Pub Date : 2026-02-28Epub 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":"2026-02-28","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 : 2026-02-28Epub Date: 2026-02-01DOI: 10.1016/j.wasman.2026.115382
Daniel Maestre-Cambronel, James Cotton, Keena Trowell
Decarbonizing residential heating requires the widespread implementation of cleaner energy infrastructures. The absence of reliable technologies to phase out natural gas from this sector remains as a key barrier in arresting residential emissions. A methodology to quantify community resources with energetic value to meet residential heating demands is developed. The enabling technology is a seasonal energy storage model that relies on community scrap metals to produce hydrogen and heat on demand via metal-water reactions. A comprehensive geospatial quantification of suitable metal stocks at the city level is derived from municipal solid waste data. The model integrates open-source data and machine learning algorithms for waste generation forecasting. Results indicate that Hamilton, Ontario, can produce between 10 and 14.6 GWh of clean heat per year between 2021 and 2050. This represents an overall reduction of 2.9 ktonnes of space heating CO2 emissions every year. An optimized machine learning model based on a gradient boosting algorithm captured 86% of the variability in the municipal waste data with a root mean square error of 11.8 kg/person. The methodology presents reproducible steps to replicate the analysis in different contexts to facilitate community energy planning.
{"title":"A GIS-based thermal mapping and forecasting approach to decarbonize residential heating systems based on metals: A city-level case study","authors":"Daniel Maestre-Cambronel, James Cotton, Keena Trowell","doi":"10.1016/j.wasman.2026.115382","DOIUrl":"10.1016/j.wasman.2026.115382","url":null,"abstract":"<div><div>Decarbonizing residential heating requires the widespread implementation of cleaner energy infrastructures. The absence of reliable technologies to phase out natural gas from this sector remains as a key barrier in arresting residential emissions. A methodology to quantify community resources with energetic value to meet residential heating demands is developed. The enabling technology is a seasonal energy storage model that relies on community scrap metals to produce hydrogen and heat on demand via metal-water reactions. A comprehensive geospatial quantification of suitable metal stocks at the city level is derived from municipal solid waste data. The model integrates open-source data and machine learning algorithms for waste generation forecasting. Results indicate that Hamilton, Ontario, can produce between 10 and 14.6 GWh of clean heat per year between 2021 and 2050. This represents an overall reduction of 2.9 ktonnes of space heating CO<sub>2</sub> emissions every year. An optimized machine learning model based on a gradient boosting algorithm captured 86% of the variability in the municipal waste data with a root mean square error of 11.8 kg/person. The methodology presents reproducible steps to replicate the analysis in different contexts to facilitate community energy planning.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115382"},"PeriodicalIF":7.1,"publicationDate":"2026-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146107730","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 : 2026-02-28Epub Date: 2026-01-23DOI: 10.1016/j.wasman.2026.115359
Jeovana Jisla das Neves Santos , Fatima Osorio Baron , Alexandre R. Cabral , Federico Galli
The acclimatization process of methane oxidation biosystems typically requires several days or even months for the establishment of efficient and stable microbial communities. Here we assessed whether inoculating methane oxidation media with compost extract from pre-acclimatized compost-based materials accelerated acclimatization and increased methane oxidation capacity. Batch assays using biosolids and leaf compost were tested by the addition of compost extract in different dilutions of 100%, 66.6% (33.3% water), and 33.3% (66.6% water) at two initial CH4 concentrations (10% and 5% v/v). The most promising dilution (33.3%) was then assessed in continuous-flow column experiments with a structured engineered media (biosolids compost–gravel mixture (1:2 v/v). Results from batch assays showed that for the biosolids compost, the addition of compost extract reduced acclimatization time by 54–82% and increased oxidation rates from 16 to 70 µg CH4·gdw−1·h−1. The test with leaf compost showed a slightly smaller gain in acclimatization time (50–66%) and increase in oxidation rates from 11 to 32 µg CH4·gdw−1·h−1. In column tests, inoculation enabled full CH4 removal within 3 days, whereas in the test without inoculation, the sample was not yet fully acclimatized after 18 days. Microbiological analysis indicated that the compost extract preserved a diverse methanotrophic community. These findings demonstrate that compost extract inoculation is a simple, low-cost, and effective approach to accelerate start-up and enhance early-stage CH4 removal in methane oxidation biosystems. Implementing this strategy at full scale will likely shorten the stabilization period needed for methane oxidation biosystems to attain their full methane mitigation capacity.
{"title":"Use of compost extract as acclimatization accelerator for methane oxidation biosystems","authors":"Jeovana Jisla das Neves Santos , Fatima Osorio Baron , Alexandre R. Cabral , Federico Galli","doi":"10.1016/j.wasman.2026.115359","DOIUrl":"10.1016/j.wasman.2026.115359","url":null,"abstract":"<div><div>The acclimatization process of methane oxidation biosystems typically requires several days or even months for the establishment of efficient and stable microbial communities. Here we assessed whether inoculating methane oxidation media with compost extract from pre-acclimatized compost-based materials accelerated acclimatization and increased methane oxidation capacity. Batch assays using biosolids and leaf compost were tested by the addition of compost extract in different dilutions of 100%, 66.6% (33.3% water), and 33.3% (66.6% water) at two initial CH<sub>4</sub> concentrations (10% and 5% v/v). The most promising dilution (33.3%) was then assessed in continuous-flow column experiments with a structured engineered media (biosolids compost–gravel mixture (1:2 v/v). Results from batch assays showed that for the biosolids compost, the addition of compost extract reduced acclimatization time by 54–82% and increased oxidation rates from 16 to 70 µg CH<sub>4</sub>·gdw<sup>−1</sup>·h<sup>−1</sup>. The test with leaf compost showed a slightly smaller gain in acclimatization time (50–66%) and increase in oxidation rates from 11 to 32 µg CH<sub>4</sub>·gdw<sup>−1</sup>·h<sup>−1</sup>. In column tests, inoculation enabled full CH<sub>4</sub> removal within 3 days, whereas in the test without inoculation, the sample was not yet fully acclimatized after 18 days. Microbiological analysis indicated that the compost extract preserved a diverse methanotrophic community. These findings demonstrate that compost extract inoculation is a simple, low-cost, and effective approach to accelerate start-up and enhance early-stage CH<sub>4</sub> removal in methane oxidation biosystems. Implementing this strategy at full scale will likely shorten the stabilization period needed for methane oxidation biosystems to attain their full methane mitigation capacity.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115359"},"PeriodicalIF":7.1,"publicationDate":"2026-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039528","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 : 2026-02-28Epub 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":"2026-02-28","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 : 2026-02-28Epub Date: 2026-01-31DOI: 10.1016/j.wasman.2026.115391
Bilash Devnath , Sami Khanal , Ajay Shah , Toufiq Reza
This study evaluates the effects of co-hydrothermal carbonization (Co-HTC) of poultry (PM), dairy (DM), and swine manure (SM) at 180, 220, and 260 °C on hydrochar yield, nutrient recovery, phytotoxicity, and heavy metal retention. Co-HTC of PM with DM (PMDM) and PM with SM (PMSM) were assessed for synergistic effects by comparing observed values to predicted additive outcomes based on individual HTC data. Hydrochar yield decreased with increasing temperature across all treatments; however, PMSM and PMDM exhibited synergistic enhancement in yield at 180 °C (synergistic coefficient: 1.13–1.23). Elemental analysis indicated that nitrogen retention was maximized in PMDM hydrochars (4.71 ± 0.61% N at 180 °C), while PMSM hydrochars exhibited superior retention of phosphorus, magnesium, and calcium. Most potassium leached into the co-HTC process liquid. Heavy metals (Zn, Cu, and Ni) were effectively immobilized, with Co-HTC resulting in lower concentrations of Mo, Pb, and Cr compared to individual HTC. Seed germination index (GI), used to assess phytotoxicity, revealed temperature- and feedstock dependent trends, with PMSM hydrochar produced at 180 °C achieving the highest GI (140.91 ± 7.05%), indicating synergistic reduction in phytotoxicity. These findings demonstrate that Co-HTC can optimize recovery of nutrients into hydrochar and enhance the agronomic and environmental quality of hydrochars through tailored feedstock interactions and process tuning.
{"title":"Nutrient recovery from Co-Hydrothermal carbonization of animal manures: Synergistic effects on hydrochar properties and agronomic potential","authors":"Bilash Devnath , Sami Khanal , Ajay Shah , Toufiq Reza","doi":"10.1016/j.wasman.2026.115391","DOIUrl":"10.1016/j.wasman.2026.115391","url":null,"abstract":"<div><div>This study evaluates the effects of co-hydrothermal carbonization (Co-HTC) of poultry (PM), dairy (DM), and swine manure (SM) at 180, 220, and 260 °C on hydrochar yield, nutrient recovery, phytotoxicity, and heavy metal retention. Co-HTC of PM with DM (PMDM) and PM with SM (PMSM) were assessed for synergistic effects by comparing observed values to predicted additive outcomes based on individual HTC data. Hydrochar yield decreased with increasing temperature across all treatments; however, PMSM and PMDM exhibited synergistic enhancement in yield at 180 °C (synergistic coefficient: 1.13–1.23). Elemental analysis indicated that nitrogen retention was maximized in PMDM hydrochars (4.71 ± 0.61% N at 180 °C), while PMSM hydrochars exhibited superior retention of phosphorus, magnesium, and calcium. Most potassium leached into the co-HTC process liquid. Heavy metals (Zn, Cu, and Ni) were effectively immobilized, with Co-HTC resulting in lower concentrations of Mo, Pb, and Cr compared to individual HTC. Seed germination index (GI), used to assess phytotoxicity, revealed temperature- and feedstock dependent trends, with PMSM hydrochar produced at 180 °C achieving the highest GI (140.91 ± 7.05%), indicating synergistic reduction in phytotoxicity. These findings demonstrate that Co-HTC can optimize recovery of nutrients into hydrochar and enhance the agronomic and environmental quality of hydrochars through tailored feedstock interactions and process tuning.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115391"},"PeriodicalIF":7.1,"publicationDate":"2026-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080094","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}
Floc size in activated sludge systems plays a critical role in shaping bacterial communities by regulating microenvironmental heterogeneity, yet its ecological influence on fungal assemblages during process upgrading remains largely unexplored. This study aimed to systematically investigate the effects of floc-size stratification on fungal community composition, assembly mechanisms, source contribution patterns, and molecular ecological co-occurrence network structures during the transition from conventional nitrification–denitrification (CND) to partial nitrification–denitrification (PND) in a full-scale landfill leachate treatment plant. Fungal communities from large (L, >100 μm), medium (M, 25–100 μm), and small (S, <25 μm) flocs were characterized across three operational stages (CND, Trans, and PND) using high-throughput ITS sequencing. Analytical approaches including neutral community model, normalized stochasticity ratio, fast expectation–maximization for microbial source tracking, and molecular ecological network modeling were applied. Results showed that S-flocs consistently contributed the largest proportion to the supernatant fungal community across all stages. Community assembly transitioned from predominantly stochastic in the CND stage to increasingly deterministic in the PND stage, especially within L and M flocs. Co-occurrence network analysis revealed a shift from small-world to scale-free modular topologies, indicating substantial remodeling of fungal co-occurrence correlations. Dissolved oxygen, representing an operational factor, and sludge physicochemical indicators jointly influenced fungal community differentiation across floc-size gradients. This study highlights the regulatory role of floc-size stratification in shaping fungal ecology and network architecture during engineered nitrogen removal process upgrading. These findings provide new insights into spatial microbial dynamics and inform floc-scale strategies for optimizing biological wastewater treatment performance.
{"title":"Ecological reorganization of fungal communities driven by floc-size stratification and process upgrading in a full-scale landfill leachate treatment plant","authors":"Shitong Liu , Shuang Zhu , Rongxin Zhang , Binbin Sheng","doi":"10.1016/j.wasman.2026.115357","DOIUrl":"10.1016/j.wasman.2026.115357","url":null,"abstract":"<div><div>Floc size in activated sludge systems plays a critical role in shaping bacterial communities by regulating microenvironmental heterogeneity, yet its ecological influence on fungal assemblages during process upgrading remains largely unexplored. This study aimed to systematically investigate the effects of floc-size stratification on fungal community composition, assembly mechanisms, source contribution patterns, and molecular ecological co-occurrence network structures during the transition from conventional nitrification–denitrification (CND) to partial nitrification–denitrification (PND) in a full-scale landfill leachate treatment plant. Fungal communities from large (L, >100 μm), medium (M, 25–100 μm), and small (S, <25 μm) flocs were characterized across three operational stages (CND, Trans, and PND) using high-throughput ITS sequencing. Analytical approaches including neutral community model, normalized stochasticity ratio, fast expectation–maximization for microbial source tracking, and molecular ecological network modeling were applied. Results showed that S-flocs consistently contributed the largest proportion to the supernatant fungal community across all stages. Community assembly transitioned from predominantly stochastic in the CND stage to increasingly deterministic in the PND stage, especially within L and M flocs. Co-occurrence network analysis revealed a shift from small-world to scale-free modular topologies, indicating substantial remodeling of fungal co-occurrence correlations. Dissolved oxygen, representing an operational factor, and sludge physicochemical indicators jointly influenced fungal community differentiation across floc-size gradients. This study highlights the regulatory role of floc-size stratification in shaping fungal ecology and network architecture during engineered nitrogen removal process upgrading. These findings provide new insights into spatial microbial dynamics and inform floc-scale strategies for optimizing biological wastewater treatment performance.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115357"},"PeriodicalIF":7.1,"publicationDate":"2026-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146006522","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 : 2026-02-28Epub Date: 2026-02-03DOI: 10.1016/j.wasman.2026.115373
Fatma Ece Sayin , Gülşen Akman , Bilge Özbay , Barış Çalli , Recep Kaya Göktaş , İsmail Özbay
The inability of municipal solid waste (MSW) to meet incineration standards often undermines the sustainability and economic feasibility of waste-to-energy applications. Biodrying offers a promising, eco-friendly pretreatment to enhance the calorific value of MSW. This study evaluated the performance of biodrying based on the final calorific value (FCV) using simple and interactive regression models. Both conventional parameters; moisture content (MC), bulk density (BD), airflow rate (AFR), and initial calorific value (ICV) and unconventional indicators; the Temperature Index (TI), Biodrying Index (BI), and oxygen consumption (L) as a measure of biodegradability were used as predictors. Besides conventional regression models (OLS), to minimize multicollinearity of the dataset with Variance Inflation Factor (VIF) of higher than 10 Ridge regression (RR) analyses were also applied. AFR was the strongest positive variable in all the tested models and achieved maximum impact in RR3 Model with value of 2189.47 at significance level of p < 0.01. In the same model, triple impact of AFR*TI*MC was strong and negative (−819.60 at p < 0.05). In both regression approaches, interactive models provided better prediction efficiencies considering higher R2 and reduced error metrics. Professionals in this sector may consider the use of RR in FCV predictions to be both an innovative and practical approach.
{"title":"Reliable prediction of biodrying efficiency using interactive regression models","authors":"Fatma Ece Sayin , Gülşen Akman , Bilge Özbay , Barış Çalli , Recep Kaya Göktaş , İsmail Özbay","doi":"10.1016/j.wasman.2026.115373","DOIUrl":"10.1016/j.wasman.2026.115373","url":null,"abstract":"<div><div>The inability of municipal solid waste (MSW) to meet incineration standards often undermines the sustainability and economic feasibility of waste-to-energy applications. Biodrying offers a promising, eco-friendly pretreatment to enhance the calorific value of MSW. This study evaluated the performance of biodrying based on the final calorific value (FCV) using simple and interactive regression models. Both conventional parameters; moisture content (MC), bulk density (BD), airflow rate (AFR), and initial calorific value (ICV) and unconventional indicators; the Temperature Index (TI), Biodrying Index (BI), and oxygen consumption (L) as a measure of biodegradability were used as predictors. Besides conventional regression models (OLS), to minimize multicollinearity of the dataset with Variance Inflation Factor (VIF) of higher than 10 Ridge regression (RR) analyses were also applied. AFR was the strongest positive variable in all the tested models and achieved maximum impact in RR3 Model with value of 2189.47 at significance level of p < 0.01. In the same model, triple impact of AFR*TI*MC was strong and negative (−819.60 at p < 0.05). In both regression approaches, interactive models provided better prediction efficiencies considering higher R<sup>2</sup> and reduced error metrics. Professionals in this sector may consider the use of RR in FCV predictions to be both an innovative and practical approach.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115373"},"PeriodicalIF":7.1,"publicationDate":"2026-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146120319","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 : 2026-02-28Epub 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":"2026-02-28","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 : 2026-02-28Epub Date: 2026-02-02DOI: 10.1016/j.wasman.2026.115387
Ming-Yue Zhang , Qi-Zhi Su , Can Xu , Tian-Long Zhang , Huai-Ning Zhong , Qin-Bao Lin , Dan Li , Ben Dong
This study systematically evaluates supercritical CO2 (scCO2) extraction for the decontamination of volatile compounds from post-consumer recycled high-density polyethylene (rHDPE), with a focus on co-solvent effects. Time-resolved extraction revealed that contaminant load strongly influenced removal efficiency, and flakes achieved 15% higher performance than pellets due to thinner morphology and reduced re-embedding. Co-solvent assistance further enhanced efficiency, with p-xylene, ethylbenzene, and cyclohexanone achieving up to 35% improvement compared to neat scCO2. Hansen Solubility Parameter (HSP) analysis indicates that solvent compatibility with HDPE is a necessary but insufficient factor for the enhanced decontamination efficiency, and further molecular descriptor analysis provided additional mechanistic insight, highlighting aromaticity, polarizability, rigidity, and topological complexity as key determinants of enhanced efficiency. Aromatic co-solvents facilitated contaminant release through π-electron delocalization and planar rigidity, while cyclohexanone achieved broad solvation capacity via polar functionality and favorable topological descriptors. These results reveal structure–performance relationships that may inform co-solvent selection and contribute to the understanding of scCO2-based decontamination strategies for rHDPE.
{"title":"Decontamination of volatile compounds from post-consumer recycled HDPE via supercritical CO2: Unravelling the critical role of co-solvent molecular structure","authors":"Ming-Yue Zhang , Qi-Zhi Su , Can Xu , Tian-Long Zhang , Huai-Ning Zhong , Qin-Bao Lin , Dan Li , Ben Dong","doi":"10.1016/j.wasman.2026.115387","DOIUrl":"10.1016/j.wasman.2026.115387","url":null,"abstract":"<div><div>This study systematically evaluates supercritical CO<sub>2</sub> (scCO<sub>2</sub>) extraction for the decontamination of volatile compounds from post-consumer recycled high-density polyethylene (rHDPE), with a focus on co-solvent effects. Time-resolved extraction revealed that contaminant load strongly influenced removal efficiency, and flakes achieved 15% higher performance than pellets due to thinner morphology and reduced re-embedding. Co-solvent assistance further enhanced efficiency, with p-xylene, ethylbenzene, and cyclohexanone achieving up to 35% improvement compared to neat scCO<sub>2</sub>. Hansen Solubility Parameter (HSP) analysis indicates that solvent compatibility with HDPE is a necessary but insufficient factor for the enhanced decontamination efficiency, and further molecular descriptor analysis provided additional mechanistic insight, highlighting aromaticity, polarizability, rigidity, and topological complexity as key determinants of enhanced efficiency. Aromatic co-solvents facilitated contaminant release through π-electron delocalization and planar rigidity, while cyclohexanone achieved broad solvation capacity via polar functionality and favorable topological descriptors. These results reveal structure–performance relationships that may inform co-solvent selection and contribute to the understanding of scCO<sub>2</sub>-based decontamination strategies for rHDPE.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115387"},"PeriodicalIF":7.1,"publicationDate":"2026-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146114388","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 : 2026-02-28Epub Date: 2026-02-03DOI: 10.1016/j.wasman.2026.115369
Jian Wang , Sujie Liu , Nan Zhang , Yonggai Duan , Yongxi Ma
Addressing the dual challenges of food waste management and sustainable protein production requires circular economy solutions. This study demonstrates a sustainable approach to convert restaurant food waste (FW) into a protein-rich feed ingredient using black soldier fly (BSF) larvae. The nutritional profile of the FW-derived BSF meal was evaluated and compared to soybean meal (SBM). BSF meal had higher digestible (20.08 MJ/kg) and metabolizable (18.74 MJ/kg) energy than SBM (P < 0.01). The standardized ileal digestibility of amino acids in BSF meal (78.90%-85.12%) was comparable to or better than that of SBM. In the subsequent experiment, 72 pigs were assigned to either a control diet (Ctrl) or an experimental diet (BSF) with 20% SBM replaced by BSF meal. Throughout the trial, the BSF group showed a 5.80% higher average daily gain (P = 0.06) and a 4.29% higher average daily feed intake (P < 0.05). BSF meal increased shoulder backfat thickness and muscle decanoic acid content by 26.68% and 83.33%, respectively (P < 0.05). Furthermore, BSF meal improved lipid metabolism and antioxidant status, as characterized by reduced serum total cholesterol and malondialdehyde levels, and up-regulation of myosin heavy chain I expression (P < 0.05). BSF meal modulated the gut microbiota by enriching taxa linked to improved meat quality and health, including Clostridium_sensu_stricto_1 (1.97-fold) and Clostridiaceae (1.94-fold) (P < 0.05). In conclusion, BSF-based bioconversion effectively transformed FW into a sustainable, high-performance feed ingredient that enhanced pig productivity and meat quality, thereby contributing to a more circular and resilient food system.
{"title":"Bioconversion of restaurant food waste via black soldier fly larvae into a high-value protein source for improving meat quality in finishing pigs","authors":"Jian Wang , Sujie Liu , Nan Zhang , Yonggai Duan , Yongxi Ma","doi":"10.1016/j.wasman.2026.115369","DOIUrl":"10.1016/j.wasman.2026.115369","url":null,"abstract":"<div><div>Addressing the dual challenges of food waste management and sustainable protein production requires circular economy solutions. This study demonstrates a sustainable approach to convert restaurant food waste (FW) into a protein-rich feed ingredient using black soldier fly (BSF) larvae. The nutritional profile of the FW-derived BSF meal was evaluated and compared to soybean meal (SBM). BSF meal had higher digestible (20.08 MJ/kg) and metabolizable (18.74 MJ/kg) energy than SBM (<em>P</em> < 0.01). The standardized ileal digestibility of amino acids in BSF meal (78.90%-85.12%) was comparable to or better than that of SBM. In the subsequent experiment, 72 pigs were assigned to either a control diet (Ctrl) or an experimental diet (BSF) with 20% SBM replaced by BSF meal. Throughout the trial, the BSF group showed a 5.80% higher average daily gain (<em>P</em> = 0.06) and a 4.29% higher average daily feed intake (<em>P</em> < 0.05). BSF meal increased shoulder backfat thickness and muscle decanoic acid content by 26.68% and 83.33%, respectively (<em>P</em> < 0.05). Furthermore, BSF meal improved lipid metabolism and antioxidant status, as characterized by reduced serum total cholesterol and malondialdehyde levels, and up-regulation of myosin heavy chain I expression (<em>P</em> < 0.05). BSF meal modulated the gut microbiota by enriching taxa linked to improved meat quality and health, including <em>Clostridium_sensu_stricto_1</em> (1.97-fold) and Clostridiaceae (1.94-fold) (<em>P</em> < 0.05). In conclusion, BSF-based bioconversion effectively transformed FW into a sustainable, high-performance feed ingredient that enhanced pig productivity and meat quality, thereby contributing to a more circular and resilient food system.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115369"},"PeriodicalIF":7.1,"publicationDate":"2026-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146114424","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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