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Emerging contaminants (ECs) present a significant risk to both the ecological environment and human health. Landfill leachate (LL) often contains elevated EC levels, posing a potential risk to localized groundwater. This study aimed to characterize ECs in municipal solid waste landfills (MSWLs) and hazardous waste landfills (HWLs) in northeast (NE) China. One and three HWLs and MSWLs in NE China with varying types, operational years, and impermeable layers were selected as case studies, respectively. Statistical analysis of 62 indicators of nine ECs in leachate and the groundwater environment indicated the presence of perfluorinated compounds (PFCs), antibiotics, alkylphenols (APs), and bisphenol A (BPA). The leachates of the four landfills exhibited elevated concentrations of ECs of 21.03 μg/L, 40.04 μg/L, 14.54 μg/L, and 43.05 μg/L for PFCs, antibiotics, Aps, and BPA, respectively. There was a positive correlation between the highest concentrations of ECs in groundwater and those in leachate as well as with operational duration of the landfill; in contrast, groundwater EC was negatively correlated with the degree of impermeability. This study can guide future management of ECs in landfills and hazardous waste sites in China, particularly in NE China. [ABSTRACT FROM AUTHOR]

Effective management of urban solid waste in the Metropolitan Region of Belém, State of Pará, Brazil is essential for conserving ecosystems and public health in eight cities, emphasizing the municipality of Marituba. Considering the vulnerability of underground water resources in Marituba to pollution due to the possible impact of leachate percolation from the landfill, this study evaluates the quality of groundwater captured in tubular wells from different adjacent locations potentially used for human consumption. For this purpose, the systematic methodologies of the groundwater quality index and human health risk assessment analysis: non-carcinogenic and carcinogenic risk to human health were used based on chronic daily intake of heavy metals by consumption and dermal adsorption of groundwater, measured through risk quotients, risk index, and incremental lifetime cancer risk. To evaluate the interrelationships of pollutants, analysis of variance, hierarchical cluster analysis, and principal component analysis were used based on the spatio-temporal quantification of pH, temperature, electrical conductivity, As, Al, Ba, Co, Cd, Cu, Cr, Fe, Hg, Ni, Pb, Sb, Se, U, and Zn. Residents of the study area are not at potential risk, as the results demonstrate that groundwater is within the potability standards of Brazilian legislation, except for aluminum concentrations, which ranged from 53.12 to 378.01 μg L−1 and 3.82 to 339.5 μg L−1 in the dry and rainy seasons, respectively, exceeding the established limit of 200.0 μg L−1. The quality index for groundwater and the heavy metal pollution index demonstrated that groundwater has good drinking quality with low metal contamination. The risk was considered low at all sampling sites in the non-carcinogenic risk assessment. Principal component analysis indicated that the sources of metal pollution are natural origins and anthropogeny. In this sense, they become worried because aluminum is a recognized neurotoxicant that can interfere with the central nervous system's critical physiological and biochemical processes. Furthermore, despite complying with potability standards, trace concentrations of highly toxic metals such as As, Pb, Cd, and Ni may indicate initial contamination by landfill leachate. [ABSTRACT FROM AUTHOR]

The reuse of waste materials has recently become appealing due to pollution and cost reduction factors. Using waste materials can reduce environmental pollution and product costs, thus promoting sustainability. Approximately 95% of calcium carbonate-containing waste eggshells end up in landfills, unused. These eggshells, a form of bio-waste, can be repurposed as catalytic electrode material for various applications, including supercapacitors, after being converted into CaO. Similarly, used waste battery electrode materials pose environmental hazards if not properly recycled. Various types of batteries, particularly lithium-ion batteries, are extensively used worldwide. The recycling of used lithium-ion batteries has become less important considering its low economic benefits. This necessitates finding alternative methods to recover and reuse the graphite rods of spent batteries. Therefore, this study reports the conversion of waste eggshell into calcium oxide by high-temperature calcination and extraction of nanographite from spent batteries for application in energy storage fields. Both CaO and CaO/graphite were characterized for their structural, morphological, and chemical compositions using XRD, SEM, TEM, and XPS techniques. The prepared CaO/graphite nanocomposite material was evaluated for its efficiency in electrochemical supercapacitor applications. CaO and its composite with graphite powder obtained from used lithium-ion batteries demonstrated improved performance compared to CaO alone for energy storage applications. Using these waste materials for electrochemical energy storage and conversion devices results in cheaper, greener, and sustainable processes. This approach not only aids in energy storage but also promotes sustainability through waste management by reducing landfills. [ABSTRACT FROM AUTHOR]

This study investigates the process of long-term (bio)degradation of polyethylene (PE) in an old municipal waste landfill (MWL) and its implications for environmental and human health. Advanced techniques, such as ICP–ES/MS and IC–LC, were used to analyze heavy metals and anions/cations, demonstrating significant concentration deviations from control samples. The soil's chemical composition revealed numerous hazardous organic compounds, further indicating the migration of additives from PE to the soil. Toxicological assessments, including Phytotoxkit FTM, Microtox® bioassay, and Ostracodtoxkit®, demonstrated phytotoxicity, acute toxicity, and high mortality in living organisms (over 85% for Heterocypris Incongruens). An unusual concentration of contaminants in the MWL's middle layers, linked to Poland's economic changes during the 1980s and 1990s, suggests increased risks of pollutant migration, posing additional environmental and health threats. Moreover, the infiltration capability of microorganisms, including pathogens, into PE structures raises concerns about potential groundwater contamination through the landfill bottom. This research underscores the need for vigilant management and updated strategies to protect the environment and public health, particularly in older landfill sites. [ABSTRACT FROM AUTHOR]

This article presents a methodology for evaluating the susceptibility of landfill areas to develop landslides by analyzing Synthetic Aperture Radar (SAR) satellite products. The deformation velocity of the landfills is computed through the Persistent Scatterer Method on SAR imagery. These data, combined with a deformation model based on the shallow water equations (SWE), form the foundation for a Monte Carlo experiment that extrapolates the current state of the landfill into the future. The results of this simulation are then employed to determine the probability of a landslide occurrence. In order to validate the methodology effectiveness, a case study is conducted on a landfill in Zaldibar, Spain, revealing its effectiveness in estimating the probability of landfill landslides. This innovative approach emerges as an asset in large landfill management, acting as a proactive tool for identifying high-risk sites and preventing potential landslides, ultimately safeguarding human life and the environment. By providing insights into landslide probabilities, this study enhances decision-making processes and facilitates the development of intervention strategies in the domain of landfill risk assessment and management. [ABSTRACT FROM AUTHOR]

This paper investigates the optimal remediation process in an aquifer using Modflow 6 software and genetic algorithms. A theoretical confined aquifer has been polluted over a long period of time by unnoticed leakage in a pipeline conveying leachate from an adjacent landfill to a wastewater treatment plant. When the extended leakage and groundwater pollution are discovered, the optimal planning of the remediation strategy is investigated using the pump-and-treat method or/and hydrodynamic control of the pollution. The practical goal is to find the optimal locations and flow rates of two additional pumping wells, which will pump the polluted water or/and control pollution, protecting an existing drinking water pumping well, securing its fully operational mode even during the remediation process with the minimum possible cost, simply represented by the pumped water volume of the additional wells. The remediation process is considered complete when the maximum concentration in the aquifer drops below a certain limit. The Modflow software (handled by the Flopy Python package) simulates the flow field and advective–dispersive mass transport, and a genetic algorithm is used as the optimization tool. The coupled simulation–optimization model, Modflow-GA, complemented by a sophisticated post-processing results analysis, provides optimal and alternate sub-optimal remediation strategies for the decision makers to select from. [ABSTRACT FROM AUTHOR]

This article presents the results of the study of the morphological composition of municipal solid waste (MSW) from the landfill of Atyrau city, and the waste's energy characteristics and presence of microorganisms, including bacteria, fungi and viruses. This study was carried out under a government order to determine the feasibility of recycling accumulated and incoming waste into electricity and its hazard to the environment and the workers involved in handling it. At the moment, there is no MSW recycling in Kazakhstan, which has led to the accumulation of more than 125 million tons of waste with an annual increase of 5 million tons. The research included four major cities (Almaty, Shymkent, Atyrau and Astana), which were selected not only on the basis of population, but also because the cities were located in different climatic zones. Samples were collected at the city landfills: 10 samples with an average distance of 100 m from each other were collected to provide a maximum coverage of both recently received waste and long-time stored waste. The research showed that neither climatic conditions nor the population size had a significant impact on MSW density, the values of which ranged from 120.1 kg/m3 to 145.4 kg/m3, as this indicator directly depends on the quality of life. The mass of the combustible fraction ranged from 39.41% to 54.62% and was mainly represented by plastic, textile and paper waste. The average value for the four cities was 50.30%. The higher calorific value fell in the range of 24.22–30.49 MJ/kg, with an average value of 26.71 MJ/kg. Microbiological studies showed little difference in average composition regardless of climatic conditions. Thus, no sharp differences in MSW composition, its energy characteristics and microbiological composition were found. The results of this study may be useful for optimising MSW recycling and disposal processes, as well as for developing measures to reduce their negative impact on the environment and human health. [ABSTRACT FROM AUTHOR]

This paper investigates the advantages of enhancing construction and demolition waste (CDW) recycling facilities to conform to circular economy (CE) models in Kazakhstan's construction sector. The industry is experiencing significant growth due to urbanization, but it faces difficulties managing CDW, frequently resulting in landfill disposal. In response, this paper provides a cost–benefit analysis of upgrading the CDW recycling centres aligned with CE needs. Reflecting legislative changes in Kazakhstan's Environmental Code, which prohibited CDW in landfills starting December 2020, the initiative to establish modern CDW recycling centres is gaining momentum in major cities. The primary objective is to maximize material recovery and eliminate contaminants that curtail the utilization of recycled sand and aggregate products. The analysis yields compelling results, indicating that the project has the potential to recycle up to 84 million tons of CDW over eight years, with an annual 25% capacity increase and a maximum possible 95% recycling efficiency. Despite an estimated cost of USD 48 million, the project demonstrates a payback period of 9.9 years, signalling eventual cost recovery. These findings underscore the project's capacity to mitigate CDW issues while generating economic benefits and contributing to a sustainable environment. In conclusion, implementing modern CDW recycling centres in Kazakhstan represents a potent solution for the construction industry as it transitions toward a CE model. This transition addresses both pressing environmental challenges and promising economic prospects. [ABSTRACT FROM AUTHOR]

Carbon containing waste has a certain calorific value and utilization value due to the presence of carbon elements. However, the current treatment methods are mostly traditional landfill disposal, incineration, or expensive physical and chemical reaction methods, which clearly do not comply with the rules of the current clean and resource-saving society. In this paper, a new technology and system for carbon containing wastes is proposed, which comprehensively treats and recycles carbon containing wastes, including solid waste, wastewater, waste gas, etc., using pyrolysis–gasification two-stage-cycle technology. The calculation results indicate that the technical scheme proposed in this article is feasible and can achieve the recycling of intermediate and final products, the efficient and clean utilization of carbon containing waste, and the graded utilization of energy. The clean utilization rate of carbon containing waste can be effectively improved, the energy consumption and cost of separate treatments can be reduced, and zero waste emissions can be completely achieved by the comprehensive pyrolysis–gasification two-stage-cycle treatment and resource utilization technology, which is one of the preferred solutions for future resource-saving societies. [ABSTRACT FROM AUTHOR]

During adaptation to waters that are rich in xenobiotics, biological systems pass through multiple stages. The first one is related to the restructuring of communities, pronounced destruction of the structure, and multiplication of active biodegradants. The purpose of the present research was to describe the microbiome restructuring that occurs during the adaptation stage in landfill leachate treatment. In a model SBR (sequencing batch reactor), a 21-day purification process of landfill leachate was simulated. Wastewater was fed in increasing concentrations. When undiluted leachate entered, the activated sludge structure disintegrated (Sludge Volume Index—4.6 mL/g). The Chemical Oxygen Demand and ammonium nitrogen concentration remained at high values in the influent (2321.11 mgO2/L and 573.20 mg/L, respectively). A significant amount of free-swimming cells was found, and the number of aerobic heterotrophs and bacteria of the genera Pseudomonas and Acinetobacter increased by up to 125 times. The Azoarcus-Thauera cluster (27%) and Pseudomonas spp. (16%) were registered as the main bacterial groups in the activated sludge. In the changed structure of the microbial community, Gammaproteobacteria, family Rhizobiaceae, class Saccharimonadia were predominantly represented. Among the suspended bacteria, Microbactericeae and Burkholderiaceae, which are known for their ability to degrade xenobiotics, were present in larger quantities. The enzymological analysis demonstrated that the ortho-pathway of cleavage of aromatic structures was active in the community. The described changes in the leachate-purifying microbial community appear to be destructive at the technological level. At the microbiological level, however, trends of initial adaptation were clearly outlined, which, if continued, could provide a highly efficient biodegradation community. [ABSTRACT FROM AUTHOR]

The accurate classification of landfill waste diversion plays a critical role in efficient waste management practices. Traditional approaches, such as visual inspection, weighing and volume measurement, and manual sorting, have been widely used but suffer from subjectivity, scalability, and labour requirements. In contrast, machine learning approaches, particularly Convolutional Neural Networks (CNN), have emerged as powerful deep learning models for waste detection and classification. This paper analyses VGG-16, InceptionResNetV2, DenseNet121, Inception V3, and MobileNetV2 models to classify real-life waste when trained on pristine and unadulterated materials, versus samples collected at a landfill site. When training on DiversionNet, the unadulterated material dataset with labels required for landfill modelling, classification accuracy was limited to 49.69% in the real environment. Using real-world samples in the newly formed RealWaste dataset showed that practical applications for deep learning in waste classification are possible, with Inception V3 reaching 89.19% classification accuracy on the full spectrum of labels required for accurate modelling. [ABSTRACT FROM AUTHOR]

The global surge in urbanization and population growth has led to a significant increase in municipal solid waste generation, posing a considerable challenge in identifying suitable landfill sites. This study proposes a novel framework that enhances landfill site monitoring and assessment by combining GIS-based hierarchical analytical processes with a fuzzy inference system (FIS). The study employs a systematic approach involving phases such as feature selection, spatial analysis, criteria weighting, FIS building, and a case study conducted in São Paulo State, Brazil. The proposed framework effectively assesses landfill suitability and offers practical recommendations for landfill management and future site selection. This framework provides actionable recommendations for landfill monitoring and assessment, supporting landfill management while minimizing environmental and social impacts. It offers a comprehensive approach to landfill assessment, enhancing the sustainability of waste management practices. Further research can improve the proposed framework by refining feature selection and incorporating real-time data for continuous monitoring. Additionally, exploring the integration of emerging technologies, such as remote sensing and artificial intelligence, can further enhance landfill site monitoring and assessment. [ABSTRACT FROM AUTHOR]

Landfilling and incineration are the most widely used methods for the management and treatment of fruit and vegetable waste (FVW) in Mediterranean markets, despite their potential environmental impact. A comparative life cycle assessment was conducted in this study to evaluate the environmental improvements from replacing the current landfill disposal method for FVW management and treatment in the wholesale market of Amman (Jordan) with an integrated anaerobic digestion process followed by composting. The proposed FVW treatment scenario is the best treatment option for all the assessed impact categories under the system expansion approach. Significant reductions in global warming and terrestrial ecotoxicity impacts categories would be achieved, reaching up to 322% and 352%, respectively, when compared to the current treatment scenario. Furthermore, the higher production of electrical energy (413%), as well as the production of co-products that would avoid the production of 100 kg/d of inorganic fertilizers, would contribute to such a low value of avoided impacts. [ABSTRACT FROM AUTHOR]

Simple Summary: Food availability plays a significant role in modulating populations, especially in species relying on human-generated food sources like landfills. Sudden changes in food access can negatively impact vital parameters such as survival. For long-lived scavenger species, understanding how different age groups respond to these changes is essential since landfills are condemned to be closed. We studied the response in terms of apparent survival of griffon vultures to a decline in landfill organic matter after a waste treatment center became operational. The proportion of transients increased in all age groups. Survival dropped in juveniles and adult residents but increased in immature residents. These findings suggest that vultures permanently emigrated at higher rates due to intensified competition after the reduction in food. Intriguingly, immature resident vultures showed resilience, indicating the presence of high-quality individuals despite the food scarcity. The reasons behind reduced survival in adult residents during the final four study years remain unclear but are potentially linked to non-natural mortality. This research highlights the challenges facing scavengers as European landfill sites close, thereby stressing the need for food scarcity studies and timely conservation measures. Food availability shapes demographic parameters and population dynamics. Certain species have adapted to predictable anthropogenic food resources like landfills. However, abrupt shifts in food availability can negatively impact such populations. While changes in survival are expected, the age-related effects remain poorly understood, particularly in long-lived scavenger species. We investigated the age-specific demographic response of a Griffon vulture (Gyps fulvus) population to a reduction in organic matter in a landfill and analyzed apparent survival and the probability of transience after initial capture using a Bayesian Cormack-Jolly-Seber model on data from 2012–2022. The proportion of transients among newly captured immatures and adults increased after the reduction in food. Juvenile apparent survival declined, increased in immature residents, and decreased in adult residents. These results suggest that there was a greater likelihood of permanent emigration due to intensified intraspecific competition following the reduction in food. Interestingly, resident immatures showed the opposite trend, suggesting the persistence of high-quality individuals despite the food scarcity. Although the reasons behind the reduced apparent survival of resident adults in the final four years of the study remain unclear, non-natural mortality potentially plays a part. In Europe landfill closure regulations are being implemented and pose a threat to avian scavenger populations, which underlines the need for research on food scarcity scenarios and proper conservation measures. [ABSTRACT FROM AUTHOR]

Limited information is available in the literature regarding the energy consumption and the greenhouse gases emitted during landfill leachates treatment. A full-scale landfill leachates treatment system that included primary sedimentation, biological treatment in sequencing batch reactors, reverse osmosis and mechanical vapor recompression evaporation was monitored and evaluated for the removal of major pollutants, energy consumption and greenhouse gas emissions. Samples were taken during a period of two years from different points of the system, while the actual power consumption was calculated considering the available mechanical equipment and the hours of operation. The quantities of greenhouse gases emitted were estimated using appropriate equations and based on the operational characteristics of the system. According to chemical analyses, biological treatment resulted in partial removal of COD and total nitrogen, while the removal of BOD5 and NH4-N was significant, reaching 90 and 98%, respectively. Use of reverse osmosis increased the removal of all pollutants, satisfying the requirements of the legislation on wastewater discharge into the environment. Power consumption was calculated to be 35.3 KWhr per m3 of treated leachate, while mechanical vapor recompression evaporation was responsible for 60.5% of the total energy required. The contribution of other processes to energy consumption was as follows, in decreasing order: sequencing batch reactors > reverse osmosis > primary treatment. The roots blower vacuum pump used for mechanical vapor recompression evaporation, and the blowers providing air to the sequencing batch reactors, were the most energy-intensive pieces of apparatus, contributing 44.2% and 11.3% of the required energy, respectively. The quantity of greenhouse gases emitted was estimated to be 27.7 Kg CO2eq per m3 of treated leachates. Among the different processes used, biological treatment and mechanical vapor recompression evaporation contributed to 45.7% and 44.1% of the total emissions, respectively. The findings of this study reveal that an integrated landfill leachate treatment system that combines biological treatment and reverse osmosis can assure the protection of the aquatic environment by producing high-quality effluent; however, further research should be conducted regarding the sustainable management of reverse osmosis concentrate. Mechanical vapor recompression evaporation contributes significantly to the environmental footprint of the landfill leachates treatment system due to both high energy consumption and elevated emissions of greenhouse gases. [ABSTRACT FROM AUTHOR]

This study evaluated the feasibility of ionizing radiation combined with coagulation–sedimentation and Fenton oxidation as a treatment method for landfill leachate. The experiments revealed a positive correlation between pollutant removal efficiency and increased ionizing radiation intensity. Remarkable pollutant removal efficiencies were achieved under ionizing radiation at 50 kGy, with a maximum of 27% removal of total organic carbon (TOC), 61% removal of total nitrogen, 51% removal of total phosphorus, and an impressive 93% removal of NO3−-N. With the addition of coagulation–sedimentation and Fenton oxidation, the treatment efficiency further increased by 33% nitrogen, 18% SCOD, and 8% phosphate. The most significant observation from the study was that for all the different treatment methods, the results were always better for leachate samples treated with ionizing radiation than for the untreated samples. Subsequently, biological treatment was applied as a post-treatment method to remove residual organic carbon and nitrogen, which found that the best removal efficiencies were only for the low salt concentration (0.5%) and the removal decreased with increasing salt concentration. These experimental results conclusively demonstrated that when treating leachate wastewater, it was more appropriate to employ physicochemical methods rather than a biological treatment, primarily due to the high salt concentration present. [ABSTRACT FROM AUTHOR]

Landfill leachate is regarded as a significant point source of pollutants that may pose a hazard to the environment, particularly to surface and ground waters. Leachates are highly variable and heterogeneous. Our study was focused on the characterization of landfill leachates derived from young (YDS) and matured (MDS) dumpsites in terms of the abundance of micropollutants, antimicrobial resistance genes (ARG), and microbial community structure. The concentrations of poly- and perfluoroalkyl substances (PFASs) were found to be higher in MDS compared to YDS, i.e., 13.19 and 7.16 μg/L, respectively. Among pharmaceutical compounds, ibuprofen was detected at the highest concentrations, i.e., 12.54, 12.81, and 13.13 μg/L, in the leachates derived from MDS, YDS, and ponds. The distribution of bacteria, archaea, eukaryotes, and viruses in the three leachate samples was as follows: 85.15 ÷ 88.04%, 9.13 ÷ 12.29%, 2.20 ÷ 2.68%, and 0.12 ÷ 0.15%, respectively. In total, 31 distinct families of ARGs were identified, comprising a total of 80 ARGs. Incubation of P. putida MSCL650 in sterile leachate from the pond resulted in decreasing the minimum inhibitory concentrations for six antibiotics as compared to cells incubated in nutrient broth. Hydrological processes, i.e., runoff and infiltration, can increase the dissemination of ARGs. [ABSTRACT FROM AUTHOR]

The leachate generated from a landfill can cause significant harm to the environment and human health, so it must be treated before being discharged. A biochemical method is effective to treat the landfill leachate, but it requires a physicochemical pretreatment to help reduce the organic load and improve the biodegradability of the landfill leachate. In this work, hydrodynamic cavitation was used to pretreat the landfill leachate due to it being cost-effective, without additional chemicals, and environmentally friendly. The pretreatment experiments were conducted under an inlet pressure of 0.4 MPa and a basic pH. The influence of operating parameters such as the orifice opening rate, the arrangement of orifices, and the reaction time on the chemical oxygen demand, ammonium nitrogen, and biochemical oxygen demand removal in landfill leachate was studied, and the energy efficiency was evaluated. The results showed that under the above conditions, the removal rate for the chemical oxygen demand of the orifice plate with an annular orifice arrangement was better than that of the orifice plate with a radiation orifice arrangement, and the orifice plate with an orifice opening rate of 0.0417 had the best effectiveness. The energy efficiency under these two optimization conditions was also the highest. When the optimal operation time was 60 min, the removal rate of the chemical oxygen demand was 22.63%. The biodegradability of the landfill leachate was significantly improved with BOD5/COD increasing by 57.27%. The study provides a theoretical basis and data support for the application of hydrodynamic cavitation as a low-cost and efficient treatment method in the pretreatment of landfill leachate. [ABSTRACT FROM AUTHOR]

Landfill leachate is generated from waste degradation in landfill sites, and its treatment includes biological or combined treatment with physico-chemical methods. A frequently applied technology in the biological stage of landfill leachate treatment plants is based on denitrification and nitrification. Nevertheless, with the availability of a huge number of scientific reports, the management of denitrification and nitrification (D/N) processes in the frame of real wastewater treatment plants (WWTPs) is rather difficult and always remains a critical technological problem. This study aims to perform a comparative assessment between denitrification and nitrification processes during landfill leachate treatment in three different situations in the WWTP of the Municipal Enterprise for Waste Treatment in Sofia City, Bulgaria. The comparative assessment is based on the biotransformation effectiveness of ammonium ions in the course of nitrification and of nitrates in the course of denitrification. Mixed samples (wastewater and activated sludge) were taken from the sequencing batch reactors operating in the mode of denitrification and nitrification. All physico-chemical (pH, dissolved oxygen, organics concentration, BOD5:COD, nitrogen and phosphorous) and biological (sludge volume index, sludge biotic index, quantity of aerobic heterotrophs, denitrifiers and nitrifiers, total dehydrogenase activity) indicators were investigated in the samples from the biobasins in the mode of denitrification and nitrification. The conditions for the implementation of the two processes were compared, along with the state of the activated sludge in the different reactors. The obtained results showed that denitrification was the critical process in the technology on the base of D/N. A major factor that managed the denitrification was the lower concentration of biodegradable organic matter which led to a deformation of the activated sludge structure, a decrease in the count of heterotrophic microorganisms, a decrease in the total activity of the activated sludge and an inhibition of the nitrate reductase activity. The nitrification processes were accomplished with high intensity. The results confirmed that D/N could be optimized and controlled using specific wastewater treatment technology parameters and purposely applied indicators. [ABSTRACT FROM AUTHOR]

This research presents a novel stand-alone device for the autonomous measurement of gas pressure levels on an active landfill site, which enables the real-time monitoring of gas dynamics and supports the early detection of critical events. The developed device employs advanced sensing technologies and wireless communication capabilities, enabling remote data transmission and access via the Internet. Through extensive field experiments, we demonstrate the high sampling rate of the device and its ability to detect significant events related to gas generation dynamics in landfills, such as flare shutdowns or blockages that could lead to hazardous conditions. The validation of the device's performance against a high-end analytical system provides further evidence of its reliability and accuracy. The developed technology herein offers a cost-effective and scalable solution for environmental landfill gas monitoring and management. We expect that this research will contribute to the advancement of environmental monitoring technologies and facilitate better decision-making processes for sustainable waste management. [ABSTRACT FROM AUTHOR]

We analyzed ground subsidence at the coal ash disposal sites of Stanton Energy Center, a power plant located in Orlando, Florida, USA, by applying 157 Sentinel-1 SAR images obtained between May 2017 and December 2022 in ascending orbit to the PSInSAR technique. A LiDAR DEM with 1 m posting was used for the DInSAR and StaMPS processing for PSInSAR. The results showed significant ground subsidence on the area where solar panels were installed on top of the coal ash landfill. The coal ash landfill was divided into three sites (A, B, and C) according to the landfill sequence. The spatially averaged PSInSAR showed subsidence rates of 7.3 mm/year, 6.2 mm/year, and 8.8 mm/year in sites A, B, and C, respectively. In particular, relatively newly deposited sites A and B showed a decreasing trend in subsidence rate with higher quadratic components in regression function, indicating a stabilization of the subsidence. On the other hand, the oldest site C exhibited the highest (and a relatively constant) subsidence rate, suggesting that the settlement occurred earlier and is now at a constant rate. It is also suspected that new dumping activity near C might have caused a higher subsidence rate than in sites A and B. No subsidence occurred at other solar panel installations on the ground outside the landfill, suggesting that the subsidence was caused by the gravitational compaction of the landfill materials rather than by the instability of the solar facilities. Comparison of PSInSAR results with lower resolution DEMs, such as SRTM and Copernicus DEM, showed range errors of the PS positions proportional to the height deviation from LiDAR DEM, highlighting the importance of accurate DEMs for the time-series analysis of SAR data. [ABSTRACT FROM AUTHOR]

High-strength wastewaters from a variety of sources, including the food industry, domestic septage, and landfill leachate, are often hauled to municipal wastewater treatment plants (WWTPs) for co-treatment. Due to their high organic loadings, these wastewaters can cause process upsets in both a WWTP's liquid and solids treatment trains and consume organic treatment capacity, leaving less capacity available to service customers in the catchment area. A novel pre-treatment method, the Waste Activated Sludge-High Rate (WASHR) process, is proposed to optimize the co-treatment of high-strength wastewaters. The WASHR process combines the contact stabilization and sequencing batch reactor processes. It utilizes waste activated sludge from a municipal WWTP as its biomass source, allowing for a rapid start-up. Bench-scale treatment trials of winery wastewater confirm the WASHR process can reduce loadings on the downstream WWTP's liquid and solids treatment trains. A case study approach is used to confirm the economic viability and environmental sustainability of the WASHR process compared to direct co-treatment, using life-cycle cost analyses and greenhouse gas emissions estimates. [ABSTRACT FROM AUTHOR]

Properly managed urban household waste landfills play a crucial role in achieving sustainable development and ecological civilization. This paper proposes an innovative design method that aims to overcome the limitations and extensive challenges of traditional urban domestic waste landfill design by combining aerial image segmentation with ecological restoration theory. We suggest an enhanced SEVnet, a combination of the basic vnet network and the sequence-and-excitation module, for precise and efficient garbage dump identification. Through this module, the network can independently analyze the significance of each feature channel and provide weights, leading to enhanced image detail recovery and more precise segmentation. We implemented the proposed SEVnet model based on an aerial photography database of urban garbage dumps. Following precise urban garbage disposal site division, we adopt ecological restoration theory to achieve sustainable design. This article presents the Saihanba area in China as a case study, collects pertinent data, and conducts image segmentation and GIS-assisted analysis. This paper examines the landscape application and design of the landfill site based on an analysis and planning of land use in its vicinity. The intervention of landscape ecology imbues the landfill site with new functions. We propose comprehensive planning and landscape restoration design measures from four perspectives, encompassing disadvantages, threats, opportunities, and strengths, using SWOT analysis to better integrate the Hebei Saihanba landfill site with the surrounding environment. This paper introduces a groundbreaking design scheme for a landfill that aligns with the principles of current green and sustainable development. [ABSTRACT FROM AUTHOR]

Groundwater contamination due to municipal solid waste landfills' leachate is a serious environmental threat. Deuterium (2H) and oxygen (18O) isotopes have been successfully applied to identify groundwater contamination processes, due to interactions with municipal solid waste landfills' leachate, including significant organic amounts. A parameter influencing the isotope content of deuterium and oxygen18 is the deuterium excess (d or d-excess). This paper presents a d-isotope-based model, defined early-warning model, depending on the assessment of the deuterium excess variations in groundwater samples. The isotopic results are corroborated with the trace elements' concentrations (Fe, Mn, Ni, Co and Zn), suggesting that the methanogenic activity diminished under trace element limitation. This model provides the determination of an index, F, as the percentage variation of d-excess, which makes it possible to define an alert level system to assess and check groundwater contamination by leachate. The procedure shows that values of F index higher than 1.1 highlight possible contamination phenomena of groundwater due to leachate and, therefore, actions by the municipal solid waste landfill management are required. This early-warning model is presented by the application to a case study in Central Italy in order to evaluate innovative aspects and opportunities to optimize the model. The application of the procedure to the case study highlighted anomalous values of the F index for the samples AD16 (Fmax = 2.069) and AD13 (Fmax = 1.366) in January, April, July and October surveys as well as the boundary values (1 ≤ F ≤ 1.1) for samples AD73 (F = 1.229) and AD68 (F = 1.219) in the April survey. The proposed model can be a useful management tool for monitoring the potential contamination process of groundwater due to the presence of landfills with municipal solid waste, including a significant organic component. [ABSTRACT FROM AUTHOR]

The likelihood of surface water and groundwater contamination is higher in regions close to landfills due to the possibility of leachate percolation, which is a potential source of pollution. Therefore, proposing a reliable framework for monitoring leachate and groundwater parameters is an essential task for the managers and authorities of water quality control. For this purpose, an efficient hybrid artificial intelligence model based on grey wolf metaheuristic optimization algorithm and extreme learning machine (ELM-GWO) is used for predicting landfill leachate quality (COD and BOD5) and groundwater quality (turbidity and EC) at the Saravan landfill, Rasht, Iran. In this study, leachate and groundwater samples were collected from the Saravan landfill and monitoring wells. Moreover, the concentration of different physico-chemical parameters and heavy metal concentration in leachate (Cd, Cr, Cu, Fe, Ni, Pb, Mn, Zn, turbidity, Ca, Na, NO3, Cl, K, COD, and BOD5) and in groundwater (Cd, Cr, Cu, Fe, Ni, Pb, Mn, Zn, turbidity, EC, TDS, pH, Cl, Na, NO3, and K). The results obtained from ELM-GWO were compared with four different artificial intelligence models: multivariate adaptive regression splines (MARS), extreme learning machine (ELM), multilayer perceptron artificial neural network (MLPANN), and multilayer perceptron artificial neural network integrated with grey wolf metaheuristic optimization algorithm (MLPANN-GWO). The results of this study confirm that ELM-GWO considerably enhanced the predictive performance of the MLPANN-GWO, ELM, MLPANN, and MARS models in terms of the root-mean-square error, respectively, by 43.07%, 73.88%, 74.5%, and 88.55% for COD; 23.91%, 59.31%, 62.85%, and 77.71% for BOD5; 14.08%, 47.86%, 53.43%, and 57.04% for turbidity; and 38.57%, 59.64%, 67.94%, and 74.76% for EC. Therefore, ELM-GWO can be applied as a robust approach for investigating leachate and groundwater quality parameters in different landfill sites. [ABSTRACT FROM AUTHOR]

This study introduced an alternative shortcut biological nitrogen removal (SBNR) process for landfill leachate treatment by developing a novel hydrodynamic sequencing batch reactor (H-SBR). The reactor could enhance the oxygen transfer rate (OTR) and nitrite accumulation ratio (NAR) by modifying internal hydrodynamic turbulence intensity. The average chemical oxygen demand (COD) and total nitrogen (TN) concentrations introduced into the reactor were 660 and 250 mg L−1, respectively, and the average removal efficiencies were 93% (COD) and 96% (TN). The effect of geometric parameters on oxygen transfer was estimated by performing a hydrodynamic model and a nonlinear least square analysis. After correcting the constants (α and β) of mass transfer coefficients (KLa) to values of 0.7361 and 1.2639, the model data fit the experiment well with an R-squared value of 0.99. The OTR improved by up to 30%, and hence, increased the NAR by up to 20% with a reduction of about 0.5 kg N kW−1 for power efficiency. The H-SBR development is innovative because the oxygen transfer efficiency was improved by the hydrodynamic modification of internal turbulence intensity, although not by mechanical equipment or chemical supplements. For the SBNR process, the modification of the reactor configuration for OTR enhancement could significantly improve nitrogen removal efficiency with successful nitrite accumulation. In addition to landfill leachate treatment, the H-SBR process can be employed in the treatment of low C/N ratio wastewaters. [ABSTRACT FROM AUTHOR]

The feasibility of a chitosan-coated coconut-shell (CS) carbon composite for landfill leachate treatment in a fixed-bed study was investigated in terms of COD and NH3-N removal. The surface of the composite was characterized using SEM, FT-IR, and XRD to assess any changes before and after column operations. To enhance its cost-effectiveness, the saturated composite was regenerated using NaOH. The results showed that the composite had significantly better removal of both COD and NH3-N, as compared to CS and/or chitosan (p ≤ 0.05; ANOVA test), respectively. The breakthrough curve obtained from the fixed-bed studies exhibited an ideal "S" shape. The breakthrough points for the adsorbents followed the order of CS at BV 76 < chitosan at 200 BV < composite at BV 305. It was also found that a low flow rate and deeper bed depth of the packed adsorbent were necessary for achieving optimal column operations. The composite achieved 96% regeneration in the first cycle. However, even with the enhanced adsorption of target pollutants by the composite through chitosan coating, the treated effluents still could not meet the required COD and NH3-N effluent limits of less than 200 and 5 mg/L, respectively, as mandated by legislation. Nonetheless, the findings suggest that low-cost composites derived from unused resources can be employed as effective adsorbents for wastewater treatment. [ABSTRACT FROM AUTHOR]

In recent times, 3D electrical resistivity and induced polarization tomographies are being used more frequently. However, it is often not possible to have regular grids of electrodes due to irregular topography, difficulty accessing urbanized or industrialized places, and other environmental and health problems. In these cases, the use of unconventional arrays is necessary, arranging the electrodes around the inaccessible area according to one or more open or closed polygonal traces. In this work, three different perimeter arrangements of electrodes are considered, and, for each, three different electrode array configurations are tested by calculating their apparent resistivity and solving the inverse problem on a three-dimensional model with resistive and conductive blocks. The comparison of the results showed that the dataset that produces the most realistic inverse model consists of electrodes arranged in concentric squares and the use of the Full Range Gradient (FRG) Array. This combination was evaluated in the field on a waste landfill, in which electrical resistivity and induced polarization tomographies were carried out, exploiting the access paths to the various sectors of the landfill to arrange the electrodes on approximately concentric polygons. The 3D models of electrical resistivity and induced polarization allowed the detection of zones of high concentration of leachate, defining their extension, and monitoring the functioning of the waterproofing membrane at the bottom of the landfill. The results proved that when it is not possible to arrange a regular grid of electrodes, the use of perimeter disposals of electrode joined to the FRG array provide a sufficiently homogeneous resolution below the area to be investigated. [ABSTRACT FROM AUTHOR]

Household waste landfills represent a huge source of trophic resources for opportunistic and versatile wildlife species. Among them, the red kite (Milvus milvus) is one of the most endangered in Europe. Several studies have pointed out the importance of landfills as a source of food for this species during the wintering season, but the information on the frequency, seasonal and daily patterns of use, and age of red kites that exploit this food source is still insufficient to understand their actual role in conservation. In this study, we evaluated the patterns of use of household waste by overwintering red kites in southeastern Madrid, central Spain. The results showed the constant presence of relatively low numbers (<30 on average) and a reduced hourly inflow and outflow of red kites throughout the day and during the whole winter period in the studied landfill. A higher proportion of juveniles was found in the landfill than in the overall wintering population. Pellet analysis clearly shows that the diet of red kites is dominated by the wild rabbit (Oryctolagus cuniculus), which is quantitatively very relevant compared to household waste obtained from the landfill. This suggests a relatively low quantitative importance of landfills as foraging grounds for the increasing population of wintering red kites in the study area. Instead, the high regional density of wild rabbits attracts large numbers of red kites that can eventually use landfills as a non-optimal last-resort foraging option, owing to the predictability of household waste, especially for juveniles. The continuous presence of red kites in landfills likely influences an uninformed positive perception about their relevance to the conservation of the wintering population, despite risks there faced, such as collision, electrocution, and intoxication. Future research is needed to assess in depth the influence of wild rabbits in Spain on the habitat use and global population dynamics of red kites. [ABSTRACT FROM AUTHOR]

Leakage in the impervious layer of a domestic waste landfill seriously pollutes the soil and groundwater. Therefore, it is necessary to carry out rapid nondestructive leakage location detection. In this research, the electrical resistivity tomography (ERT) method and the opposing-coils transient electromagnetic method (OCTEM) were used to detect the leakage location. The inversion sections of both methods showed a clear low–middle–high resistivity spectrum in the longitudinal direction that could be used to speculate the distribution pattern of the upper waste body layer, the bottom impermeable layer, and the lower limestone layer. The leakage area was identified in Zone B of the landfill on the basis of inversion results and drilling verification results. The results indicate that OCTEM and ERT were both sensitive to leakage detection. However, OCTEM had higher longitudinal resolution and more refined inversion results, resulting in more effective delineation for the location of the damage and leakage of the impervious landfill layer, thereby providing a new technical basis for landfill leakage detection. [ABSTRACT FROM AUTHOR]

Landfill leachate recirculation is applied to manage the landfill as a bioreactor to enhance biogas production, limiting the impact due to greenhouse gas emissions and optimizing the energy recovery from biogas. This study deals with the geophysical monitoring of the leachate recirculation within the waste of a pretreated waste landfill. For this aim, electrical resistivity tomography (ERT) was adopted, detecting the main distribution of moisture within the waste both through the surface and through several boreholes. The electrical resistivity of waste mainly depends on water content, leachate salinity and temperature. The method is sensitive to the transient phenomena associated with leachate flow within the waste; moreover, the ERT long-term monitoring data suffer from anomalous and unexpected polarization phenomena induced by the measurements themselves. Results demonstrated the reliability of this approach to qualitatively detect the landfill volume affected by the leachate circulation. The effects of moisture changes by leachate infiltration on biogas production are still challenging, notwithstanding a positive effect on methane concentration in biogas itself is evident. [ABSTRACT FROM AUTHOR]

Threats from landfill leachate leakage to groundwater quality in remote areas is a major concern globally. Buffering distance (BFD) maintained between landfill site and groundwater supply wells is important to prevent drinking water from contamination of hazardous pollutant. Ignoring the leakage increase in the end of landfill life leads to an underestimate of BFD demand, posing potential threat to drinking safety. This paper constructs a framework for BFD prediction with the consideration of landfill performance degradation by coupling landfill performance evaluation model with the aging and defect evolution model of landfill engineering materials, and carries out model application and verification in a coastal hazardous waste landfill. The results show that during the life cycle of a landfill, its BFD experienced a 1.5-time increase from the start of its operation to its life end and reached 3000 m. Under the condition of landfill performance degradation, the BFDs required to attenuate heavy metals experience more increase than those of organic pollutants; BFD required for zinc (Zn), for example, increases 720 m over the no-degradation condition, while 2,4-dichlorophenol(2,4-D) increases by only 288 m. Considering the uncertainty sourced from model parameter and structure, the BFD should be more than 4050 m to ensure long-term safe drinking under unfavorable conditions such as large amount of leachate, weak degradation and fast diffusion of pollutant in vadose and aquifer. If the BFD cannot meet the demand at the end of the landfill life, the leaching behavior of solid waste can be controlled to reduce it depending on BFD. For example, when the leaching concentration of Cd in the waste is reduced from 0.6 mg/L to 0.17 mg/L, the buffering distance is be reduced from 3000 m to 500 m. [ABSTRACT FROM AUTHOR]

Leachate generation is among the main challenging issues that landfill operators must handle. Leachate is created when decomposed materials and rainwater pass through the waste. Leachate carries many harmful pollutants, with high concentrations of BOD, COD, colour, heavy metals, ammoniacal nitrogen (NH3-N), and other organic and inorganic pollutants. Among them, COD, colour, and NH3-N are difficult to be completely eliminated, especially with a single treatment. They should be handled by appropriate treatment facilities before being safely released into the environment. Leachate remediation varies based on its properties, the costs of operation and capital expenditures, as well as the rules and regulations. Up until now, much scientific and engineering attention was given to the development of comprehensive solutions to leachate-related issues. The solutions normally demand a multi-stage treatment, commonly in the form of biological, chemical, and physical sequences. This review paper discussed the use of contemporary techniques to remediate landfill leachate with an emphasis on concentrated COD, colour, and NH3-N levels with low biodegradability that is normally present in old landfill or dumping grounds in developing countries. A semi-aerobic type of landfill design was also discussed, as this concept is potentially sustainable compared to others. Some of the challenges and future prospects were also recommended, especially for the case of Malaysia. This may represent landfills or dumpsites in other developing countries with the same characteristics. [ABSTRACT FROM AUTHOR]

In this study, coagulation combined with the electro-Fe0/H2O2 reaction was developed to treat refractory organics in the landfill leachate effluent of a membrane bioreactor (MBR), and the change in biodegradability was investigated. The results showed that polymerized ferric sulfate (PFS) was the best coagulant, with removal efficiencies of chemical oxygen demand (COD) and chromaticity of 74.18% and 72.22%, respectively, when the dosage was 2 g/L and the initial pH (pH0) was 6. Under the optimal conditions of pH0 of 3, current density of 5 mA/cm2, Fe0 dosage of 3 g/L, and H2O2 dosage of 0.059 M, the electro-Fe0/H2O2 reaction showed the removal efficiencies of COD and chromaticity for coagulated effluent were 76.68% and 74%, respectively. UV-vis and 3D-EEM spectral analysis showed that humic and fulvic acids were effectively degraded, and the effluent was mostly small molecules of aromatic protein-like substances. The whole process increased the BOD5/COD from 0.049 to 0.46, indicating that the biodegradability was substantially improved. This is due to the conjunction of the Fe0/H2O2 reaction with electrochemistry, which accelerated the reduction of Fe3+ to Fe2+ on the Fe0 surface and cathode and improved the efficiency of hydroxyl radical (•OH) generation, thus promoting the removal of pollutants. The operating cost was only 4.18 $/m3, with the benefits of less Fe0 loss and no pH adjustment. In summary, coagulation combined with the electro-Fe0/H2O2 reaction is a cost-effective method for treating refractory organics in leachate and enhancing biodegradability. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study was to measure the environmental impact of five different laboratory-scale constructed wetland (CW) treatment systems with varying design approaches, which have been employed to treat different types of wastewater. Moreover, the present study also assessed the feasibility of treating landfill leachate using four different hybrid wetlands built outdoors, and analyzed the environmental viability based on the life cycle assessment (LCA). Primarily, the choice of media materials has been the focus of evaluating the sustainability of the systems, as for each system the media materials cover major material consumption and define treatment performance. Methods: This study applied a life cycle assessment using the SimaPro software tool to quantify the environmental impacts from the constructed wetland systems. Primarily, the LCA has been applied by adopting the ReCiPe 2016 method with cross-validation using the Impact 2002+ method. Moreover, an uncertainty analysis has been performed to determine any uncertainties involved in the datasets, along with sensitivity analysis on the inventory. Results and discussions: As the results suggest, the systems employed for wastewater treatment using cement mortar have the highest environmental burden. In contrast, the natural media choices, sugarcane bagasse and coco-peat, have proved to be environmentally favorable. Media employment from recycled materials like brick and steel slag could significantly redeem the previous environmental burdens of these materials, providing treatment efficiency. However, the systems employed for landfill leachate treatment revealed the CW using brick chips as the most vulnerable system with regards to environmental concerns, implying that the media brick chips are certainly the major contributor behind this high leap in the scale. However, both the systems worked very well in the carcinogenic category, providing good treatment performance, and eventually exerting lesser impact. Conclusion: The overall assessments suggested choice of media materials are essential to deciding the sustainability of a CW design. However, the CW is more beneficial and environmentally friendly than the other treatment methods, until the design scale has a high capacity. Nevertheless, the choice of the LCA method is also significant, while measuring impact scales. [ABSTRACT FROM AUTHOR]

Industrial production has brought increased wellbeing in the last years, but the amount of solid waste has undoubtedly increased. Thus, open dumpsites and landfills have been created throughout the world, with serious impacts on the environment and public health. In such a context, occupational health and safety (OHS) issues related to workers that have to deal with landfill characterization or management have not been considered sufficiently. To reduce such a research gap, in 2019 a research project started in Italy on OHS risk assessment in landfills. In fact, in such facilities, workers can be subjected to direct contact with the polluted environment and might not be completely aware of the entity and type of pollution (e.g., in open dumpsites). Starting with the analysis of INAIL data on accidents at work which occurred in Italy during the period 2008–2019, a specific risk analysis was carried out with the goal of defining risk determinants and profiles by means of K-means cluster analysis. Such an analysis allowed us to recognize the use of work equipment and the work environment as the main determinants of the accidents on the one hand, and the "driver of the excavator" as the most risky activity on the other. The achieved results take a step forward towards the characterization of occupational health and safety issues in landfills. Accordingly, the research outcomes represent a basis on which to address further research work in this field. [ABSTRACT FROM AUTHOR]

The increasing amounts of municipal solid waste and their management in landfills caused an increase in the production of leachate, a liquid formed by the percolation of rainwater through the waste. Leachate creates serious problems to municipal wastewater treatment plants; indeed, its high levels of ammonia are toxic for bacterial cells and drastically reduce the biological removal of nitrogen by activated sludge. In the present work, we studied, using a metagenomic approach based on next-generation sequencing (NGS), the microbial composition of sludge in the municipal wastewater treatment plant of Porto Sant'Elpidio (Italy). Through activated sludge enrichment experiments based on the Repetitive Re-Inoculum Assay, we were able to select and identify a minimal bacterial community capable of degrading high concentrations of ammonium (NH4+-N ≅ 350 mg/L) present in a leachate-based medium. The analysis of NGS data suggests that seven families of bacteria (Alcaligenaceae, Nitrosomonadaceae, Caulobacteraceae, Xanthomonadaceae, Rhodanobacteraceae, Comamonadaceae and Chitinophagaceae) are mainly responsible for ammonia oxidation. Furthermore, we isolated from the enriched sludge three genera (Klebsiella sp., Castellaniella sp. and Acinetobacter sp.) capable of heterotrophic nitrification coupled with aerobic denitrification. These bacteria released a trace amount of both nitrite and nitrate possibly transforming ammonia into gaseous nitrogen. Our findings represent the starting point to produce an optimized microorganisms's mixture for the biological removal of ammonia contained in leachate. [ABSTRACT FROM AUTHOR]

As a new type of biological treatment process, membrane aerated biofilm reactors (MABRs), which have received extensive attention and research in recent years, could reduce energy consumption by 70% compared to the traditional activated sludge process. The MABR system uses bubble-free aeration membrane material as the carrier, the counter-diffusion mechanism of oxygen and pollutants enables ammonium oxidizing bacteria (AOB) and nitrate oxidizing bacteria (NOB) to adhere to the membrane surface so that simultaneous nitrification and denitrification (SND) can occur to achieve simultaneous nitrogen and carbon removal. Currently, MABR technology has been successfully applied to the treatment of municipal sewage, various industrial wastewater, pharmaceutical, high salinity, high ammonia, aquaculture wastewater, landfill leachate and black and odorous water bodies in rivers. Many laboratory experiments and pilot-scale MABR reactors have been used to study the performance of membrane materials, the mechanism of pollutant removal and the effects of different factors on the system. However, the performance of MABR is affected by factors such as dissolved oxygen (DO), pH, C/N, biofilm thickness, hydraulic retention time (HRT), temperature, etc., which limits large-scale promotion. Therefore, membrane materials, membrane modules, biofilm, application of MABR technology, influencing factors of MABR system performance, and limitations and perspectives of MABR are reviewed in this paper, and we expect to provide valuable information. [ABSTRACT FROM AUTHOR]

The treatment of leachate by vegetative filters composed of short-rotation willow coppice (SRWC) has been shown to be a cost-effective alternative to conventional and costly methods. However, few studies have considered the treatment capability of willow filters at a scale large enough to meet the industrial requirements of private landfill owners in North America. We report here on a field trial (0.5 ha) in which a willow plantation was irrigated with groundwater (D0) or aged leachate at two different loadings (D1 and D2, which was twice that of D1). Additionally, half of the D2-irrigated plots were amended with phosphorus (D2P). The system, which operated for 131 days, was highly efficient, causing the chemical oxygen demand concentration to drop significantly with the total removal of ammonia (seasonal average removal by a concentration of 99–100%). D2P efficacy was higher than that of D2, indicating that P increased the performance of the system. It also increased the willow biomass 2.5-fold compared to water irrigation. Leaf tissue analysis revealed significant differences in the concentrations of total nitrogen, boron, and zinc, according to the treatment applied, suggesting that the absorption capacity of willows was modified with leachate irrigation. These results indicate that the willow plantation can be effective for the treatment of landfill leachate in respect of environmental requirements. [ABSTRACT FROM AUTHOR]

Microplastics are generated from plastic waste in landfills due to physical, chemical, and biological effects, and eventually enter into the leachate. Leachate is a potential source of environmental microplastics which has not been emphasized. Here, we summarized the investigation of microplastics in leachate in 9 countries from 28 papers, provided a comprehensive review of the sampling, detection, and separation of microplastics in leachate, and elaborated on the quality control in each process. There are more than forty types of microplastics in leachate, with diverse shapes, wide size distribution, and concentrations of 0–25 items/L. Commonly used techniques are FTIR, Raman, SEM, and py-GC–MS for characterizing microplastics, while standardization of micro- or nanoplastics for leachate with a complex composition should be further studied. We also discussed in depth the degradation mechanism of microplastics in advanced oxidation processes (AOPs). Microplastics can be decomposed into small molecules such as aldehydes and ketones, and some can even eventually be degraded into CO2 and H2O in AOPs, which may be further implemented in leachate treatment plants. This review provides the scientific fundamentals for understanding the microplastics in landfill leachate and proposes removal strategies for future research. [ABSTRACT FROM AUTHOR]

The release of siloxane from landfill leachate has attracted wide attention. In this study, dodecamethylcyclohexasiloxane (D6) and dodecamethylpentasiloxane (L5) were chosen as the target pollutants to investigate the adsorption characteristics of cyclosiloxane and linear siloxane on municipal solid waste (MSW) under the landfill circumstance. The adsorption behavior could be well described by the Langmuir–Freundlich model, with a maximum adsorption capacity of 0.677 μg g−1 and 15.864 μg g−1 for L5 and D6, respectively. It seems that D6 has a stronger affinity to MSW compared with L5. The maximum adsorption was observed when the pH was 5.0 and 5.5 for D6 and L5. The optical temperature was 30 °C. The organic acid and inorganic ions in the leachate could restrict the adsorption to a low level. The results suggested that the adsorption of siloxane on MSW could be limited at the methanogenic and mature stages, which may promote the distribution of siloxane in the leachate. The results could help to understand the release behavior of siloxane from landfill leachate during the running of a landfill. [ABSTRACT FROM AUTHOR]

The discharge of lindane wastes in unlined landfills causes groundwater and soil pollution worldwide. The liquid waste generated (a mixture of 28 chlorinated organic compounds, COCs) constitutes a dense non-aqueous phase liquid (DNAPL) that is highly persistent. Although in situ chemical oxidation (ISCO) is effective for degrading organic pollutants, the low COCs solubility requires high reaction times. Simultaneous injection of surfactants and oxidants (S-ISCO) is a promising technology to solve the limitation of ISCO treatment. The current work studies the remediation of highly polluted soil (COCs = 3682 mg/kg) obtained at the Sardas landfill (Sabiñáñigo, Spain) by ISCO and S-ISCO treatments. Special attention is paid to acute soil toxicity before and after the soil treatment. Microtox®, modified Basic Solid-Phase Test (mBSPT) and adapted Organic Solvent Sample Solubilization Test (aOSSST) were used for this scope. Persulfate (PS, 210 mM) activated by alkali (NaOH, 210 mM) was used in both ISCO and S-ISCO runs. A non-ionic and biodegradable surfactant selected in previous work, Emulse®3 (E3, 5, and 10 g/L), was applied in S-ISCO experiments. Runs were performed in soil columns filled with 50 g of polluted soil, with eight pore volumes (Pvs) of the reagents injected and 96 h between successive Pv injections. The total treatment time was 32 days. The results were compared with those corresponding without surfactant (ISCO). After remediation treatments, soils were water-washed, simulating the conditions of groundwater flux in the subsoil. The treatments applied highly reduced soil toxicity (final soil toxicity equivalent to that obtained for non-contaminated soil, mBSPT) and organic extract toxicity (reduction > 95%, aOSSST). Surfactant application did not cause an increase in the toxicity of the treated soil, highlighting its suitability for full-scale applications. [ABSTRACT FROM AUTHOR]

Groundwater quality and human health assessment in the vicinity of landfills can be performed with the use of numerous index methods. The aim of this paper is to present the results of the Environmental Risk Assessment (ERA) and Health Risk Assessment (HRA) in the vicinity of a municipal landfill complex for monitoring data from 1995, 2003, 2010, and 2021 and in the context of average statistical data about Poles. The calculations take into account an extended range of parameters, including sulphates, chlorides, and ammonium ions. The calculation results for the Horizontal ratio indicate that it should not be used for all parameters. This was mainly reflected in the low sulfate content of the water monitored by a piezometer directly below the old landfill. Other indicators, reaching as high as around 2000 (the Nemerow Pollution Index) or approx. 18,000 (the enrichment factor), confirm the negative impact of the landfill. The Hazard Index values reached almost 700, which would indicate a high risk to human health when consuming water with similar parameters. Overall, the results illustrate that using the selected indices to assess groundwater risk can be a valuable method for supporting long-term observations of groundwater quality, which can be used to make predictions using artificial intelligence methods. [ABSTRACT FROM AUTHOR]

Currently, a total of about 15,000 tons/day of waste is generated in the entire Dhaka city with an average per capita waste generation of 0.641 kg/day. Only 37% of this waste is collected and dumped into the two sanitary landfill sites, which is the only waste management system in Dhaka. To investigate the impact of landfill leachate of Amin Bazar landfill on the environmental compartments, a total of 14 composite samples (two leachates, three surface water, three groundwater, three soil, and three plants) were collected and analyzed for physicochemical parameters and heavy metal(loid)s concentration. Based on the result of physicochemical parameters, all results were found higher in the leachate samples than the permissible limit. The heavy metal(loid)s in leachate samples have a value of high levels of contamination. Surface water, groundwater, soil, and vegetation are all polluted as a result of high levels of metal contamination. Although the Water Quality Index values of the samples based on heavy metal(loid)s concentrations were within the acceptable range, heavy metal concentrations in the soil and plants were quite high. The concentrations of lead (Pb—8 mg/kg), cadmium (Cd—0.4 mg/kg), chromium (Cr—2.26 mg/kg), and cobalt (Co—1.72 mg/kg) in all plant samples were found to be higher than the allowable limit. The individual concentration of arsenic (As—0.021 mg/L) in the leachate was higher than the maximum allowed limit. Inverse Distance Weighted analysis through ArcGIS showed that landfill leachate has the maximum probability of contaminating the surrounding environment with heavy metal(loid)s. Results showed that samples collected near the landfill have higher concentrations of heavy metal(loid)s than others, which establishes the contribution of landfill leachate in contaminating the environment with heavy metal(loid)s. The improper leachate management of landfill has a high impact on the environment. [ABSTRACT FROM AUTHOR]

Compaction is a common ground improvement technique based on the densification of soils for an energy level and optimum water content, mainly influenced by the particle size and curve gradation. Poorly compactable sands, characterized as cohesionless, fine and uniformly graded, are a challenge for earthworks since compaction is not effective due to the lack of a larger range of particle sizes to infill the voids and the compaction energy is not relevant either. These characteristics are common to other materials, i.e., desert sand, industrial or mining by-products or quarry fines, which are mostly discarded to landfill and replaced by proper soils, causing serious environmental issues. To enlarge the technical feasibilities of poorly compactable sands, reducing construction waste and raw material consumption, a mechanical stabilization, based on a repetitive series of recycling and recompaction without binder, is experimentally explored. The behavior observed is also analyzed from reported correlations and a packing particle approach, attending to densification stage, saturation degree, recompaction series, coordination number and packing density. The improvement achieved is moderate and dependent on the cycles applied, showing a characteristic repetitive pattern in the compaction curve, and approaching the estimated minimum void ratio and the theoretical maximum packing possibilities without degradation of the material. [ABSTRACT FROM AUTHOR]

Anaerobic digestion (AD) is an attractive process for bioenergy production and is considered to be an alternative way to reduce landfills. AD improves municipal solid waste (MSW) management, representing a profitable application of the circular economy and could reduce environmental impact. The methane (CH4) potential of four different organic fractions of MSW—paper (PFW), garden (GFW), food (FFW), and a mixture of these three (OFMSW)—via AD was used to investigate the energy potential and the economic and environmental impact of Campinas. Theoretical and experimental biochemical methane potential (BMP) and substrate biodegradability were determined using the Buswell and Müller equation and the VDI 4630 method. The Gompertz model was used to predict the kinetics of the biochemical processes. The highest experimental BMP (410.7 NmLCH4 gVS−1) and biodegradability (86.6%) were reached with OFMSW. OFMSW can avail an energetic potential of approximately 119 GWh year−1, with a biomethane production equivalent to diesel at 49.9 × 103 m3 year−1, hence, potentially curtailing the CO2 emissions of heavy-duty vehicles by almost 133 kt year−1. The electricity demand for approximately 11% of the households in Campinas could be met by the biogas produced by OFMSW, thus increasing local energy security. The replacement of fossil diesel with biomethane to fuel garbage trucks in Campinas could reduce 25% of the diesel demand. [ABSTRACT FROM AUTHOR]

The current EU energy policy aims to diversify energy sources to ensure energy security while decarbonising the economy and promoting low carbon and clean energy technologies. These tasks are carried out under the European Green Deal Program. Therefore, the overriding goal at present is to search for new sources of energy, including energy recovery from waste. In EU countries, the legal system for waste management is adapted to the circular economy. In Poland, due to the legal possibility of temporary storage and disposal of waste, a substantial volume of industrial waste is temporarily stored and landfilled (above 40%), compared to the importance of waste subjected to treatment. Moreover, energy recovery from waste accounts for a negligible share (below 5%). It may be due to the high costs of these processes, stringent emissions and environmental quality standards. Therefore, as in certain EU countries, the problem of landfill site arson attacks has been exacerbated in Poland (177 fires in 2019). The aim of this article is to determine the relationship between the application of the existing regulations concerning closed-loop waste management and the effectiveness of methods, ways and economic instruments preventing the illegal burning of landfill waste in Poland under the current EU energy policy. Therefore, it can be assumed that this system is not complete. Based on factor force analysis at a scale 1–5, it was found that technological (3.4), legal (3.16) and economic (3.0) factors have the greatest impact on this system. The waste management system should be oriented towards increased waste recovery and a more significant reduction in the volume of temporarily stored waste and landfill waste. It should be considered whether the current move away from the incineration of waste, according to the new EU energy policy, is a better solution in environmental and economic terms than incurring very high costs due to eliminating the effects of the incineration of landfill waste that causes environmental damage. [ABSTRACT FROM AUTHOR]

Refractory organic wastewater mainly includes wastewater from papermaking, textile, printing and dyeing, petrochemical, coking, pharmaceutical and other industries, as well as landfill leachate and its membrane-treated concentrate. The traditional biochemical method is difficult to adapt to its harsh conditions such as high toxicity, high organic load and high salinity. Compared to other methods, the electro-oxidation (EO) process owns the attractive characteristics of being clean and eco-friendly, highly efficient and producing no secondary pollution. EO systems mainly include electrodes, a reactor, a power supply and other basic units. The design of reactors with different electrodes was the key link in the application of EO technology. This paper mainly reported the different configurations of electrochemical reactors (ECRs) for refractory organic wastewater treatment, and summarized the advantages and disadvantages of them, including reactor structure, flow mode, operation mode and electrode construction. Compared with traditional reactors, the improved reactors such as 3D-ECR achieve higher mass transfer efficiency by increasing the contact area between the electrode and the fluid. Additionally, it has a higher removal rate of organics and a lower energy consumption. Finally, the future perspectives of the treatment of refractory organic wastewater by ECRs is discussed. This paper is expected to provide a reliable scientific basis for the real application of EO technology in refractory organic wastewater treatment. [ABSTRACT FROM AUTHOR]

There is a great demand for human–machine interfaces (HMIs) in emerging electronics applications. However, commercially available plastic-based HMIs are primarily rigid, application-specific, and hard to recycle and dispose of due to their non-biodegradability. This results in electronic and plastic waste, potentially damaging the environment by ending up in landfills and water resources. This work presents a green, capacitive pressure-sensitive (CPS), touch sensor-based keypad as a disposable, wireless, and intelligent HMI to mitigate these problems. The CPS touch keypads were fabricated through a facile green fabrication process by direct writing of graphite-on-paper, using readily available materials such as paper and pencils, etc. The interdigitated capacitive (IDC) touch sensors were optimized by analyzing the number of electrode fingers, dimensions, and spacing between the electrode fingers. The CPS touch keypad was customized to wirelessly control a robotic arm's movements based on the touch input. A low-pressure touch allows slow-speed robotic arm movement for precision movements, and a high-pressure touch allows high-speed robotic arm movement to cover the large movements quickly. The green CPS touch keypad, as a disposable wireless HMI, has the potential to enforce a circular economy by mitigating electronic and plastic waste, which supports the vision of a sustainable and green world. [ABSTRACT FROM AUTHOR]

The composition of municipal solid waste (MSW) in the Cairo metropolitan area is investigated. The outputs of MSW sorting analysis at various locations in Cairo with different waste management schemes are presented. Organics (58–75%) and plastic waste (19–28%) are the main components of MSW in Cairo with a higher percentage of organics in landfills compared to dumpsites. The leachate quality is analyzed, and the analysis results indicate that the concentration of macro inorganic pollutants (NH4+, Na+, Ca2+, and Cl−) and heavy metals (e.g., Cd2+ and Zn2+) are exceeding the majority of values reported in the literature in various cities all over the world. There was no evidence of an effect of the recycling process on chloride concentration in leachate, while the concentration of iron was reduced. The variation of leachate quality with time for two samples collected from the same municipal solid waste landfill is presented. The first leachate sample is a two-year-old, and the second sample is a sixteen-year-old. There was a significant increase in the concentration of chloride, sodium, chromium, calcium, and magnesium. The implications of the leachate quality in Cairo on the longevity of barrier systems in an MSW landfill are discussed. [ABSTRACT FROM AUTHOR]