Pub Date : 2026-01-29DOI: 10.1016/j.wasman.2026.115383
Jiankang Yang , Weitao Li , Jian Tang , Wei Sun , Qiyue Li
To address the fluctuating combustion caused by the complex and variable composition of municipal solid waste incineration (MSWI), this paper proposes a state recognition system for MSWI based on a deep convolutional stochastic configuration machine (DCSCM). The system consists of high-temperature cameras, a network switch, an industrial control computer, and a server, which employs DCSCM for intelligent assessment of combustion states. The DCSCM simulated expert prior knowledge via a linear predictive basis model, incrementally constructed convolutional structure, and incorporated an adaptive optimization mechanism based on error feedback. The mechanism dynamically evaluated the model convergence and enabled adaptive construction of model width and depth before convolutional kernels were populated. The results demonstrated that the trained DCSCM achieved a parameter size of 376 KB and a recognition accuracy of 97.32%, with its operational deployment and self-optimization in complex environments improving the average accuracy by 1.20%. The study provides support for precise combustion parameter control in MSWI, enabling automated monitoring of combustion states and reduced pollutant emissions.
{"title":"Municipal solid waste incineration state recognition system based on deep convolutional stochastic configuration machine","authors":"Jiankang Yang , Weitao Li , Jian Tang , Wei Sun , Qiyue Li","doi":"10.1016/j.wasman.2026.115383","DOIUrl":"10.1016/j.wasman.2026.115383","url":null,"abstract":"<div><div>To address the fluctuating combustion caused by the complex and variable composition of municipal solid waste incineration (MSWI), this paper proposes a state recognition system for MSWI based on a deep convolutional stochastic configuration machine (DCSCM). The system consists of high-temperature cameras, a network switch, an industrial control computer, and a server, which employs DCSCM for intelligent assessment of combustion states. The DCSCM simulated expert prior knowledge via a linear predictive basis model, incrementally constructed convolutional structure, and incorporated an adaptive optimization mechanism based on error feedback. The mechanism dynamically evaluated the model convergence and enabled adaptive construction of model width and depth before convolutional kernels were populated. The results demonstrated that the trained DCSCM achieved a parameter size of 376 KB and a recognition accuracy of 97.32%, with its operational deployment and self-optimization in complex environments improving the average accuracy by 1.20%. The study provides support for precise combustion parameter control in MSWI, enabling automated monitoring of combustion states and reduced pollutant emissions.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115383"},"PeriodicalIF":7.1,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.wasman.2026.115352
Peter Sántha , Peter Tamás-Bényei
The widespread adoption of carbon fiber–reinforced polymers (CFRPs) across high-performance sectors such as aerospace, automotive, wind energy, and construction has significantly increased the global demand for carbon fibers (CFs). However, the energy-intensive production process and growing volume of end-of-life (EoL) CFRP waste present significant environmental and economic challenges. This review offers a comprehensive analysis of the state of the art in carbon fiber recycling, focusing on the reclamation, remanufacturing, and reuse of recycled carbon fibers (rCFs) to support a sustainable circular economy. These waste streams are projected to grow substantially, driven by the decommissioning of wind turbines and aircraft. The valuable fibers are lost in traditional waste management practices, such as landfilling and incineration. Landfilling is also detrimental to the environment and unsustainable. Hence, recovering CFs through recycling is essential for minimizing environmental impacts and preserving material value.
This review presents a comprehensive assessment of recycling technologies, including mechanical, thermal, chemical, and emerging methods. Each technique is assessed based on quantified fiber retention, energy efficiency, scalability, and technological readiness. The study further explores remanufacturing technologies for rCFs, detailing their transformation into intermediate forms suitable for reuse. The alignment of discontinuous fibers is critical for maximizing mechanical performance. Analytical and numerical modeling tools applied to predict fiber orientation, alignment efficiency, and composite behavior are included. In addition to technical insights, the article integrates economic viability, quality assurance, and life cycle assessment (LCA) to evaluate environmental performance, supporting market acceptance and regulatory compliance by quantifying the sustainability advantages of rCFs.
{"title":"A comprehensive overview of the potential of recycled carbon fiber from composite waste: reclamation, remanufacturing, and performance","authors":"Peter Sántha , Peter Tamás-Bényei","doi":"10.1016/j.wasman.2026.115352","DOIUrl":"10.1016/j.wasman.2026.115352","url":null,"abstract":"<div><div>The widespread adoption of carbon fiber–reinforced polymers (CFRPs) across high-performance sectors such as aerospace, automotive, wind energy, and construction has significantly increased the global demand for carbon fibers (CFs). However, the energy-intensive production process and growing volume of end-of-life (EoL) CFRP waste present significant environmental and economic challenges. This review offers a comprehensive analysis of the state of the art in carbon fiber recycling, focusing on the reclamation, remanufacturing, and reuse of recycled carbon fibers (rCFs) to support a sustainable circular economy. These waste streams are projected to grow substantially, driven by the decommissioning of wind turbines and aircraft. The valuable fibers are lost in traditional waste management practices, such as landfilling and incineration. Landfilling is also detrimental to the environment and unsustainable. Hence, recovering CFs through recycling is essential for minimizing environmental impacts and preserving material value.</div><div>This review presents a comprehensive assessment of recycling technologies, including mechanical, thermal, chemical, and emerging methods. Each technique is assessed based on quantified fiber retention, energy efficiency, scalability, and technological readiness. The study further explores remanufacturing technologies for rCFs, detailing their transformation into intermediate forms suitable for reuse. The alignment of discontinuous fibers is critical for maximizing mechanical performance. Analytical and numerical modeling tools applied to predict fiber orientation, alignment efficiency, and composite behavior are included. In addition to technical insights, the article integrates economic viability, quality assurance, and life cycle assessment (LCA) to evaluate environmental performance, supporting market acceptance and regulatory compliance by quantifying the sustainability advantages of rCFs.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115352"},"PeriodicalIF":7.1,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.wasman.2026.115364
Vigneshwar N. Gnanasekaran , Ayush Dave , Sivamohan N. Reddy
A novel catalytic hydrothermal technique for the conversion of post-consumer paper cups (PCPC) containing polyethylene (PE) linings into hydrogen-rich fuel gas and synthesizing value-added nickel-decorated carbon composites (NDCC). The impact of operating gasification parameters such as temperature, residence time, and nickel concentration on the degradation of PCPC was investigated. A maximum H2 yield (9.71 ± 0.19 mmol/g), total gas yield (TGY) (23.79 ± 0.47 mmol/g), carbon gasification efficiency (CGE) of 38.27%, and lower heating value (LHV) of 2994 KJ/Nm3 was attained at 600 °C, 40 min, and a Ni concentration of 0.3 wt%. The incorporation of nickel enhances the degradation of PCPC by catalyzing the water–gas shift and cracking reactions. Compared with deionized water, the in-situ doping of nickel elevates the H2 yield by 1.8 times, and TGY, CGE, and LHV by ∼ 1.7 times. The NDCC obtained at 600 °C has a cubical structure with an average particle size of 40 nm, as examined by FESEM and TEM analysis. Additionally, the synthesized NDCC was employed as an external catalyst for the degradation of glucose to hydrogen-rich fuel gas. It retained catalytic activity for up to 7 consecutive cycles, producing a maximum H2 yield of 20.34 mmol/g of glucose.
{"title":"Post-consumer paper cups to hydrogen and functional catalytic material","authors":"Vigneshwar N. Gnanasekaran , Ayush Dave , Sivamohan N. Reddy","doi":"10.1016/j.wasman.2026.115364","DOIUrl":"10.1016/j.wasman.2026.115364","url":null,"abstract":"<div><div>A novel catalytic hydrothermal technique for the conversion of post-consumer paper cups (PCPC) containing polyethylene (PE) linings into hydrogen-rich fuel gas and synthesizing value-added nickel-decorated carbon composites (NDCC). The impact of operating gasification parameters such as temperature, residence time, and nickel concentration on the degradation of PCPC was investigated. A maximum H<sub>2</sub> yield (9.71 ± 0.19 mmol/g), total gas yield (TGY) (23.79 ± 0.47 mmol/g), carbon gasification efficiency (CGE) of 38.27%, and lower heating value (LHV) of 2994 KJ/Nm<sup>3</sup> was attained at 600 °C, 40 min, and a Ni concentration of 0.3 wt%. The incorporation of nickel enhances the degradation of PCPC by catalyzing the water–gas shift and cracking reactions. Compared with deionized water, the in-situ doping of nickel elevates the H<sub>2</sub> yield by 1.8 times, and TGY, CGE, and LHV by ∼ 1.7 times. The NDCC obtained at 600 °C has a cubical structure with an average particle size of 40 nm, as examined by FESEM and TEM analysis. Additionally, the synthesized NDCC was employed as an external catalyst for the degradation of glucose to hydrogen-rich fuel gas. It retained catalytic activity for up to 7 consecutive cycles, producing a maximum H<sub>2</sub> yield of 20.34 mmol/g of glucose.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115364"},"PeriodicalIF":7.1,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.wasman.2026.115370
Siqi Chen , Zhenjie Gu , Yan Fang , Yunxiang Weng , Haiqing Liu , Qinhui Chen
The improper disposal of dredged silt may lead to land occupation, ecological contamination, reduced river flood discharge capacity, and navigation channel obstruction. Based on its inherent characteristics, a dual-functional composite solidifier used for simultaneous flocculation and solidification was developed. Its flocculation efficacy was evaluated by specific resistance to filtration (SRF), capillary suction time (CST), unconfined compressive strength (UCS) testing coupled with moisture transformation analysis etc. Results demonstrate that 3% of shell powder addition is optimal through Ca2+-mediated charge neutralization, electrical double layer compression and alkaline-stimulated gelation. Fluorogypsum facilitates the formation of AFt crystal for pore-filling, while the hydration of shell powder provides alkaline Ca(OH)2 to drive pozzolanic reactions to form C-S(A)-H gels which play a role in cementation and densification. The UCS of solidified soil reaches 2.52 MPa at the synergistic effect of the comprehensive waste utilization which displays superior sustainability and cost-effectiveness over conventional cement-based approaches. The solidified soil exhibits friendliness towards green plants. This disposal method achieves the recycling and resource recovery of three types of solid waste.
{"title":"Sustainable development solidification of dredged silt by fluorogypsum with the flocculation and activation of shell powder","authors":"Siqi Chen , Zhenjie Gu , Yan Fang , Yunxiang Weng , Haiqing Liu , Qinhui Chen","doi":"10.1016/j.wasman.2026.115370","DOIUrl":"10.1016/j.wasman.2026.115370","url":null,"abstract":"<div><div>The improper disposal of dredged silt may lead to land occupation, ecological contamination, reduced river flood discharge capacity, and navigation channel obstruction. Based on its inherent characteristics, a dual-functional composite solidifier used for simultaneous flocculation and solidification was developed. Its flocculation efficacy was evaluated by specific resistance to filtration (SRF), capillary suction time (CST), unconfined compressive strength (UCS) testing coupled with moisture transformation analysis etc. Results demonstrate that 3% of shell powder addition is optimal through Ca<sup>2+</sup>-mediated charge neutralization, electrical double layer compression and alkaline-stimulated gelation. Fluorogypsum facilitates the formation of AFt crystal for pore-filling, while the hydration of shell powder provides alkaline Ca(OH)<sub>2</sub> to drive pozzolanic reactions to form C-S(A)-H gels which play a role in cementation and densification. The UCS of solidified soil reaches 2.52 MPa at the synergistic effect of the comprehensive waste utilization which displays superior sustainability and cost-effectiveness over conventional cement-based approaches. The solidified soil exhibits friendliness towards green plants. This disposal method achieves the recycling and resource recovery of three types of solid waste.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115370"},"PeriodicalIF":7.1,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.wasman.2026.115371
Felix Brück , Florian Schmutzler , Jan Reeh , Christine Fröhlich , Harald Platen , Harald Weigand
Lime treatment is widely applied for stabilizing and conditioning municipal sewage sludge to improve handling and hygienic properties. It also offers the potential for carbon dioxide (CO2) sequestration through lime recarbonation. Thereby, atmospheric CO2 reacts with calcium hydroxide (Ca(OH)2) to form calcium carbonate (CaCO3), partly or fully offsetting process CO2 emissions generated during lime production. However, its extent and rate are largely unexplored.
We investigated the spontaneous recarbonation of lime-treated sewage sludge using samples from two full-scale wastewater treatment plants (WWTPs). WWTP1 applies hydrated lime prior to dewatering, while WWTP2 adds quicklime after dewatering. Samples were incubated under controlled conditions for six months and analyzed using thermogravimetry–mass spectrometry (TGA–MS), X-ray diffraction (XRD), and bulk element determinations.
Progressive transformation of Ca(OH)2 into CaCO3 confirmed spontaneous recarbonation. Within four months, WWTP1 samples reached near-complete carbonation with rates approaching 100 % of the calcination-related process CO2 emissions. By contrast, WWTP2 samples exhibited lower rates of recarbonation, with a maximum of ∼94 %, likely due to heterogeneous lime distribution, and encapsulation of unreacted lime along with differences in lime quality.
These findings provide the first conclusive evidence for substantial spontaneous recarbonation of lime-treated sewage sludge under ambient conditions. They demonstrate that CO2 uptake is strongly influenced by lime type, dosing strategy, and sludge composition. This establishes a robust basis for integrating lime recarbonation into carbon accounting frameworks and for evaluating the long-term carbon sink potential of lime-treated sludge, while fuel-related emissions from lime production remain outside the scope of this study.
{"title":"From lime stabilization to CO2 sequestration: spontaneous recarbonation in municipal sewage sludge","authors":"Felix Brück , Florian Schmutzler , Jan Reeh , Christine Fröhlich , Harald Platen , Harald Weigand","doi":"10.1016/j.wasman.2026.115371","DOIUrl":"10.1016/j.wasman.2026.115371","url":null,"abstract":"<div><div>Lime treatment is widely applied for stabilizing and conditioning municipal sewage sludge to improve handling and hygienic properties. It also offers the potential for carbon dioxide (CO<sub>2</sub>) sequestration through lime recarbonation. Thereby, atmospheric CO<sub>2</sub> reacts with calcium hydroxide (Ca(OH)<sub>2</sub>) to form calcium carbonate (CaCO<sub>3</sub>), partly or fully offsetting process CO<sub>2</sub> emissions generated during lime production. However, its extent and rate are largely unexplored.</div><div>We investigated the spontaneous recarbonation of lime-treated sewage sludge using samples from two full-scale wastewater treatment plants (WWTPs). WWTP1 applies hydrated lime prior to dewatering, while WWTP2 adds quicklime after dewatering. Samples were incubated under controlled conditions for six months and analyzed using thermogravimetry–mass spectrometry (TGA–MS), X-ray diffraction (XRD), and bulk element determinations.</div><div>Progressive transformation of Ca(OH)<sub>2</sub> into CaCO<sub>3</sub> confirmed spontaneous recarbonation. Within four months, WWTP1 samples reached near-complete carbonation with rates approaching 100 % of the calcination-related process CO<sub>2</sub> emissions. By contrast, WWTP2 samples exhibited lower rates of recarbonation, with a maximum of ∼94 %, likely due to heterogeneous lime distribution, and encapsulation of unreacted lime along with differences in lime quality.</div><div>These findings provide the first conclusive evidence for substantial spontaneous recarbonation of lime-treated sewage sludge under ambient conditions. They demonstrate that CO<sub>2</sub> uptake is strongly influenced by lime type, dosing strategy, and sludge composition. This establishes a robust basis for integrating lime recarbonation into carbon accounting frameworks and for evaluating the long-term carbon sink potential of lime-treated sludge, while fuel-related emissions from lime production remain outside the scope of this study.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115371"},"PeriodicalIF":7.1,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-28DOI: 10.1016/j.wasman.2025.115306
Junlong Huang , Yiping Wu , Fangming Xu , Hongtao Wang , Yanjun Liu
In-situ aeration, achieved by injecting air into municipal solid waste, accelerates landfill stabilization, yet current designs remain largely empirical. This study introduces landfillFoam, an open-source solver built on OpenFOAM and porousMultiphaseFoam, integrating unsaturated two-phase flow, the dusty gas model for multicomponent transport, Monod-type aerobic and anaerobic degradation, methane oxidation, and heat transfer. Validation against analytical solutions and field data confirmed its accuracy. A 1,200-day baseline simulation identified four aerobic stabilization stages, with aerobic processes contributing 36% of total organic degradation. Aeration shortened stabilization time by 10-15% relative to non-aerated conditions. Parametric analyses showed that higher permeability enhanced injection rates but increased overheating risk, while water saturation of 40-60% provided an optimal balance between degradation and oxygen transport. A hexagonal well layout improved energy efficiency by 40% compared with a square layout, and reducing spacing from 15 m to 12 m yielded marginal benefits. In contrast, alternating injection-extraction wells and intermittent injection hindered stabilization relative to continuous injection. Early aeration initiation markedly enhanced stabilization, with a critical delay threshold beyond which benefits diminished. These findings provide quantitative guidance for optimizing aeration strategies to reduce landfill aftercare requirements.
{"title":"Numerical study of in‑situ aeration using landfillFoam: effects of landfill properties and aeration strategies","authors":"Junlong Huang , Yiping Wu , Fangming Xu , Hongtao Wang , Yanjun Liu","doi":"10.1016/j.wasman.2025.115306","DOIUrl":"10.1016/j.wasman.2025.115306","url":null,"abstract":"<div><div>In-situ aeration, achieved by injecting air into municipal solid waste, accelerates landfill stabilization, yet current designs remain largely empirical. This study introduces <em>landfillFoam</em>, an open-source solver built on OpenFOAM and porousMultiphaseFoam, integrating unsaturated two-phase flow, the dusty gas model for multicomponent transport, Monod-type aerobic and anaerobic degradation, methane oxidation, and heat transfer. Validation against analytical solutions and field data confirmed its accuracy. A 1,200-day baseline simulation identified four aerobic stabilization stages, with aerobic processes contributing 36% of total organic degradation. Aeration shortened stabilization time by 10-15% relative to non-aerated conditions. Parametric analyses showed that higher permeability enhanced injection rates but increased overheating risk, while water saturation of 40-60% provided an optimal balance between degradation and oxygen transport. A hexagonal well layout improved energy efficiency by 40% compared with a square layout, and reducing spacing from 15 m to 12 m yielded marginal benefits. In contrast, alternating injection-extraction wells and intermittent injection hindered stabilization relative to continuous injection. Early aeration initiation markedly enhanced stabilization, with a critical delay threshold beyond which benefits diminished. These findings provide quantitative guidance for optimizing aeration strategies to reduce landfill aftercare requirements.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115306"},"PeriodicalIF":7.1,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-27DOI: 10.1016/j.wasman.2026.115368
Tomas Makaras, Brigita Gylytė, Janina Pažusienė, Roberta Valskienė
Leachate toxicity is influenced by multiple landfill factors, yet the drivers and the biological levels at which effects manifest remain poorly understood. We conducted a multi-level biological assessment of Daphnia magna exposed to leachates from non-hazardous/industrial landfills differing in operational status (operational vs. non-operational), environmental exposure (precipitation-protected vs. unprotected), and treatment stage (untreated, partially, or fully treated). Acute effective (EC50) and low-effect equivalent (EC5, 1/4, and 1/16 EC5) concentrations were evaluated to compare treatments and relate response magnitude to leachate physicochemical characteristics and landfill-specific factors. This approach enabled biologically equivalent comparisons across sites and spanned four interconnected levels—physiological, behavioural, growth, and reproductive—providing insights beyond standard endpoints. Even treated leachates retained toxicity at the lowest concentrations tested. Specific physicochemical parameters driving leachate toxicity were identified, guiding testing and risk assessment. Based on toxicity unit (TU) values, the highest toxicity was observed in precipitation-protected leachate (108.36), followed by precipitation-unprotected leachates (19.69–60.24), non-operational leachate (6.70), and partially treated leachate after mechanical/biological treatment (4.84). No toxic effects on D. magna immobilization were detected in fully treated leachate following reverse osmosis. Sublethal exposures affected heart rate, behaviour, and growth, with reproduction largely unaffected; heart rate was the most sensitive endpoint, responding even at 1/16 EC5, including in post-treated leachates. These results show that landfill age, composition, management, and post-treatment collectively shape leachate toxicity, influencing both magnitude and type of biological response. Further studies should explore interactions with environmental factors and identify suitable test organisms and endpoints for rapid, sensitive assessment.
{"title":"Linking landfill operational characteristics and treatment conditions to Daphnia magna toxicity of leachates","authors":"Tomas Makaras, Brigita Gylytė, Janina Pažusienė, Roberta Valskienė","doi":"10.1016/j.wasman.2026.115368","DOIUrl":"10.1016/j.wasman.2026.115368","url":null,"abstract":"<div><div>Leachate toxicity is influenced by multiple landfill factors, yet the drivers and the biological levels at which effects manifest remain poorly understood. We conducted a multi-level biological assessment of <em>Daphnia magna</em> exposed to leachates from non-hazardous/industrial landfills differing in operational status (operational vs. non-operational), environmental exposure (precipitation-protected vs. unprotected), and treatment stage (untreated, partially, or fully treated). Acute effective (EC<sub>50</sub>) and low-effect equivalent (EC<sub>5</sub>, 1/4, and 1/16 EC<sub>5</sub>) concentrations were evaluated to compare treatments and relate response magnitude to leachate physicochemical characteristics and landfill-specific factors. This approach enabled biologically equivalent comparisons across sites and spanned four interconnected levels—physiological, behavioural, growth, and reproductive—providing insights beyond standard endpoints. Even treated leachates retained toxicity at the lowest concentrations tested. Specific physicochemical parameters driving leachate toxicity were identified, guiding testing and risk assessment. Based on toxicity unit (TU) values, the highest toxicity was observed in precipitation-protected leachate (108.36), followed by precipitation-unprotected leachates (19.69–60.24), non-operational leachate (6.70), and partially treated leachate after mechanical/biological treatment (4.84). No toxic effects on <em>D. magna</em> immobilization were detected in fully treated leachate following reverse osmosis. Sublethal exposures affected heart rate, behaviour, and growth, with reproduction largely unaffected; heart rate was the most sensitive endpoint, responding even at 1/16 EC<sub>5</sub>, including in post-treated leachates. These results show that landfill age, composition, management, and post-treatment collectively shape leachate toxicity, influencing both magnitude and type of biological response. Further studies should explore interactions with environmental factors and identify suitable test organisms and endpoints for rapid, sensitive assessment.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115368"},"PeriodicalIF":7.1,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-27DOI: 10.1016/j.wasman.2026.115362
Jacopo de Tommaso, Alexandre Gaillard, Elodie Mattio, Chloé Ardizzone, Antoine Leybros
The automotive industry consumes 7 % of global plastics, with polymers accounting for nearly half the volume of the vehicle. End-of-life automotive plastics are heterogeneous mixtures of polymers, fillers, and additives that current sorting systems cannot handle, preventing their otherwise feasible conversion into monomers or chemical building blocks. To address this challenge, we treated hydrothermally a representative unsorted automotive plastic waste stream of polyethylene terephthalate (PET), polyamide 6 (PA6), polyurethane (PU), polypropylene (PP) and polyvinyl chloride (PVC) under sub/supercritical water at 250 to 400 °C. Between 250 and 300 °C, PET converts to terephthalic acid (TPA) with 80–95 % yield, recovered as a solid, and PA6 depolymerizes to caprolactam and aminohexanoic acid. Water cleaves PU into amines and polyols, PVC dechlorinates, while PP remains intact after subcritical water treatment. PA6 hinders PET hydrolysis, while PU and PVC improve TPA’s yield, and PP has no effect. Starting at 300 °C, PA6 and PU monomers recombine and degrade, but PU at least quadruplicates its yield in nitrogenous aromatics. Above the critical point, TPA fragments to a range of oxygenated aromatics, PA6 monomers disappear, PP and PVC cracks into C8-C14 branched aliphatic, and PU yield increase only slightly (10 % compared to 300 °C). We demonstrate that no single condition valorises all polymers simultaneously. Instead, process design must prioritize the most valuable products, for instance via staged heating: subcritical conditions recover PA6 and PU monomers as liquids, PET hydrolyses optimally at 300 °C as a solid, and PP converts to fuels above supercritical conditions.
{"title":"Hydrothermal recycling of step and chain growth mixed plastics under sub- and supercritical conditions: chemical synergies, and antagonisms","authors":"Jacopo de Tommaso, Alexandre Gaillard, Elodie Mattio, Chloé Ardizzone, Antoine Leybros","doi":"10.1016/j.wasman.2026.115362","DOIUrl":"10.1016/j.wasman.2026.115362","url":null,"abstract":"<div><div>The automotive industry consumes 7 % of global plastics, with polymers accounting for nearly half the volume of the vehicle. End-of-life automotive plastics are heterogeneous mixtures of polymers, fillers, and additives that current sorting systems cannot handle, preventing their otherwise feasible conversion into monomers or chemical building blocks. To address this challenge, we treated hydrothermally a representative unsorted automotive plastic waste stream of polyethylene terephthalate (PET), polyamide 6 (PA6), polyurethane (PU), polypropylene (PP) and polyvinyl chloride (PVC) under sub/supercritical water at 250 to 400 °C. Between 250 and 300 °C, PET converts to terephthalic acid (TPA) with 80–95 % yield, recovered as a solid, and PA6 depolymerizes to caprolactam and aminohexanoic acid. Water cleaves PU into amines and polyols, PVC dechlorinates, while PP remains intact after subcritical water treatment. PA6 hinders PET hydrolysis, while PU and PVC improve TPA’s yield, and PP has no effect. Starting at 300 °C, PA6 and PU monomers recombine and degrade, but PU at least quadruplicates its yield in nitrogenous aromatics. Above the critical point, TPA fragments to a range of oxygenated aromatics, PA6 monomers disappear, PP and PVC cracks into C<sub>8</sub>-C<sub>14</sub> branched aliphatic, and PU yield increase only slightly (10 % compared to 300 °C). We demonstrate that no single condition valorises all polymers simultaneously. Instead, process design must prioritize the most valuable products, for instance via staged heating: subcritical conditions recover PA6 and PU monomers as liquids, PET hydrolyses optimally at 300 °C as a solid, and PP converts to fuels above supercritical conditions.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115362"},"PeriodicalIF":7.1,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-24DOI: 10.1016/j.wasman.2026.115367
Qingling Zhang , Jinlong Liu , Longxin Li , Youliang Cheng , Chengkun Liu , Yu Zhao , Changqing Fang
Waste cigarette filters are a primary source of solid waste pollution, primarily due to the non-biodegradability and the persistent leaching of toxic chemicals. The recycling and reuse of discarded cigarette filters are therefore critically significant for environmental protection and sustainable resource management. Herein, this study proposed an innovative approach to convert waste cigarette filters into freestanding electrode materials, and it requires no complex pre-treatment of the collected used cigarette filters. The N/S co-doped carbon nanofiber membranes were fabricated from waste cigarette filters via electrospinning, deacetylation, and carbonization. The as-prepared N/S co-doped carbon membrane exhibits a specific surface area of 385 m2·g−1 at the carbonization temperature of 900 °C, and it presents the highest specific capacitance of 229F·g−1 due to the synergistic effect of porosity and heteroatoms doping. The assembled symmetric flexible supercapacitor achieved an energy density of 24 Wh·kg−1 at a power density of 2500 W·kg−1, and it shows an impressive capacitance retention rate of 78.1 % after 10,000 cycles. The results indicate that converting waste cigarette filters into freestanding carbon membranes is a promising strategy for developing high-performance supercapacitor electrode materials.
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This study systematically investigated the reinforcement mechanisms of waste-tire-derived pyrolytic carbon black (CBp) in natural rubber (NR) composites at the component level through controlled demineralization strategies and modification treatments. This study identifies three main findings. First, SiO2 acts as a rigid structural skeleton that improves filler polarity and interfacial bonding, increasing the tensile strength by 16.8% (21.39 MPa) and the modulus M300 by 9.77 MPa. Second, ZnS negatively impacts composite performance by inducing stress concentration and weakening adhesion; its removal markedly improves the mechanical strength. Third, KOH activation increases the mesopore surface area from 36.27 to 45.69 m2/g, but this benefit is realized only when KOH activation is combined with SiO2 retention, resulting in optimal mechanical properties (22.17 MPa tensile, 10.48 MPa M300). This work delineates component-level reinforcement contributions, demonstrating that purified CBp with retained SiO2 exhibits performance comparable to that of fossil-derived carbon black (CB), whereas ZnS-free CBp-ZK shows superior dynamic mechanical properties (e.g., a reduced Payne effect). These findings advance the high-value utilization of CBp as a sustainable reinforcing filler, addressing critical gaps in waste tire pyrolysis product applications. This study further highlights the dual role of inorganic components, with SiO2 enhancing compatibility and ZnS impairing interfacial bonding, providing a foundation for industrial-scale CBp modification strategies.
{"title":"Strategic purification and activation of waste-tire-derived pyrolytic carbon black for enhanced natural rubber reinforcement: Mechanistic insights and practical considerations","authors":"Longfei Xie , Ping Zhou , Xiaoyan Chen , Pei-Gao Duan","doi":"10.1016/j.wasman.2026.115358","DOIUrl":"10.1016/j.wasman.2026.115358","url":null,"abstract":"<div><div>This study systematically investigated the reinforcement mechanisms of waste-tire-derived pyrolytic carbon black (CBp) in natural rubber (NR) composites at the component level through controlled demineralization strategies and modification treatments. This study identifies three main findings. First, SiO<sub>2</sub> acts as a rigid structural skeleton that improves filler polarity and interfacial bonding, increasing the tensile strength by 16.8% (21.39 MPa) and the modulus M300 by 9.77 MPa. Second, ZnS negatively impacts composite performance by inducing stress concentration and weakening adhesion; its removal markedly improves the mechanical strength. Third, KOH activation increases the mesopore surface area from 36.27 to 45.69 m<sup>2</sup>/g, but this benefit is realized only when KOH activation is combined with SiO<sub>2</sub> retention, resulting in optimal mechanical properties (22.17 MPa tensile, 10.48 MPa M300). This work delineates component-level reinforcement contributions, demonstrating that purified CBp with retained SiO<sub>2</sub> exhibits performance comparable to that of fossil-derived carbon black (CB), whereas ZnS-free CBp-ZK shows superior dynamic mechanical properties (e.g., a reduced Payne effect). These findings advance the high-value utilization of CBp as a sustainable reinforcing filler, addressing critical gaps in waste tire pyrolysis product applications. This study further highlights the dual role of inorganic components, with SiO<sub>2</sub> enhancing compatibility and ZnS impairing interfacial bonding, providing a foundation for industrial-scale CBp modification strategies.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115358"},"PeriodicalIF":7.1,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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