Search Results (617)

The informal waste recycling sector provides livelihoods for roughly 0.2% of the urban population in developing economies, yet its formalization amid economic development creates trade-offs among social welfare, environmental performance, and fiscal sustainability. This study formulates the informal-to-formal recycling transition as a three-objective problem: minimizing the residual informal waste-picker headcount (an exit/displacement proxy rather than a measure of integration success), maximizing recycling rates, and minimizing government expenditure. We solve this problem with NSGA-II and SPEA2 on a stylized model whose parameters are calibrated for order-of-magnitude consistency with publicly documented Chinese municipal waste-management benchmarks, a directional sanity check rather than a formal parameter fit; each algorithm runs 30 times. SPEA2 attains a modestly higher hypervolume than NSGA-II (0.733 vs. 0.714; two-sided Mann–Whitney U rank test, $p\approx 3\times {10}^{-11}$), and both algorithms converge within roughly 50 generations on this tractable two-variable problem. An unconstrained random search remains highly competitive, underscoring how readily this low-dimensional frontier can be approximated. The decision space comprises two policy levers, the formalization target $\alpha$ and the enforcement intensity E; a subsidy dimension is excluded because it would enter the fiscal objective only as a cost without a benefit channel. All fiscal values are expressed in abstract model currency units. A one-at-a-time sensitivity analysis identifies the formalization gain coefficient ${\gamma }_1$ as the parameter with the highest hypervolume coefficient of variation (CV = 13.2%), pinpointing where empirical estimation effort matters most within this model. Scenario simulations under boom, recession, and transition conditions shift the Pareto frontier in distinct ways. A bi-objective ablation indicates that the three objectives are largely independent, since only a small share of bi-objective solutions is strictly dominated in the full three-objective space; a quantitative hidden-cost penalty is not established. A representative compromise strategy ($\alpha \approx 0.97$, $E\approx 0.33$) reaches a 44.5% recycling rate with near-complete formalization at modest fiscal cost. The framework thus serves as a transparent, reproducible decision-support tool for urban waste governance in developing economies, making explicit the trade-offs that the model implements. Full article

Growing material pressure and dependence on external supplies require an assessment of the circular economy not only in terms of recycling but also in terms of the structural conditions supporting resource resilience. The aim of the study was to assess and compare such conditions across the 27 Member States of the European Union and to identify the diverse profiles of their strengths and weaknesses. To this end, a multi-criteria framework was developed based on averages from 2021 to 2023 for eight Eurostat indicators with complete data coverage for material consumption, municipal waste, resource productivity, recycling, the use of secondary materials, import dependency and the economic significance of circular economy sectors. Weights were determined using the Criteria Importance Through Intercriteria Correlation (CRITIC) method, and the ranking was carried out using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method. Estonia, Italy and Germany achieved the highest scores, whilst Luxembourg, Cyprus and Denmark achieved the lowest; however, similar aggregate scores were achieved through different configurations of the criteria. The broad structure of the ranking was relatively stable across several methodological variants (Kendall’s W = 0.8716), but this global consistency coexisted with substantial country-specific sensitivity, particularly to the weighting scheme; CRITIC–TOPSIS and Entropy–TOPSIS showed only moderate pairwise agreement (Spearman’s ρ = 0.5629). A leave-one-country-out jackknife confirmed high stability for most omissions while identifying the Netherlands and Estonia as influential reference-set observations. Replacing domestic material consumption (DMC) with the material footprint did not substantially alter the results. The index should be interpreted as a diagnostic tool for assessing structural conditions, rather than a direct measure of the dynamic response to a shock. Full article

Nanomaterials (NMs) have shown broad application potential in wastewater deep treatment, but the actual application is constrained by some issues such as nanoparticle (NP) aggregation and poor recyclability. Different from previous comprehensive reviews, this article systematically synthesizes data from over 100 peer-reviewed studies (2012 to 2026) to review the preparation methods, purification mechanisms, and removal efficiencies for various pollutants, and the technical and economic feasibility of NMs, with an emphasis on carrier-assisted immobilization and NM–microbial aggregate interactions. To start with, the methods of preparation were roughly distinguished into two categories which were “top-down” and “bottom-up” methods. The advantages, disadvantages, and utilities of the physical, chemical, and eco-friendly methods of biosynthesis were investigated while paying particular attention to the function of the loading technique in preventing NP aggregation and improving recyclability. By using the technique of loading in the carrier, the growth of NPs could be restricted up to 2–50 nm. Secondly, seven basic mechanisms that underlie the process of removing pollutants by using NPs were explained: adsorption, catalytic degradation, ion exchange, surface complexation, antibacterial action, redox transformation, and waste recycling. Particular focus was placed on understanding the interactions between NMs, microbial aggregates, and extracellular polymeric substances in wastewater treatment systems. Extracellular polymeric substances (EPS) could capture >90% NMs and mitigate their toxicity. Once again, the removal efficiency and main influencing factors associated with different types of NMs, for the treatment of heavy metals, dyes, antibiotics, and pathogenic microorganisms were summarized. Removal efficiencies of the pollutants ranged from 70% to over 99%, but these values were strongly influenced by pH and matrix and often decreased substantially in real wastewater. The existing literature was used to classify the experimental substrates (single-solute systems, multi-solute synthetic systems, municipal wastewater, industrial wastewater, secondary effluent). The performance of NMs in different categories was compared, revealing the huge performance gap between ideal laboratory conditions and practical applications. Lastly, the economic viability of the methods based on the use of NMs for purifying water was assessed taking into consideration various factors such as raw materials’ prices, energy costs of the process of making materials, recyclability of the materials, and the possibility of introducing the use of NMs on a larger scale. Unlike existing reviews, this article aims to provide a quantitative mechanistic framework bridging the rational design, safe application, and engineering promotion of NMs in deep wastewater treatment. Full article

Plastic is a valuable material for packaging of food and pharmaceuticals, protective wrappings in construction and agriculture, and fluid storage. Flexible plastic or plastic film waste from packaging, agriculture, and construction applications grows at a rate of at least 92 million metric tons a year, is considered challenging to recycle, and is typically landfilled. In recent years, there have been great advancements in plastic recycling technology in order to deal with the global challenge of plastic waste buildup and support legislation from a local to national level to implement recycling. This work highlights the most recent advancements in plastic film recycling. Plastic films are mono- or multilayered based on what their applications will be, with multilayer multimaterial films being the more challenging feedstock for recycling. Mechanical recycling cannot easily process flexible films. Pyrolysis can use polyolefin-based film as feedstock but is not practiced at scale to match the rate of plastic film waste generation, and incineration can recover energy from film feedstock but is not recycling plastic. This has motivated the development of new recycling technologies designed around plastic films. Better characterization technologies to identify film compositions in municipal waste streams have been key to sorting out film feedstock for mechanical recycling and the baling of flexible plastic waste, but they struggle with multilayer films and black plastic. Compatibilization enables the recycling of mixed plastic waste but requires polymer compositions for selecting specific compatibilizers. Dissolution–precipitation recovers individual types of polymers from multilayer films and, at the same time, can purify polymers from additives or contaminants, but requires intense solvent processing and associated energy. Delamination of multilayer films can separate and recover solid films of polyolefins at relatively low amounts of solvent but requires quality feedstock to be efficient. Both dissolution–precipitation and delamination recycling of films recover the original polymer molecules and maintain their embodied energy, hence support circularity. In the case of PET-containing films, depolymerization to recover PET monomers offers opportunities to recycle challenging film feedstock. Full article

Over the past six decades, municipal solid waste (MSW) generation in the United States of America (USA) has increased substantially alongside population growth, urbanization, and changing consumption patterns. This study examined historical MSW data from 1960 to 2018 to evaluate long-term relationships among population, total MSW generation, per-capita waste, recycling and composting, combustion with energy recovery, and landfilling. A bounded forecasting framework was then applied to project future MSW pathways through 2200, using official population projections through 2100 and a quadratic extension beyond that horizon. Recycling and composting were capped at 70%, and combustion was fixed at 12.9% of total MSW generation. The results show that although recovery efficiency improves over time, continued growth in total waste generation sustains substantial landfill demand in absolute terms. The findings suggest that long-term MSW sustainability will require not only higher diversion efficiency, but also source reduction, reuse, and broader changes in production and consumption systems. Full article

Mechanical treatment recovers combustible and recyclable fractions from mixed municipal solid waste (MSW), but full-scale performance is sensitive to front-end operation, line loading, and feedstock heterogeneity. This study examined material recovery trade-offs at a municipal mechanical treatment facility in Satun, Thailand. Four inverter-controlled regimes were assessed by adjusting the bag opener and trommel motor frequencies, giving measured line throughputs of 14.75, 13.45, 8.03, and 6.54 t·h⁻¹. Output was classified as refuse-derived fuel (RDF), residual waste, recyclables, and bulky/loss material, with composition-based indicators of stream cleanliness and leakage. Each regime was a single short trial on waste from a different collection vehicle, without replication or input homogenization; no statistical comparison is possible, and results are reported as preliminary observations rather than isolated effects of inverter frequency. RDF yield fell from 42.06% of input at the highest throughput to 18.12% at the lowest, whereas recyclable recovery peaked at 4.95% under an intermediate regime that also returned the highest gross revenue. Residual-disposal methane generation potential was 7.78% higher under the lowest-throughput regime than under business-as-usual. Three trade-offs emerged: throughput against selectivity, RDF quantity against cleanliness, and recovery against leakage. The findings help operators select front-end settings on multi-criteria indicators rather than throughput alone. Full article

The transition to a circular economy (CE) is central to achieving SDG 12, yet institutional transformation varies significantly across countries. This study conducts a comparative institutional analysis of CE transitions in China and Russia to quantify Russia’s institutional lag and assess the maturity of both systems in the context of SDG indicator 12.5.1 (Circular Material Use Rate—CMUR). Drawing on neo-institutional theory, multi-level governance, and institutional trap theory, we develop an original methodology that computes institutional lag through three key milestones, an integrated maturity index across eight institutional components, and CMUR estimates based on official statistics, legislative acts (1998–2025), and industry reports. Our results show that Russia’s average institutional lag relative to China is 15.3 years: Russia’s 2024 municipal solid waste recycling rate (13.9%) matched China’s 2009–2010 level, while China achieved Russia’s 25% target for 2030 in 2018. The integrated maturity index is 8.25 for China versus 5.25 for Russia, with the largest gaps in industrial symbiosis, R&D and human capital, and international integration. Russia’s CMUR stands at 5–7%, compared to 25–30% in China. We also demonstrate that Russia’s high recycling growth is driven by a low-base effect and is not evidence of institutional efficiency; the compound annual growth rate (CAGR) of Russian recycling volume (33.0%) significantly exceeds China’s (13.1%), but this reflects the much lower starting point rather than systemic maturity. We conclude that without systemic institutional reforms—including eco-industrial parks, green finance, and competence centres—Russia will remain at an early CE stage, failing to substantially contribute to SDG 12 by 2030. Full article

Municipal waste composition is commonly measured at a single point, even though recovery, mixing and handling can alter the stream before disposal. This study examined municipal solid waste in Sialkot, Pakistan, during an eight-day campaign from 27 December 2021 to 3 January 2022. A total of 672 physical-characterization samples was obtained from residential, commercial, institutional, industrial and street-sweeping sources. Household generation was 0.42, 0.46 and 0.51 kg per person per day in low-, middle- and high-income proxy areas, respectively. Kitchen waste declined from 45.91% at the source to 34.20% at communal storage and 23.45% at the dumpsite. Recyclable paper and plastic also declined, whereas dust and fines increased from 2.05% at the source to 19.60% at storage and 21.78% at disposal. Six mixed-waste composites showed moisture contents of 30.72–53.06%, ash contents of 15.85–45.04% and gross calorific values of 2924–12,530 kcal kg⁻¹. The results demonstrate that monitoring location materially affects estimated recycling and treatment potential. A multi-point monitoring protocol is therefore recommended for cities with mixed collection and informal material recovery. Full article

This study explores the behavioral intersection of nutritional health and environmental literacy among pre-service teachers within the national higher education context. Utilizing the Sustainable Healthy Diet Index (SHED Index) for the first time in Croatia, this research systematically examines the dietary habits, lifestyle choices, and socio-cultural patterns of future educators (N = 164) at the University of Split. The survey instrument evaluated the core SHED domains, Healthy Eating (HE) and Sustainable Eating (SE), alongside supplementary indicators monitoring food logistics, hydration, and waste management. Descriptive analysis revealed moderately high standardized overall SHED scores (M = 62.86), aligning with the original normative distribution. Notably, students achieved significantly higher descriptive sub-scores in the HE domain (M = 24.68) than in the SE domain (M = 18.06). Although domestic food consumption and circular recycling practices were well integrated, critical biospheric behaviors—such as reducing animal protein, consuming legumes, purchasing organic food, and composting—remain limited by cultural resistance and municipal infrastructure deficits. Furthermore, an independent t-test indicated no significant differentiation across study levels, highlighting a potential institutional stagnation throughout the five-year teacher education program. Regression analysis demonstrated that sustainable dietary choices appear to be strongly anchored in personal health concerns rather than biospheric altruism, with healthy eating emerging as the single strongest explanatory factor for of sustainable behavior. These findings indicate that to cultivate authentic ecological literacy in the future teaching workforce, higher education curricula require a systemic redesign that explicitly links sustainability to personal well-being through localized, experiential learning. Full article

The transition to a low-carbon economy requires sustainable alternatives to fossil fuels. Up-recycling municipal solid waste and forestry biomass into solid biofuels presents a promising waste-to-energy strategy. This study aimed to develop a high-calorific, highly durable hybrid solid fuel without synthetic binders, utilizing the natural interlocking of lignocellulosic and plastic matrices under mild slow pyrolysis. Blends of Eucalyptus sawdust and municipal solid waste rejects (40 wt%) were densified with and without a glycerol binder. The optimal binder-free blend underwent slow pyrolysis at 400 °C and 500 °C to evaluate energy upgrading. Results showed that the binder-free formulation achieved mechanical durability of 99.67%, whereas glycerol severely compromised the dimensional stability of the pellets. Mild pyrolysis (400 °C, 30 min) increased the higher heating value to 27.75 MJ/kg—significantly outperforming local coal (18.3 MJ/kg)—while maintaining trace chloride levels, confirming the production of an environmentally safe, premium-grade energy vector. Full article

São Paulo is the largest city in Brazil and the second in Latin America. Its domestic waste production reached 3,515,678.96 tons in 2024. Historically, the city has a low recycling rate, and several laws and policies have been implemented to reverse this situation. The objective of this study was to investigate whether there have been advances in the recycling of household solid waste in São Paulo 15 years after the National Solid Waste Policy, from municipal and intra-urban perspectives. The extended period studied and segregated data by regional administration represent the innovative approach of this manuscript. The methodology consisted of a case study with an analysis of the legislation, official data research and evaluation of goals, and socio-spatial distribution. The separate collection rate grew from 0.69% in 2006 to 2.85% in 2024, but this volume represents less than 10% of the target originally projected for the period. A socio-spatial inequality was found as well as a lack of dedicated collection for the organic fraction. It can be concluded that progress is incremental, but limited by structural barriers and urban inequities. Results indicate for São Paulo and for other large cities, mainly in low and middle-income countries, recycling success cannot depend on legislation as it is also correlated with demographic factors, such as educational level, and to the need of targeted policies for a progressive increase in source-separated recycling. Full article

Municipal waste management is a major challenge for sustainable development, as it is strongly influenced by socioeconomic dynamics, seasonality, and the local institutional framework. In this context, this study aims to analyze the seasonality and structure of municipal waste streams at the county level, using monthly operational data provided by the Integrated Waste Management System in Bacău County, Romania. The analysis is based on descriptive statistical methods, seasonal indicators, nonparametric statistical tests, and exploratory multivariate techniques. Seasonal variability was assessed by calculating monthly and seasonal indices, and differences between seasons were tested using the Kruskal–Wallis test. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) were used to explore the relationships between waste generation patterns and selected temporal, socioeconomic, calendar, and climatic factors. The results of the analyses reveal a pronounced seasonal pattern, characterized by minimum waste generation during the cold season and maximum generation during the summer months. Residual waste dominates the overall composition throughout the year, while the share of recyclable waste remains low, and the fractional composition remains relatively stable across seasons. Statistical tests confirm the existence of significant seasonal differences between contrasting periods, and multivariate analyses indicate that municipal waste variability is more closely associated with temporal factors and with the socioeconomic indicator considered in this study (average monthly net wage), while climatic variables show weaker associations. From an operational perspective, the results highlight the need to seasonally adjust municipal waste collection, transportation, and treatment capacities, particularly during peak generation periods. By providing a detailed case study at the county level, based on real data, the research contributes to the literature on the seasonality of municipal waste and supports evidence-based management decisions at the local and regional levels, in line with European policy objectives. Full article

In most developing countries, the composition of municipal solid waste (MSW) arriving at final disposal sites (FDSs) differs from that at the source due to informal segregation of potentially recyclable waste (PRW) during its management, as well as because FDSs typically receive MSW from multiple municipalities. After exhaustively reviewing methods and studies of MSW characterization at their source, in collection trucks, and at FDSs, a lack of standardized methods for in situ characterization was identified, so this work proposes an innovative methodology to characterize MSW in situ at FDSs through the integration of geographic information systems to delimit the FDS or the selected cell(s) and the application of systematic sampling based on the NMX-AA-132-SCFI-2016 standard. To validate its applicability, MSW was sampled and characterized during the 2023 and 2024 dry (DS) and rainy seasons (RS) at a waste integral center in Tenango del Valle, Estado de México. The average compositions of organic waste were 15.3 ± 0.8% and 10.6 ± 0.1%; for PRW, they were 59.3 ± 5.4% and 50.5 ± 4.0%; and for the residual fraction, they were 25.4 ± 4.6% and 39.0 ± 4.1% in DS and RS, respectively; however, significant differences between seasonal or annual means could not be determined due to the limited sample size. The high percentages of PRW determined in situ are attributed to mixed household collection and show the potential to be recovered. The use of the proposed methodology enables representative in situ characterization of MSW after disposal with a lower level of significance, and it can be useful for decision-making regarding sustainable waste management projects. Full article

Construction and demolition waste is one of the most voluminous yet poorly managed waste streams in developing cities, and Fez, Morocco, is no exception. With over 1.2 million inhabitants and an expanding construction sector, the city produces large quantities of building debris annually. Until this study, no systematic inventory of illegal dumpsites existed, and municipal documents contained no data on volumes, composition, or spatial distribution. We addressed this gap through three approaches: a field survey of 43 illegal dumpsites, a permit-based Waste Generation Rate (WGR) analysis with projections to 2040, and a Simplified Material Flow Analysis (MFA) integrating field-observed stocks and theoretical generation estimates into a city-scale mass balance. The 43 surveyed sites hold a combined volume of 15,626,019 m³, with an average inert content of 51.60%, below the 65% benchmark, reflecting systematic co-deposition with no sorting. Only 11.6% of sites showed high recovery potential. The waste generation rate estimates a total generation of 419,269–1,426,302 tonnes over 2016–2025, with demolition accounting for 64% of the output. The materiel flow analysis reveals a 2- to 7-fold discrepancy between observed stock levels and theoretical estimates. Without intervention, generation is projected to increase sevenfold by 2040. Fez is caught in an informal disposal trap. Three actions are needed: mandatory traceability, targeted enforcement at high-flow sites, and on-site recycling capacity. Full article

Accurate instance segmentation of recyclable waste is important for automated sorting and circular economy applications. Mixed metal and glass municipal waste is challenging because metal surfaces are often reflective, while glass objects have transparent boundaries and high visual variability. This paper presents a controlled computer vision framework that uses instance segmentation as an object-level perception layer for mixed metal and glass waste and links eligible detections to screening-level WARM-based environmental interpretation. A seven-class annotated dataset of 1667 images was evaluated using a fixed train/validation/test split. Model development used the validation split for architecture screening, optimization tuning, transfer learning analysis, seed selection, and NMS selection, and the held-out test set was used only for final evaluation. Using mask mAP@50:95 as the primary segmentation metric, the selected YOLOv8m-seg model achieved 0.9435 on the locked test set and obtained a higher mask mAP@50:95 than Mask R-CNN and RF-DETR-Seg under the same locked test protocol. Image-level bootstrap 95% confidence intervals were also used to characterize uncertainty around the locked test segmentation comparison. For environmental reporting, mass-bearing detections were mapped to class-specific mass priors and EPA WARM v16 factors rather than direct mask area-to-mass conversion; the masks were used for instance-level separation, localization, and visual verification, not as direct physical mass measurements. Under the stated assumptions, the framework produced screening-level environmental estimates of 1113.57 MJ of energy savings and 70.20 kg CO₂e of avoided emissions, decreasing to 445.67 MJ and 28.62 kg CO₂e after applying recycling rate priors. Overall, the framework provides a leakage-aware workflow linking instance segmentation to material-specific WARM-based environmental screening. Full article