Pub Date : 2026-02-13DOI: 10.1016/j.wasman.2026.115396
A. Sofi , Praveen Nagarajan , T.S. Kumanan
The disposal of waste tires has a significant environmental impact, and there is growing interest in their integration as supplementary cementitious materials. Using recycled waste tire fines as a cementitious material can declare that rubber addition develops a practical pathway for valorising tire waste in concrete production without compromising the strength of concrete. In this study, pulverized waste tire rubber fines were incorporated as a substitute for cement at varying dosages, and their influence on the mechanical behavior of concrete was investigated. The microstructural arrangements of the waste tire concrete were examined to ensure the appropriate reactions between waste tire rubber and the rest of the materials and gelation matrix development. To compute the influence of waste tire rubber fines on the observed nonlinear pattern of experimental results, a transformed square root statistical approach was applied for the significant predictions and effect correlations. From this approach, predictive transform models C1 and F2 achieved better predictions with a higher significance level. The key findings are optimal rubber dosage for maintaining satisfactory mechanical properties and instigating an effective waste disposal pathway. The machine learning model results were in good association with nonlinear experimental trends and highlight the beneficial replacement range of waste tire rubber fines.
{"title":"Machine learning approach for predicting the influence of pulverized waste tire rubber fines as a sustainable cement alternative in concrete","authors":"A. Sofi , Praveen Nagarajan , T.S. Kumanan","doi":"10.1016/j.wasman.2026.115396","DOIUrl":"10.1016/j.wasman.2026.115396","url":null,"abstract":"<div><div>The disposal of waste tires has a significant environmental impact, and there is growing interest in their integration as supplementary cementitious materials. Using recycled waste tire fines as a cementitious material can declare that rubber addition develops a practical pathway for valorising tire waste in concrete production without compromising the strength of concrete. In this study, pulverized waste tire rubber fines were incorporated as a substitute for cement at varying dosages, and their influence on the mechanical behavior of concrete was investigated. The microstructural arrangements of the waste tire concrete were examined to ensure the appropriate reactions between waste tire rubber and the rest of the materials and gelation matrix development. To compute the influence of waste tire rubber fines on the observed nonlinear pattern of experimental results, a transformed square root statistical approach was applied for the significant predictions and effect correlations. From this approach, predictive transform models C<sub>1</sub> and F<sub>2</sub> achieved better predictions with a higher significance level. The key findings are optimal rubber dosage for maintaining satisfactory mechanical properties and instigating an effective waste disposal pathway. The machine learning model results were in good association with nonlinear experimental trends and highlight the beneficial replacement range of waste tire rubber fines.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"214 ","pages":"Article 115396"},"PeriodicalIF":7.1,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192660","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}
Manure is a significant source of phosphorus (P) fertilizer, but its P solubility may influence both environmental impacts and fertilizer effectiveness. The transformation of P fractions in manure during long-term storage remains unclear. This study evaluated P speciation dynamics during extended swine manure storage under both unsealed and sealed conditions, and examined corn straw as an amendment to enhance P stabilization. Results showed that during unsealed conditions, Olsen-P (H2O-P and NaHCO3-P) concentration decreased by 16%, while Fix-P (NaOH-P + HCl-P) concentration increased by 150%, indicating the conversion of P to more stable forms. In contrast, sealed conditions had smaller effects on P concentration and solubility, with Fix-P increased by 3%. The incorporation of corn straw in unsealed system resulted in a 45% increase in total phosphorus (TP) concentration and a 12% reduction in Olsen-P, suggesting that the addition of corn straw enhanced chemical precipitation and organic complexation of P. Sealed conditions with straw amendment exhibited similar trends to those in sealed and unamended ones. Under long-term unsealed storage, soluble P in swine manure converted to more stable minerals including MgNH4PO4·6H2O, Fe3(PO4)2·H2O, and AlPO4·2H2O, and the manure particles aggregated more. This study may provide valuable insights for developing cost-effective swine manure management practice to reduce P runoff potential.
{"title":"Effects of air availability and straw amendment on swine manure phosphorus runoff potential","authors":"Wenchao Xing , Hongzhen Ma , Zhenyu Xue , Shixiao Xu , Lixin Jia , Pengxiang Xu , Danping Jiang , Fuqing Xu","doi":"10.1016/j.wasman.2026.115374","DOIUrl":"10.1016/j.wasman.2026.115374","url":null,"abstract":"<div><div>Manure is a significant source of phosphorus (P) fertilizer, but its P solubility may influence both environmental impacts and fertilizer effectiveness. The transformation of P fractions in manure during long-term storage remains unclear. This study evaluated P speciation dynamics during extended swine manure storage under both unsealed and sealed conditions, and examined corn straw as an amendment to enhance P stabilization. Results showed that during unsealed conditions, Olsen-P (H<sub>2</sub>O-P and NaHCO<sub>3</sub>-P) concentration decreased by 16%, while Fix-P (NaOH-P + HCl-P) concentration increased by 150%, indicating the conversion of P to more stable forms. In contrast, sealed conditions had smaller effects on P concentration and solubility, with Fix-P increased by 3%. The incorporation of corn straw in unsealed system resulted in a 45% increase in total phosphorus (TP) concentration and a 12% reduction in Olsen-P, suggesting that the addition of corn straw enhanced chemical precipitation and organic complexation of P. Sealed conditions with straw amendment exhibited similar trends to those in sealed and unamended ones. Under long-term unsealed storage, soluble P in swine manure converted to more stable minerals including MgNH<sub>4</sub>PO<sub>4</sub>·6H<sub>2</sub>O, Fe<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>·H<sub>2</sub>O, and AlPO<sub>4</sub>·2H<sub>2</sub>O, and the manure particles aggregated more. This study may provide valuable insights for developing cost-effective swine manure management practice to reduce P runoff potential.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"214 ","pages":"Article 115374"},"PeriodicalIF":7.1,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146166471","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 : 2026-02-10DOI: 10.1016/j.wasman.2026.115397
Benjamin Martinez Castellanos , Unnikrishna Menon , Neelanjan Bhattacharjee , Amit Kumar
The growing imperative for sustainable waste management and cleaner energy production has spurred global interest in advanced thermochemical processes for valorising municipal solid waste (MSW). This study investigates the thermo-catalytic reforming (TCR®) of pelletized source-separated organic (SSO) feedstock from landfill-diverted waste via a 2 kg h−1 hybrid intermediate pyrolysis system to optimise yields of high-quality bio-oil and hydrogen-rich syngas. There is very limited research on thermo-catalytic reforming of SSO globally. As H2, bio-oil, and biochar gain focus for climate mitigation, this TCR system offers balanced production of all three valuable by-products, leveraging the inherent catalytic activity of the biochar enriched with alkali and alkaline earth metals to enhance reforming reactions and H2 yield. The research identifies optimal reactor/reformer temperatures for maximising bio-oil yield (6.20%), with the highest production observed at 500/500°C. At 500/650°C reactor/ reformer temperatures, syngas contained 36.36 vol% H2 and 11.05 vol% CH4, with a higher heating value (HHV) of 20.12 MJ kg−1, suitable for use as feedstock in Fisher-Tropsch synthesis for chemicals or fuel production. The produced bio-oil has low viscosity (31.79 mPa s−1), low aromatic hydrocarbon content, low total acid number (11.35 mg KOH g−1), and reduced monocyclic and polycyclic aromatic hydrocarbons (6.02% and 15.92% at 400/650°C); biochar at optimal conditions displays low HHV and increasing inorganic content (from 6.02 to 8.89 wt%) with temperature, supporting potential soil remediation applications. These findings demonstrate that TCR® enables efficient waste-to-energy conversion and provides a scalable model for organics valorisation with potential to guide global strategies for MSW management.
{"title":"Converting source-separated organics from municipal solid waste into high-quality bio-oil and hydrogen-rich syngas through a hybrid intermediate pyrolysis system","authors":"Benjamin Martinez Castellanos , Unnikrishna Menon , Neelanjan Bhattacharjee , Amit Kumar","doi":"10.1016/j.wasman.2026.115397","DOIUrl":"10.1016/j.wasman.2026.115397","url":null,"abstract":"<div><div>The growing imperative for sustainable waste management and cleaner energy production has spurred global interest in advanced thermochemical processes for valorising municipal solid waste (MSW). This study investigates the thermo-catalytic reforming (TCR®) of pelletized source-separated organic (SSO) feedstock from landfill-diverted waste via a 2 kg h<sup>−1</sup> hybrid intermediate pyrolysis system to optimise yields of high-quality bio-oil and hydrogen-rich syngas. There is very limited research on thermo-catalytic reforming of SSO globally. As H<sub>2</sub>, bio-oil, and biochar gain focus for climate mitigation, this TCR system offers balanced production of all three valuable by-products, leveraging the inherent catalytic activity of the biochar enriched with alkali and alkaline earth metals to enhance reforming reactions and H<sub>2</sub> yield. The research identifies optimal reactor/reformer temperatures for maximising bio-oil yield (6.20%), with the highest production observed at 500/500°C. At 500/650°C reactor/ reformer temperatures, syngas contained 36.36 vol% H<sub>2</sub> and 11.05 vol% CH<sub>4</sub>, with a higher heating value (HHV) of 20.12 MJ kg<sup>−1</sup>, suitable for use as feedstock in Fisher-Tropsch synthesis for chemicals or fuel production. The produced bio-oil has low viscosity (31.79 mPa s<sup>−1</sup>), low aromatic hydrocarbon content, low total acid number (11.35 mg KOH g<sup>−1</sup>), and reduced monocyclic and polycyclic aromatic hydrocarbons (6.02% and 15.92% at 400/650°C); biochar at optimal conditions displays low HHV and increasing inorganic content (from 6.02 to 8.89 wt%) with temperature, supporting potential soil remediation applications. These findings demonstrate that TCR® enables efficient waste-to-energy conversion and provides a scalable model for organics valorisation with potential to guide global strategies for MSW management.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"214 ","pages":"Article 115397"},"PeriodicalIF":7.1,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146166371","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 : 2026-02-06DOI: 10.1016/j.wasman.2026.115392
Tala Jano , Aya Nabil Sayed , Md Mosarrof Hossen , Christos Sardianos , Ridha Hamila , Faycal Bensaali , Iraklis Varlamis , George Dimitrakopoulos
The proliferation of technological advancements, knitted with volatile consumption patterns and poor end-of-life management of discarded electronics, is currently outpacing sustainability transitions, putting increasing strain on finite material resources and heightening ecological vulnerability. This, in turn, has made electronic waste a stealth contributor to climate change with adverse impacts on the environment, economy, and society at large. This reality underscores the urgent need for a strategic shift from linear waste-disposal methods to circular pathways, where Artificial Intelligence (AI) can build more sustainable feedback loops. At the nexus of AI and circular e-waste management, this study systematically reviews 147 articles from 2019 to October 2025. The analysis reveals a steady increase in AI adoption, particularly in deep learning-based detection and classification applications. To structure the evidence from the literature, a six-tier taxonomy is proposed, encompassing AI methods, lifecycle stages, data, waste types, limitations, challenges, and future pathways and opportunities. Beyond technical interventions, systemic and operational barriers that demand strategic levers to address regulatory ambiguities, legislative gaps, managerial inefficiencies, and logistical fragmentation are elucidated. These challenges underpin data availability and generalizability, as well as the lack of standardization, interoperability gaps, and barriers to the ethical and regulatory adoption of AI. In practice, these constraints limit the development of uncertainty-aware electronic waste systems capable of functioning under realistic operational dynamics. To this end, the paper reframes AI-based systems from terminal sinks to regenerative loops, aligning technological progress with sustainable electronic waste management.
{"title":"Closing the loop: A systematic review of artificial intelligence in circular e-waste management","authors":"Tala Jano , Aya Nabil Sayed , Md Mosarrof Hossen , Christos Sardianos , Ridha Hamila , Faycal Bensaali , Iraklis Varlamis , George Dimitrakopoulos","doi":"10.1016/j.wasman.2026.115392","DOIUrl":"10.1016/j.wasman.2026.115392","url":null,"abstract":"<div><div>The proliferation of technological advancements, knitted with volatile consumption patterns and poor end-of-life management of discarded electronics, is currently outpacing sustainability transitions, putting increasing strain on finite material resources and heightening ecological vulnerability. This, in turn, has made electronic waste a stealth contributor to climate change with adverse impacts on the environment, economy, and society at large. This reality underscores the urgent need for a strategic shift from linear waste-disposal methods to circular pathways, where Artificial Intelligence (AI) can build more sustainable feedback loops. At the nexus of AI and circular e-waste management, this study systematically reviews 147 articles from 2019 to October 2025. The analysis reveals a steady increase in AI adoption, particularly in deep learning-based detection and classification applications. To structure the evidence from the literature, a six-tier taxonomy is proposed, encompassing AI methods, lifecycle stages, data, waste types, limitations, challenges, and future pathways and opportunities. Beyond technical interventions, systemic and operational barriers that demand strategic levers to address regulatory ambiguities, legislative gaps, managerial inefficiencies, and logistical fragmentation are elucidated. These challenges underpin data availability and generalizability, as well as the lack of standardization, interoperability gaps, and barriers to the ethical and regulatory adoption of AI. In practice, these constraints limit the development of uncertainty-aware electronic waste systems capable of functioning under realistic operational dynamics. To this end, the paper reframes AI-based systems from terminal sinks to regenerative loops, aligning technological progress with sustainable electronic waste management.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"214 ","pages":"Article 115392"},"PeriodicalIF":7.1,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146137660","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 : 2026-02-05DOI: 10.1016/j.wasman.2026.115390
Carmela Chianese , Alessandro Dal Pozzo , Valentina Scognamiglio , Giulia Masi , Maria Chiara Bignozzi , Valerio Cozzani
Air Pollution Control (APC) residues deriving from acid gas (HCl, HF, SO2) removal processes are typically disposed of in hazardous waste landfills. This study explores the potential reuse of these residues as alternative CO2 sorbents in the Calcium Looping process, leveraging their content of unreacted lime. APC residues originating from different industrial sources (waste-to-energy, ceramic, and glass plants) were subjected to multiple carbonation–calcination cycles and benchmarked against a reference hydrated lime. The observed performance was linked to the morphological and compositional variability of the residues. Ceramic APC residues exhibited an inverse correlation between CO2 uptake and the presence of stable fluorinated and sulfated phases. The monotonic decline in CO2 carrying capacity upon cycling was ascribed to sintering. Waste-to-energy residues displayed a more complex cyclic behavior, associated with the melting of chlorinated phases under calcination conditions and the consequent rearrangement of product layers on sorbent particles. Despite their lower performance compared to virgin hydrated lime, APC residues achieved up to 140 mg CO2/g sorbent after 10 cycles.
{"title":"Analysis of the performance of Air Pollution Control residues as CO2 sorbents in the calcium looping process","authors":"Carmela Chianese , Alessandro Dal Pozzo , Valentina Scognamiglio , Giulia Masi , Maria Chiara Bignozzi , Valerio Cozzani","doi":"10.1016/j.wasman.2026.115390","DOIUrl":"10.1016/j.wasman.2026.115390","url":null,"abstract":"<div><div>Air Pollution Control (APC) residues deriving from acid gas (HCl, HF, SO<sub>2</sub>) removal processes are typically disposed of in hazardous waste landfills. This study explores the potential reuse of these residues as alternative CO<sub>2</sub> sorbents in the Calcium Looping process, leveraging their content of unreacted lime. APC residues originating from different industrial sources (waste-to-energy, ceramic, and glass plants) were subjected to multiple carbonation–calcination cycles and benchmarked against a reference hydrated lime. The observed performance was linked to the morphological and compositional variability of the residues. Ceramic APC residues exhibited an inverse correlation between CO<sub>2</sub> uptake and the presence of stable fluorinated and sulfated phases. The monotonic decline in CO<sub>2</sub> carrying capacity upon cycling was ascribed to sintering. Waste-to-energy residues displayed a more complex cyclic behavior, associated with the melting of chlorinated phases under calcination conditions and the consequent rearrangement of product layers on sorbent particles. Despite their lower performance compared to virgin hydrated lime, APC residues achieved up to 140 mg CO<sub>2</sub>/g sorbent after 10 cycles.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"214 ","pages":"Article 115390"},"PeriodicalIF":7.1,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116413","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 : 2026-02-05DOI: 10.1016/j.wasman.2026.115393
Kun Tong , Qian Chen , Nana Zhang , Yuhao Yan , Zhiguo Shao , Huijun Wu , Wen Ren
To address the challenges of complex composition, high stability, and poor dewaterability of oily scum, this study applied hydrothermal treatment for its processing. The effects of reaction temperature, time, and stirring speed on dewatering performance were investigated, with flash evaporation and mechanical dewatering integrated to enhance treatment. Optimal conditions (170 °C, 30 min) achieved a dewatering efficiency of 66.64%. Analytical techniques including Nuclear Magnetic Resonance (NMR), Scanning Electron Microscopy − Energy Dispersive X-ray Spectroscopy (SEM-EDS), particle size analysis, and four-component analysis revealed that hydrothermal treatment converted constrained water into free water, markedly improving dewaterability. With increasing temperature, sludge particles became smaller and the surface morphology turned smoother and more compact. Recovered oil mainly contained saturates and aromatics, indicating good quality, while hydrothermal gas was rich in CO2 and light hydrocarbons, with temperatures above 200 °C favoring hydrogen production. In summary, hydrothermal treatment not only improved the dewatering and solid conversion of oily scum but also facilitated the recovery of high-quality oil.
{"title":"Synergistic enhancement of dewatering and Co-recovery of oil and gas from oily scum via integrated Hydrothermal-Mechanical process","authors":"Kun Tong , Qian Chen , Nana Zhang , Yuhao Yan , Zhiguo Shao , Huijun Wu , Wen Ren","doi":"10.1016/j.wasman.2026.115393","DOIUrl":"10.1016/j.wasman.2026.115393","url":null,"abstract":"<div><div>To address the challenges of complex composition, high stability, and poor dewaterability of oily scum, this study applied hydrothermal treatment for its processing. The effects of reaction temperature, time, and stirring speed on dewatering performance were investigated, with flash evaporation and mechanical dewatering integrated to enhance treatment. Optimal conditions (170 °C, 30 min) achieved a dewatering efficiency of 66.64%. Analytical techniques including Nuclear Magnetic Resonance (NMR), Scanning Electron Microscopy − Energy Dispersive X-ray Spectroscopy (SEM-EDS), particle size analysis, and four-component analysis revealed that hydrothermal treatment converted constrained water into free water, markedly improving dewaterability. With increasing temperature, sludge particles became smaller and the surface morphology turned smoother and more compact. Recovered oil mainly contained saturates and aromatics, indicating good quality, while hydrothermal gas was rich in CO<sub>2</sub> and light hydrocarbons, with temperatures above 200 °C favoring hydrogen production. In summary, hydrothermal treatment not only improved the dewatering and solid conversion of oily scum but also facilitated the recovery of high-quality oil.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"214 ","pages":"Article 115393"},"PeriodicalIF":7.1,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116412","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 : 2026-01-31DOI: 10.1016/j.wasman.2026.115372
Jessica Leindorf de Almeida, Jacopo De Tommaso, Federico Galli, Alexandre Cabral
Methane (CH4) emissions from landfills represent a challenge in global climate mitigation efforts. Methane oxidation biosystems (MOB) offer a low-cost solution for addressing residual and fugitive CH4 emissions, yet the role of the acclimatization phase has not received enough attention in the technical literature. Here we optimize the acclimatization of compost-based MOBs through controlled landfill gas (LFG) ramp-up strategies. Four identical laboratory-scale columns were subjected to distinct flow increase patterns: exponential, linear, first-order-like, and constant inlet loading. The results showed that exponential and linear strategies accelerated the attainment of 100% CH4 removal faster than the constant-flow system. Additionally, the axial gas concentration profile revealed that ramp-up strategies influenced the depth required for complete oxidation. Notably, exponential ramp-up led to full CH4 removal within the first 50 mm of the methane oxidation layer (MOL) when actively aerated, suggesting the potential to significantly reduce its thickness in field systems. An additional 175-day column test, designed to estimate the maximum methane oxidation capacity under increasing loadings, confirmed the benefits of gradual acclimatization. By assuming that the oxidation rate follows the Michaelis–Menten model, the system achieved sustained removal efficiencies (>90%) and reached a maximum oxidation rate () of 3811 gCH4·m−3·d-1 and a of 12 gCH4·m−3. These findings highlight the importance of ramp-up strategies in designing efficient and more compact MOBs that can quickly attain design loadings.
{"title":"Landfill gas loading ramp-up strategies: Acclimatization optimization and long-term oxidation capacity of methane oxidation biosystems","authors":"Jessica Leindorf de Almeida, Jacopo De Tommaso, Federico Galli, Alexandre Cabral","doi":"10.1016/j.wasman.2026.115372","DOIUrl":"10.1016/j.wasman.2026.115372","url":null,"abstract":"<div><div>Methane (CH<sub>4</sub>) emissions from landfills represent a challenge in global climate mitigation efforts. Methane oxidation biosystems (MOB) offer a low-cost solution for addressing residual and fugitive CH<sub>4</sub> emissions, yet the role of the acclimatization phase has not received enough attention in the technical literature. Here we optimize the acclimatization of compost-based MOBs through controlled landfill gas (LFG) ramp-up strategies. Four identical laboratory-scale columns were subjected to distinct flow increase patterns: exponential, linear, first-order-like, and constant inlet loading. The results showed that exponential and linear strategies accelerated the attainment of 100% CH<sub>4</sub> removal faster than the constant-flow system. Additionally, the axial gas concentration profile revealed that ramp-up strategies influenced the depth required for complete oxidation. Notably, exponential ramp-up led to full CH<sub>4</sub> removal within the first 50 mm of the methane oxidation layer (MOL) when actively aerated, suggesting the potential to significantly reduce its thickness in field systems. An additional 175-day column test, designed to estimate the maximum methane oxidation capacity under increasing loadings, confirmed the benefits of gradual acclimatization. By assuming that the oxidation rate follows the Michaelis–Menten model, the system achieved sustained removal efficiencies (>90%) and reached a maximum oxidation rate (<span><math><mrow><msub><mi>V</mi><mrow><mi>max</mi></mrow></msub></mrow></math></span>) of 3811 g<sub>CH4</sub>·m<sup>−3</sup>·d<sup>-1</sup> and a <span><math><mrow><msub><mi>K</mi><mi>m</mi></msub></mrow></math></span> of 12 g<sub>CH4</sub>·m<sup>−3</sup>. These findings highlight the importance of ramp-up strategies in designing efficient and more compact MOBs that can quickly attain design loadings.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115372"},"PeriodicalIF":7.1,"publicationDate":"2026-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080098","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 : 2026-01-31DOI: 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":"2026-01-31","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}
Pub Date : 2026-01-29DOI: 10.1016/j.wasman.2026.115353
Caroline J. Saul , Paul T. Imhoff , Yixuan Wang , Morton A. Barlaz
Landfills are considered the third largest source of anthropogenic methane emissions in the U.S. and there is considerable interest in estimating emissions from individual landfills. Collection efficiency (CE) or methane collection index (MCI) is used in models to estimate emissions. The objective of this review is to critically analyze literature describing measured CEs and MCIs. Reported values ranged from 14 to 95% for intermediate covers and 53–100% for final covers. Many factors contribute to the ranges including: covers were classified as intermediate or final which is overly simplistic; variability in operational factors (e.g., well coverage, maintenance quality); waste characteristics such as age, composition, and mass in place which influence methane generation and likely collection; and uncertainty in emissions measurements and sometimes collected methane. A desired outcome of this review was to recommend values or ranges for intermediate and final covers that could be used in methane emissions models as applied to U.S. landfills. Such a recommendation is difficult considering the ranges reported in the literature and numerous site-specific factors that influence methane collection. Ultimately, each reported measurement is valid for a specific landfill at a specific time. Models that relate cover type and operational variables to MCI would best support estimation of a site-specific MCI, but such models are not available. Based on this review, the authors do not recommend a specific value for the MCI for an intermediate or final cover but rather expect the operator to select a value considering factors applicable to their landfill and the information presented here.
{"title":"Critical analysis of literature on landfill gas collection efficiency and its application to emissions estimates","authors":"Caroline J. Saul , Paul T. Imhoff , Yixuan Wang , Morton A. Barlaz","doi":"10.1016/j.wasman.2026.115353","DOIUrl":"10.1016/j.wasman.2026.115353","url":null,"abstract":"<div><div>Landfills are considered the third largest source of anthropogenic methane emissions in the U.S. and there is considerable interest in estimating emissions from individual landfills. Collection efficiency (CE) or methane collection index (MCI) is used in models to estimate emissions. The objective of this review is to critically analyze literature describing measured CEs and MCIs. Reported values ranged from 14 to 95% for intermediate covers and 53–100% for final covers. Many factors contribute to the ranges including: covers were classified as intermediate or final which is overly simplistic; variability in operational factors (e.g., well coverage, maintenance quality); waste characteristics such as age, composition, and mass in place which influence methane generation and likely collection; and uncertainty in emissions measurements and sometimes collected methane. A desired outcome of this review was to recommend values or ranges for intermediate and final covers that could be used in methane emissions models as applied to U.S. landfills. Such a recommendation is difficult considering the ranges reported in the literature and numerous site-specific factors that influence methane collection. Ultimately, each reported measurement is valid for a specific landfill at a specific time. Models that relate cover type and operational variables to MCI would best support estimation of a site-specific MCI, but such models are not available. Based on this review, the authors do not recommend a specific value for the MCI for an intermediate or final cover but rather expect the operator to select a value considering factors applicable to their landfill and the information presented here.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115353"},"PeriodicalIF":7.1,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080096","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.2026.115363
Stefania Volante , Rif Atussaufiyah , Federico Maria Vivaldi , Pietro Zaccagnini , Mara Serrapede , Andrea Lamberti , Anna Maria Raspolli Galletti , Federico Bella , Fabio Di Francesco , Domenico Licursi , Claudia Antonetti
In the last decades, the use of biochar has been receiving increasing attention for the development of electrochemical energy storage devices. In this work, the waste hazelnut shell biomass, a low cost and abundant agriculture residue within our territory, was valorized as feedstock for the synthesis of alkali-derived activated carbons, which were properly characterized and electrochemically tested, in the perspective of their use as new electrode material in energy storage applications. Two activated carbons have been identified as promising materials for this application and their electrochemical performances were further improved by including a doping step with copper (I) oxide, achieving the best specific capacitance of 123 F/g. Moreover, one of the two most promising activated carbons was tested in an EDLC symmetric device outperforming, at low power rates, reference materials in terms of specific energy density, reaching the value up to 40 Wh/kg, due to its remarkable specific capacitance of 55 F/g. In summary, this work proposes a sustainable and low energy demanding approach to transform waste biomasses into high value activated carbon materials for energy storage applications. The strategy not only promotes the reuse and valorization of hazelnut shell waste biomass, but it also supports a circular model with promising environmental and economic advantages.
{"title":"Valorization of hazelnut shell waste biomass into sustainable carbons for energy storage applications","authors":"Stefania Volante , Rif Atussaufiyah , Federico Maria Vivaldi , Pietro Zaccagnini , Mara Serrapede , Andrea Lamberti , Anna Maria Raspolli Galletti , Federico Bella , Fabio Di Francesco , Domenico Licursi , Claudia Antonetti","doi":"10.1016/j.wasman.2026.115363","DOIUrl":"10.1016/j.wasman.2026.115363","url":null,"abstract":"<div><div>In the last decades, the use of biochar has been receiving increasing attention for the development of electrochemical energy storage devices. In this work, the waste hazelnut shell biomass, a low cost and abundant agriculture residue within our territory, was valorized as feedstock for the synthesis of alkali-derived activated carbons, which were properly characterized and electrochemically tested, in the perspective of their use as new electrode material in energy storage applications. Two activated carbons have been identified as promising materials for this application and their electrochemical performances were further improved by including a doping step with copper (I) oxide, achieving the best specific capacitance of 123 F/g. Moreover, one of the two most promising activated carbons was tested in an EDLC symmetric device outperforming, at low power rates, reference materials in terms of specific energy density, reaching the value up to 40 Wh/kg, due to its remarkable specific capacitance of 55 F/g. In summary, this work proposes a sustainable and low energy demanding approach to transform waste biomasses into high value activated carbon materials for energy storage applications. The strategy not only promotes the reuse and valorization of hazelnut shell waste biomass, but it also supports a circular model with promising environmental and economic advantages.</div></div>","PeriodicalId":23969,"journal":{"name":"Waste management","volume":"213 ","pages":"Article 115363"},"PeriodicalIF":7.1,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080091","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}