Journal of Material Cycles and Waste Management最新文献

This study investigates the usability of marble wastes generated in the Emirdağ (Afyonkarahisar, Türkiye) region as alternative raw materials for lime production. Quarry sites exploiting predominantly Mesozoic grey to dark grey carbonate rocks around Alibeyce, Beyköy, and Bağlıca were selected, and representative waste materials were systematically characterized. The analytical framework combined petrographic and mineralogical examinations, geochemical analyses, stable isotope measurements, and lime suitability tests performed in accordance with Turkish Standards Institution (TS EN 459-2) procedures. Calcite was identified as the dominant mineral phase, accompanied locally by minor opaque constituents. Geochemical results indicate high CaO and very low impurity contents, whereas Sr is the most notable trace element. Calcination and post-calcination tests, including free CaO determination, loss on ignition, reactivity, color, chemical composition, and particle-size analyses, show that most samples possess favorable characteristics for the production of high-calcium lime. The results demonstrate that marble wastes from the study area represent a technically suitable and environmentally valuable industrial raw material.

The rapid growth of construction and demolition waste (CDW) in Vietnam has intensified interest in recycling materials such as recycled concrete aggregate (RCA) from CDW for roadbed applications. RCA offers high bearing capacity, while mixing with autoclaved aerated concrete (AAC) grains enhances the water retention, improving the cooling potential of permeable pavement systems (PPS), making these materials useful for urban heat island (UHI) mitigation. In practice, roadbed material is used in both well–graded and poorly– graded forms depending on the engineering requirements and site-specific conditions. Gas diffusivity (D_p/D₀) is a key parameter for evaluating coupled heat and moisture transfer, and thus the effectiveness of PPS in mitigating UHI impacts. This study, therefore, used well– and poorly–graded RCA and RCA–AAC mixtures to measure the D_p/D₀ in the laboratory under a controlled main drying process. Then, the applicability of the excluded–volume expansion of Archie’s law for predicting D_p/D₀ was examined. The results showed that the percolation threshold for well–graded mixtures generally exhibited lower values than poorly–graded ones, with average values of ~ 0.01 and ~ 0.04 cm³/cm³, respectively. However, both well– and poorly– graded samples can be well predicted by using a unified model parameter of 0.7.

Polyacrylonitrile-based carbon fiber (PAN CF) is widely applied in aerospace and wind power. Precursor production contributes approximately 40–50% of the environmental impact of PAN CF, considering the cradle-to-gate system boundary. China, the largest PAN precursor producer, primarily employs DMAc two-step wet spinning and DMSO one-step dry-jet wet spinning, but local environmental footprint studies are scarce. This study develops detailed life cycle inventory (LCI) datasets for 1 t of PAN precursor via the two mainstream processes and performs life cycle assessment (LCA) to quantify environmental impacts, including global warming potential (GWP) and primary energy demand (PED). Results show GWP of 8771.5 and 11085.4 kg CO₂e/t for the DMAc and DMSO routes, respectively. Electricity carbon intensity, steam heat utilization, and acrylonitrile production were identified as key drivers. Driving factor and electricity scenario analyses were conducted to evaluate process-specific carbon reduction strategies and identify a grid carbon intensity threshold (< 0.2865 kg CO₂e/kWh) for switching from steam to electric heating. This study fills the gap of LCI data for PAN precursor production in China, captures technological differentiation patterns in Chinese industry, and provides quantitative guidance for low-carbon industrial development.

Garbage leachate (GL) was one of the main factors polluting the environment; it not only disrupted the ecological balance but also posed a threat to human health. Therefore, it had received increasing attention. The relevant strategies had been proposed to treat this type of wastewater, which had high pollutant concentrations, complex compositions and large amounts of toxic and harmful substances. Hence, this review summarized the sources, composition and characteristics of GL, analysed the different influencing factors and detailedly investigated the influence of different factors on the processing efficiency. Specifically, the self-composition and characteristics of GL affected the selection of treatment processes. After the treatment process was determined, it could be further optimized, and the relevant parameters could be continuously adjusted. These factors ultimately determined the removal efficiency of the process through physical, chemical or biological actions. On this basis, practical engineering applications were further identified to clarify the current handling status. This comprehensive review not only provided a deeper understanding of GL but also served as a reference for choosing better treatment methods in the future.

Marine litter accumulation along complex coastal systems is shaped by interactions among human activities, coastal morphology, and offshore transport processes, yet the relative influence of these drivers remains poorly resolved at regional scales. This study investigated spatial heterogeneity in coastal litter accumulation across western Kyushu, Japan, using litter composition and anthropogenic–environmental proxy variables. Surveys conducted at 19 coastal sites in Hakata Bay, Itoshima Peninsula, Tsushima Island, and Goto Islands revealed pronounced regional differentiation in both litter abundance and composition. Offshore-exposed island coasts, particularly in Tsushima Island and Goto Islands, exhibited substantially greater accumulation of fishing-related debris and packaging waste than the comparatively managed urban coasts of Hakata Bay. Correlation analysis, principal component analysis (PCA), and non-metric multidimensional scaling (NMDS) consistently demonstrated clear separation between offshore island systems and enclosed urban bay environments. These findings suggest that coastal litter accumulation in western Kyushu is structured not only by local anthropogenic pressure, but also by broader oceanographic connectivity associated with Tsushima Current.

Separation of used paper is a critical issue to increase recovered paper and reduce waste. However, accurate classification of mixed paper remains challenging. The key reason is that there are so many different types of mixed paper. This study proposes an AI-based support system for used paper separation using object detection. The system is developed based on the YOLO (You Only Look Once) framework and is designed to classify 12 categories of recyclable and non-recyclable paper. Experimental results show that the proposed system achieved a mean Average Precision (mAP50) of 0.714 under general conditions. When images without overlapping objects were used, the mAP50 improved to 0.836. These results suggest that the proposed system has high potential to support paper separation tasks. And detection performance was significantly affected by object overlaps. Therefore, when performing object detection on used paper under general conditions where objects may overlap, this factor should be taken into account. As future, we aim to implement this system on a mobile device and promote recycling behavior.

A significant opportunity to mitigate environmental impacts in the sugarcane (Saccharum officinarum L.) industry lies in quasi-circular biorefinery routes, such as the Swenson Process (SP), which employs sustainable methods for raw wax extraction, where careful solvent selection and regional energy matrix choices are crucial. This study conducts a Life Cycle Assessment (LCA) of the SP, focusing on two key aspects: (1) Comparative energy advantages in Northeast Brazil versus Cuba (Global Warming Potential over a 100-year timescale - GWP-100). (2) Environmental impact assessment of heptane-based extraction versus toluene-based alternatives, selected using Hansen Solubility Parameters in Practice (HSPiP^©) software database. The LCA was conducted using openLCA^© software and Ecoinvent^© database, monitoring 16 input and output variables in a production flow processing 15 t/h of filter cake to produce 5.54 t/d and 4.95 t/d of raw wax using heptane and toluene, respectively. Monte Carlo simulations indicate that the total GWP-100 of the SP is (9.6 ± 2.8)×10³ and (11.0 ± 3.4)×10³ kg CO₂ eq/t raw wax for heptane and toluene, respectively, in Cuba, while for Brazil these values decrease to (4.9 ± 1.3)×10³ and (6.1 ± 1.8)×10³ kg CO₂ eq/t raw wax, respectively. The analysis also revealed that while heptane showed no significant toxicity risks, toluene exhibited measurable human non-cancer toxicity effects. The lower GWP-100 impact estimated for Brazil versus Cuba, primarily due to differences in electricity grid composition, suggests significant environmental benefits for implementing this technology in this leading sugarcane-producing country. These findings provide valuable guidance for the sustainable development of sugarcane biorefineries and contribute to understanding environmental considerations in SP.

Rapid urbanization has intensified the challenge of managing solid waste, especially in densely populated cities across the globe. Traditional landfill-based disposal methods not only strain land resources but are also major contributors to greenhouse gas emissions—particularly methane, which has over 25 times the global warming potential of CO₂ over a 100-year period. This paper explores the transformative potential of innovative urban solid waste management practices as a strategic tool for climate change mitigation. By examining decentralized composting, waste-to-energy (WTE) technologies, and artificial intelligence (AI)-driven sorting systems, this study highlights practical approaches that can be integrated into urban infrastructure to improve resilience and environmental performance. Decentralized composting initiatives help reduce organic waste at the source, offering community-level climate benefits. Waste-to-energy plants, when appropriately regulated, can provide renewable energy alternatives while significantly reducing landfill reliance. Moreover, AI-powered sorting systems offer a high-efficiency method for maximizing recycling rates and minimizing contamination in material recovery facilities. Using case studies from cities like San Francisco, Copenhagen, and Pune, the paper evaluates implementation frameworks, policy drivers, and community engagement models that have enabled these innovations to thrive. The research concludes with a policy-oriented framework for scaling these strategies in rapidly urbanizing regions, emphasizing multi-stakeholder collaboration, financial innovation, and data-driven monitoring tools. This paper contributes to the discourse on sustainable urban development by framing waste not as a burden, but as a climate-smart resource, turning “waste to worth” for the cities of tomorrow.

As the global transition to a circular economy accelerates, the development of robust and effective evaluation frameworks has become essential to monitor systemic progress. Previous studies have primarily focused on developing individual indicators or comparing performance, with relatively limited comparative analysis of how the circular economy is being evaluated within national contexts. This study analyzes the circular economy implementation indicators and evaluation frameworks used by international organizations (EU, UNECE, ISO) and nine major countries (France, Netherlands, Italy, Denmark, Finland, Portugal, Colombia, Japan, and South Korea) to derive policy implications for developing more effective evaluation frameworks. Indicators were extracted from each framework and categorized into six domains: Resource Circularity, Resource Efficiency, Waste Generation, Economy, Innovation, and Natural Ecosystem Sustainability. The analysis revealed that Resource Circularity and Resource Efficiency were universally prioritized, yet inconsistencies existed in indicator definitions and calculation methodologies. To address these differences, this study proposes the necessity of a hybrid assessment system integrating standardized global core indicators with complementary indicators reflecting each country’s unique context to ensure international comparability while maintaining the flexibility required for effective national policy implementation.

Existing technology can handle heavy metals in hazardous wastes (HW) to a certain extent, but there are still potential pollution hazards. Therefore, optimizing HW transfer and treatment, especially by considering heavy metal pollution resulting from different treatment technologies, is of paramount importance. This study constructs a transfer and treatment network based on treatment technologies and establishes a multi-objective optimization model that incorporates heavy metal pollution. Using data on HW with high heavy metal content, the network is optimized concerning cost, risk and heavy metal pollution. Compared with the three single-objective scenarios, the multi-objective solution achieved a better balanced trade-off among cost, risk and heavy metal pollution, with a cost of 12,250 *10³ USD, a risk of 495 persons*ton and a heavy metal pollution index of 1285. Furthermore, the sensitivity analyses confirm the model robustness, while simultaneously highlighting that greater emphasis on heavy metal pollution and higher recovery rates (> 0.9) are critical factors for improving optimization performance. Additionally, correlation analysis reveals a positive relationship between heavy metal pollution and cost. This study provides a novel optimization framework for HW transfer and treatment, with its results also offering valuable insights for heavy metal pollution control and the formulation of management policies.