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Heterogeneity of pyrolytic parameters in municipal solid waste (MSW) significantly hinders its waste-to-energy efficiency. So far, hardly any light has been shed on current pyrolytic heterogeneity conditions or feasible pyrolytic homogeneity enhancement approaches of MSW. Accordingly, pyrolytic properties (E a and logA) of 130 MSW samples in 6 categories were collected from literature. A kinetic parameters clustering-based sorting strategy for MSW was proposed. A so-called C index was established to compare their sorting performance for E a and logA against two traditional sorting strategies (substance categorization and density clustering). Results showed that the proposed sorting strategies outperformed the traditional ones in pyrolytic homogeneity enhancement, where the optimal C_E a and C_logA reached 1578.30 kJ/mol and 93.11 -log min. Among investigated clustering methods, k-means clustering outperformed hierarchical clustering, which could be attributed to its adaptability to the sample structure. Future perspectives involving data set expansion, model framework development, and downstream technologies matching were also discussed. The index C established in this study can be used to evaluate other clustering models., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

An artificial neural network (ANN) is a biologically inspired computational technique that imitates the behavior and learning process of the human brain. In this study, ANN technique was applied to assess the gasification of municipal solid waste (MSW) with the aim of enhancing the H 2 production. The experiments were conducted using a horizontal tube reactor under different parameters: temperatures, MSW loadings, residence times, and equivalence ratios. The input and output variables (released gases) were tested and trained using back-propagation algorithm, and the data distribution by K-fold contrivance. The values of the training (80% data) and validation (20% data) dataset were found satisfactory. The values of regression coefficient (R 2 ) for the training phase were lied between 0.9392 and 0.9991, and 0.9363 and 0.993824 for the testing phase. Whereas; the values of root mean square error (RSME) for the training phase were lied between 0.4111 and 0.8422, and between 0.1476 and 0.7320 for the testing phase. Higher H 2 production of 42.1 vol% was produced at the higher reaction temperature of 900 °C with LHV of 11.2 MJ/Nm 3 . According to the tar analysis, the dominant compounds were aromatics (17 compounds) followed by polycyclic aromatic, phenyl, aliphatic, aromatic heterocyclic, polycyclic, and aromatic ketone compounds., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

This study explored the composition and energy potential of university solid waste (USW) in China. Five combustible components, namely hard plastics (HP), paper (PP), soft plastics (SP), biomass (BM), and rubber (RB), were screened with the compositions 51%, 29%, 9%, 4%, and 3%, respectively. Each USW sample was gasified using a thermogravimetric analyzer (TGA) coupled with mass spectrometry (MS) at the heating rates of 5, 10, and 15 ℃/min and a final process temperature of 900 ℃. Thermal weight loss (TG) curves exposed the degradation in the order HP > SP > RB > BM > PP. Derivative thermogravimetric (DTG) peaks revealed that HP, PP, BM, and SP were degraded in three temperature-oriented phases in the range 172-731 ℃. The RB took an additional phase in the range 584-660 ℃. Major released gases, H 2 , CH 4 , CO, and CO 2 , were detected using MS via mass-to-charge (m/z) ratios. Higher H 2 and total gas yield produced in the case of the HP dominated other materials at the lower heating rate of 5 ℃/min. Validation of data was assessed by equating experimental and calculated curves; therefore, the regression coefficient (R 2 ) ranged between 0.884 and 0.997. The kinetics of the process were estimated by applying the Flynn-Wall-Ozawa (FWO) model at the conversion rates (α) of 0.2, 0.5, and 0.8, which presented reasonable results. Overall, the lower heating rates supported higher thermal conversion and a high quantity of gaseous products for all the components., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Phosphorus (P) is a necessary element for plant growth and animal health. Most P utilized by anthropogenic activities is released within the generation of various solid wastes such as sewage sludge, animal manure, and wetland plant, which increase the risk of water contamination. (Hydro)thermal treatment could be employed for solid waste treatment with the production of value-added hydro/bio-char, and the behavior of P during the thermochemical treatment process is critical for the further utilization of hydro/bio-char. This study provides a systematic review of the migration and transformation mechanisms of P during thermochemical treatment of various solid wastes, and special emphasis is given to the potential applications of P-enriched hydro/bio-char. Future challenges and perspectives in the thermal treatment of P-enriched solid waste are presented as well. The distribution and speciation of P were affected by feedstock properties, thermal technique, and reaction conditions, correspondingly affecting hydro/bio-char applications. The derived P-enriched hydro/bio-char was mainly applied as an agricultural soil amendment, P recovery source, and heavy metal sorbent, which could be adjusted by varying treatment process parameters. Additionally, potentially toxic substances, such as heavy metals in the solid waste, should be addressed during the production and application of hydro/bio-char. Overall, the production of P-enriched hydro/bio-char from solid waste is a promising route to simultaneously achieve P reclamation and solid waste treatment., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Flue gas torrefaction (FGT) was proposed as the pretreatment of the municipal solid waste (MSW) combustion process to improve the fuel properties of MSW and achieve better combustion performance. The optimal FGT parameters were obtained at 300 ℃ and 30 min, with the energy-mass co-benefit index (EMCI) reaching the maximum of 23.38. FGT could significantly increase the heating value and energy density of MSW while reducing the H/C and O/C ratio. Then, the pyrolysis and combustion experiments were performed by tube furnace and TG-MS. The results proved the chemical compositions of MSW were altered, and the heat transfer was enhanced. With FGT, NO x and SO 2 emissions could be reduced by 25.7 % and 52.4 %, respectively. This study provides an in-depth understanding of the mechanism of FGT and paves the way for the clean treatment and energy utilization of MSW., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Plastic wastes have posed serious threats to the environment, including decrease of soil nutrient effectiveness and agricultural production as well as emerge of ecological instability. Fuel conversion from plastic waste is regarded as a promising strategy for its disposal and energy utilization. Plastic wastes can be converted into target fuels by adjusting cracking of chemical bonds. Currently, numerous technologies regarding fuel conversion from plastic wastes have been reported, including conventional pyrolysis, novel heat treatment and advanced oxidation. However, systematic summary and comparative analysis of different technologies are still scarcely reported. In this review, fuel conversion from plastic wastes was summarized comprehensively, highlighting novel heat treatment and advanced oxidation technologies reported in recent years. Furthermore, the superiority and drawbacks of each technology were analyzed, and future prospects of technology application were proposed. With lower reaction temperature and higher-value fuel, novel heat treatment of plastics is more popular than traditional one. Advanced oxidation can be controlled to convert plastics into fuels under room temperature and pressure, guiding the new normal in energy utilization of plastic wastes. This review aims to provide inspiration for energy utilization of solid waste, addressing the issues of white pollution and energy shortage., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Co-pyrolysis is a promising approach to recover energy from sewage sludge (SS) and municipal solid waste (MSW). Hg emission during this process has serious environmental risks. To reduce the environmental impact, orthogonal experiments on the blending ratio, heating rate, pyrolysis temperature, and residence time were conducted during SS and MSW co-pyrolysis. Variance analysis was used to determine the influence and synergetic effects of these factors. Multivariate nonlinear, neural network, random forest, and support vector machine models were used to simulate the Hg distribution based on four parameters, which were later optimized to optimize the Hg fixing ratio in pyrolysis char. The Hg was mainly distributed in the pyrolysis gas and char. The variance analysis results indicate that the blending ratio is the key factor influencing Hg distribution, and there is little synergetic effect among the four factors. Further experiments showed that a blending ratio of 87.5 SS wt% could enhance Hg fixation in char. The neural network model shows the best simulation performance with a mean relative error of 8.92%. The optimal parameters are a heating rate of 7 °C/min, pyrolysis temperature of 300 °C, and residence time of 10 min, resulting in a Hg fixing ratio of 25.68 wt% in pyrolysis char. The simulated Hg fixation characteristics correlate with the experimental results. This study provides insights into Hg distribution under various conditions during co-pyrolysis of SS and MSW. It is hoped that this work can contribute to the control of Hg during the waste treatment and utilization process., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Heterogeneity is a most serious obstacle for treatment and utilization of biomass and waste (BW). This paper proposed a fast characterization method based on infrared spectroscopy and machine learning models, thus to roughly predict the elemental composition and heating value of BW. The fast characterization results could be used to sort different BW components by their suitable downstream utilization techniques. The infrared spectra based hybrid model contained a feature compression section to extract core information from raw infrared spectra, a classification section to distinguish inorganic dilution, and a regression section to generate the elemental composition and heating value results. By parameters optimization, the accuracy of this hybrid model reached 95.54%, 85.53%, 92.40%, and 92.49% for C content, H content, O content, and low heating value prediction, respectively. The robustness analysis was conducted by completely rearranging the training and test sets, and it further validated the hypothesis that the infrared spectra contains enough qualifying and quantifying information to characterize these properties of BW. Compared with previous literature, the C-H, C-O, and O-H correlations in BW were also well kept in the predicted results. This work is hoped to enhance upstream sorting system design for treatment and utilization of BW., Competing Interests: Declaration of interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

This paper describes the effect of oxygen-enriched combustion (OEC) on the flue gas emission and combustion performance of municipal solid waste (MSW) in a full-scale waste incineration plant without flue gas recirculation. Input gas with different oxygen concentrations (21%, 24%, 27%) were supplied into the MSW grating furnace with a capacity of 150 t/d to evaluate the effect of inlet oxygen content on the emissions of NO X , NO, SO 2 , HCl as well as dioxins (PCDDs and PCDFs). Combustion temperature in the incinerator, unburnt rate and thermal efficiency were also examined to assess the combustion performance under OEC condition. Results showed that the amount of SO 2 and HCl decreased to lower levels during OEC condition, while the average concentrations of NO X and NO increased with increase in oxygen content of input gas. Dioxins (PCDDs and PCDFs) in both flue gas and fly ash were highly increased elevated by the oxygen intake, especially for PeCDFs and HxCDFs. The average temperature in three grates of incinerator increased as oxygen concentration increased, while the unburnt rate gradually decreased, indicating a slight improvement of MSW thermal efficiency and more complete combustion under OEC condition., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

A self-sustained municipal solid waste (MSW) pyrolysis-gasification process with self-produced syngas as heat source was proposed and an equilibrium model was established to predict the syngas reuse rate considering variable MSW components. Simulation results indicated that for constant moisture (ash) content, with the increase of ash (moisture) content, syngas reuse rate gradually increased, and reached the maximum 100% when ash (moisture) content was 73.9% (60.4%). Novel ternary diagrams with moisture, ash and combustible as axes were proposed to predict the adaptability of the self-sustained process and syngas reuse rate for waste. For wastes of given components, its position in the ternary diagram can be determined and the syngas reuse rate can be obtained, which will provide guidance for system design. Assuming that the MSW was composed of 100% combustible content, ternary diagram shows that there was a minimum limiting value of 43.8% for the syngas reuse rate in the process., (Copyright © 2017. Published by Elsevier Ltd.)

Landfills have long been widely used to dispose of Municipal Solid Waste (MSW). However, many landfills have faced early closure issues in recent years due to overload operations. Although in-situ aeration technology can quickly stabilize MSW, low oxygen utilization rates present a general problem that results in high energy-consuming and operating costs. This research aims to improve oxygen utilization efficiency by observing the dynamic respiratory index and the removal of contaminants. Three continuous reactors were constructed and designed with targeted aeration and re-circulation schemes for different landfill ages. The results show that a well-designed aerobic, semi-aerobic, and anaerobic reactor can fully degrade the organic components of MSW with different landfill ages, and the quantity of waste has been reduced by more than 60%. Additionally, it was disclosed that gas-water joint technology has a promotional effect on activating microorganisms. [ABSTRACT FROM AUTHOR]

• Noise-assisted data enhancement was used to overcome the poor picture quality in MSW sorting. • CNN and DRSN accuracies were boosted from 64.56 % and 70.30 % to 81.78 % and 90.32 %. • Noise-assisted data enhancement also relieved the over-fitting problem of CNN and DRSN models. • Detailed improvements were discussed by confusion matrix and ROC analysis. Data enhancement is an emerging approach to solve the limited sample size for computer vision-based municipal solid waste (MSW) classification. To overcome the unmatched features between real MSW pictures and those generated by data enhancement, this paper examined the potential of noise-assisted data enhancement methods on two representative MSW classification models: Convolutional Neural Networks (CNN) and Deep Residual Shrinkage Networks (DRSN). The experimental results showed that data enhancement significantly improved the model's accuracy compared with no data enhancement. Specifically, CNN model's test accuracy increased from 64.56 % to 81.78 %, while DRSN model rose from 70.30 % to 90.32 %. Notably, DRSN demonstrated exceptional robustness under noise conditions, achieving over 90 % accuracy in training and test sets. Analysis of the confusion matrix revealed the accuracy significantly improved in identifying glass, plastic, and metal under noise enhancement. These findings emphasized the importance of enhancement strategies in noisy industrial scenarios, offering guidance for MSW management. [Display omitted] [ABSTRACT FROM AUTHOR]

Waste incineration is a process of full combustion reaction between waste and oxygen at high temperature. It is a new problem whether the special natural environmental conditions of Tibet Plateau, such as low air pressure, low oxygen content, and low temperature, will affect the waste incineration in the plateau area. In this work, the influence of different parameters on MSW incineration efficiency and flue gas emission were investigated. The results showed that the temperatures exhibited a significant impact on the flue gas emission. Under the lower temperature, CO was determined to be the main pollutant. With the increase of temperature, NOx became the main pollutant. The optimal temperature range of flue gas emission was between 800 and 900°C. A slight negative pressure in incinerator was benefit for incineration system safety and flue gas emissions. The optimal range was −50 to 0Pa. Lower oxygen content (3–6%) in the incinerator affected the incineration efficiency and flue gas emission. Meanwhile, the high oxygen content had no obvious impact on the flue gas emission, but the cost increased and the service life of the incinerator was affected. The optimal oxygen content in the incinerator was controlled at 6–8%. Furthermore, the air temperatures, pressures, and oxygen content in the natural environment had no significant effect on MSW incineration process. Increasing the air volume would bring about the increase of N2 in the incinerator. This work provides the basic data support for MSW incineration technology in plateau area. [ABSTRACT FROM AUTHOR]

This study aims to investigate the influence and interaction of experimental parameters on the production of optimum H 2 and other gases (CO, CO 2 , and CH 4) from gasification of municipal solid waste (MSW). Response surface method in assistance with the central composite design was employed to design the fifteen experiments to find the effect of three independent variables (i.e., temperature, equivalence ratio and residence time) on the yields of gases, char and tar. The optimum H 2 production of 41.36 mol % (15.963 mol kg-MSW−1) was achieved at the conditions of 757.65 °C, 0.241, and 22.26 min for temperature, ER, and residence time respectively. In terms of syngas properties, the lower heating value and molar ratio (H 2 /CO) ranged between 9.33 and 12.48 MJ/Nm3 and 0.45–0.93. The predicted model of statistical analysis indicated a good fit with experimental data. The gasification of MSW utilizing air as a gasifying agent was found to be an effective approach to recover the qualitative and quantitate products (H 2 and total gas yield) from the MSW. Image 1 • Hydrogen production from the gasification of MSW was focused. • Effect of experimental variables investigated on the MSW conversion. • Temperature found as the most influencing experimental parameter. • Optimum values of experimental parameters for optimum H 2 production were found. [ABSTRACT FROM AUTHOR]

• A gas-Fe surface reaction kinetic mechanism was developed. • Corrosion behaviour of pure Fe metal was simulated and experimentally investigated. • Different concentrations of KCl, SO 2 , H 2 O, and HCl were tested for corrosion of Fe. • 10 vol% H 2 O and 300–500 ppm SO 2 were the concentrations for lowest corrosion rate. Combustion of municipal solid waste (MSW) in waste-to-energy plants have an advantage of energy recovery. However, corrosion of super-heaters induced by KCl, H 2 O, and S in MSW is the major problem limiting the efficient utilisation of MSW. Corrosion reactions of metals are not well understood at molecular/atomic levels, regarding how they evolve. This situation emphasizes the need to understand the reaction pathways and their reaction rates in order to identify operating conditions that reduces the corrosion rates. In this study, a novel kinetic model for the gas-surface reactions of KCl, S, and H 2 O with Fe was developed. The rate constants for the elementary reactions were estimated based on density functional theory and conventional transition state theory computations. Fe-clusters (Fe n , n = 2–4) were used in estimating the kinetic constants of the surface reactions. Reaction model was used to predict the corrosion behaviour of Fe in simulated flue-gas of combustion of MSW at 500 °C and 4 bars. A perfectly stirred reactor code of chemkin-PRO was employed for the predictions. Due to the novel nature of the mechanism, independent experimental results from the literature and experimental results from well-controlled conditions at 500 °C and 4 bars for 50 h were used to validate model predictions. Comparison of model predictions and all experimental results showed good agreement. The concentration of KCl accelerated the corrosion of Fe by a parabolic behaviour while SO 2 between 300–500 ppm showed the lowest mass loss. Water vapour of ∼10 vol% was the critical point at which above corrosion rate was accelerated. [ABSTRACT FROM AUTHOR]

Tibetan tourism solid waste (TSW) has attracted worldwide attention due to its increased production and the potential environmental risks associated with its improper disposal. According to a survey on TSW, catering industry is the main source of TSW, thus a mixture of starch and low-density polyethylene (LDPE) was selected to simulate Tibetan TSW, and pyrolysis of single and mixed components has been performed in a vertical tube furnace with variable pressure. The effects of temperature (400–700 ℃) and pressure (0.02–0.1 MPa) on the distribution of pyrolysis products and the composition of the gas and liquid phases were investigated. The results show that the simulated TSW pyrolysis has a synergistic effect, more obviously, promoting the production of C 1 -C 3 hydrocarbons in the gas phase and inhibiting the production of oxygenated organic matter in the liquid phase. In addition, the properties of the simulated TSW pyrolysis process and the time evolution of various functional groups were studied by TG-FTIR, and it was observed that the simulated TSW pyrolysis followed two stages of degradation: biomass degradation from 250° to 370 °C and then plastic degradation from 420° to 510 °C. This study provides basic knowledge of thermochemical process in Tibet, thus paving the way for clean and efficient treatment of TSW. • Simulated Tibetan TSW was pyrolyzed in variable pressures and temperatures. • LDPE promotes the yield of C 1 -C 3 hydrocarbons and inhibits oxygenated compounds. • Free radicals generated from starch by pyrolysis promote LDPE depolymerization. • A synergy effect was found during pyrolysis of TSW. [ABSTRACT FROM AUTHOR]

• Hyperspectral data contain enough but obscure information for MSW characterization. • Machine learning helps utilizing the full range of hyperspectral pattern. • Accuracy for organic/inorganic components classification reached nearly 100%. • Predicting accuracies of C/H/O contents and LHV reached 92.6%, 86.9%, 80.4%, 90.5%. • This work provides promising fundamentals for downstream treatment of MSW. Determining thermochemical properties and eliminating inorganic components of municipal solid waste (MSW) are crucial to its thermochemical treatment. Traditional characterization and classification technologies have shortcomings including long duration, complex operation, and inevitable sample consumption. This study proposed a hyperspectral imaging and machine learning models based method to solve these problems. Under the optimal parameter conditions, the identification accuracy of inorganic components by F1 scoring reached nearly 100% in MSW, and the prediction accuracy of carbon, hydrogen, oxygen, nitrogen contents and low heating value (LHV)of organic components by mean relative error value reached 92.6%, 86.9%, 80.4%, 54.7% and 90.5%, respectively. The results validated the hypothesis that combination of hyperspectral imaging and machine learning models are promising to accomplish fast characterization and classification of components in MSW, where principal component analysis was capable to abstract crucial information from the spectral pattern, and artificial neural network presented satisfactory classification and regression performance. [Display omitted] [ABSTRACT FROM AUTHOR]

• MSW derived-biochar with acid-base treatment has larger specific surface area. • The food waste-derived biochar exhibits superior activity towards persulfate. • Waste paper-derived biochar with high ash content adsorbs heavy metals effectively. • -COOH, C = O, -OH, Fe and n sites on biochar contribute to PS activation. A huge amount of municipal solid waste (MSW) is produced with urbanization process, posing serious threats to the surroundings and human health. The preparation of MSW-derived biochar is an effective strategy for the waste reclamation. MSW-derived biochar possesses great potential in wastewater purification by adsorption and catalysis. In this review, biochar prepared from classified MSW (e.g. food waste and waste paper) was found with larger specific surface area and porosity than the mixed MSW-derived biochar. Meanwhile, pre-treatment and post-treatment means are summarized to improve the structure and composition of biochar, which could further strengthen its adsorption capacity and catalytic activity. The -COOH, -C = O, -C = C, -OH group sites and aromatic structure of MSW-derived biochar could adsorb pollutants through electrostatic interaction, surface complexation, ion exchange, hydrogen bonding and π-π interaction. Moreover, thanks to the -COOH, -C = O, -OH groups, N-doped structures, defective sites and iron ion species, the food waste-derived biochar exhibits excellent persulfate activation properties. Finally, the future challenges and research directions are suggested, which is conductive to promoting the resource utilization of MSW. Some consideration and recommendation about MSW-derived biochar for water treatment are provided, which facilitates the popularization of the innovative mode "waste control by waste" in aquatic environment remediation. [Display omitted] [ABSTRACT FROM AUTHOR]

Effective management of municipal solid waste (MSW) is essential for the conservation of ecosystems in the Qinghai-Tibetan Plateau (QTP). Considering the landfill is the major method of MSW management, the factors influencing groundwater contamination near MSW landfill sites in the QTP were studied, based on field investigations, environmental impact assessment, and meteorological and hydrogeological analyses. Results indicated that the groundwater was contaminated heavily by nitrate (PI = 7.5), particularly in the landfill without an anti-seepage system, followed by nitrite (PI = 3.5) and heavy metals including arsenic (PI = 4.1) and hexavalent chromium (PI = 2.8). Total hardness, total dissolved solids, nitrate, and lead in the groundwater near the investigated landfill sites were significantly different between the monsoon and the cold seasons. Both the rainfall infiltration and the leachate infiltration were considerably limited by environmental characteristics in the QTP, including high evaporation, low rainfall, and the presence of permafrost. Soil sample contamination near landfill sites was considered as moderate (28.6% of the soil samples) and moderate to heavy (71.4% of the soil samples), based on the geoaccumulation index of mercury. However, comparatively low generation and concentrations of leachate and good topsoil quality (PI = 0.84) reduced the quantity of pollutants infiltrating into the groundwater. The alkaline leachate (pH = 7.45–9.23) and soil (pH = 7.08–8.72) also considerably decreased the concentrations of contaminants dissolved in the infiltrated rainfall and leachate. Additionally, low groundwater level can delay preferential flow and enhance attenuation. Therefore, the groundwater contamination near the landfill sites was simply point pollution, which was influenced by leachate, soil, climate, and hydrogeology characteristics in the QTP. The anti-seepage system is a potential strategy for use in the prevention of groundwater contamination by MSW landfills in the QTP. ga1 • Groundwater was contaminated heavily by nitrate in landfills without anti-seepage system. • Significant differences of TDS, nitrate, lead occurred between monsoon and cold season. • Rainfall and leachate infiltration were restrained by the climate characteristics in QTP. • Low pollutant concentration in leachate and topsoil reduced pollutants infiltration. • Low groundwater level, alkaline leachate and topsoil enhanced pollutant attenuation. [ABSTRACT FROM AUTHOR]

Co-incineration is promising for disposal of sewage sludge (SS) and municipal solid waste (MSW) with energy recovery, although mercury (Hg) emission in this process is non-negligible. In this work, a series of experimental and simulation works was conducted to provide knowledge about the distribution, ecological toxicity, and transformation of Hg during co-incineration of SS and MSW. The experimental results show that co-incineration can increase the Hg content in incineration ash and reduce the amount of Hg released into the atmosphere. The optimal blending ratio for Hg enrichment was 54 wt% SS and 46 wt% MSW. A modified three-step sequential extraction method was used to investigate the chemical species of Hg in incineration ash. It was found that when SS accounted for 50 wt% ∼75 wt% of the feedstock, the direct toxicity risk of Hg in incineration ash was reduced because of the presence of less hazardous chemical forms of Hg. Thermodynamic equilibrium simulation was also conducted on incineration flue gas. The results show that co-incineration caused more gaseous Hg0 to be oxidized to Hg2+ during the cooling process, leading to less environmental risk to the atmosphere. It is hoped that this work can help develop better co-incineration strategies and guide downstream Hg control technology, to dispose of and recover energy from SS and MSW with a cleaner approach. Image 1 • Behaviour of Hg during co-incineration of sewage sludge and municipal solid waste. • Co-incineration makes more Hg in ash and less in atmosphere. • Co-incineration reduces direct ecological toxicity risk of Hg in ash. • Co-incineration rises potential ecological toxicity risk of Hg in ash. • Cl concentration affects Hg0 oxidization during flue gas cooling process. [ABSTRACT FROM AUTHOR]

• Exploration was conducted on MSW coupled with CLG for H 2 production via SR. • The proposed CLG-SR model yields an RSM of 4.17%, verifying its high accuracy. • The product outcomes and H mass flow in CLG-SR were analyzed in detail. • An evaluation for CLG-SR in MSW treatment covered environmental aspects. • The evaluation of MSW treatment in CLG-SR covers economic and energy aspects. Chemical looping gasification combined with steam reforming (CLG-SR) holds great promise for improving energy efficiency and streamlining the production of renewable H 2 and synthetic fuels. In this investigation, the process underwent simulation and analysis using Aspen Plus, offering valuable insights into product outcomes, environmental impacts, and economic performance. The accuracy of the model was validated against experimental results from the literature, yielding a root mean square (RMS) of 4.17 %, thereby demonstrating its high feasibility. The findings demonstrate that within the temperature range of 700–800 °C, H 2 achieves notable selectivity, reaching 60.68 % selectivity at 700 °C. When the steam-to-municipal solid waste (MSW) ratio surpasses 0.9, H 2 demonstrates elevated selectivity. Notably, it is crucial to observe that the selectivity of CO 2 also escalates concurrently with that of H 2. Specifically, at steam-to-MSW ratio (SMR) of 0.9, the selectivity of H 2 attains 60.72 %, whereas the selectivity of CO 2 attains 27.69 %. Under these parameter conditions, H 2 , purified through pressure swing adsorption (PSA), constitutes 68.59 % of the total input H elements, leading to an impressive energy efficiency of 47.76 %. The economic analysis, based on the model, discloses a material consumption of 7.40 tons per ton of H 2 , resulting in a total production cost of 2487.20 USD per ton of H 2. The study bears paramount strategic significance for advancing the in-depth research and development of chemical looping gasification technology. [ABSTRACT FROM AUTHOR]

[Display omitted] • H 2 production from chemical looping gasification of MSW was explored. • ASPEN simulation model of the CLG process with continuous MSW feeding was built. • The lattice oxygen transfer process of CuFe 2 O 4 spinel in the CLG was simulated. • The CLG model was validated using scientific data to demonstrate its feasibility. • The energy flows and H mass flows along the CLG process were analyzed in detail. Combined with carbon capture, chemical looping gasification (CLG) provides a clean and carbon-negative approach to converting municipal solid waste (MSW) into high-quality syngas without air separation units. An Aspen Plus simulation of the CLG process with continuous MSW feeding was constructed and investigated in this work. The CuFe 2 O 4 spinel oxygen carrier (OC) was utilized to provide lattice oxygen. This model was validated using the experimental results from the literature to demonstrate its feasibility for CLG of MSW. The effects of gasification temperature, steam-to-municipal solid waste ratio (SMR) and OC mass flow (OCMF) on H 2 selectivity were throughout investigated. Results demonstrated that at 750 °C, the H 2 selectivity peaked at 51.44%. The H 2 selectivity rose from 43.89% to 56.29% when SMR varied from 0.1 to 2.1. Lower OCMF availed H 2 production. At 800 °C, SMR of 1.1 and OCMF of 100 kg h−1, 67.85% of the initially introduced H in the CLG process can be recovered as pure H 2 by the end, resulting in an energy efficiency of 57.66% based on the low heat value (LHV) of MSW, the electricity consumption and H 2. The process consumed 7.93 t/t H 2 with a corresponding product cost of 2941.21 USD/t. Additionally, it contributes 66.90% and 66.73% to the overall global warming and acidification potentials of the entire process, respectively. The combined impact of temperature and SMR, while maintaining a constant OCMF, highlights that the temperature within the lower range primarily governs the H 2 selectivity. Although both OC and steam can supply oxygen during CLG, their effects on gasification efficiency are diametrically opposed due to their varying oxidation capabilities. Notably, utilizing CuFe 2 O 4 OC, the maximum H 2 selectivity of 63.30% was achieved at 700 °C, SMR of 2.1 and OCMF of 100 kg h−1. [ABSTRACT FROM AUTHOR]

The study investigated the effect of a bimetallic supported catalyst in biodiesel production. Calcined waste bone derived hydroxyapatite (HAP), a solid waste from animal, was served as the support for CaO-CeO 2 catalyst. Various characterization techniques such as FT-IR, BET, SEM-EDS, CO 2 -TPD and XRD analysis were used to analyse the activity of this heterogeneous catalyst. The effect of main parameters in preparation process such as calcination temperature and active component loading on catalyst performance were discussed to obtain the optimal preparation conditions. Under the optimal reaction conditions (11 wt.% dosage of 30%CaO-CeO 2 /HAP-650 catalyst and 9:1 methanol to oil molar ratio at 65 °C for 3 h) the highest biodiesel yield of 91.84% was obtained. Stability test indicated that the yield (84.4%) of fatty acid methyl ester was produced after 8 re-used cycles due to the low leaching of catalyst components. The experimental results showed that biodiesel production cost might be lowered while producing relatively high yield at the present of long life-span catalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pyrolysis of PCW as a typical solid waste in 3D printing industry was investigated. • PCW decomposed most in the range of 320–550 °C with a mass loss of 93.34 wt% • FWO method was found optimal to fit PCW pyrolysis kinetics with a R2 of 0.9947. • The composition of the hazardous volatiles during PCW pyrolysis were discussed. • This work provides pioneering fundamentals for thermochemical disposal of PCW. The emerging photopolymerization-based 3D printing industry has led to a growing concern for the disposal of photocured waste (PCW), which is inevitably generated during the life cycle of photopolymerization-based 3D printing. In order to shed light on suitable thermochemical treatment and utilization approaches of PCW, this work comprehensively investigated the properties and kinetics during PCW pyrolysis via TG-FTIR/GC–MS analysis. The results demonstrated that the main decomposition of PCW sample happened in the range 320–550 °C with a total weight loss of 93.34 wt%. According to the result of four kinetic models, the activation energy of PCW sample was approximately 228.58–245.05 kJ/mol. Finally, the FTIR and GC–MS results manifested that the main components of volatiles released at different heating rates were the same. The volatiles mainly include (S)-(+)-2-hydroxy-2-phenylprop, benzaldehyde, benzophenone (photo-initiator), benzoic acid, benzoylformic acid etc., which have a multitude of potential applications. However, these volatiles produced by PCW pyrolysis have a certain toxicity and potential hazard. This study demonstrates insightful fundamentals for thermochemical disposal of PCW, which appears to be potentially valuable with the rapid development of the photopolymerization-based 3D printing industry. [ABSTRACT FROM AUTHOR]

• Required energy for pyrolyzing RSW in different moisture contents was evaluated. • An ERPC index was developed to evaluate the energy and mass flows. • Optimal parameters were proposed to achieve a self-sustaining pyrolysis. • RSW Pyrolysis was analyzed from aspects of energy, pollutants and carbon footprint. Rural solid waste (RSW) is a serious problem which not only causes environmental pollution, but also limits the development of rural areas. Pyrolysis is an alternative since it can efficiently reduce RSW, meanwhile, the treatment capacity is matched for RSW production. However, conventional pyrolysis of RSW faces two important issues: energy cost and pollutant emission. Therefore, in this work, food waste (FW) was taken as the representative of high-moisture and low-heating-value organic waste in RSW, the energy required for pyrolysis, and the heat produced by combusting pyrolytic products were investigated. Based on calculating the Energy Ratio of Production to Consumption (ERPC) index, the self-sustaining pyrolysis-combustion conditions were established, and the carbon footprints in various scenarios were discussed. Additionally, waste paper, plastic, fabric and poplar scraps were selected as the representative organic wastes (OW) in RSW. The pyrolytic behaviors and pollutant emission (NO x and SO 2) of individuals and blended OW were investigated. Compared to direct combustion of OW, the NO x and SO 2 emissions can be reduced by 86 % and 100 %, respectively, during pyrolysis-combustion process. Combined the above aspects, it is proved pyrolysis-combustion can be a feasible approach to treat RSW, due to it can be operated without extra energy supply, and also shows obvious environmental benefits compared to direct combustion technology. [ABSTRACT FROM AUTHOR]

This review systematically introduces the current status and development trend of inorganic industrial solid waste (IISW)-based materials. IISWs have the characteristics of wide sources, large land occupation, low utilization rate, and high environmental risk. In this paper, IISWs from different sources are introduced firstly, including coal (coal fly ash, coal gangue, flue gas desulfurization gypsum), metallurgy (steel slag, blast furnace slag, electrolytic manganese residue, red mud, etc.), chemistry (phosphogypsum, lithium slag), construction (waste glass, ceramic waste), mining (tailings) and other industries. Then the main research progress of IISWs in building material preparation (cement, aggregate, glass, ceramic, road, brick), water/air treatment (catalyst and adsorbent), and soil improvement (fertilizer and remediation agent) is discussed in detail. At the same time, the role of IISWs in material systems and the solidification/stabilization (S/S) mechanisms of heavy metals in IISW-based materials are emphasized. Finally, the challenges of IISWs material utilization are discussed, and prospects for the development of this field are proposed. Overall, the construction industry is expected to achieve large-scale and comprehensive utilization of IISWs, while the research in other fields requires more value-oriented and industrialized exploration. More importantly, the migration and transformation of heavy metals in IISWs during material utilization need full attention. [Display omitted] • Recycling of IISW in material preparation is comprehensively introduced. • Characteristics of IISW and the role IISW played in derived material are summarized. • S/S mechanisms of heavy metals in IISW are emphasized. • Challenges and prospects of IISW-based materials are presented. [ABSTRACT FROM AUTHOR]

[Display omitted] • Four carried gases were used for torrefaction experiments. • The HHV of oxygenated torrefied MSW was nearly twice as much as raw MSW. • Chlorine decreased from 35.57% in N 2 torrefied MSW to 9.73% in air torrefied MSW. • After flue gas torrefaction, 44% of chlorine was left in torrefied MSW. Flue gas torrefaction (FGT) is a promising pretreatment to improve the fuel properties of municipal solid waste (MSW). Four torrefaction carrier gases (N 2 , flue gas, flue gas/air (1:1), and air) were employed for the comparative investigations. As expected, the higher heating value (HHV) of the oxygenated torrefied MSW was nearly twice as much as the raw MSW. In particular, the chlorine content in torrefied MSW decreased from 35.57 % in the N 2 atmosphere to 14.50 %–9.37 % in oxidative torrefaction. Furthermore, the dominant form of chlorine was converted from organic to inorganic. TG-MS results envisaged that the thermodynamic properties of torrefied MSW were affected by the choice of carrier gases. Among them, oxygen carrier gas effectively improved the thermal stability and fuel properties of torrefied MSW. During pyrolysis, the release of H 2 and CH 4 was enhanced by flue gases (flue gas and flue gas/air). The release of H 2 O was reduced during combustion. The emissions of HCl and CH 3 Cl were inhibited. After FGT, 44 % of chlorine was present in torrefied MSW. Notably, torrefaction increased slagging and fouling inclination and was exacerbated with increasing oxygen content. This study provides a reference for further improving the theoretical system and application of flue gas torrefaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sorting strategies based on source, physical and chemical properties were compared. • The gasification efficiency of sorted RMSW was 40.89% higher than that of unsorted. • The yield of syngas can be increased by 37.14% after waste sorting. • The emission of CO 2 can be reduced by 81 t·per year after waste sorting. • Elemental composition based sorting method benefited to efficient gasification. Gasification is a promising way to convert residual municipal solid waste (RMSW) to high-valued syngas. Waste sorting is helpful to alleviate the heterogeneity problem of waste on gasification. This paper aimed to search for an optimal sorting strategy and evaluate the influence of waste sorting on downstream gasification. A sorting strategy based on elemental composition was proposed and compared with common source and density based strategies. The results validated the enhancement of waste sorting on RMSW gasification, where the elemental composition based strategy showed optimal gasification. The yield of syngas, cold gas efficiency, the lower heating value of syngas and H 2 /CO were increased by 37.14 %, 38.95 %, 2.18 % and 8.81 %, respectively. It also showed a good effect on the improvement of air gasification compared with the literature, especially for H 2 /CO. This paper also discussed the economic and environmental potential of the elemental composition based sorting method. The waste sorting can help increase 29,250 RMB/year and reduce CO 2 emission by 81 t/year. This method has potential for industrial application. It is suggested that further fast elemental composition characterization technologies and intelligent sorting equipment can be developed. Limitations and future perspectives were discussed from gasification simulation models, more energy utilization technologies, the underlying logic of waste sorting and sustainability evaluation. It is hoped that this work can provide insightful fundamentals to their applications in RMSW sorting, thus benefiting resource recovery and circular economy. [ABSTRACT FROM AUTHOR]

Sewage sludge (SS) and municipal solid waste incineration fly ash (MSWIFA) have characteristics of high yield, scattered distribution, and strong harm. Co-disposal of SS and MSWIFA in the existing cement kilns is a prospective way to deal with these two types of solid waste. In this study, the pyrolysis kinetic, thermogravimetric analysis, heat and mass transfer characteristics and pollutant release during SS and MSWIFA co-disposal were investigated through a series of experiments and simulations. In the experiment, pulverized coal (PC) was used as fuel to imitate the real environment of a cement kiln. According to the results, the interaction of the two solid wastes was observed mainly during the devolatilization and combustion periods. At an average blending ratio (60%) and 25 ℃/min heating rate, the blend actual mass loss rate has the largest difference compared to the linearly calculated mass loss rate (0.74%/min), with higher comprehensive combustion characteristic index (3.54), and the blends have better overall heat transfer, internally converging to 350 K. Meanwhile, when SS proportion in PC-SS-MSWIFA is between 20% and 30%, the emission concentration of SO 2 and NO was low, and it has good environmental benefits. This research aims to offer theoretical support for the co-disposal of SS and MSWIFA. [Display omitted] • Interaction of SS and MSWIFA co-disposal process are analyzed. • The interaction between mainly occurs during the devolatilization and combustion. • Blending ratio of 60 SS wt% and heating rate of 25 °C /min can better enhance the interaction. • When the MSWIFA blending ratio is larger, there is a more violent reaction in the volatile phase. • When the mixing ratio of SS in PC-SS-MSWIFA is 20%∼30%, the production of SO 2 and NO is the smallest, and the environmental benefit is the best. [ABSTRACT FROM AUTHOR]

Heavy metal stabilization by chemical chelating agent and solidification by cement are technologies currently used to reduce the leaching of heavy metals in municipal solid waste incineration (MSWI) fly ash. This paper studied the physico-chemical properties of the fly ash, heavy metals content in the fly ash, and the leaching concentration of the heavy metals from fly ash. The effect of four chelating agents namely dithiocarbamate (1#), dithiocarbamic acid dipotassium salt (2#), amino dithiocarbamate chelating resin (3#) and thiourea (4#) on the stabilization and leaching of heavy metals were investigated. Different addition ratios (1%, 2% and 3% w/w) of the chelating agents, various curing time (7, 14, 28 days), and different amounts of the cement (10%, 15% and 20% w/w) were used in order to find the agent with the optimum stabilization and leaching of heavy metals as well as find the effect of combining the agent and cement. The results showed that the dithiocarbamate (1#) chelating agent had the best stabilizing performance due to the three-dimensional structure after their reaction. The addition of cement to the fly ash led to the immobilization of heavy metals due to the C-S-H gel formation. The technology of cement solidification and chelating agent stabilization was optimal from the point of economic cost and the complexity aspect. Image 10654 • The stabilization performance of four chemical chelating agents in MSWI fly ash was compared. • Dithiocarbamate presents the best stabilization character among the four agents. • Stabilized agents combined with solidified cements show better performance. • Cd is more difficult to stabilized/solidified than the other heavy metals. [ABSTRACT FROM AUTHOR]

• A comprehensive model for MSW incineration in a packed bed developed and validated. • In-bed combustion mechanism depends on feedstock property and primary air flowrate. • Large MSW particles tend to delay ignition but promote burnout of the fuel bed. • Low operation pressures can remarkably delay the burnout of the packed fuel bed. • Methods to transfer the model to travelling grates and accommodate real MSW given. Grate-firing technology is one of the commonly used technologies for municipal solid waste incineration, which recovers energy and largely reduces the volume of the solid wastes for landfilling. In grate-fired incinerators, the solid wastes are packed in the fuel bed on the grate, where the major heterogeneous conversion takes place. A proper modeling of the fuel conversion process in the bed not only benefits an in-depth understanding of the in-bed incineration but also facilitates the freeboard simulation. In this paper, a comprehensive model is developed to simulate solid wastes incineration in a packed bed, which advances the state-of-the-art with corrected boundary conditions, homogeneous reactions, and calculation method for pyrolysis products. The model is first validated by a simplified analytical problem. Then, the model is validated in detail by a dedicated experimental study in literature, in which the pyrolysis and gas combustion front and the subsequent char oxidation front both propagate from the bed surface to the grate due to the abundant oxygen availability in the fuel bed. The model also outperforms a latest modeling study in literature for reproducing the same experimental study. Finally, a model-based parametric study is conducted to investigate the effects of solid waste particle sizes and solid waste incineration in high-altitude areas. This paper also clearly explains the methods to transfer the packed-bed model to travelling grates and to accommodate the different waste fractions in real municipal solid waste, in order to make the model applicable to travelling grate-firing of real municipal solid wastes. [ABSTRACT FROM AUTHOR]

Few studies have comprehensively taken into account the source apportionment and human health risk of soil heavy metals in the vicinity of municipal solid waste incinerator (MSWI) in high population density area. In this study, 8 elements (Cr, Pb, Cu, Ni, Zn, Cd, Hg, and As) in fly ash, soil samples from different functional areas and vegetables collected surrounding the MSWI in North China were determined. The single pollution index, integrated Nemerow pollution index, principal component analysis (PCA), absolute principle component score-multiple linear regression (APCS-MLR) model and dose-response model were used in this study. The results showed that the soils around the MSWI were moderately polluted by Cu, Pb, Zn, and Hg, and heavily polluted by As and Cd. MSWI had a significant influence on the distribution of soil heavy metals in different distances from MSWI. The source apportionment results showed that MSWI, natural source, industrial discharges and coal combustion were the four major potential sources for heavy metals in the soils, with the contributions of 36.08%, 29.57%, 10.07%, and 4.55%, respectively. MSWI had a major impact on Zn, Cu, Pb, Cd, and Hg contamination in soil. The non-carcinogenic risk and carcinogenic risk posed by soil heavy metals surrounding the MSWI were unacceptable. The soil heavy metals concentrations and health risks in different functional areas were distinct. MSWI was the predominate source of non-carcinogenic risk with the average contribution rate of 36.99% and carcinogenic risk to adult male, adult female and children with 4.23 × 10 −4 , 4.57 × 10 −4 , and 1.41 × 10 −4 respectively, implying that the impact of MSWI on human health was apparent. This study provided a new insight for the source apportionment and health risk assessment of soil heavy metals in the vicinity of MSWI. [ABSTRACT FROM AUTHOR]

[Display omitted] • An M−ADM1 framework based on ML and ADM1 was proposed to simulate biomass anaerobic digestion. • SVM model was embed in M−ADM1 to predict crucial kinetic parameters during anaerobic digestion. • An average R2 of 0.92 and RMSE of 0.167 were obtained for predicting the crucial kinetic parameters. • The TIC for municipal solid waste, kitchen waste, and sludge reached 0.0163, 0.0327, and 0.0361. • The results provide promising potentials towards simulation of biomass anaerobic digestion. This work proposed a so-called M−ADM1 model for anaerobic digestion simulation, which uses machine learning model to predict the kinetic parameters in anaerobic digestion model No.1 (ADM1). A total of 75 biomass samples were used to establish the machine learning model. Inputs used to predict the kinetic parameters included C, H, O, N, S contents, and digestion temperature. The sensitivities of 17 kinetic parameters were evaluated, and 7 kinetic parameters with the highest sensitivities were selected as model outputs. After model optimization, the average R2 for predicting the 7 kinetic parameters reached 0.92, and the root mean square error reached 0.167. The accuracy of the overall M−ADM1 expressed by Theil inequality coefficient of municipal solid waste, kitchen waste, and sludge were 0.0163, 0.0327, and 0.0361, respectively. The results validated the hypothesis that accurately predicting some crucial intermediate parameters using machine learning models could enhance the performance of tradition ADM1. [ABSTRACT FROM AUTHOR]

An inhalation health risks assessment of 96 waste to energy (WtE) plants and 178 landfills in the Bohai Rim, located in northeast China, has been conducted. Based on the latest emission inventories in 2020, WRF/CALPUFF was used to simulate the diffusion of pollutants. Population-weighted hazard index (HI) and carcinogenic risk (CR) of incineration and landfill for each pollutant and each target organ impacted were calculated. The health risks of incineration and landfill were correlated with per capita municipal solid waste (MSW) disposal quantity, emission factors, pollutant toxic effects and local migration and diffusion conditions. The HI of incineration and landfill in the Bohai Rim were 4.07 × 10−3 and 4.79 × 10−3, respectively, which was lower than the acceptable level (HI < 1), while the CR of incineration and landfill were 4.72 × 10−7 and 2.58 × 10−7, respectively, which was also lower than the acceptable level (CR < 1 × 10−6). The non-carcinogenic risks of incineration mainly targeted respiratory system and development system, while the non-carcinogenic risks of landfill mainly targeted nervous system and respiratory system. The carcinogenic risks of incineration mainly targeted respiratory system and digestive system, while the carcinogenic risks of landfill mainly targeted hepatic system and respiratory system. With the trend that incineration phase in, while landfill phase out, the number of patients for 15 target organ diseases caused by the disposal of unit mass MSW would decrease in the Bohai Rim, ranging from 1.8 × 10−8 – 1.8 × 10−2 (pop/t)，especially in developed provinces, such as Beijing and Tianjin. However, the number of patients for 4 target organ diseases caused by the disposal of unit mass MSW would increase, ranging from 1.18 × 10−6 - 5.28 × 10−3 (pop/t). Based on pollutants' pathogenic mechanisms, this study innovatively accessed and compared incineration and landfill's health risks of target organs, and provide technical and policy suggestions based on the changing trend of MSW disposal methods in the future. [Display omitted] • Inhalation health risk assessment of WtE plants and landfills in the Bohai Rim. • Quantification of risks from WtE plants and landfills, on impacted target organs. • HI of incineration and landfill were 4.07 × 10−3 and 4.79 × 10−3 in the Bohai Rim. • CR of incineration and landfill were 4.72 × 10−7 and 2.58 × 10−7 in the Bohai Rim. • Landfill phase-out will reduce 15 organ diseases caused by unit mass MSW's disposal. [ABSTRACT FROM AUTHOR]

The first Municipal solid waste incineration (MSWI) plant in Lhasa, Tibet, the plateau region of China, started its operation in 2018. Considering the elevation and extreme climate (low pressure and low oxygen content) in Tibet, noticeable differences may be envisaged compared to MSWI elsewhere. The aim of this study is to evaluate the environmental impacts, economic benefits, and energy efficiency of this MSWI project with three representative MSWI case in plain region using Life cycle assessment (LCA), Cost-benefit analysis (CBA), and energy analysis methods. The result showed that enhancing blast volume and cross-sectional area of the boiler help adapt to the oxygen-deficient environment. GaBi model was employed based on the CML 2001 methodology to perform LCA. LCA shows that the Lhasa MSWI project has lower positive environment impacts than the projects in plain region. More attention is needed for the deficiencies in flue gas emissions of MSWI in the plateau region. CBA shows that the payback period is 11.97 years and the internal rate of return is 8.75%. The energy analysis indicates that the boiler energy efficiency is up to 81.92%. MSWI subject to minor changes seems suitable to Tibetan plateau, and can be deployed further. • A comparative study of MSWI in plateau and plain area was conducted. • Lhasa MSWI case was analyzed in terms of environment economic and energy aspects. • The environmental impact of Lhasa case has lower positive impacts than plain cases. • Technology improvements can't offset the impact of the environment completely. • The Lhasa MSWI case showed good economic benefit with policy support. [ABSTRACT FROM AUTHOR]

Flue gas torrefaction (FGT) is a promising pretreatment to improve the fuel properties of municipal solid waste (MSW). A synergistic effect between paper, wood and PVC was studied in flue gas and nitrogen torrefaction atmospheres. FGT presented superior potential in improving fuel properties compared to nitrogen torrefaction (NT). Notably, the synergistic effect between different ingredients in FGT could reduce mass and energy losses effectively, especially the combination of PVC with other materials. Besides, the FGT samples exhibited better thermal stability than NT samples during pyrolysis and combustion. Simultaneously, FGT led to the released flammable gases (H 2 and CO) increase, while H 2 O decrease. Satisfyingly, less gaseous pollutants were released during the FGT samples combustion, attributed to the reduction of light volatiles and the enrichment of char and heavy volatiles. Moreover, the positive synergistic effects of FGT or NT blended samples were found in the pyrolysis (in phase B: ∆W NT-DTG = 4.79–5.20 and ∆W FGT-DTG = 0.78–1.18) and combustion (in phase B: ∆W NT-DTG = 6.03–16.07 and ∆W FGT-DTG = 1.56–13.4). This study can provide a theoretical reference for the efficient and clean treatment of MSW. [Display omitted] • A synergy was found in flue gas or N 2 torrefied (FGT/NT) blended samples. • The synergies of FGT blended samples could reduce mass and energy losses. • FGT char exhibited better thermal stability and released more combustible gas. • FGT char had better burning potential and lower pollution emission. [ABSTRACT FROM AUTHOR]

The Qinghai-Tibet Plateau is a typical ecologically fragile region. Lhasa, as the most densely populated area on the plateau, is generating a large amount of municipal solid waste (MSW) with the development and improvement of living standards. However, due to the special geographical distribution, the energy utilization of MSW is limited, which is considered to be guided by the energy distribution of the MSW. In this work, Geographic Information System (GIS) technology is proposed to map the potential energy distribution of MSW in Lhasa City, which could provide a piece of reliable information on MSW management and energy utilization in Lhasa City. The potential energy value of MSW is high in urban areas, up to 2.082 × 109 MJ in Chengguan District, and low in suburban regions, up to 6.95 × 107 MJ. The energy potential per unit area of MSW is 87.7 kJ/m2 to 3980 kJ/m2 in urban regions and 10.5 kJ/m2 to 67.1 kJ/m2 in suburban regions. Therefore, the MSW in the urban regions and the suburban regions is suitable for centralized energy utilization and decentralized processing, respectively. The potential energy per unit mass of dry-based MSW is 13100 kJ/kg to 21600 kJ/kg and per unit mass of wet-based MSW is 8110 kJ/kg to 14300 kJ/kg due to the high moisture content of food waste, which is above 70% in most regions. Therefore, the separation of food waste and the MSW can reduce the moisture content of MSW, which is beneficial to its subsequent energy recovery and utilization, not only improving the lack of data on the potential energy distribution of MSW in high altitude plateaus, but also providing sound recommendations for the management of energy utilization in MSW incineration at high altitude. [Display omitted] • Geographic Information System was proposed for mapping the potential energy spatial distribution of municipal solid wastes. • The energy potential of municipal solid wastes in Lhasa city indicated the favorable energy utilization. • The energy spatial distribution maps favored the municipal solid wastes management. • A case study in the typical ecologically fragile region of Lhasa city. [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) is one of the most common 3D printing materials. However, once processed, the properties of its raw material are altered. 3D printed PLA waste (3DP-PLAW) has a relatively high calorific value with low impurities, which makes waste-to-energy utilization effective through thermal conversion. In this study, the pyrolysis characteristics of 3DP-PLAW were investigated using thermogravimetric–Fourier infrared spectroscopy/gas chromatography−mass spectrometry (TG-FTIR/GC-MS). Two main pyrolysis stages were observed at 260–390 ℃ and 390–500 ℃ during 3DP-PLAW pyrolysis, which contradicts with findings from previous research. Upon reaching 390 °C, residual ash and char triggered a secondary reaction. It is speculated that the occurrence of a second pyrolysis stage is attributed to changes in the physicochemical properties of the PLA during the 3D printing process. It was also found that 3DP-PLAW had a higher heating value (HHV) (20.949 MJ·kg−1) than that of the raw PLA. The pyrolysis kinetics of 3DP-PLAW was analyzed using the distributed activation energy model (DAEM) as well as Flynn-Wall and Ozawa (FWO), Starink, and Friedman methods; it was found that the activation energies obtained from these methods were similar (approximately 206 kJ·mol−1). Therefore, these methods are suitable for biomass plastics. The TG-FTIR/GC-MS results showed that CO, CO 2 , CH 4 , CH 3 CHO, esters, carbon-based compounds, and ethene were the main gaseous products of 3DP-PLAW pyrolysis. In contrast to a previous study on raw PLA, no ketone was detected in the gaseous products during 3DP-PLAW. These findings allow for the production of energy products, instead of the usage of natural gas for recycling, which underlines the potential value of 3DP-PLAW for energy recovery and subsequent improvements on the current 3DP-PLAW disposal methods. [Display omitted] • Pyrolysis of 3DP-PLAW as an emerging solid waste was studied via TG-FTIR/GC-MS. • 3DP-PLAW mainly decomposed in temperature stages of 260–390 ℃ and 390–500 ℃. • Activation energy of 206 kJ/mol was obtained via 4 pyrolysis kinetic methods. • Pyrolysis products distribution of 3DP-PLAW towards energy recovery was studied. • The results provide fundamentals for thermochemical utilization of 3DP-PLAW. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effects of anaerobic digestion on pyrolysis performance was described. • The properties and applications of both food waste and its digestate were discussed. • The pyrolysis mechanisms were revealed by experimental and kinetic analysis. • The production and distribution of N-containing compounds were investigated. The effects of anaerobic digestion (AD) on pyrolysis were elaborated by comparing the pyrolysis performance of food waste (FW) and food waste solid digestate (FWSD). The pyrolysis mechanisms of FW and FWSD were revealed by experimental and kinetic analysis. The properties and potential applications of pyrolytic products from FW and FWSD were discussed. The results showed that part of organic matters of FW were consumed during AD, which altered the pyrolysis performance of FWSD. The pyrolytic gas from FW had better quality due to its higher lower heating value (LHV) (20.52 kJ/Nm3). The pyrolytic oil and biochar derived from FWSD showed better qualities as oil fuel and carbon-based absorbent. Pyrolysis of FWSD produced less nitrogen-containing pollutants (NCPs) indicated that AD coupled with pyrolysis is more environmental-friendly to treat FW. This study provides potential approach and theoretical guidance for the treatment and resource utilization of FW and FWSD. [ABSTRACT FROM AUTHOR]

Urgent need for waste disposal and renewable energy have opened up promising pathways for renewable and sustainable fuel production to substitute traditional fossil fuels. In this study, catalytic co-pyrolysis of waste paper (WP) and polyvinyl chloride (PVC) as typical municipal solid wastes was experimentally investigated towards hydrogen-rich syngas production. Results indicated the maximum H 2 yield (429 μmol·g cat −1·min−1) was obtained with 60% PVC weight ratio under 900 °C which was higher than single component pyrolysis. Higher hydrogen yield (681.76 μmol·g cat −1·min−1) appeared over Fe/CeO 2 –CaO under the optimal conditions compared to that of Ru/ZSM-5-CaO (445.54 μmol·g cat −1·min−1). From the calculated non-isothermal kinetic parameters, both catalysts could reduce activation energies. Proper porous structure and CaO content in the catalyst could enhance hydrogen production via carbon species fixation. • Catalytic co-pyrolysis of waste paper and PVC blends for hydrogen production is firstly investigated. • Enhanced interactions of PVC/waste paper during pyrolysis was found for H 2 production. • Non-isothermal kinetics were implemented to evaluate catalytic co-pyrolysis. • High H 2 yield was obtained over Fe/CeO 2 –CaO for its pore structure and sorption enhancing effect. [ABSTRACT FROM AUTHOR]

Thermal plasma treatment has been considered as one of promising methods for fly ash disposal. In this study, firstly, the characteristics of municipal solid waste incineration (MSWI) fly ash and sewage sludge incineration (SSI) fly ash were analyzed, followed by the raw material formulations of low melting temperature determined by thermodynamic equilibrium calculation. Then verified experiments were carried out by thermal plasma system, focused on the formation condition of vitrified slags with various CaO-SiO 2 -Al 2 O 3 ratios and the influence factors of heavy metals (Cd, Cr, Ni, Pb, Zn, Cu) transference. According to the results: During the co-treatment process of fly ashes, a lower temperature of vitrified slag formation as low as 1230 ℃ was observed. Vitrification is determined by the molten phase content during melting process, the correlation coefficient between the glass phase content of slag and the molten phase content was 0.81 (P < 0.01). CaO content of raw materials was a major element for the volatilization of Cd and Pb. High Al 2 O 3 content can remain more Cr, Cu and Ni in slags, but it is not conducive to the solidification of Zn. The synthetic toxicity index of heavy metals would greatly reduce from 23153.15 to 663.29–820.63 after thermal plasma treatment. ga1 • The co-treatment of incineration fly ashes is beneficial for vitrification. • The formulation at 20–35% CaO, 20–35% Al 2 O 3 , 30–60% SiO 2 is more easily vitrified. • CaO and Al 2 O 3 contents are the main influencing factors of heavy metals migration. • The synthetic toxicity index of heavy metals is reduced from 23153.15 to 663.29. [ABSTRACT FROM AUTHOR]

• Weibull distribution-based model is found a great fit with the experimental data. • The synergistic effects are described as a quantitative calculation result. • The synergistic effects affect the pyrolysis process in different reaction stages. • Synergism can be characterized by both Weibull parameters and experiment analysis. The synergistic effects of polyvinyl chloride (PVC) and biomass were crucial for the pyrolysis of combustible municipal solid waste (CMSW). In this study, a Thermogravimetric analyzer-Fourier-Transform Infrared Spectrometer (TG-FTIR) was employed for experimental verification of the synergistic effects of (PVC) and the biomass in CMSW during pyrolysis, and a Weibull distribution-based model was established to comprehensively analyze the variation in the synergistic effects. The TG-FTIR results showed that the mass loss of separate CMSW compounds occurred mainly between 210 °C and 526 °C, while under the synergistic effects, the solid residue of CMSW increased from 12.0 wt% to 25.0 wt%. Additionally, the experimental results confirmed that the synergistic effects could make the overall pyrolysis of cellulose and hemicellulose happen earlier and increased the solid residual rate of lignin. The prediction of the Weibull distribution-based model was in good agreement with the experimental results. The synergistic effects were quantified by the parameters of the model and further distinguished into different reaction stages. The model described the synergistic effects using three aspects: the reaction degree, scale and efficiency. The characterization of the Weibull distribution-based model enabled us to obtain additional information about the synergistic effects, which were not attainable from the results of the conventional experimental analysis. [ABSTRACT FROM AUTHOR]

China is facing severe environmental problems, the total municipal solid waste (MSW) generation has dramatically increased and presented great challenges all over the country. Cities have different characteristics in MSW components, generation quantity, influencing factors and disposal ways. Beijing, Guangzhou and Lhasa of Beijing-Tianjin-Hebei economic circle, Pearl River Delta economic zone, and Qinghai-Tibet plateau regions were selected as representative cities, to compare and analyze the features, influencing factors to the MSW generation quantities, and its components by grey correlation analysis. Predictions of MSW generation quantities for Beijing, Guangzhou and Lhasa in 2025 would be 1251.22, 704.71 and 71.040 million tons, respectively, made by BP (back propagation) nerve work using MATLAB software. Results showed that the main indicators of influencing factors to MSW in three cities were all of economic development levels, population and investments of government input. Based on the analysis of internal relationship and characteristics of MSW, some barriers of MSW management were analyzed, and recommendations were given. Our study analyzed the influencing factors and forecasted quantities of MSW generation in representative cities in China, providing valuable evidences for the severe MSW disposal situation of different economic zones in China. • Socioeconomic factors of MSW generation in different economic zones of China were studied by GCA. • MSW generation in Beijing, Guangzhou and Lhasa were predicted by BP nerve network. • Barriers, challenges and recommendations of MSW treatment and management were provided. [ABSTRACT FROM AUTHOR]

• Fate of chlorine and interrelationship with alkalis, Zn, Pb and S was reviewed. • Chlorine-initiated corrosion mechanisms were explained. • The roadmap for chlorine during combustion of MSW was presented. • Combustion optimization to mitigate deposition and corrosion was highlighted. Municipal solid waste (MSW) incineration plays an important role in waste treatment systems throughout the world, due to the advantages of fast volume reduction by 80–90%, heat recovery, and power generation. However, waste-to-energy (WtE) plants have low electrical efficiency of 15–25%, due to the low steam temperature and pressure used in order to minimize boiler deposition and corrosion problems. Undoubtedly, the high Cl-content in MSW is the reason for the severe corrosion problem. Chlorine also forms volatile compounds with trace metals (e.g., Zn, Pb), and, influences the fate of other key elements, e.g., Na, K, and S. Different from alkali metals in biomass, which have been thoroughly investigated, the behavior of chlorine during MSW incineration has not been systematically and comprehensively studied. Up until now, there are few in-depth studies that have been conducted on the thermal behavior of chlorine or on the remedial measures against Cl-induced problems. An up-to-date review on the behavior of chlorine from incineration via freeboard chemistry to corrosive attack is therefore needed, in order to provide knowledge on process optimization and reactor design, thereby enabling high-efficient energy utilization and safe operation of large-scale WtE units. This review provides a critical summary of the progress of research on chlorine in MSW (origins, species, and analytical methods); the thermal behavior of chlorine, including chlorine vaporization, aerosol formation and transformation (freeboard chemistry), deposit formation, and Cl-initiated corrosion mechanisms. In addition, the interrelationship of chlorine with other key elements (S, Na, K, Zn, Pb), and, the chlorine roadmap in the incineration process is presented, along with the influence of feedstock composition and the temperature of both the flue gas and boiler tube metal on chlorine-induced deposition and corrosion. Mitigation measures against Cl-initiated problems such as Segher boiler prisms, mixed secondary air injection, and eco-tube systems, are also thoroughly discussed. Finally, challenges and further research questions, are identified. [ABSTRACT FROM AUTHOR]