. Developing and widely adopting fly-ash geopolymer composites could bring substantial benefits. It could significantly reduce the construction industry's carbon footprint and contribute to global efforts to combat climate change. Additionally, ongoing research aims to enhance these composites' strength, heat resistance, and chemical durability, further promoting sustainable construction and supporting a circular economy by turning industrial waste into valuable construction materials.

Analyzing the lifecycle of solar panels including raw material sourcing, manufacturing, and end-of-life disposal

The lifecycle of photovoltaic systems, encompassing the procurement of raw materials, manufacturing processes, and eventual disposal at the end of their operational lifespan, presents considerable ecological challenges notwithstanding their contribution to the enhancement of renewable energy sources. This research offers an exhaustive examination of the ecological ramifications associated with each phase of the lifecycle of photovoltaic systems. The extraction of essential materials, including silicon, silver, and rare earth metals, necessitates energy-demanding processes and leads to resource depletion, while the manufacturing phase is associated with the emission of greenhouse gases and resource consumption, particularly in the fabrication of crystalline silicon panels. The disposal at the end of life is becoming increasingly significant, as retired panels accumulate, and existing recycling technologies provide minimal recovery of valuable materials. Despite the substantial reduction in greenhouse gas emissions attributable to solar panels throughout their operational lifespan, there is a pressing need for enhancements in material efficiency, manufacturing methodologies, and recycling frameworks to mitigate their lifecycle repercussions. The investigation underscores the imperative for sustainable methodologies, circular economy paradigms, and policy measures to guarantee the enduring environmental sustainability of solar energy.

Action research on circular economy strategies in fashion retail

PurposeThe aim of this study is to explore the role and impact of action research in the adoption of circular economy strategies by a fashion retail brand. This exploration is motivated by the need to address the underutilization of action research in management studies, despite its potential to foster a deep understanding of organizational processes and to drive positive transformations. The study seeks to illustrate how action research can contribute to the practical implementation of sustainability initiatives, specifically within the context of new environmental legislation and growing demands for sustainable practices in retailing.Design/methodology/approachThis research employs an action research methodology, particularly suited to the retail field, where understanding and influencing organizational processes are key. Through a detailed case study of a fashion retail brand, the study illustrates how action research facilitates the adoption of circular economy strategies.FindingsThe findings of this study underscore the effectiveness of action research in implementing circular economy strategies within the fashion retail industry. Specifically, it highlights how this approach has led to the successful reduction of waste and reintegration of products into their lifecycle.Originality/valueThe originality of this study lies in its thorough application of action research to measure and refine the outcomes of circular economy strategies in retailing. This novel approach provides substantial insights into the potential of the circular economy to drive practical innovations in business practices within retail.

Sustainable and Environment-Friendly Management of Shrimp Processing Waste through High-Quality Chitosan Production

The shrimp processing industry generates substantial waste, including shells, heads, and tails, which, if not properly managed, can contribute to significant environmental issues, such as pollution and disease transmission. This study explores the conversion of shrimp waste into chitosan, a valuable biopolymer with applications across multiple industries, by utilizing its chitin, protein, and mineral content. The extraction process involved demineralization with 1M HCl, deproteinization with 3.5% NaOH, and deacetylation with 60% NaOH. The resulting chitosan exhibited high quality, characterized by a crystal structure, white color, odorless powder form, 73.7% degree of deacetylation (DD), 64% yield, solubility in acetic acid, and water content of 1.5%. This research highlights an environmentally responsible approach to shrimp waste management, providing a method for repurposing waste into a high-value material that meets industry standards, supporting environmental sustainability and circular economy practices.

Harnessing Oxygenic Photosynthetic Microorganisms for Sustainable Wastewater Treatment Systems: A Comprehensive Review

Aquaculture systems globally face significant environmental challenges, particularly concerning wastewater management. This review explores the innovative application of oxygenic photosynthetic microorganisms (OPhMs), specifically microalgae and cyanobacteria, as a sustainable solution for wastewater treatment within these systems. OPhMs offer a dual role in wastewater treatment by removing harmful pollutants such as nitrogen, phosphorus, and heavy metals, while simultaneously improving water quality through oxygenation. We evaluate the integration of OPhMs into existing aquaculture operations, considering key factors such as system design, operational conditions, and economic viability. Additionally, we discuss the potential of algal biomass as a secondary resource for producing biofuels, animal feed, and other bio-products, contributing to the circular economy model. Our findings highlight the ability of OPhM systems to significantly reduce the ecological footprint of aquaculture while recovering valuable resources. However, challenges such as process stability, especially under low-temperature conditions, and the efficiency of biomass harvesting, require further research. This study provides a comprehensive framework for future development and optimization of OPhM-based wastewater treatment systems to improve the sustainability of aquaculture operations.

Factors influencing environmental and circular economy disclosure of Viet Nam listed companies

This study examines the environmental and circular economy disclosures (ECED) level and factors influencing this level of 32 Vietnamese listed companies from 2018 to 2022. The content and frequency analyses are performed to determine the level of ECED, and regression analysis is to investigate the influencing factors. Drawing on a sample of 160 sustainable development and annual reports following the Global Reporting Initiative frameworks (GRI), the study evidenced that 32 listed companies paid great attention to the GRI 300 category (on environment topics) with the top three GRI standards 302 (energy), 307 (environmental compliance), and 303 (water and effluents), respectively. In addition, the Feasible Generalized Least Square method results showed that the companies with government ownership and Big4 audit services had a higher level of ECED. In comparison, larger companies had a lower disclosure level. Meanwhile, companies in the manufacturing sector with foreign shares and the independence of the Board of Directors did not affect the disclosure information disclosure level in the studied sample.

Better Ce (III) Sorption Properties of Unprocessed Chitinous Waste from Hermetia illucens than Commercial Chitosans

Insect farming generates a new type of chitinous waste in the form of dead specimens that have died of natural causes and insect moults (puparia), particularly large amounts of which are generated during the rearing of holometabolous insects. Following the circular economy paradigm, we treated waste in the form of puparia and dead adults of H. illucens as a valuable material, i.e., as sources of chitin, and tested it as a sorbent for cerium, a lanthanide of great industrial importance. For comparison, non-treated, raw insect materials and commercial chitosans were also investigated. Chitin extracted from H. illucens showed an adsorption capacity at the same level as commercially available, marine-source chitin (approximately 6 mg Ce·g−1). However, more interestingly, raw materials exhibited much higher adsorption capacities—dead adults were similar to commercial chitosans (approximately 32 mg Ce·g−1), while puparia demonstrated twice the performance (approximately 60 mg Ce·g−1). This indicates that unprocessed waste can be used as environmentally friendly, cost-effective Ce biosorbents with comparable or even better sorption capacity than chitosans, whose production requires intense chemical processing.

ASSESSING PROGRESS TOWARDS A CIRCULAR CARBON ECONOMY IN THE G20 COUNTRIES

As cornerstones of worldwide sustainable development, the circular economy and the circular carbon economy are profoundly interrelated. However, opinions differ on how to optimize the circular economy towards reducing carbon dioxide emissions. This article aims to investigate the different levels of readiness for the circular carbon economy within G20 member countries in the domain of economic efficiency. In that regard, a selection of circular carbon economy sub-indicators has been analysed. Through the use of secondary data, tendencies towards change in this variability were found. The degree of adoption of a circular carbon economy differs among the G20 economies. In terms of the various factors considered in the G20 member countries, the current analysis has determined that there continue to be substantial differences between the best performers and their enabling factors.

Circular Economy: Municipal Solid Waste and Landfilling Analyses in Slovakia

The pursuit of shifting Slovakia towards a circular economy is met with a multitude of obstacles, including the pervasive consumerist mindset among Slovakians. This mindset favors packaged food, leading to its improper disposal in municipal waste instead of being recycled. Furthermore, the inclination towards landfills poses a significant challenge in the management of municipal solid waste (MSW). To address this issue, a quantitative analysis was conducted using developed and validated models, incorporating various factors related to MSW management in Slovakia. Our study confirmed the significance of parameters such as MSW management costs and population size in the amount of MSW generated. Furthermore, our findings include a short-term forecast for MSW generation in Slovakia for the next two years. These results, based on quantitative data, provide valuable insights for policymakers and waste management authorities in Slovakia, emphasizing the urgent need for a transition towards a more sustainable and circular economy.

The Limitations of Building Circular Economies in the EU Considering Present Structural Indicators: Country Cases

This paper summarises the essence of circular economy, as a desired future position of economies for building sustainability. Next it introduces indicators, which can measure the position of economies along the way to becoming circular. Based on the indicators the paper compares the situation of a few European Union (EU) countries in terms of their present development position for these indicators. In conclusion, the paper calls attention to the great differences among the examined countries, and suggests strategic actions to narrow down development gaps.

Tradeoffs and synergy between material cycles and greenhouse gas emissions: Opportunities in a rapidly growing housing stock

AbstractManagement of building materials’ stocks and flows is a major opportunity for circularity and de‐carbonization. We examine the relationship between material consumption and associated greenhouse gas (GHG) emissions under different scenarios in Israel, a developed country with an already high population density that expects tremendous growth in its housing stock by 2050. We created scenarios of varying housing unit sizes and additional material efficiency practices: fabrication yield, lifetime extension, material substitution, recycling, and their combination, resulting in 18 scenarios. In each scenario, the material flows and stocks needed to supply the housing demand and the resulting life‐cycle GHG emissions are quantified. No single material efficiency practice achieves a reduction in all indicators, suggesting a potential conflict between circular economy and decarbonization policies: The material substitution scenario allows for the biggest reduction in material consumption (12%–40% concrete reduction and 15%–51% steel reduction in 2050 compared with the baseline), while the recycling scenario achieves the biggest reduction in GHG emissions (22%–43% reduction in 2050 compared with the baseline). In the long‐term, the life‐extension scenario reduces most demolition waste. These findings can help policymakers and stakeholders consider the impacts of raw materials consumption and implement this knowledge in light of their priorities in policy packages. The results suggest a narrow window of opportunity within the next decade to influence material consumption and emissions to 2050. The findings could also shed light on the sustainability trajectories of other countries with similarly rapidly developing building stock, which have received little attention in this field.