Journal of Material Cycles and Waste Management最新文献

Achieving efficiency in urban solid waste management (USWM) has been a major challenge worldwide. Factors such as scarcity of resources, disregard for impacts, and the trivialization of the waste sector have made progress in USWM unfeasible, mainly in developing countries. This article aims to analyze the effect of socioeconomic and structural explanatory variables on the efficiency of USWM in 940 Brazilian municipalities by means of a two-stage analysis. In the first stage, the technical efficiency scores were estimated using data envelopment analysis; in the second stage, the Tobit regression model was applied to analyze the effect of the explanatory variables on the efficiency scores. The results of the first stage showed efficiency in only 13.72% of municipalities. The results of the second stage did not show significant statistical differences between the types of management, taking as a reference the type of management known as direct public administration. There was no difference in efficiency between municipalities that had an integrated USWM plan and those that did not. Municipalities that had selective collection initiatives were 3% more efficient than those that did not. Municipalities that charged the generator for the urban solid waste collection service were 5% less efficient than municipalities that did not charge for the service provided. There was a positive correlation between municipal human development index and efficiency of USWM. However, no significant effect was observed for municipal gross domestic product per capita in relation to efficiency indices of USWM.

By studying the spectral variation characteristics of dissolved organic matter (DOM) in sheep manure compost caused by the addition of lignite, the influence of lignite on the maturity degree of sheep manure compost was explored. Sheep manure was used as the raw material for composting and fermentation. Lignite was added in proportions of 10%, 20% and 30% respectively. Characterization techniques such as total organic carbon analyzer, ultraviolet-visible absorption spectroscopy, Fourier transform infrared spectroscopy, fluorescence spectroscopy and three-dimensional fluorescence spectroscopy were used to study the spectral change characteristics of DOM in sheep manure compost after adding lignite in different proportions, as well as the changes of pH and EC values. The results show that adding 10% lignite has a significant effect on the dissolved organic matter DOM during the composting process of sheep manure. The non-humus in DOM continuously condenses to form humus, the benzene ring structure of organic matter increases, the degree of humification of compost increases, and the content of soluble salts in sheep manure decreases. During the composting process, some humic acid substances are transformed into fulvic acid substances. This study provides a theoretical basis for the collaborative and comprehensive utilization of aquaculture waste and lignite resources.

Lentinula edodes is valued for its nutritional and medicinal benefits, yet concerns remain regarding heavy metal and pesticide contamination. This study assessed five strains (DMRO-34, DMRO-35, DMRO-356, DMRO-388s, and DMRO-623) for food safety and reuse potential of spent mushroom substrate (SMS). ICP-MS analysis showed SMS contained Pb (0.0909–0.1636 mg/kg), Cd (0.03–0.09 mg/kg), Hg (0.0444–0.0667 mg/kg), As (0.0533–0.2667 mg/kg), and Ni (0.0286–0.0714 mg/kg), all within WHO/FAO limits. Fruiting bodies exhibited minimal transfer (< 0.20 mg/kg), confirming safe consumption. Pesticide residues were below detection (< 0.01 mg/kg). Strain-specific SMS variation was observed, with DMRO-356 showing the highest nitrogen depletion (0.95%). Lignocellulosic degradation ranged for cellulose (34.8–41.4%), hemicellulose (25.6–31.3%), and lignin (26.4–27.3%). Multivariate analyses (PCA, HCA) revealed distinct strain clustering, linking heavy metal uptake with biodegradation efficiency, highlighting DMRO-356 and DMRO-388s as superior for bioremediation and bioenergy applications. A comparative economic evaluation indicated composting as a low-cost, agronomically beneficial reuse option, while biofuel production offered higher economic returns; a hybrid pathway was recommended to maximize SMS valorization. Overall, the study demonstrates both food safety of L. edodes and sustainable reuse of SMS, supporting circular bioeconomy strategies in agriculture and industry.

Natural fiber textile fabrics can be finished with flame-retardant chemicals to meet safety standards. Calcium phosphate is an effective flame retardant for cotton, but its preparation needs to be scaled up using cheaper, eco-friendly raw materials. Chicken bone waste causes environmental pollution due to odor and visual impact. Repurposing chicken bones as a source of calcium phosphate offers a sustainable solution, reducing waste and enhancing fabric flame resistance. The extraction process involves digesting chicken bones with hydrochloric acid, precipitating calcium phosphate using ammonia, then filtering and drying the product. The extracted calcium phosphate was applied to cotton fabric through a coating process. Various finishing conditions—such as flame-retardant dosage, finishing liquor pH, ammonia concentration, curing temperature, and curing time—were evaluated using a Taguchi L9 experimental design to optimize the process. The flame-retardant performance was assessed by a vertical burning test, showing that treated fabrics had lower flammability than untreated ones. Treated fabrics developed char and ash after burning, while untreated fabrics burned completely with only ash residue. Burning times increased from 42 s for untreated fabric to 64 s for treated fabric, demonstrating the effectiveness of the calcium phosphate treatment in improving flame resistance.

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Residues left after sorting useful plastics at the plastic recycling facility are literally garbage that can only be incinerated or landfilled. We transformed these residues into hydrochar through hydrothermal carbonization using saturated steam at 230 °C. The characteristics of the hydrochar were evaluated, and blends composed of various polymers and hydrochar were fabricated through melt blending in an extruder. The polymers used included recycled polypropylene (PP), recycled polyethylene (PE), virgin PP, virgin PE, and polyamide 6 (PA6). The mechanical properties of PP/hydrochar and PE/hydrochar blends were found to be high without the need for a compatibilizer. On the other hand, polyamide 6/hydrochar blends showed typical characteristics of poor compatibility. A significant negative deviation was observed in the PA6/hydrochar blend, which may be due to the fact that around 60% of the hydrochar consists of PP and PE. By incorporating elastomers commonly used in PP compounds into recycled PP/hydrochar blends, the impact strength of the blends was significantly improved. The impact strength of the recycled PP/hydrochar (70 wt%/30 wt%) blend increased significantly when just 5 phr of elastomer was added, surpassing even the impact strength of recycled PP alone. This study provides proof of the viability of physically recycling plastic sorting waste.

Municipal solid waste (MSW) features complex composition and a high proportion of combustible materials. Through waste classification and collection, its primary components can be processed into refuse-derived fuel (RDF) to replace fossil fuels in industrial kilns, or serve as an auxiliary fuel to improve the combustion stability of waste-to-energy incineration boilers. In this paper, the influence of RDF component composition, particle size, moisture content, additives, and forming process parameters on its physical properties were systematically investigated. Experimental research and kinetic analysis were conducted to elucidate the combustion characteristics and pollutant emission patterns of RDF. Key findings showed that paper-rich RDF held the optimal durability and moderate moisture content was crucial for balancing molding effectiveness and maintaining RDF calorific value. Although smaller particle sizes and higher forming pressure were beneficial for RDF molding, moderate values should be adopted when comprehensively considering the corresponding energy consumption efficiency. Thermochemical analysis revealed that an elevated plastic content in RDF significantly enhanced the calorific value and combustion performance index, but concurrently resulted in higher activation energy and ignition temperature, exacerbating SO₂ emissions and promoting the volatilization of heavy metals during combustion. An estimation and analysis of the economic benefits of its commercial applications were conducted.

One of the materials used in food packaging is paper and cardboard. Paper used in the food packaging industry is either buried as solid waste, released into the environment, or reused. Endocrine-disrupting compounds are found in paper and cardboard. One of these compounds is estrogenic or xenoestrogenic compounds, which are found in the papers based on the evidence. This systematic study was conducted to summarize the results of studies on estrogenic compounds in virgin and recycled papers. Manuscripts were searched in databases with relevant keywords without any time limit on publication. Based on the geographical distribution of the studies, most of the selected manuscripts belonged to European countries. The tests used to evaluate estrogenic compounds were both analytical methods and bioassay tests. In the bioassay tests, estrogen receptor-positive cell lines were used, and all of these tests yielded positive results. The most commonly identified compounds following the analytical method were bisphenol A(BPA) and phthalates. In most studies, the estrogenic activity of recycled paper was higher than that of virgin paper. This was due to the increased concentration of compounds such as bisphenol and phthalates after recycling.

In this study, the potential for transforming valuable metals in industrial waste sludge into a useful product and thus reducing the amount of waste was investigated. So, waste sludge from the metal coating industry with high Fe and Zn content and waste glass were vitrified by adding 1-5-10-15-20-25% by weight of sludge to glass. The structural, optical and antimicrobial (antibacterial and antifungal) analyses were carried out. XRD results of the products showed that there are no peaks associated with any crystalline phase, as expected for an amorphous structure. According to XRF analysis, the products can be classified as soda-lime-silicate glass. FT-IR results revealed the presence of intense silicate and iron oxide peaks in vitrified products. TCLP analysis proved that all heavy metals leached from sludge were successfully stabilized in vitrified products. According to the optical transmittance, vitrified products including 20–25% waste sludge have potential use as the bandpass optical filter. These vitrified products showed 93–94% antibacterial activity against E. coli and 93 − 91% antibacterial activity to S. aureus, respectively. Additionally, these vitrified products have broad spectrum antimicrobial effect (91%).

The high-strength composition of leachate, intensive energy consumption, and substantial external carbon demand constrain conventional biological nitrogen removal systems for treating landfill leachate. This study employed a hybrid system based on partial nitrification (PN)-anaerobic ammonium oxidation (Anammox) as the core autotrophic nitrogen removal process. For organic capture, 1.5 g/L FeCl₃ coagulant and anaerobic treatment were used to remove approximately 48% and 70% of COD, respectively, and to provide suitable influent conditions for the PN-Anammox process. The PN process was established by controlling dissolved oxygen and in-situ accumulation of free ammonia (FA) and free nitrous acid (FNA), achieving a suitable effluent NO₂⁻-N/NH₄⁺-N ratio (1.10). The Anammox reactor removed 83% of nitrogen in Phase I (25% leachate) compared to 60% in Phase II (50% leachate). Possible suppression of the Anammox process by organic matter and heavy metals may explain this reduction, which was confirmed by measuring extracellular polymeric substances (EPS), dehydrogenase activity (DHA), and a luminescent bacterial toxicity test. After final biological oxidation, the effluent quality met Chinese discharge standards for organic concentration, while nitrogen required further removal. This study provides valuable guidance for transitioning from energy- and chemical-intensive nitrogen removal techniques to an autotrophic system for treating landfill leachate.

The increasing amount of waste globally requires more efficient recycling processes and increases the importance of intelligent, automatic classification systems. Since traditional waste separation methods are time-consuming and have high error rates, artificial intelligence-based solutions have great potential in this area. In this study, the effectiveness of deep learning-based waste classification models was investigated, and nine different waste types were classified using DenseNet121, EfficientNetB0, ResNet50, ViT, DenseNet121-ViT, EfficientNetB0-ViT, ResNet50-ViT. Experimental results show that hybrid CNN-ViT models achieved the highest accuracy rates. Mainly, the EfficientNetB0-ViT model exhibited the best performance with a 95% accuracy rate and made a balanced classification for all waste types. The model can optimize recycling processes by ensuring the correct separation of wastes and contribute to environmental sustainability by reducing misclassification. Artificial intelligence-supported waste management systems offer an effective solution in critical areas such as reducing greenhouse gas emissions, saving energy, and supporting environmentally friendly urban planning. The findings of this study reveal that deep learning-based artificial intelligence models are an important tool for sustainable environmental management.