The participation of third-party companies in the recycling of livestock and poultry breeding waste (LPBW) is an effective way to solve the pollution problems of small- and medium-scale livestock and poultry farming. This article constructs a dynamic differential game model for LPBW recycling based on the differential game, which includes small and medium-scale livestock and poultry farmers (SM-LPF), third-party companies, and local governments in the same analytical framework, and introduces corporate social responsibility into the model. Four waste recycling scenarios, namely the no cost-sharing contract scenario, the polluter-pays scenario, the third-party pays scenario, and the centralized decision-making scenario, are considered, and the four scenarios are solved, analyzed, and simulated. The results show that: (1) in the absence of government subsidies, both polluter-pays contracts and third-party pays contracts are effective in increasing system utility and achieving pareto improvements. (2) The polluter pays contract is established on the premise that the environmental liability coefficient of the SM-LPF needs to reach a certain threshold, and the third-party pays for the recycling contract is established on the condition that the spillover effect of cleaner production reaches a certain threshold. (3) Government subsidies can provide incentives and coordinate the interests of the waste recycling system, and the size of the optimal subsidy coefficients of the government for the SM-LPF and the third-party firms is related to the positions of the two parties in the structure of the game. This study provides an important theoretical basis and practical guidance for promoting the recycling of LPBW.
With the growing demand for precise and intelligent solid waste management, developing efficient and intuitive identification and traceability technologies has become critical. Radar charts, as a multidimensional information visualization tool, integrate complex multivariate features into unique "graphical fingerprints," showing significant potential in material classification and source tracing. This mini‑review systematically examines the principles of radar charts and their application in solid waste classification, with a focus on feature fusion, fingerprint construction, and artificial intelligence (AI)‑based identification. A bibliometric analysis based on CiteSpace examines the evolution of radar chart research over the past 15 years, highlighting its shift from methodological exploration to deep integration with machine learning and intelligent sensing. The study summarizes methods for acquiring fingerprint characteristics, feature extraction and dimensionality reduction, and AI-based identification models, emphasizing the core advantage of radar charts in converting high-dimensional data into discriminative graphical profiles. A comprehensive technical framework-"data acquisition, feature extraction, intelligent modeling, and visual representation"-is proposed, offering a systematic solution for precise classification, traceability, and intelligent management of solid waste.
This research focuses on the investigation of structure-property relationships in open-structured fancy weaves, for example, Mock Leno and Huckaback manufactured from recycled and virgin cotton yarn. A full-factorial design of experiments and analysis of variance approach was employed to systematically evaluate the effects of yarn type, weave structure, pattern complexity (move number), and construction parameters on the physical, mechanical, and comfort properties of the fabrics used for household applications. It was concluded that mechanical and comfort properties are affected by weave structure and pattern complexity enabling recycled yarn fabrics to meet performance criteria for functional applications. Among the main effects, Weave Type exerts the largest and most statistically significant influence on air permeability (coefficient = -37.91, p = 0.000). Yarn Type (A) shows no significant effect (coefficient = -4.53, p = 0.404), indicating that substituting recycled for virgin yarn does not systematically compromise breathability. The fabric's mechanical properties (strength, tear, stiffness) and moisture management (overall moisture management capacity) are highly controllable through the specific material and structural choices studied-Yarn Type (A), Weave Type (B), Move Number (C), and Construction (D)-making them ideal for targeted design, as evidenced by high R2 (>95%) and Predicted R2 (>90%) values. In contrast, thermal resistance is essentially unaffected by these factors, with an R2 of only 12.54% and a Predicted R2 of 0.00%. Finally, elongation properties in both the warp and weft directions are difficult to predict reliably within this experimental space, as shown by low Predicted R2 values (0.00% and 11.98%, respectively).
Demand for neodymium-iron-boron (NdFeB) magnets is rising due to their use in clean energy technologies, such as wind turbines and electric cars. Their production based on rare earth elements (REE) creates significant geopolitical and supply chain dependencies. Recycling could mitigate this reliance, yet progress is limited by the absence of a dedicated recovery supply chain. Moreover, devices rich in NdFeB magnets - such as electric motors - are typically processed in plants optimized for the recovery of iron, copper, and aluminum, so REE content is often dispersed within ferrous waste streams because of the ferromagnetic nature of magnets. The aim of our study is to apply a thermal demagnetization step to electric motors prior to the traditional recovery operations for separating ferrous and non-ferrous streams, such as shredding and magnetic separation, to separate a magnet-enriched fraction from the rest of the material flows, without disrupting conventional recycling processes. This approach enables the disintegration of motor components while preserving the downstream recovery of base metals, ultimately producing a magnet-enriched fraction within the non-ferrous matrix. A comprehensive material flow analysis was conducted to quantify and visualize these recovery pathways. Results demonstrated that a portion of the magnet mass bypassed the drum separator and was successfully recovered through an additional magnetic screening step, yielding a magnet-enriched fraction with a final concentration of 50.8% w/w. These findings demonstrate the potential for optimizing pretreatment and separation processes to enhance both NdFeB recovery and separation efficiency, supporting the development of more sustainable magnet recycling systems.
Coal-fired thermal power plants occupy a significant amount of land for ash disposal. Too often, ash disposal sites are not properly designed, constructed, or operated, resulting in uncontrolled emissions of pollutants to the local and regional environment due to the accumulation of toxic elements and limited natural attenuation. This review describes current strategies for reclamation of ash disposal sites through various remediation and stabilization techniques. Application of in situ chemical stabilization methods, such as chemical column technique, has proven effective in immobilizing heavy metals, reducing leachability, and enhancing the engineering properties of the ash bed for subsequent land use. Furthermore, phytoremediation is a bio-remedial strategy that involves the use of various plant species to reduce contaminants and enhance nutrient content in ash beds as well as adjacent soil, presenting a long-term sustainable approach. The efficacy of phytoremediation through various plant species, aiming at its effectiveness in reducing contaminants through phytoextraction, phytostabilization, phytodegradation, and phytovolatilization, along with the associated challenges and limitations of these remediation techniques, has been discussed thoroughly. These combined methods mitigate the environmental impacts of ash disposal while reclaiming degraded land for subsequent reuse by optimizing land utilization while facilitating the construction of small structures: lightweight industrial shelters, temporary storage units, service sheds, and possibly generating revenue through the establishment of consumable vegetation. Moreover, this review highlights the global viability and scalability of ash stabilization by chemical column and phytoremediation techniques, aligning with various Sustainable Development Goals, while providing useful information to industry experts and researchers striving for sustainable management of ash disposal sites.
Extended producer responsibility (EPR) has emerged as a transformative policy instrument intended to improve waste management by shifting the end-of-life responsibility of products from government agencies and consumers to producers. This study explored the theoretical basics, policy frameworks, global implementation practices, effectiveness, challenges, and future directions of EPR in the context of domestic waste disposal. Additionally, a case study from Vietnam is also provided. Drawing from international experiences, it highlights the role of EPR in enhancing recycling rates, promoting eco-design, and facilitating the transition toward a circular economy. The article also examined the integration of informal sectors, the role of digital tools, and the necessary governance reforms needed to scale EPR initiatives globally.
Swift growth in urban areas has led to increased plastic waste, causing concerns in environmental sustainability and public health issues. Addressing these challenges in rapidly urbanising countries such as India requires more efficient and transparent plastic waste management (PWM) systems. This study aims to consolidate fragmented evidence to assess how digital technologies (DTs) shape sustainability outcomes across different stages of PWM. Methodologically, this study employs a two-phase, comprehensive systematic literature review. In phase 1, a wide range of studies were reviewed to examine the stage-wise adoption of DTs globally. The findings resulted in the selection of 75 peer-reviewed articles. Phase 2 focused on analysing keyword trends using VOSviewer. This analysis showed that the research has evolved into newer areas such as artificial intelligence (AI), the Internet of things (IoT), Blockchain, and the circular economy. Some of the findings include AI-driven sorting and IoT-based collection systems, which have improved efficiency and material recovery. Geographic Information System-based routing has effectively lowered transportation costs and emissions, whereas blockchain-based traceability has enhanced transparency in recycling processes. This review also examines the current governance systems and interventions related to PWM in India. It provides perspectives on how DTs can support sustainable PWM in India, offering urban policymakers and practitioners a holistic DT-based PWM system.
Unmanaged fishing gear, whether lost at sea or discarded on land, represents a significant source of marine litter and a growing challenge for waste management systems. Although global initiatives for the management of end-of-life fishing gear (EOLFG) are largely concentrated in the Northern Hemisphere, examples from the Global South remain limited. In Brazil, for instance, recent national and regional policies that address marine litter have encouraged the circular management of EOLFG. Following this trend, the present study presents the outcomes of an initiative in Ubatuba, São Paulo, which integrates waste management and community engagement. Over a 24-month period, we collected data to assess material flows and identify opportunities for recycling and repurposing EOLFG and to identify key stakeholders engaging with our initiative. In all, 1570 kg of polyethylene and 1439 kg of polyamide were received and processed. Ropes and gillnets were the most common types of fishing gear, representing 92.3% of items. From our results, the lack of large-scale reverse logistics, the heterogeneity and highly degraded nature of EOLFG, and the limited recycling infrastructure in the region constrain the feasibility of recycling initiatives. Despite these challenges, the participation of artisanal fishers and net menders, who ensured a supply of clean and dismantled nets, was pivotal for the continued operation of our management system. Our findings demonstrate that community-based actions, when aligned with regulatory incentives, are essential to advance Brazil's contribution towards the global effort against marine plastic pollution.
Energy recovery from agricultural residues through anaerobic digestion represents a viable pathway for renewable electricity generation and rural energy self-sufficiency. This study evaluated the energy and economic performance of five full-scale distributed generation biogas plants in southern Brazil using swine and poultry manure as feedstock. Energy performance was assessed through output-input ratios (EOR), volatile solids energy factors, electrical efficiency, and renewable energy efficiency. Economic feasibility was evaluated across electricity tariff scenarios (USD 0.07-0.15 kWh-1) and discount rates (3.5%, 8.5%, and 13%), using net present value, internal rate of return (IRR), discounted payback period, and levelized cost of energy (LCOE). The plant equipped with a continuously stirred tank reactor achieved the highest energy performance, reaching EOR2 of 16% and net electrical efficiency of 20%. However, despite its superior technical performance, its high capital cost resulted in the lowest economic attractiveness, with LCOE values reaching USD 0.19 kWh-1 and payback periods exceeding 19 years under high-interest scenarios. By contrast, the covered lagoon system (Plant B) demonstrated the strongest economic performance, achieving the lowest LCOE (USD 0.05 kWh-1), an IRR of 42%, and a payback period under 3 years, despite its comparatively lower energy efficiency. The results demonstrate that greater technological sophistication does not necessarily translate into superior economic viability in rural biogas systems. Economic feasibility was primarily governed by capital investment, electricity tariff levels, and financing conditions. These findings offer evidence-based guidance for policymakers and rural energy planners seeking to scale up distributed biogas generation from agricultural residues in Brazil.
Landfill mining (LFM) has gained momentum worldwide as a strategy to remediate legacy landfills (LeLas). Despite growing global interest, a systematic understanding of the factors guiding LFM suitability and composition of landfill mined residues (LMRs) has been meagre. Whether a LeLa is considered suitable for LFM depends on factors, including motivations for LFM, environmental impacts, economic impacts, the usability of LMRs, and the availability of alternative remediation strategies. Our review shows that LFM projects and studies worldwide are primarily driven by environmental remediation and resource recovery, with these motivations accounting for 34% and 25%, respectively. Key motivations in developing countries are less diverse than in developed countries, largely due to the severe environmental impacts caused by dumpsites in former setups. The availability of alternative remediation strategies could act in favour of or opposition to mining a landfill and is discussed for case studies in India and Estonia. The composition of LMRs, which is relevant to evaluating environmental and economic impacts, varies from one project to another. Based on data from 73 LeLas, age and depth of LMRs, geographical location, and income levels are identified as major factors influencing the composition of LMRs. Regardless of these factor dependencies, landfill-mined-soil-like-fraction is the major fraction (accounting for 35% and 75%) of LMRs. These findings support estimating material stocks in LeLas and prospective material flows from field-scale projects as a basis for developing effective LFM strategies. The novelty of this review includes (i) the first systematic distinction between major LFM motivations in developed and developing countries, and (ii) the first global quantification of LMRs' composition dependencies on-site-specific factors (age and depth) and system-specific factors (geographical settings and income level). Overall, these insights establish a strong empirical basis for assessing LFM feasibility and supporting informed decision-making.
Managing marine pollution from expanded polystyrene (EPS) is a critical environmental challenge, yet reliable empirical data on the actual recovery burden are often lacking. This investigation addresses this gap by using primary field data from three comprehensive sampling cycles. Through a combined life cycle assessment and cost analysis, the environmental and economic impacts of remediation versus industrial prevention were compared. The results quantify the cost of inaction, showing that collection from hard-to-reach shores accounts for 99.5% of the total cost and 83% of CO2 emissions, with geographic dispersion and labour intensity as the main limiting factors. In contrast, mechanical processing is technologically mature and has low operating costs. The investigation also redefines sustainability metrics based on the waste's end use, valorizing recycled EPS as a substitute for natural mineral aggregates (sand). This approach turns the disadvantage of low density into an advantage, achieving a greater than 99% reduction in carbon footprint per cubic metre compared to mineral aggregates. The present article clearly highlights that collecting waste before entering the marine environment is essential. At the same time, converting marine EPS into a resource is viable, as the environmental benefits of preserving natural deposits offset the high recovery costs, supporting a practical circular economy strategy.
Urban sustainability challenges in many Global South cities occur within fragmented institutional environments where no single authority holds full legitimacy or capacity to govern. This study examines how pluralistic governance-characterized by overlapping mandates among public agencies, non-governmental organizations, landlords, and regulators-can still generate coordinated environmental performance. Drawing on stakeholder and dynamic-capabilities theories, it introduces relational capability as a sustainability-oriented governance mechanism that enables adaptive coordination and substitutes for weak formal structures. Findings from Nairobi's solid waste management system show that coordination arises not from technical capacity or centralized control but from distributed relational processes that align diverse actors around shared environmental goals. Relational capability thus functions as a meta-governance competence that transforms institutional incoherence into adaptive efficiency. The study highlights the importance of relational infrastructure-trust-building, joint planning, and shared accountability-in strengthening environmental governance across fragmented urban systems.
This paper examines consumers' hypothetical willingness to pay (WTP) for sustainable fashion products, distinguishing between green attributes (e.g., natural fibers) and circular attributes (e.g., second-hand and recycled materials). It focuses on how economic considerations and environmental attitudes jointly influence consumers' valuation and purchasing behavior. Using original survey data from a sample of Italian consumers, we analyze stated WTP for identical t-shirts differing only in their production attributes: new (linear), second-hand (circular), made of natural fibers (green), and made of recycled materials (circular). Results reveal that while second-hand garments are perceived as highly sustainable, they display a significantly lower WTP, confirming the presence of a sustainability-related attitude-behavior gap. In contrast, t-shirts made of natural fibers and recycled materials receive positive and statistically significant green and circular premium, respectively. Regression results further show that pro-environmental behavior positively affects WTP only for second-hand products, whereas quality, comfort, and versatility negatively influence their valuation. Conversely, economic considerations significantly reduce WTP for green and recycled garments, highlighting the dominance of explicit economic preferences over environmental ones. Overall, the findings provide empirical evidence relevant to SDG 12, highlighting the challenges of promoting responsible consumption in the fashion industry.
To address the increasing demand for platinum (Pt) and the accumulation of hazardous waste, this study proposes a novel and sustainable pyrometallurgical co-smelting strategy for recovering Pt from spent automotive catalysts (SACs) using electric arc furnace dust (EAFD) as a co-smelting agent. Thermodynamic analysis confirmed the feasibility of reducing Pt oxides and sulfides to their metallic form under high-temperature, reductive conditions, enabling efficient alloying with iron (Fe). A five-component slag system (SiO2-Al2O3-CaO-MgO-FeO) was designed to lower the melting temperature and viscosity, thereby improving the separation efficiency of slag and alloy. Through systematic single-factor experiments, the effects of alkalinity (CaO/SiO2), EAFD addition amount, reducing agents amount, and smelting temperature on Pt recovery were investigated. Optimal recovery (96.4%) was achieved under the conditions of CaO/SiO2 = 0.7, 20 wt% EAFD addition amount, 6 wt% reducing agents amount, and a smelting temperature of 1550°C. Microstructural characterizations using X-ray diffraction and scanning electron microscopy and energy dispersive spectroscopy revealed that Pt was predominantly incorporated into the Fe matrix through substitutional solid solution mechanisms. Furthermore, the resulting slag exhibited a dense, amorphous glassy microstructure, indicating excellent environmental stability and inertness, thereby minimizing the risk of secondary pollution. Overall, this integrated co-smelting approach not only offers a technically viable and environmentally benign method for the high-efficiency recovery of Pt from SACs but also establishes a novel paradigm for the cross-sectoral recycling of hazardous industrial residues such as EAFD. The proposed strategy thus holds significant potential for advancing circular economy practices within the waste management industries.
As many developing countries struggle to manage waste effectively and lack the resources to mechanise collection systems, there is a pressing need to identify and adopt successful interim models until adequate mechanisation becomes feasible. Haritha Karma Sena (HKS) in Kerala, one of the states in India, is a decentralised initiative responsible for door-to-door waste collection. The work of HKS women is unique and distinct from both conventional waste collection and the activities of waste pickers. According to the Kerala government’s 2024 report and field data, monthly HKS women collect approximately 4000 to 6000 tonnes of plastic and other waste from various panchayats and municipal areas across 14 districts. Semi-structured interviews with 117 HKS women revealed that most participants reported feeling satisfied and empowered in their work. Drawing on Nussbaum’s affiliation principle, the research demonstrated how the structuring of waste collection, together with administrative support, empowered HKS women, enhanced their social respect, public acceptance, and dignity, and led to the recognition of their rights and to their inclusion as valued members of society, and improved the environment. However, apart from other challenges, such as socio-cultural, political, financial, infrastructural, and logistic factors, occupational health and safety issues constitute a critical concern, with the job entailing considerable risks and workers frequently lacking adequate health insurance, an issue that must be addressed to strengthen and improve the model.
This study provides a social life-cycle assessment (S-LCA) of municipal solid waste management to evaluate citizen engagement in a southeastern Brazilian municipality. S-LCA followed UNEP/SETAC guidelines, including 3 social impact categories, 6 subcategories, and 13 indicators. Primary data were collected by means of a questionnaire which resulted in 413 valid responses. The results are expressed as normalized, dimensionless social performance indices on a scale of 0-1, where scores <0.5, equal to 0.5, and >0.5 indicate low, intermediate, and satisfactory performances, respectively. The analysis revealed weaknesses in transparency (0.099), driven mainly by lack of citizens' knowledge regarding recycling and waste destination. Community satisfaction had an intermediate performance (0.382), reflecting inconsistent recyclable waste collection services. Responsibility for waste generation had also an intermediate score (0.561), but the practice of materials donation had a high score (0.884). Access to services achieved a satisfactory performance (0.829), showing availability but not necessarily user satisfaction. Governance scored 0.447, with partial effectiveness of public commitments to sustainability (0.540) and low knowledge about the municipal waste plan (0.353). Beyond confirming known transparency deficits, the findings reveal that high operational infrastructure coverage does not guarantee social satisfaction or system legitimacy without participatory governance and environmental education.
Lithium-ion batteries (LIBs) have become indispensable in present-day energy storage applications, containing portable electronics, electric vehicles, and renewable energy systems. However, rapid growth in LIBs usage has caused a parallel surge in end-of-life batteries, presenting environmental and resource recovery challenges. Among the various components, such as cathode, anode, electrolyte, separators, of LIBs, electrolyte has received minimal attention in recycling efforts. Electrolytes, characterized by their flammable, toxic, and volatile nature, pose significant environmental hazards, including the release of harmful gases and pollutants during disposal. This review focuses on the critical need for efficient recovery and reutilization of electrolytes from spent LIBs. Various recovery methods, including solvent extraction, supercritical fluid extraction, pyrolysis, and freezing, are studied for their effectiveness, efficiency, and environmental impact. Additionally, methods for recycling and regenerating recovered electrolytes into high-purity components for direct reuse are explored, addressing economic and sustainability considerations. Finally, major challenges and research gaps have been discussed. Key research gaps include the degradation of electrolytes during battery operation, complex composition of spent electrolytes, and economic feasibility of large-scale recovery technologies.
Aviation is a major source of greenhouse gases emission in the world, and the invention of sustainable aviation fuel (SAF) is a hope that this source of carbon footprint can be minimized. This article assesses the economic and environmental trade-offs of different feedstock routes in China to produce SAF considering the waste cooking oil (WCO), agricultural residues, and municipal solid waste (MSW). A cost-benefit analysis, conducted under explicit modeling assumptions including an 8% discount rate and 20-year project horizon, reveals WCO to be highly efficient in terms of conversion and large-scale emission cuts (up to 80%), but its economic viability is undermined by fluctuations in prices. The MSW and agricultural residues are more stable and cost-effective sources of alternative but need more complex conversion technologies to yield higher. The study identifies the considerable importance of the government policies, including subsidies and carbon prices, to make SAF production feasible. The research article adds new information to SAF sourcing in China, and the findings have practical suggestions on multi-feedstock strategies and technology to boost the scalability of SAF production. The future of the research should be to understand the socioeconomic effects, regional differences, and longitudinal research in order to enlighten policy and industry stakeholders of the area.
