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In the context of the shift toward a closed-loop economy, soil-like fractions from landfills are increasingly seen as a potential raw material. Pollution, including potentially toxic elements (PTEs), limits the use of soil-like fractions. The study objective was to assess the level of contamination with PTEs and the ecological risk of the soil-like fraction from a landfill using an interval method on the basis of a quantile analysis. Quantile analysis allows visualization and interpretation of data based on statistical principles using a cumulative distribution function for the data. Quantiles divide the entire dataset into equal parts by probability, and they indicate the proportion of observations that have a value less than or equal to a given quantile. A study was conducted at a landfill in Volgograd. The contents of Cd, Ni, Pb, Hg, Cu, and Zn were studied in a soil-like fraction. The contents of Hg, Pb, and Zn were low and did not pose any risks to the environment. Cd, Ni, and Cu were the main reasons for the contamination of the soil-like fraction. Quantile analysis has shown that the soil-like fraction is polluted unevenly and is described by several contamination levels. The pollution level with PTEs in the soil-like fraction is low, with a probability of 27–31%. The other part of the soil-like fraction has a pollution level ranging from moderate to very high. The environmental risk of a soil-like fraction is associated with Cd and Ni. With a probability of 23.5%, a soil-like fraction is a high environmental risk and requires a responsible attitude and measures to ensure environmental safety. With probabilities of 29.4% and 47.1%, the complex potential environmental risks of a soil-like fraction are low and moderate, respectively. The soil-like fraction located at a depth of more than 2.5 m has a low level of pollution and a low environmental risk. Potentially, this part of a soil-like fraction can be isolated and, after detoxification, used. The significance of this research lies in providing a novel approach to evaluate the ecological risk of soil-like fractions from landfills, which can inform more effective sustainable waste utilization practices in landfill mining. [ABSTRACT FROM AUTHOR]

Groundwater contamination from non-engineered landfills has been extensively documented. However, there is a gap in extensive field research regarding whether engineered landfills can also contribute to groundwater contamination. We selected 62 engineered municipal landfills in Eastern China and collected both leachate samples from the landfills and groundwater samples from nearby wells. Through the analysis of inorganic solute indicators in both groundwater and leachate samples, we explored the impact of landfill leachate on the inorganic solute composition of groundwater. Our findings revealed that over half of the groundwater samples surrounding the landfill sites exceeded recommended drinking water limits for inorganic solutes. The correlation analysis demonstrates a significant relationship between Cl−, SO42−, Na+, and K+ levels in leachate and groundwater, highlighting the direct impact of landfill activities on groundwater quality. Moreover, specific characteristics of the landfill, such as its age, the total waste volume, and geographic location, were found to influence the inorganic solute composition in the groundwater. This effect was apparent in the positive correlations between the age of the landfill and NH3-N, Ca2+, and Mg2+ levels in groundwater, the total waste volume of the landfill and Ca2+ content in groundwater, and the latitude of the landfill and Cl− and HCO3− concentrations in groundwater. This work carries implications for assessing environmental risks associated with engineered landfills and enhancing landfill design, management, and monitoring practices. [ABSTRACT FROM AUTHOR]

Composite indicators (CIs) are being utilized more frequently to assess and monitor environmental systems. The revised leachate pollution index (r-LPI) is one such composite indicator used to quantify the pollution potential of landfill leachate on a scale of 5–100. The development of CIs involves several steps, and each of these steps has various methodological choices, each of which could lead to different results. Thereby, the reliability of the quantified pollution potential of leachate may be questioned. This study investigated the techniques for developing the r-LPI, examining decisions related to parameter selection, normalization technique, weighting approach, sub-indicator weights, and their aggregation. As the index developer made the decisions, each of these stages was fraught with uncertainty. The uncertainty in the various stages of the development of r-LPI was quantified using the Monte Carlo-based uncertainty analysis and the sensitivity analysis approach. Uncertainty analysis is a helpful but seldom-used step of index development that identifies the model's most dependable sections. Sensitivity analysis was carried out to ascertain the degree of impact the input parameters have on the r-LPI values. The combined use of sensitivity and uncertainty analysis in this study for the formulation of r-LPI affirmed the transparency, credibility, and accuracy of the index. [ABSTRACT FROM AUTHOR]

Waste generation has seen a significant surge in the last decade, presenting an urgent need for efficient and sustainable waste management strategies. The mounting piles of landfill waste underscore the criticality of segregating recyclable from non-recyclable waste, a measure that could alleviate numerous global environmental challenges. The increasing necessity to differentiate waste into specific categories such as paper, plastic, and metal is becoming evident; these categories demand distinct disposal and recycling methods. Addressing this automatic detection and segregation issue calls for an automated garbage classification system, achievable through computer vision. This paper introduces a deep learning and computer vision-based Smart Ensembled Framework for Waste Management (SEFWaM) to categorize garbage into various classes for improved waste management. This innovative model employs a fusion of transfer learning—a deep learning technique and boosting to devise an ensembled approach for efficient waste classification. Our proposed approach, trained on the Trashnet 2.0 dataset, has demonstrated superior performance over competing algorithms in terms of Weighted Macro Precision (WMP), Weighted Macro Recall (WMR), Weighted Macro F1-Score (WMF), and test accuracy. The proposed SEFWaM model achieves an accuracy of 94.2% for the considered dataset, proving its superior efficiency over other deep learning-based models. This research thereby contributes to a pressing environmental issue by offering an automated, efficient solution for waste management. [ABSTRACT FROM AUTHOR]

Managing waste tires presents a significant challenge globally, particularly in regions experiencing high temperatures and shortage of landfill sites. This issue is affecting countries like Kuwait, where the abundance of waste tires is a major source of environmental and safety risks, particularly during the intensely hot summer months. This extreme heat has sparked numerous fires, leading to substantial air pollution due to thick black smoke. Given the limited disposal options, recycling waste tires and finding practical applications for ground tire rubber (GTR) is essential. To address the challenge, a comprehensive laboratory testing program was conducted, using locally produced rubber aggregates as an additive to Kuwait's local surface sands. Two new variables were examined namely the size and gradation of the GTR, and the density of the compacted mixes. For this purpose, two different sizes of rubber aggregates, fine and coarse produced locally, were utilized, and the impact of relative compaction on the strength and compressibility of the mixtures was investigated by testing samples compacted to the maximum density and to 95% of the maximum density. The results suggest that combining local surface sands with rubber tire additives results in a lighter, more permeable, and compressible material, contributing significantly to sustainable waste management. With 20% rubber additive the maximum dry density decreased by nearly 20%, and the permeability increased by 1.74–3.11 times and the compression index increased by 6.15 and 3.8 times with fine and coarse rubber respectively. The angle of friction remained unchanged at 36° with the addition of coarse rubber and decreased by 3°–4° with fine rubber. The change in behavior although not an increase in the strength and stiffness, offers a range of suitable practical applications in civil engineering and environmental management, including use as a drainage layer, embankment construction on soft ground, earth fill around retaining walls, an additive in asphalt mixes, and in manufacturing compressible tiles for sports facilities. [ABSTRACT FROM AUTHOR]

To reduce uncertainties regarding seismic loading scenarios and numerical modeling limitations, the performance-based fragility curves of two California clayey-core earth fill dams (the Anderson and Lexington dams) were developed for the first time using the results of over 170 finite difference seismic analyses. Permanent deformations were considered as the damage index (DI), and fragility curves were generated based on three intensity measures, including the peak ground acceleration (PGA), specific energy density (SED), and Arias intensity (Ia). The results illustrated that the intensity measure significantly affected damage possibilities, and it was essential to simultaneously use all fragility curves based on various intensity measures for proper assessment of seismic vulnerability. Furthermore, evaluation of SED- and Ia-based fragility curves demonstrated that separation of near- and far-field records was critical to generate correct fragility curves when using energy-based parameters as intensity measures. Besides, SED-based fragility curves had the most conservative results, followed by PGA- and Ia-based ones. [ABSTRACT FROM AUTHOR]

Municipal solid wastes are contained in landfills that occupy large areas over several decades and have a significant environmental footprint. The deformation and flow through properties of these materials are important for infrastructure construction on and leachate migration in municipal landfills. However, these properties are not regularly determined because of material heterogeneity, variable constituents, lengthy testing, and pungent odor. The main contribution of this research is the application of consolidation theory to understand the geotechnical behavior of synthetic municipal solid wastes. For this purpose, a synthetic material was prepared in a large cell and incrementally loaded with hydraulic conductivity measured after each load. Test results indicated that void ratio decreased from 0.90 to 0.78 during consolidation as the applied stress increased from 70 to 1225 kPa. The compression index of 0.20 (similar to degraded municipal solid wastes) bounced back with a swell index of 0.022; both indices fell within the range for silt and clay. Likewise, the measured hydraulic conductivity decreased by two orders of magnitude from 10–6 to 10–8 m/s and closely matched those of fine-grained soils. It is concluded that compression of municipal solid wastes follows the consolidation theory and this property is affected by initial void ratio (arising from composition, saturation, and sample disturbance) and particle rearrangement (due to pore water expulsion of during loading). In contrast, the measured conductivity is marginally affected by compression and is quite different from that estimated using the consolidation theory primarily due to alterations in the pore network. [ABSTRACT FROM AUTHOR]

National strategic documents set ambitious goals for reducing greenhouse gas emissions. This also applies to the solid waste management sector, which is experiencing a steady dynamic growth in emissions. The planned measures within the framework of the National Project "Ecology" will not be sufficient for reducing the volume of solid waste disposal and emissions from waste. Positive changes are only possible with a simultaneous increase in new waste recycling capacity and launching a large-scale process of reclaiming land currently occupied by landfills. Pursuing such a course of action has a pronounced social character while its macroeconomic effectiveness is low. The low-emission transformation of the waste management sector requires significant and continuous government incentives through financial support, setting targets, and monitoring their implementation. [ABSTRACT FROM AUTHOR]

Landfills are widely employed as the primary means of solid waste disposal. However, this practice generates landfill gas (LFG) which contains methane (CH4), a potent greenhouse gas, as well as various volatile organic compounds and volatile inorganic compounds. These emissions from landfills contribute to approximately 25% of the total atmospheric CH4, indicating the imperative need to valorize or treat LFG prior to its release into the atmosphere. This review first aims to outline landfills, waste disposal and valorization, conventional gas treatment techniques commonly employed for LFG treatment, such as flares and thermal oxidation. Furthermore, it explores biotechnological approaches as more technically and economically feasible alternatives for mitigating LFG emissions, especially in the case of small and aged landfills where CH4 concentrations are often below 3% v/v. Finally, this review highlights biofilters as the most suitable biotechnological solution for LFG treatment and discusses several advantages and challenges associated with their implementation in the landfill environment. [ABSTRACT FROM AUTHOR]

A major roadblock towards the realisation of a circular economy are the lack of high-value products that can be generated from waste. Black soldier flies (BSF; Hermetia illucens) are gaining traction for their ability to rapidly consume large quantities of organic wastes. However, these are primarily used to produce a small variety of products, such as animal feed ingredients and fertiliser. Using synthetic biology, BSF could be developed into a novel sustainable biomanufacturing platform to valorise a broader variety of organic waste feedstocks into enhanced animal feeds, a large variety of high-value biomolecules including industrial enzymes and lipids, and improved fertiliser. This perspective describes how insects, such as Hermetia illucens, which are already used to process organic wastes at industrial scales, could be developed as a synthetic biology platform for sustainable biomanufacturing and bioremediation. [ABSTRACT FROM AUTHOR]

Municipal solid wastes (MSWs) disposed in landfills are generally exposed to drying and wetting cycles because of the variation in environmental conditions, decomposition of organics and leachate recirculation. This paper studies the water retention curves (WRCs) of fresh and degraded MSWs under various numbers of drying and wetting cycles with water and leachate exposure. The result indicates that the water retention capacities of MSWs decrease with drying and wetting cycles. The maximum hysteresis between the drying and wetting cycles is observed in the first cycles for all MSW samples. The WRCs of medium to highly decomposed MSWs under drying and wetting cycles are similar to those of soils. The WRCs of fresh MSWs can undergo substantial changes due to the discharge of intra-particle moisture caused by decomposition and compression. For both fresh and decomposed MSWs, the WRCs stabilize after 3 drying and wetting cycles. However, only the MSWs of one initial composition with similar void ratios were investigated. Further research should be conducted to investigate the water retention behavior of MSWs with diverse initial compositions (e.g., food contents) and void ratios. [ABSTRACT FROM AUTHOR]

This study investigated seasonal variations in the physico-chemical properties of leachate from the Kupferberg landfill site, examining the influence of landfill age and climatic factors. Data provided by the Windhoek Municipality during the years 2017 to 2022 facilitated the exploration of critical concerns related to groundwater protection and human health. Guided by two research questions and anchored in hypotheses tested at a 95% confidence level, the study employed Statistical Packages for Social Scientists (SPSS) for analysis. Significant temperature variations were observed across years [F (5, 21) = 4.493, p < 0.05], indicating a substantial relationship between landfill age and seasonal variations in leachate physico-chemical properties. Further ANOVA tests revealed temperature trends impacting leachate parameters, such as organic content and pH. While COD displayed a declining trend with landfill age, inorganic components like Cl- and alkalinity exhibited no distinct age-related pattern. Wet seasons demonstrated higher EC and Cl--mean values than dry seasons, correlating with elevated COD levels. The study underscored the incremental rise in parameter values over time and during the rainy season, attributed to solid waste degradation and rainwater percolation. Notably, climatic conditions significantly influenced seasonal variations in leachate physico-chemical properties (p < 0.05). Based on this outcome, null hypothesis 1 was rejected. The second null hypothesis was also rejected because climatic conditions do influence the seasonal variations in physico-chemical properties. These findings are crucial for emphasizing the need for effective leachate management strategies and providing valuable insights for arid regions. Future research can expand on a national scale, employing one-way ANOVA tests on other landfills in Namibia, and engaging local communities for comprehensive data collection on cross-contamination. [ABSTRACT FROM AUTHOR]

This paper offers a survey of progress in utilizing bio-oil from wood and forestry waste for creating eco-friendly asphalt pavements, with a focus on sustainability and future research directions. The substantial yearly production of wood and forestry waste often ends up in landfills. However, using pyrolysis to convert this waste into bio-oil presents an alternative to petroleum-based asphalt binders. Bio-oil shares characteristics with traditional binders used in asphalt, resulting in three main applications: bio-asphalt, bio-rejuvenator, and polyurethane (PU)-modified bio-asphalt. Bio-asphalts, though similar to traditional binders, display vulnerability to aging, experiencing mass loss and volatile component evaporation when aged. Bio-oil incorporation affects high- and low-temperature performance grades adversely, limiting its usage due to susceptibility to aging and impact on high-temperature performance. To tackle these issues, additives like rejuvenators, polymers, nanomaterials, and crumb rubber have been introduced to enhance aging resistance and overall performance of bio-asphalt. Wood-based bio-oil, due to its low viscosity and compatibility with petroleum-based binders, is suitable for rejuvenating aged asphalt. The optimal wood-based bio-rejuvenator percentage is 5–20%, with recommended mixing conditions of 130–145 °C, 1000–3000 rpm, and 10–30 min. Innovatively, polyurethane (PU) modification involves incorporating isocyanate into bio-asphalt to create PU-modified bio-asphalt, yielding improved strength, increased high-temperature viscosity, enhanced elastic recovery, and resistance to low-temperature cracking. [ABSTRACT FROM AUTHOR]

Borehole samples were collected from a municipal solid waste (MSW) landfill in Xi'an, China, and subjected to a series of basic geotechnical and compression tests. This study aims to investigate the influence of composition, dry unit weight, moisture content, organic content, and landfill age on the compressibility of MSW. The results show that with increasing landfill age, the compressible components and organic content exhibit a decreasing trend while the dry unit weight increases. The moisture content does not vary significantly. There is also a linear trend between the logarithm of the primary compression strain and vertical stress. In addition, with an increase in compressible components content, moisture content, and organic content, the modified primary compression index (Cc') shows an increasing trend, whereas with an increase in dry unit weight and landfill age, Cc' shows a decreasing trend. Furthermore, regarding the 34 sets of data, authors only selected five data points for a detailed comparative analysis, this decision was made on the basis that these data points are representative. A modified primary compression index prediction model that considers the dry unit weight, moisture content, and landfill age of the MSW as influencing factors results in a fitting coefficient of 0.797. The Cc' values in this study are within the range of 0.12 to 0.36. These findings provide a reference for the vertical expansion design of existing landfills. [ABSTRACT FROM AUTHOR]

Plastic pollution poses a worldwide environmental challenge, affecting wildlife and human health. Assessing the biodegradation capabilities of natural microbiomes in environments contaminated with microplastics is crucial for mitigating the effects of plastic pollution. In this work, we evaluated the potential of landfill leachate (LL) and estuarine sediments (ES) to biodegrade polyethylene (PE), polyethylene terephthalate (PET), and polycaprolactone (PCL), under aerobic, anaerobic, thermophilic, and mesophilic conditions. PCL underwent extensive aerobic biodegradation with LL (99 ± 7%) and ES (78 ± 3%) within 50–60 days. Under anaerobic conditions, LL degraded 87 ± 19% of PCL in 60 days, whereas ES showed minimal biodegradation (3 ± 0.3%). PE and PET showed no notable degradation. Metataxonomics results (16S rRNA sequencing) revealed the presence of highly abundant thermophilic microorganisms assigned to Coprothermobacter sp. (6.8% and 28% relative abundance in anaerobic and aerobic incubations, respectively). Coprothermobacter spp. contain genes encoding two enzymes, an esterase and a thermostable monoacylglycerol lipase, that can potentially catalyze PCL hydrolysis. These results suggest that Coprothermobacter sp. may be pivotal in landfill leachate microbiomes for thermophilic PCL biodegradation across varying conditions. The anaerobic microbial community was dominated by hydrogenotrophic methanogens assigned to Methanothermobacter sp. (21%), pointing at possible syntrophic interactions with Coprothermobacter sp. (a H2-producer) during PCL biodegradation. In the aerobic experiments, fungi dominated the eukaryotic microbial community (e.g., Exophiala (41%), Penicillium (17%), and Mucor (18%)), suggesting that aerobic PCL biodegradation by LL involves collaboration between fungi and bacteria. Our findings bring insights on the microbial communities and microbial interactions mediating plastic biodegradation, offering valuable perspectives for plastic pollution mitigation. [ABSTRACT FROM AUTHOR]

The waste produced around the world increases daily due to population increase and the fact that life expectancy is longer. Waste production is higher in urban environments; therefore, managing Urban Solid Waste must be more rigorous to avoid environmental problems and health effects. For this reason, standards are created to properly manage landfills so that each life cycle stage is managed responsibly. However, a solid commitment from the community and more management regulations from the government are needed to be focused on reducing, reusing, and recycling materials as much as possible. This commitment needs to be reinforced to the extent that regulatory policies are created at the household level as much as education and awareness programs are implemented. This study presents a method to evaluate how imposing waste management goals before they reach landfills can increase the lifetime of landfills and, consequently the suitableness of a treatment plant implementation. [ABSTRACT FROM AUTHOR]

The development of effective and cost-efficient landfill liners is crucial to prevent groundwater contamination from leachate, safeguarding soil quality and the environment. Composite liners, particularly those combining bentonite with supplementary materials such as fly ash or marble dust, present a promising solution. This study delves into a comprehensive investigation of the physical properties of landfill liners composed of bentonite-fly ash and bentonite-marble dust mixtures through an extensive series of laboratory tests. The research systematically analyzes various proportions of bentonite with fly ash and marble dust, evaluating their impact on liner performance in comparison to Bentonite-sand mixtures. Physicochemical analyses are employed to understand the interactions and behaviors of these distinct substances within the amended bentonite. A wide array of physical properties, including Atterberg's limits, compaction characteristics, free swell index, modified free swell index, California bearing ratio, cohesion, and angle of internal friction, are meticulously examined. Collectively, these properties offer a comprehensive overview of the suitability and performance potential of bentonite-fly ash and bentonite-marble dust mixtures as landfill liners, presenting a viable alternative to traditional bentonite-sand mixtures. The study reveals synergistic effects between bentonite and both fly ash and marble dust, highlighting their significant contributions to enhancing the physical traits of landfill liners. This advancement in landfill liner design holds the promise of effectively mitigating detrimental environmental impacts associated with waste disposal. While this study provides a robust foundation, it is essential for future investigations to prioritize long-term performance assessments and real-world implementation. Validation and fine-tuning of these findings are crucial to ensuring practical applicability and efficacy within authentic landfill construction scenarios. This holistic approach will contribute to the continued evolution and optimization of landfill liner design, addressing the pressing challenges of sustainable waste management and environmental protection. [ABSTRACT FROM AUTHOR]

Landfill leachate, which is a complicated organic sewage water, presents substantial dangers to human health and the environment if not properly handled. Electrochemical technology has arisen as a promising strategy for effectively mitigating contaminants in landfill leachate. In this comprehensive review, we explore various theoretical and practical aspects of methods for treating landfill leachate. This exploration includes examining their performance, mechanisms, applications, associated challenges, existing issues, and potential strategies for enhancement, particularly in terms of cost-effectiveness. In addition, this critique provides a comparative investigation between these treatment approaches and the utilization of diverse kinds of microbial fuel cells (MFCs) in terms of their effectiveness in treating landfill leachate and generating power. The examination of these technologies also extends to their use in diverse global contexts, providing insights into operational parameters and regional variations. This extensive assessment serves the primary goal of assisting researchers in understanding the optimal methods for treating landfill leachate and comparing them to different types of MFCs. It offers a valuable resource for the large-scale design and implementation of processes that ensure both the safe treatment of landfill leachate and the generation of electricity. The review not only provides an overview of the current state of landfill leachate treatment but also identifies key challenges and sets the stage for future research directions, ultimately contributing to more sustainable and effective solutions in the management of this critical environmental issue. [ABSTRACT FROM AUTHOR]

As a crucial hydrolytic enzyme, urease plays a vital role in anaerobic biological treatment. It is well-known that manganese ions are abundant in landfill leachate, but their concentration fluctuates significantly. However, few studies have investigated the effect and mechanism of different concentrations of Mn2+ on urease activity during anaerobic biological treatment of landfill leachate. This paper aimed to investigate the effects and mechanisms of different concentrations of Mn2+ on urease activity. The results showed that an appropriate amount of Mn2+ could significantly enhance urease activity, while a high concentration of Mn2+ could inhibit it. Insight into the mechanisms behind this phenomenon, various methods such as Zeta potential, particle size, ultraviolet spectroscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and statistical analysis were employed in our study. Research suggested that, on one hand, Mn2+ may form hydrogen bonds with the side chain amino or carboxyl groups of urease amino acid residues, affecting the structure of urease through hydrogen bonding. Additionally, Mn2+ also binds to urease through hydrophobic interactions. On the other hand, the C–OH and C-N functional groups in urease have a strong affinity for Mn2+, and changes in these functional groups can greatly enhance the activity of urease. Furthermore, under the action of high concentrations of Mn2+, while the structure of urease becomes more stable, there is also a steric hindrance phenomenon that affects the substrate from entering the catalytic center. Therefore, studying the mechanism of Mn2+ affecting urease activity has significant biological significance and provides a new perspective for exploring the impact of metals on anaerobic bioprocessing of landfill leachate. [ABSTRACT FROM AUTHOR]

Reasonable treatment of large amounts of sludge excavated from landfills has gained increasing attention due to the diminishing availability of landfill space in China. In this study, five landfill sludge (LS) treatment technologies using life cycle assessment (LCA) and life cycle cost (LCC) were investigated, i.e., co-incineration in coal-fired power plants (CFPP) and waste incineration power plant (WIPP), co-processing in cement kiln, bricks production, and sintering ceramsite. The LCA results demonstrate that sintering ceramsite outperforms other technologies and LCC results indicate sintering ceramsite also provides the highest economic benefit ($869.94). To further enhance environmental and economic performances of the LS treatment, the substitution of coal with natural gas and biomass can reduce Energy Conservation and Emission Reduction (ECER) index by 74% and 98%, respectively. This substitution can increase economic returns by 24% and 26%, respectively. Furthermore, national-level economic benefit and carbon emission reduction potential of different LS treatment technology alternative scenarios were assessed. Results display that a combination of 50% CFPP, 25% bricks, and 25% ceramsite (biomass) offers the highest economic gain, which is 3.02 times that of 50% CFPP and 50% cement (original case). Conversely, the replacement of 25% brick with 25% cement in the above combination result in the lowest carbon reduction, which is 9.35 times that of the original case. [ABSTRACT FROM AUTHOR]

Landfill leachate contains antibiotic resistance genes (ARGs) and microplastics (MPs), making it an important reservoir. However, little research has been conducted on how ARGs are enriched on MPs and how the presence of MPs affects pathogens and ARGs in leachates and soil. MPs possess the capacity to establish unique bacterial populations and assimilate contaminants from their immediate surroundings, generating a potential environment conducive to the growth of disease-causing microorganisms and antibiotic resistance genes (ARGs), thereby exerting selection pressure. Through a comprehensive analysis of scientific literature, we have carried out a practical assessment of this topic. The gathering of pollutants and the formation of dense bacterial communities on microplastics create advantageous circumstances for an increased frequency of ARG transfer and evolution. Additional investigations are necessary to acquire a more profound comprehension of how pathogens and ARGs are enriched, transported, and transferred on microplastics. This research is essential for evaluating the health risks associated with human exposure to these pollutants. [ABSTRACT FROM AUTHOR]

Most of the materials used in landfill liners are not based on the local soil conditions which increases the cost of landfill construction. It is essential to develop a composite mix based on local soil that fulfills the design parameters of the municipal solid waste (MSW) landfill at a reasonable cost as per USEPA 1989 guidelines. The current study investigates the use of local soil, fly ash, and bentonite mixtures to obtain an optimum composite mix with specific properties for landfill liners. The experimental investigation was conducted on different proportions of local soil-bentonite-fly ash mixes to evaluate the optimum mix proportion for liner materials. The curing period of different mixes is also considered. The geotechnical properties like liquid limit (LL), free swell index (FSI), and optimum moisture content (OMC) increased whereas the maximum dry density (MDD) and permeability decreased with an increase in bentonite content up to 20% with soil. It was also observed that fly ash mixed with soil in proportion (80:20) meets the optimum range of landfill liner properties. And, the composite mix comprised of soil–bentonite–fly ash in proportion (65:15:20) directs toward the optimum design parameters of landfill liner. These mixes were compacted at OMC and MDD satisfying plasticity (i.e., LL ≥ 20% and plasticity index, PI ≥ 7%) and permeability criteria (k ≤ 1 × 10−7 cm/s) as well as unconfined compressive strength criteria. Moreover, the scanning electron microscopy of local soil–bentonite–fly ash mixes was investigated for the optimum mixes for a comparative assessment of results. [ABSTRACT FROM AUTHOR]

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Effective waste management in Tehran faces significant challenges arising from urbanization and population growth. This study delves into the current state of municipal solid waste management in Tehran, examining technical, social, economic, environmental health, and structural dimensions to identify key issues. Data collection involved questionnaires and consultations with experts. Results indicate various problems, including incomplete waste production data recording systems, inefficient source separation programs, inappropriate waste storage, high collection frequencies, subpar compost production, unregulated informal waste picking, landfill non-compliance, and limited management capacities. Evidence-based solutions encompass comprehensive waste production monitoring systems, public education, improved storage infrastructure, reduced collection frequencies, modern composting technology adoption, and landfill upgrades. Policymaking recommendations include incentivizing informal waste collectors to formalize, preventing child labor, enhancing public participation, mitigating corruption, streamlining contracts, and promoting coordination. Overall, a collaborative approach, emphasizing personnel training, infrastructure enhancement, public awareness campaigns, and research and development, is pivotal in establishing an effective and sustainable waste management system in Tehran. This study contributes to crucial insights into Tehran's waste management challenges and offers potential pathways for improvement. [ABSTRACT FROM AUTHOR]

Construction and demolition waste consists of residue and discarded materials that result from construction, renovation, remodelling, and demolition activities. This waste typically includes various materials, such as concrete, wood, steel, bricks, drywall, asphalt, glass, plastics, and other construction-related materials. This research quantified the environmental consequences of managing earthquake-generated construction and demolition waste in Turkey using diverse techniques. The study employed a life cycle assessment to compute these impacts. First, the impacts of the currently used landfill process were calculated and then a scenario in which concrete is reused, recyclable wastes are separated and recycled, and the remaining waste is sent to a landfill was created. According to the findings, it is seen that if all the debris is sent to a landfill, 11.9 t CO2eq will be generated in the short term, while 18,428.3 t CO2eq can be saved, especially by reusing concrete. These findings may vary due to the involvement of different unforeseen processes, but they show that although it is often very difficult to utilize such wastes, especially those generated as a result of unusual disasters, such as earthquakes, very significant environmental gains can be achieved through appropriate treatment. [ABSTRACT FROM AUTHOR]

The predominant solid waste disposal method in the world is landfilling, which has led to significant gas emissions. The aim of this study is to estimate the emissions of alternative solid waste management practices in the Gulf Cooperation Council (GCC) using the Solid Waste Emissions Estimation Tool developed by the U.S. Environmental Protection Agency. The study focuses on the South Seven Ring Road landfill in Kuwait and covers the period from 2025, when alternative scenarios will start, to 2036, which is one year after the predicted closure of the landfill. The study explores various waste management strategies grouped into two distinct approaches. The Baseline scenario, where all waste is landfilled, serves as a reference, reflecting the current main treatment method in the GCC. In the first approach, we evaluated four distinct scenarios: composting 25% of the total compostable waste, recycling 50% of recyclable waste, combusting 25% of combustible waste, and a scenario combining these strategies. The second approach further intensified these strategies: composting was increased to 70% of compostable waste, recycling remained at 50% of recyclable waste, and combustion was expanded to include 100% of combustible waste for energy production. The study reveals that no single waste management alternative is the optimum solution for reducing all emissions. Each alternative displays the capacity to reduce certain emission types while potentially increasing others, necessitating a consideration of specific emission types when choosing the most suitable strategy. For overall emission mitigation, composting emerges as the most effective alternative in the GCC. [ABSTRACT FROM AUTHOR]

This current study evaluates the effect of waste disposal sites on soil physicochemical qualities in Enugu State, Southeast Nigeria. A total of 216 soil samples were taken in 2020, 2021 and 2022 from soil depth (0–20 cm, 20–40 cm and 40–60 cm) using standard analytical methods. In addition, seasonal (wet and dry) effects were also considered. Data sets were analysed using Fisher's Significance Least Difference (F-LSD) at 0.05 probability level. The study showed that at 0–20 cm soil depth profile, bulk density in the study period significantly (p < 0.05) decreased by 48, 38, and 41%, and by 14, 9, and 12% in the wet and dry periods at the study sites relative to the controls. Similar results were obtained at 20–40 cm and 40–60 cm soil depth profiles. Consequently, there was a significant (p < 0.05) increase in the values of other studied soil physical parameters in both periods relative to the controls. Across the three soil depth profiles, hydraulic conductivity values ranged from 12.25 to 95.89 ± 5.63 cm/hr (a CV of 12%) and 8.73 to 122.23 ± 5.80 (a CV of 10%); 10.15 to 91.66 ± 4.03 (a CV of 22%) and 18.41 to 64.48 ± 4.21 (a CV of 21%); and 1.55 to 155.33 ± 6.71 (a CV of 14%) and 10.66 to 134.10 ± 6.23 (a CV of 11%) in wet and dry periods at Enugu, respectively. Based on these new findings, it is concluded that waste disposal sites had a positive effect on the fertility of the soil. [ABSTRACT FROM AUTHOR]

The dynamic changes in dissolved organic matter (DOM) during the transport of landfill leachate (LL) in porous medium should be explored, considering the high levels of DOM in the LL of municipal solid waste. Column experiments were carried out at 25 °C at a Darcy's flux of 0.29 cm/h for 2722 h to compare the transport of Cl−, ultraviolet absorbance at 254 nm (UV254), chemical oxygen demand (COD), and dissolved organic carbon (DOC) in the simulated porous medium by using the CXTFIT2.1 code. Results showed that the convection–dispersion equation (CDE) could describe Cl− transport well. The high levels of λ and D could be highly correlated with the physicochemical properties of the porous medium. The transport of the studied DOM with evident aromatic character could be described appropriately by the CDE model with the first-order reaction assumption, considering the similar variation trends of UV254, COD, and DOC in the effluent during experiments. Specifically, the values of retardation factor (R) were in the following order: DOC > UV254 > COD, whereas the low values of the first-order decay coefficient (k1) for DOC and COD were still higher than that for UV254. High contents of humic-like substances in the DOM with complex toxic components resulted in the natural low removal efficiencies of COD, DOC, and UV254 (≤ 23%), which could be confirmed by the variations of fluorescence index (FI) and humification index (HIX) in the effluent. The results should be helpful in evaluating the environmental risk induced by the LL leakage in a landfill site. [ABSTRACT FROM AUTHOR]

Landfill leachate raises a huge risk to human health and the environment as it contains a high concentration of organic and inorganic contaminants, heavy metals, ammonia, and refractory substances. Among leachate treatment techniques, the biological methods are more environmentally benign and less expensive than the physical–chemical treatment methods. Over the last few years, fungal-based treatment processes have become popular due to their ability to produce powerful oxidative enzymes like peroxidases and laccases. Fungi have shown better removal efficiency in terms of color, ammonia, and COD. However, their use in the treatment of leachate is relatively recent and still needs to be investigated. This review article assesses the potential of fungi and fungal-derived enzymes in treating landfill leachate. The review also compares different enzymes involved in the fungal catabolism of organic pollutants and the enzyme degradation mechanisms. The effect of parameters like pH, temperature, contact time, dosage variation, heavy metals and ammonia are discussed. The paper also explores the reactor configuration used in the fungal treatment and the techniques used to improve leachate treatment efficacy, like pretreatment and fungi immobilisation. Finally, the review summarises the limitations and the future direction of work required to adapt the fungal application for leachate treatment on a large scale. [ABSTRACT FROM AUTHOR]

On February 6, 2023, the earthquakes centered on Kahramanmaraş-Pazarcık and Kahramanmaraş-Elbistan affected several provinces in the region and generated a vast amount of demolition waste. This study aims to develop a site selection model for the most suitable landfill areas after the earthquake using open-source Geographic Information Systems (GIS) software and the Best-Worst Method (BWM). First, the study identifies decision criteria with a Delphi expert panel. Next, it determines the weights using the BWM based on pairwise comparison. Spatial data of the determinants were obtained from open data portals, and proximity, overlay, and slope analyses were carried out for the disaster region. Combining the output data layer of each criterion, a suitability map of the landfills was produced. As a result, 36,2% (29,826 kms square) of the study area was classified as suitable and very suitable. In this study, a cloud GIS-based decision support platform was developed to act quickly and initiate recovery processes within the scope of disaster management of the destructive earthquake. The suitability map and potential sites were shared with the responsible teams in the disaster area so that the potential sites could be displayed on the map and the suitable areas could be navigated on appropriate routes. The findings of the study revealed that the use of open data and cloud GIS framework in the disaster management process enables quick, reliable, and cost-effective actions in the immediate aftermath of disasters. [ABSTRACT FROM AUTHOR]

The water retention curve (WRC) of municipal solid waste (MSW) is the important hydraulic parameter for the study of unsaturated seepage analysis in landfills. Due to the compressibility and degradability of the waste, the search for a method to quickly and accurately test its water retention curve (WRC) is a current problem that needs to be solved. In this paper, considering the volume change of the waste specimens in test, the test principle of centrifuge testing of WRC is corrected to make it applicable to the testing of waste WRC. In addition, the WRCs of 20 MSW specimens with typical landfill compositions and porosities are measured using the corrected centrifuge test. The effects of compositions and porosities of waste specimens on WRC parameters were analyzed. The results are summarized as follows. Disregarding the height reduction of specimens resulted in overestimated matric suction values and underestimating volume water content values. By comparing uncorrected and corrected values, the maximum difference of the matric suction and volumetric water content reach 233 kPa and 11%, respectively. This study can provide a reference for accurately measuring the WRC of MSW using a centrifuge. For the waste specimen without kitchen and yard waste, composition had less of an effect on the WRC of waste compared to porosity. The effect of the content of the non-absorbable fraction on the residual volumetric water content θr and the parameter nv in the van Genuchten model was significant. The initial porosity n had a great effect on the parameter α. [ABSTRACT FROM AUTHOR]

The Hydrologic Evaluation of Landfill Performance (HELP) model (v 3.04) was used to assess the hydrological performance of two large-scale (~ 80 × 80 × 90 cm) laboratory-based landfill cap models. Desiccation cracking under simulated climate change precipitation (CCP) events was modelled to predict the performance of landfill caps over a 50-year period in Cumbria England, UK. Cumulative infiltration values under different climate conditions were highly sensitive to macro-pore development in the clay liner which is represented by the changing hydraulic conductivity in HELP simulations. Simulation results of cap design 1 (a clay barrier layer only) show that cumulative annual infiltration under normal precipitation (NP) and CCP events, with the initial hydraulic conductivity, ranged between 1 and 2% of the annual precipitation; however, cumulative annual infiltration was 10 to 68% when maximum (degraded) hydraulic conductivity values were used in simulations. A geosynthetic clay liner (GCL) included in cap design 2 significantly reduce cumulative infiltration. [ABSTRACT FROM AUTHOR]

To reduce the volume of landfill sludge, a more environmentally friendly technology is used to study the effects of different freeze–thaw–vacuum pretreatment modes. In addition to the cumulative effect of cooling time within different temperature bands, we analyse the temperature difference loss rate of shallow sludge over the period of cooling. During the annular freezing process, the mechanism of ice front formation is revealed by exploring the energy transfer process of landfill sludge. When repeated freeze–thaw–vacuums are performed, the pretreatment modes of a single pre-freeze–thaw and two consecutive pre-freeze–thaws are compared. The superiority of two modes is discussed in the light of local differences in dewatering performance and overall settlement trend characteristics. Furthermore, the final micromorphological structure indicates that the repeated freeze–thaw–vacuum pretreatment mode of sludge is affected by its depth to a certain extent. It is found that factors such as sludge depth and radial water migration have a significant impact on the time accumulative effect and energy transfer of frozen sludge. The sludge treatment mode of two consecutive pre-freeze–thaws has a better effect on the overall dewatering and reduction. [ABSTRACT FROM AUTHOR]

The present study directs the need for the development of an economical composite mix comprised locally available soil and industrial waste which satisfy the design parameters of the municipal solid waste (MSW) landfill. The local soil, bentonite, and fly ash mixtures are mixed in different proportions to evaluate the geotechnical and microstructural characteristics for suggesting an optimum composite mix that fulfills the design parameters of landfill liners. The curing periods of different mixes are also considered while evaluating the unconfined compressive strength (UCS) characteristics. The microstructure of the mixtures is examined using advanced imaging techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDAX) to gain insights into the changes at the microscale level due to the inclusion of fly ash. It is observed that soil-bentonite-fly ash composite mix in a ratio of 65:15:20 aligns with the optimal design characteristics required for a landfill liner. Notably, for this composite mix, both liquid limit (LL) and plastic limit (PL) show a significant increase of 48.57% and 32.33% respectively, while the optimum moisture content (OMC) rises by 11.25%. Conversely, maximum dry density (MDD) experiences an 8.79% decrease. Moreover, the free swell index (FSI) escalates by 113%, whereas hydraulic conductivity (HC) records a substantial reduction of 96.04%. Moreover, the UCS exhibited a notable increase of 209% after a 28-day curing period. The highest strength is achieved initially by soil mixed with 20% fly ash, followed by a blend containing 15% bentonite. Therefore, proper fly ash content in filler and other binder materials is an effective and sustainable approach that not only solves the disposal issue but also enhances the material's engineering characteristics, justifying its suitability to be used as a landfill liner. [ABSTRACT FROM AUTHOR]

The efforts to encourage sustainable development have brought to attention the use of secondary materials in civil engineering applications. Global experimental data suggest that municipal solid waste (MSW) incineration bottom ash (IBA) can potentially replace natural aggregates in field applications. However, IBA is currently disposed in open dumps or sanitary landfills in India. Assessing contaminant leaching from IBA is crucial to ascertain its options for disposal or reuse. The current study analyzes the mineralogy, chemical constituents, organic content, and leaching of contaminants from IBA collected from two incineration plants in Delhi. The study takes into consideration the effect of particle size, liquid-to-solid (L/S) ratio, and pH on contaminant leaching. The experimental results revealed that the leaching concentration of contaminants and organic content of IBA decreases with an increase in particle size. A considerable influence of pH was noted on the leaching of all contaminants except chlorides, sulfates, and antimony. The results further indicate that IBA is suitable for disposal in non-hazardous waste landfills regardless of particle size at its intrinsic pH. However, it is recommended to dispose IBA in monofils as co-disposal with MSW in sanitary landfills can cause the pH of IBA to shift toward the acidic range, which may exacerbate the contaminant leaching from IBA. The comparison of leaching test results with international regulatory standards for reuse demonstrates that using IBA in unbound applications is feasible in paved roads and earthworks subjected to minimal infiltration of water. [ABSTRACT FROM AUTHOR]

Due to the abundance of agrochemicals, feces, urine, and landfill leachates, nitrates ( NO 3 - ) are one of the most prevalent forms of inorganic pollutants in water bodies and groundwater. In this work, EC treatment was carried out in continuous flow with a Mg/Zn system for the treatment of a drinking water well near a landfill. The maximum efficiency of 93.15% was achieved at optimal operating conditions: current intensity of 0.6 A, flow of 2.9 mL/min and TRH of 86.81 min. In addition, 73% of silica was removed (from 65.05 to 17.76 mg/L), which interacts with magnesium and calcium to form silicates of both elements. EC is an efficient treatment technology with an operating cost of 2.65 US$/m3. In addition, Si causes interference in the EC system by prioritizing reactions with calcium and magnesium, and 72.69% Si was removed by EC. Finally, the inorganic ions were also significantly removed: 100% phosphates, 82.37% sulfates, 47% total hardness, and 42.28% chlorides. Conclusively, EC improved the water quality and thus minimized the health effects of consumers, and the drinking water studied in this work was used for the hydration of 212,500 L per day of milk formula for infant consumption and older adults. Highlights: Mg/Zn electrocoagulation was used for the treatment of drinking water polluted with nitrates. The maximum efficiency of 93.15% was achieved at 0.6 A, flow of 2.9 mL/min and TRH of 86.81 min. In addition, 73% of silica was removed from 65.05 to 17.76 mg/ L. EC is an efficient treatment technology with an operating cost of 2.65 US$/m3 EC improved the water quality minimizing the health effects of consumers. [ABSTRACT FROM AUTHOR]

Landfill leachate contains a significant amount of organic matter, making it a valuable source for CH4 production. However, due to its liquid form, the mono-digestion of leachate could result in a reduced CH4 yield per unit reactor volume. This necessitates its utilization in anaerobic digesters alongside solid waste streams. The objective of this study was to evaluate co-digestion performance of landfill leachate with different wastes using biomethane potential test and assess the optimum combination in terms of CH4 productivity. Modified Gompertz model was used for kinetic characterization. Experiments were held under mesophilic conditions and lasted for 30 days. Among mono-digestion of substrates, landfill leachate exhibited the highest CH4 productivity and yield: 83.17 mL/gVS.d and 793 ± 6.85 mL/gVS, respectively. Fish waste was found to have the lowest energy potential with 350 mL/gVS CH4 yield and 18.24 mL/gVS.d CH4 productivity. CH4 productivities for co-digestion cases ranged from 5.48 to 67.85 mL/gVS.d. Mixing landfill leachate and chicken manure with the same amount on wet weight basis yielded the highest CH4 productivity. On the other hand, inclusion of fish waste consistently resulted in decreased CH4 yield and productivity for all incubations, which suggests that fish waste may not be suitable as a co-substrate for landfill leachate in terms of CH4 production. Monitoring of chemical parameters revealed that buffering capacity of the system and free ammonia formation were the main parameters governing CH4 production. [ABSTRACT FROM AUTHOR]

Despite policies to restrict the mixing of organic waste with other general waste and improve its separation at source, municipal solid waste still contains a high proportion of organic waste. The residual organic waste is generated as a by-product of the mechanical treatment of municipal solid waste (MSW) and is mainly disposed in landfills after composting. Its reuse and recovery status varies across European countries. Most countries restrict the use of biostabilised residual waste (BSRW) to landfill cover, whereas others have regulated it as marketable compost. Crucially, BSRW is set to lose its "recycled" status under the revised European Union waste framework, with probably tighter restrictions and increased costs imposed for the landfilling of organic waste. Our research aimed to investigate pyrolysis as an alternative technology to treat the 10–40 mm fraction of BSRW (representing 50% of BSRW generated). Pyrolysis at 700 °C was carried out and feedstock and pyrolysis products were characterized. Mass and energy balances showed that pyrolysis produced hot vapour/gas whose combustion may render the pyrolysis process energetically sustainable. Biochar comprises 30–50% of BRSW mass after removal of glass, metal and stones. Our results indicate that pyrolysis has the potential to create options for contributing to reduce the landfilling of BSRW; however, the presence of residual impurities may limit biochar applications. [ABSTRACT FROM AUTHOR]

Landfill leachate forms when waste-inherent water and percolated rainfall transfer are highly toxic, corrosive, acidic, and full of environmental pollutants. The release of leachate from municipal solid waste (MSW) landfill sites poses a severe hazard to human health and aquatic life. This study examined the impact of leachate from Delhi's Ghazipur landfill on the nearby groundwater quality. Analysis of leachate samples was done to determine various parameters such as total dissolved solids (TDS), hardness, alkalinity, electrical conductivity, pH, BOD5, COD, nitrate, sulphate, chloride and iron, and presence of coliform bacteria. Significant dissolved elements (22,690–34,525 mg/L) were observed in the samples, indicated by the high conductivity value (1156–1405 mho/cm). However, a stable pH range (6.90–7.80) of leachate samples was observed due to high alkalinity concentrations between 2123 and 3256 mg/L. The inverse distance weighing (IDW) interpolation tool from QGIS 3.22.7 developed spatial interpolated models for each parameter across the Ghazipur area. The IDW interpolated graphs of various parameters over the whole study area confirmed these contaminations. In addition, leachate and groundwater samples were physio-chemically analyzed, and temporal fluctuation in landfill waste has also been studied. The temporal fluctuation results showed that when heat is produced, transmitted, and lost throughout the waste system, the maximum temperature position fluctuates over time. The findings of this study highlight the critical importance of landfill management in reducing groundwater contamination from MSW leachate. [ABSTRACT FROM AUTHOR]

Landfill leachate contributes to groundwater pollution. The Permeable Reactive Barrier (PRB) is a sustainable in-situ method to remediate groundwater. Finding cost-effective and efficient reactive materials is a key problem with PRBs. Hence, the present study aimed to assess the applicability of two composite reactive media beds derived from several waste materials (building waste, sludge, sea sand, iron particles, bagasse, saw dust, bio char, fly ash and coconut coir pith) for PRBs to treat groundwater contaminated by landfill leachate. The study comprised two identical laboratory-scale PRB reactors: an experimental reactor and a control reactor. Each reactor included two reactive media beds in series. In the experimental reactor, one of the two beds was filled with a composite reactive media derived from waste materials with high particle densities, while the other was filled with waste materials of low particle densities. In contrast, both the beds of the control reactor were filled with Granular Activated Carbon (GAC). The experimental PRB demonstrated removal rates of 97.08 ± 0.11% (Pb), 65.01 ± 2.14% (Mn), 55.03 ± 1.06% (Fe) and 78.34 ± 1.58% (COD). The control reactor achieved removal rates of 99.26 ± 0.08% (Pb), 94.46 ± 1.13% (Mn), 80.23 ± 0.93%(Mn) and 98.83 ± 0.14% (COD). The shear strength reductions were 19%, 27%, and 11% for the high-density, low-density, and GAC beds, respectively. The associated reductions in hydraulic conductivity were 24%, 12%, and 35%. The waste-derived reactive media possess multiple properties sourced from different materials and can address the removal of multiple contaminants simultaneously, comparable to GAC. [ABSTRACT FROM AUTHOR]

Construction waste is unavoidable in the process of urban development, causing serious environmental pollution. Accurate assessment of municipal construction waste generation requires building construction waste identification models using deep learning technology. However, this process requires high-quality public datasets for model training and validation. This study utilizes Google Earth and GF-2 images as the data source to construct a specific dataset of construction waste landfills in the Changping and Daxing districts of Beijing, China. This dataset contains 3,653 samples of the original image areas and provides mask-labeled images in the semantic segmentation domains. Each pixel within a construction waste landfill is classified into 4 categories of the image areas, including background area, vacant landfillable area, engineering facility area, and waste dumping area. The dataset contains 237,115,531 pixels of construction waste and 49,724,513 pixels of engineering facilities. The pixel-level semantic segmentation labels are provided to quantify the construction waste yield, which can serve as the basic data for construction waste extraction and yield estimation both for academic and industrial research. [ABSTRACT FROM AUTHOR]

The research aimed to determine the influence of endophytic fungi on tolerance, growth and phytoremediation ability of Prosopis juliflora in heavy metal–polluted landfill soil. A consortium of 13 fungal isolates as well as Prosopis juliflora Sw. DC was used to decontaminate heavy metal–polluted landfill soil. Enhanced plant growth (biomass and root and shoot lengths) and production of carotenoids, chlorophyll and amino acids l-phenylalanine and l-leucine that are known to enhance growth were found in the treated P. juliflora. Better accumulations of heavy metals were observed in fungi-treated P. juliflora over the untreated one. An upregulated activity of peroxidase, catalase and ascorbate peroxidase was recorded in fungi-treated P. juliflora. Additionally, other metabolites, such as glutathione, 3,5,7,2′,5′-pentahydroxyflavone, 5,2′-dihydroxyflavone and 5,7,2′,3′-tetrahydroxyflavone, and small peptides, which include Lys Gln Ile, Ser Arg Ala, Asp Arg Gly, Arg Ser Ser, His His Arg, Arg Thr Glu, Thr Arg Asp and Ser Pro Arg, were also detected. These provide defence supports to P. juliflora against toxic metals. Inoculating the plant with the fungi improved its growth, metal accumulation as well as tolerance against heavy metal toxicity. Such a combination can be used as an effective strategy for the bioremediation of metal-polluted soil. [ABSTRACT FROM AUTHOR]

The Anaerobic Baffled Reactor (ABR) is an effective solution for landfill leachate treatment using an anaerobic fermentation process, which helps to reduce operating costs and sludge volume. To better understand the biological, chemical, and physical processes involved, especially when combining the ABR with an aerobic component, the study aimed to investigate the performance of an Anaerobic–Aerobic Hybrid Baffled Reactor (AABR) that includes an Anaerobic Filter (AF) for treating landfill leachate. This research utilized two glass reactors. The first reactor, designated as AABR-AF, consisted of six independent rectangular glass chambers arranged side by side. The third and sixth chamber designed for aerobic treatment and AF, respectively. The second reactor was used as a control reactor and did not include any aerobic chamber. The highest Removal Efficiencies (REs) for turbidity, COD, BOD, TP, TKN, nitrate, TOC, and TSS in the AABR-AF and ABR-AF were found to be (65.4% and 56.3%), (98.3% and 94.1%), (98.1% and 93.2%), (86.4% and 65%), (89.2% and 76.7%), (81.2% and 64.4%), (88.2% and 79.4%), and (72.4% and 68.5%), respectively. These optimal REs were achieved at an HRT of 48 h and an OLR of 10 kg/m3.d. Also, the highest and the lowest REs in Heavy Metals (HMs) were 89.57% for manganese in AABR-AF and 6.59% for nickel in ABR-AF, in an OLR of 10 kg/m3.d, respectively. The effective removal of Organic Matters (OMs) from landfill leachate using the AABR-AF and ABR-AF was found to be strongly influenced by HRT and OLR. The AABR-AF configuration, featuring a single aerobic chamber in the reactor, exhibited a higher efficiency in removing OMs compared to the ABR-AF configuration. [ABSTRACT FROM AUTHOR]

Clay liners have been widely used in landfill engineering. However, large-scale clay excavation causes secondary environmental damage. This study investigates the feasibility of replacing clay liners with high-density polyethylene (HDPE) geomembranes with different specifications and parameters. Laboratory interface shear tests between municipal solid waste (MSW) samples of different ages and geomembranes were conducted to study the influence of landfill age on interface shear strength. Finite element method was adopted to compare the long-term stability of landfills with HDPE geomembrane versus clay as intermediate liner. The interfacial shear test results show that the cohesion of MSW increases in a short term and then decreases with landfill age. The internal friction angle exhibits an increasing trend with advancing age, however, the rate of its increment declines with age. The rough accuracy of the film surface can increase the interfacial shear strength between MSW. The simulation results show that, unlike clay-lined landfills, the sliding surface of geomembrane-lined landfills is discontinuous at the lining interface, which can delay the penetration of slip surfaces and block the formation of slip zone in the landfill. In addition, the maximum displacement of landfills with geomembrane is 10% lower than that with clay, and the absolute displacement of slope toe decreases with the increase of roughness at the interface of geomembrane. Compared with clay-lined landfills, the overall stability safety factor increased by 18.5–30%. This study provides references for landfill design and on-site stability evaluation, contributing to enhanced long-term stability. [ABSTRACT FROM AUTHOR]

Construction and demolition waste (CDW) landfills around the city have caused serious damage to the ecological environment and menaced the public health. Restoration of closed CDW landfills is critical to compensate for the degraded ecosystem and ensure safety in further development and utilization. Vegetation restoration is an essential part of the restoration of CDW landfills, in which the use of spontaneous plants is the foundation of the nature-based strategy. In this study, Fenghuangshan CDW landfill in Suzhou, China, was selected as the research site, and the species composition and diversity of the spontaneous plants were analyzed. Moreover, the types of habitats and growth indexes of 8 species with high frequency and 18 species with medium frequency in the CDW landfill were investigated, and a comprehensive evaluation of growth rate and expansion capacity of the 26 species was conducted. The results showed that, herbs were the main type of the spontaneous plants in the CDW landfill. The species and quantities of the spontaneous plants in the CDW landfill were obviously fewer than those in the surrounding areas of the CDW landfill, and the Shannon–Wiener index and Pielou index of the spontaneous plants were lower compared with the surrounding areas of the CDW landfill. Meanwhile, the differences of dominant families and the distribution of origins, life forms and growth types between these two fields were insignificant. The heliophilous and drought tolerance species were widely distributed in the CDW landfill while the shade-tolerant or hygrophilous species were few. The relatively large comprehensive evaluation indexes of Elymus dahuricus, Daucus carota, Sonchus asper, Geranium carolinianum, Rumex acetosa, Metaplexis japonica, Carex breviculmis, Erigeron canadensis, Trigonotis peduncularis, Lamium amplexicaule reflected their high growth rates and strong expansion capacity, demonstrating their great potentiality in the vegetation restoration of CDW landfills as indispensable components of the nature-based solution. [ABSTRACT FROM AUTHOR]

Landfills are associated with significant environmental problems that pose serious concerns to the environment due to the continuous emission of methane and other greenhouse gases. This study uses the ZODM, FODM, MTM, and six simulations in the LandGEM-V-3.03 model to estimate and predict the methane emissions from the Rajbandh landfill in Khulna city. The predicted average emissions from 2000 to 2036 demonstrate remarkably close emissions (2.14–2.97 Gg/year) from FODM, MTM, and three LandGEM-V-3.03 simulations (site-specific SP, CAAA, and IC). This study compares the output and underlying assumptions of each model and suggests the FODM and LandGEM SP simulations can be suitable for estimating methane emissions in the conditions of Khulna. In addition, this study also investigated the feasibility of electricity generation using emitted methane at the landfill site. It reveals that the Rajbandh landfill holds the economically viable potential to establish a 1 MW power plant without subsidy. The total environmental lifetime benefits from this electricity generation project are estimated to reduce 0.563 MMTCO2-eq emissions. The outcome of this study may apply to other Bangladeshi landfills and improve waste management planning and energy security. [ABSTRACT FROM AUTHOR]

Globally, more than 2 billion tonnes of municipal solid waste (MSW) are generated each year, with that amount anticipated to reach around 3.5 billion tonnes by 2050. On a worldwide scale, food and green waste contribute the major proportion of MSW, which accounts for 44% of global waste, followed by recycling waste (38%), which includes plastic, glass, cardboard, and paper, and 18% of other materials. Population growth, urbanization, and industrial expansion are the principal drivers of the ever-increasing production of MSW across the world. Among the different practices employed for the management of waste, landfill disposal has been the most popular and easiest method across the world. Waste management practices differ significantly depending on the income level. In high-income nations, only 2% of waste is dumped, whereas in low-income nations, approximately 93% of waste is burned or dumped. However, the unscientific disposal of waste in landfills causes the generation of gases, heat, and leachate and results in a variety of ecotoxicological problems, including global warming, water pollution, fire hazards, and health effects that are hazardous to both the environment and public health. Therefore, sustainable management of MSW and landfill leachate is critical, necessitating the use of more advanced techniques to lessen waste production and maximize recycling to assure environmental sustainability. The present review provides an updated overview of the global perspective of municipal waste generation, composition, landfill heat and leachate formation, and ecotoxicological effects, and also discusses integrated-waste management approaches for the sustainable management of municipal waste and landfill leachate. [ABSTRACT FROM AUTHOR]

This study comprehensively explores the compaction and compressibility characteristics of snail shell ash (SSA) and ground-granulated blast-furnace slag (GBFS) in stabilizing local bentonite for landfill baseliner applications. The untreated soil, with a liquid limit of 65%, plastic limit of 35%, and plasticity index of 30%, exhibited optimal compaction at a moisture content of 32% and a maximum dry density of 1423 kg/m3. SSA revealed a dominant presence of 91.551 wt% CaO, while GBFS contained substantial 53.023 wt% SiO2. Treated samples with 20% GBFS and 5% SSA exhibited the highest maximum dry density (1561 kg/m3) and optimal moisture content (13%), surpassing other mixtures. The 15% SSA-treated sample demonstrated superior strength enhancement, reaching an unconfined compressive strength of 272.61 kPa over 28 days, while the 10% GBFS-treated sample achieved 229.95 kPa. The combination of 15% SSA exhibited the highest shear strength (49 kPa) and elastic modulus (142 MPa), showcasing robust mechanical properties. Additionally, the 15% SSA sample displayed favourable hydraulic conductivity (5.57 × 10–8 cm/s), outperforming other mixtures. Notably, the permeability test, a critical aspect of the study, was meticulously conducted in triplicate, ensuring the reliability and reproducibility of the reported hydraulic conductivity values. Treated samples with SSA and GBFS showed reduced compressibility compared to the control soil, with the 15% SSA-treated sample exhibiting a more consistent response to applied pressures. Scanning Electron Microscopy analysis revealed substantial composition changes in the 15% SSA mixture, suggesting its potential as an effective base liner in landfill systems. In conclusion, the 15% SSA sample demonstrated superior mechanical properties and hydraulic conductivity, presenting a promising choice for landfill liner applications. [ABSTRACT FROM AUTHOR]

In Switzerland, municipal solid waste incineration bottom ash is deposited in open landfills, which leads to its interaction with rainwater and thus the formation of a polluted leachate. This study attempts to provide a better understanding of the hydraulic and geochemical properties of bottom ash landfills by combining field and laboratory investigations. The results show that a bottom ash landfill can be described as a generally unsaturated body with several layers of different grain sizes. Three different water domains with variable hydraulic and geochemical properties were identified in the landfill: (1) zones of preferential flow, (2) a reservoir of mobile porewater, and (3) an immobile porewater reservoir. Preferential flow systems account for approximately 5–10 vol.%. The landfill layering is primarily responsible for the formation of various flow systems during heavy rainfall events. The domains and reservoirs provide variable volumetric contribution to the leachate, depending on precipitation rates and duration of dry periods. Sampling of leachate during heavy rainfall events revealed dilution effects for Na (− 59–61% compared to concentrations prior to the event), Ca (− 44–47%), Cl (− 57–77%), and SO4 (− 35–47%), while pH (+ 7–8%) and concentrations of Al (+ 368–1416%), Cu (+ 7–58%), Cr (+ 29–48%), V (+ 100–118%), and Zn (+ 289%) increased significantly. The findings of this study serve as a basis for the development of a hydrogeochemical model of a bottom ash landfill, which allows better prediction of the future evolution of leachate quality. [ABSTRACT FROM AUTHOR]

Cracking behavior can reduce soil hydraulic and mechanical properties and is a preferential pathway for water flow and pollutant transportation, resulting in polluted environment, such as application to landfill liners and capping. Recently, researchers have advocated the use of waste materials for clay mixtures using various measurement and analysis methods. Therefore, this study aims to conduct a bibliometric analysis of the scientific literature published between 2002 and 2021 obtained from Scopus to quantitatively identify research trends, key research areas, and future research paths in this field on desiccation and crack behavior using waste materials as landfill liners. The VOS viewer software was used to analyze 41 articles in which the paper selection process was filtered. The results showed that the fly ash mixture's application as a landfill liner could reduce cracking significantly. Furthermore, fractal analysis and X-ray computed tomography measurements have proven to be good candidates for measuring cracks because they are the most accurate for calculating the crack value. Waste materials such as fly ash can be applied as landfill liners with other materials, such as bentonite and coconut coir fibers. This study is beneficial for improving the design and selecting the appropriate materials for landfill liners. [ABSTRACT FROM AUTHOR]