Solid Waste Landfill Research Articles

Ambient noise imaging for municipal solid waste landfill structure detection based on the common-midpoint two-station analysis with distributed acoustic sensing

SUMMARY Distributed acoustic sensing (DAS) enables high-density sampling of seismic wavefields at low cost compared to conventional geophones. This capability facilitates structural detection of a municipal solid waste (MSW) landfill, which is important for protecting the surrounding ecosystem. However, processing the vast amount of data from DAS array for ambient noise imaging can be computationally intensive. To address this, we employed the common-midpoint two-station (CMP-TS) analysis to enhance the efficiency of ambient noise imaging in the MSW landfill. CMP-TS analysis involves selecting pairs of traces at equal distances on both sides with the subarray midpoint as symmetry, which reduces the number of DAS array recordings for cross-correlation calculations. After positioning the DAS arrays linearly on top of the MSW landfill to automatically collect ambient noise, we used the CMP-TS analysis in the cross-correlation calculations to speed up the measurement of dispersion. The S-wave velocity structure of the study region was obtained quickly by inverting the extracted dispersion curves using the gradient optimization method. Ambient noise imaging based on CMP-TS analysis with DAS was applied to a test of an area-type MSW landfill. The resulting S-wave velocity section revealed a discontinuous low-velocity zone, validated by the high-density resistivity method. This low-velocity zone was interpreted as containing leachate from waste decomposition, and its discontinuity may be caused by excessive differences in the waste residues settling rates under compaction. Employing CMP-TS analysis in ambient noise data collected by DAS offers more cost-effective monitoring and a reliable basis for environmental pollution prevention and control.

Precipitation and evaporation affecting landfill gas migration into passive methane oxidation biosystems: Models development and verification

Passive methane oxidation biosystems (PMOBs) are developed as an innovative and cost-effective solution to reduce methane (CH4) emissions from municipal solid waste landfills. A PMOB consists of a methane oxidation layer (MOL) and an underlying gas distribution layer (GDL). The length of unrestricted gas migration (LUGM) has been recently proposed as the design criterion for PMOBs where the LUGM is calculated as the horizontal length along the MOL-GDL interface with the volumetric gas content (θa) exceeding the threshold volumetric gas content (θa,occ). This paper examined water and gas migration within three PMOBs with different MOL-GDL interfaces subject to precipitation and evaporation using verified numerical models. The results show that the use of a single-phase flow model underestimates the LUGM values of the PMOB for heavy precipitation events, and a two-phase flow model should be used to calculate both the LUGM and the total gas mass flow rate into the MOL when designing PMOBs. Both zig-zag and trapezoidal MOL-GDL interfaces can redistribute the gas mass flow rate at the MOL-GDL interface, while the trapezoidal MOL-GDL interface slightly outperforms the zig-zag MOL-GDL interface for enhancing the total gas mass flow rate into the MOL when comparing with the planar MOL-GDL interface. The zig-zag and trapezoidal MOL-GDL interfaces allow gas migration in the upper part of each PMOB segment even when the lower part of each PMOB segment was filled with water, and thus have a potential to minimize hotspot formation.

Adaptation of Ochrobactrum rhizosphaerae IMV B-7956 Bacteria to the Influence of Copper (II) Chloride

In technologically altered habitats, an increased content of organic compounds, nitrogen, phosphorus, sulfur compounds, antibiotic substances, etc. is found. Therefore, microorganisms that are systematically exposed to various stressors have developed adaptation mechanisms. The strain Ochrobactrum rhizosphaerae IMV B-7956, isolated from the infiltrate lakes of the Lviv solid waste landfill, is resistant to copper, chromium, manganese, and iron in concentrations exceeding the maximum permissible concentrations. The work aimed to study the response of O. rhizosphaerae IMV B-7956 cells to CuCl2 exposure by detecting changes in the content of lipid peroxidation products, products of the oxidative modification of proteins, activity of antioxidant defense system enzymes, and synthesis of extracellular polymers. Methods. To study the effect of CuCl2 on prooxidant indicators and the activity of enzymes of the antioxidant defense system, bacteria were pre-incubated in Tris-HCl buffer containing 2–10 mM CuCl2. After one hour of incubation, the bacterial cells were washed and cultured for 1, 12, 24, and 48 h in metal-free media. The copper content in the bacterial cells was determined by atomic absorption spectrometry. The content of lipid peroxidation indicators, carbonyl groups in proteins, total low-molecular-weight thiols, enzymatic activity, and the content of exopolysaccharides and extracellular proteins were determined photometrically. Results. Within an hour, O. rhizosphaerae IMV B-7956 bacteria accumulated 2.3–7.8 mg Cu/g of biomass. Under these conditions, an increased content of lipid peroxidation products was detected. During the first hour of growth in bacterial cells, enzymes with catalase and peroxidase activity were activated. During further cultivation, an increase in the activity of other antioxidant defense enzymes was detected. Carbonyl groups in proteins are probably formed due to an increase in the content of lipid peroxidation products, as they are formed later. Within 12–48 h of growth, the copper content in the bacterial cells decreases. This leads to the restoration of growth. Conclusions. The main damaging effect of CuCl2 on bacterial cells was detected during the first 24 h of growth. Activation of the enzymes of the antioxidant system and synthesis of exopolysaccharides are among the adaptations that ensure the survival of bacteria under these conditions.

Metal(loid)s in urban soil from historical municipal solid waste landfill: Geochemistry, source apportionment, bioaccessibility testing and human health risks

Landfills, especially those poorly managed, can negatively affect the environment and human beings through chemical contamination of soils and waters. This study investigates the soils of a historical municipal solid waste (MSW) landfill situated in the heart of a residential zone in the capital of Slovakia, Bratislava, with an emphasis on metal (loid) contamination and its consequences. Regardless of the depth, many of the soils exhibited high metal (loid) concentrations, mainly Cd, Cu, Pb, Sb, Sn and Zn (up to 24, 2620, 2420, 134, 811 and 6220 mg/kg, respectively), classifying them as extremely contaminated based on the geo-accumulation index (Igeo >5). The stable lead isotopic ratios of the landfill topsoil varied widely (1.1679–1.2074 for 206Pb/207Pb and 2.0573–2.1111 for 208Pb/206Pb) and indicated that Pb contained a natural component and an anthropogenic component, likely municipal solid waste incineration (MSWI) ash and construction waste. Oral bioaccessibility of metal (loid)s in the topsoil was variable with Cd (73.2–106%) and Fe (0.98–2.10%) being the most and least bioaccessible, respectively. The variation of metal (loid) bioaccessibility among the soils could be explained by differences in their geochemical fractionation as shown by positive correlations of bioaccessibility values with the first two fractions of BCR (Community Bureau of Reference) sequential extraction for As, Cd, Mn, Ni, Pb, Sn and Zn. The results of geochemical fractionation coupled with the mineralogical characterisation of topsoil showed that the reservoir of bioaccessible metal (loid)s was calcite and Fe (hydr)oxides. Based on aqua regia metal (loid) concentrations, a non-carcinogenic risk was demonstrated for children (HI = 1.59) but no risk taking into account their bioaccessible concentrations (HI = 0.65). This study emphasises the need for detailed research of the geochemistry of wastes deposited in urban soils to assess the potentially hazardous sources and determine the actual bioaccessibility and human health risks of the accumulated metal (loid)s.

A review of soil pollution around municipal solid waste landfills in Iran and comparable instances from other parts of the world

A review of soil pollution around municipal solid waste landfills in Iran and comparable instances from other parts of the world

Microplastic-free, single-layered functional surface with localized liquid-discharging molecular channels for disposable hygiene products

Conventional disposable absorbent hygiene products (DAHPs) currently represent a significant type of solid waste in landfills and are a substantial producer of fiber-based microplastics. In this work, a novel multifunctional cellulose nonwoven (CNW) is reported. The key structural design of this material was achieved by covalently grafting a naturally cycloheptatriene product namely hinokitiol and a silane covalent bridge, successfully transforming the original super hydrophilic substrate into a single-layered, multifunctional material with precisely designed liquid-discharging molecular channels and a tailored, sophisticated hydrophobic/hydrophilic distribution structure. This 3D structure perfectly mimics the conventional adhesive-bonded polyolefin/polyesters laminates comprising a top sheet and a liquid acquisition and distribution layer (ADL). The results of XPS and 1H NMR indicated the hinokitiol was successfully chemically bonded to the CNW surface. Compared with polyolefin or cotton substrates, the optimal CNW product (CNW-H-A-2) exhibits significantly improved long-term wearing comfort by minimizing the liquid strike-through time (by 26–27%), reducing wet-back amount (by 65–90%), and ensuring an outstanding air-permeability (3011 mm·s-1). Excellent antibacterial properties against Staphylococcus aureus (86.4%) and Escherichia coli (97.3%) were achieved due to the good preservation of the bioactive phenol groups of hinokitiol. Additionally, it can be completely enzymatically-degraded within 24 h. This strategy holds promise as a potential solution for mitigating fiber-based microplastics pollution of DAHPs.

Assessment of the risk to public health from soil contamination on the territory of solid waste landfills

Introduction. Domestic waste management is an extremely important issue for all countries of the world, especially for the countries of the former Soviet Union, as the current state of solid waste disposal in Ukraine is extremely unsatisfactory. According to the European Commission, the amount of waste in the European Union has increased in recent years to more than 2.5 billion tons per year. The results of the Waste Atlas report on the world's 50 largest landfills show that 64 million people are affected by the 50 largest landfills every day. Ukraine has a total of 6045 landfills and dumpsites. The general trend in Ukraine, in contrast to European countries, is a low level of recycling and utilization of solid waste and a high rate of landfill disposal. The vast majority of landfills (80 to 90%) operate in overload mode. Landfills, in particular solid waste landfills, are the main pollutants of the atmosphere, hydrosphere and soil. Therefore, determining the level of environmental hazard of heavy metals in the soil as a result of the impact of landfills and solid waste dumps is very important. Objective. The purpose of the article is to determine the impact of solid waste landfills on public health due to soil contamination with heavy metals. Methodology. In order to determine the level of environmental hazard of household waste storage at landfills and dumps, the paper assesses the risk to public health from soil contamination in the area of the Hrybovychi landfill (Lviv oblast), Rohan landfill (Kharkiv oblast), and Novovodolazhske landfill (Kharkiv oblast). The risk to public health from soil contamination at solid waste landfills was assessed using the traditional US EPA method and a new method for determining the potential risk to public health from soil contamination with heavy metals. Results. The article compares two fundamentally different methodological approaches to determining the level of environmental hazard of soil contamination with heavy metals. The risk to public health from soil contamination on the territory of solid waste landfills according to the US EPA method corresponds to hazard class 5 (extremely high hazard level) according to all calculations. The results of the assessment of the potential risk to public health from soil contamination using the new method at solid waste landfills correspond to hazard classes 2-4. Comparison of methodological principles for assessing the risk to public health from soil pollution has shown the advantages of using the new method of potential risk assessment. The use of the new method of assessing the potential risk to public health from soil pollution will help improve science-based management of household waste and direct financial resources to reduce the environmental hazard of soil and land pollution in Ukraine. Scientific novelty. The article presents an improved method for assessing the risk to public health from soil pollution, which represents the scientific novelty of the work Practical significance. Determining the environmental hazard of soil pollution due to the impact of landfills and solid waste dumps makes it possible to prioritize the implementation of environmental protection measures and will contribute to the implementation of environmentally sound environmental management, so the research is of practical importance.

Stability Analysis of Waste Landfills on Potentially Unstable Territory

Abstract The article presents the stability analysis of two adjacent waste landfills located in a potentially unstable territory. One of the waste landfills is reclaimed and consists of ash. Municipal solid waste is actively deposited in the second landfill. In the space between the landfills, the expansion of the municipal solid waste landfill is planned, with a partial overlap of the reclaimed ash landfill. The instability of the area where the landfills are located is due to its susceptibility to the formation of landslides. The article presents the results of experimental verifications of the peak shear strength parameters of the ashes and the peak and residual shear strength of the soils forming the subsoil of both landfills and serve as input for stability analyses. The shear strength parameters of municipal waste are defined on the basis of literature research. The potential instability of both waste landfill territories was taken into account using the parameters of the residual shear strength of the subsoil. The stability analysis of waste landfills is expressed using both the peak and residual shear strength parameters of the subsoil of waste landfills. In addition, the effect of seismic loading on both landfills is considered in the stability analysis.

Investigation into the Contamination of Soil With Multiple Components in the Vicinity of Municipal Solid Waste Landfills

Investigation into the Contamination of Soil With Multiple Components in the Vicinity of Municipal Solid Waste Landfills

Mathematical Modeling of The Estimate of Methane Gas Generation, of The Organic Fraction Of Msw From The Agreste Alagoano Sanitary Landfill, From Standard Data And Experimental Data

Objective: The objective of this study is to carry out mathematical modeling in the generation of methane gas, through two mathematical models, using standard data and data obtained in the laboratory. Theoretical framework: The emission of methane gas, generated by the decomposition of solid waste in landfills, is one of the serious problems of air pollution and one way to minimize the impacts of methane on the environment is through its use to generate energy. To this end, there are ways to estimate the generation of CH4 during the useful life of the landfill. Method: For modeling, the computer programs of LandGEM and the Intergovernmental Panel on Climate Change (IPCC) were used to carry out the theoretical estimate of CH4 production during the useful life of the Agreste Alagoano landfill in two scenarios: one with standard program values for the local climate region and another with information obtained from experimental data from research by Santana (2022). Results and Discussion: When standard input data was adopted, the LandGEM model presented a 38% higher value in CH4 production compared to the IPCC model. When considering input data obtained experimentally, the IPCC showed CH4 generation 32.66% higher than the LandGEM, this was possible due to the COD value that was high as a result of the L0 of the organic fraction, exceeding the theoretical value of 0.15 to the experimental value of 0.27 in the new scenario. Implications of the research: Determining parameters for modeling methane gas generation will help in managing landfill waste and its energy recovery potential, in addition to the application of mathematical models for estimating biogas production potential as tools essential for both energy and environmental studies. Originality/value: This research presents as originality the determination of experimental parameters applied to the mathematical modeling of methane gas generation in landfills in the rural region, since studies on modeling in landfills with the climatic conditions of the rural region of Brazil are not common in the literature.

Analysis of ammonia-nitrogen removal kinetics by stage in pilot scale vertical flow wetlands treating landfill leachate in series

This study explored the effect stage number and plant type have on ammonia-nitrogen (NH3–N) removal kinetics in a two-stage pilot-scale vertical flow constructed wetland (VFCW) system treating landfill leachate. Half of the VFCW columns were planted with Typha latifolia and the other half Scirpus californicus, and half of the columns were loaded with municipal solid waste landfill leachate (diluted to 1 part leachate to 2 parts total) with the effluent from these columns was collected in two separate barrels. The remaining columns were loaded with the effluent collected from the first columns, creating a two-stage VFCW system with four unique pairs to be tested. The leachate used here experienced no prior pre-treatment, and average influent concentrations of NH3–N for the first- and second-stage VFCWs were 508 and 321 mg L−1, respectively— much higher than many other VFCW treatment systems. Some reduction in chemical oxygen demand was observed, as well as generation of nitrate and nitrite, evidence of nitrification. No apparent correlation between aboveground biomass and removal of NH3–N was observed. Overall removal efficiency of NH3–N through two stages of VFCWs was 53.7% for columns planted with T. latifolia and 58.3% for those planted with S. Californicus. Average NH3–N removal efficiencies for the first stage VFCWs were 32.7% and 34.3%, while those in the second stage were 31.3% and 36.5%; no significant difference was observed between the first and second stage, suggesting that stage number does not have a significant effect on the removal efficiency of NH3–N in the primary treatment of landfill leachate via VFCWs. However, average mass removal rates of NH3–N in the first stage were 166 and 175 mg L−1 d−1; the second stage was significantly lower at 99.4 and 112 mg L−1 d−1, indicating that the first stage removed more pollutants overall.

Assessing the stability of slopes in municipal solid waste landfills

Assessing the stability of slopes in municipal solid waste landfills

Compacted sand–bentonite mixtures for the confinement of waste landfills

AbstractThis paper illustrates the results of an experimental study on sand–bentonite mixtures for their use as confinement barriers for solid waste landfills. The mixtures have been prepared parametrically varying the percentage of bentonite. The sample preparation method was established willing to simulate the compaction processes on site. In fact, the compacted samples were tested following two different stress-wetting paths representative of the possible stress and imbibition sequences occurring on a landfill confinement barrier. In the first case, the barrier comes into contact with rainwater before being subjected to the overloading stress induced by waste disposal, while, in the second case, the barrier is overloaded by the waste before being wetted by the leachate. The compressibility and permeability of the sand–bentonite mixtures were determined, in both cases, by oedometric compression tests. The experimental results are analysed and compared in order to evaluate the influence of the bentonite content on the mechanical and hydraulic behaviour of the mixture. Interpretation of the results is also accomplished with a micro-mechanical investigation of the mixtures fabric. Suitable compositions of sand and bentonite are finally proposed for the design of effective confinement barriers.

Experimental comparison of foam flow and gas flow in municipal solid waste

Foam is found to be a special fluid (i.e., gas divided by liquid film) that exists in municipal solid waste (MSW) landfills. As a disconnected phase, the unsaturated flow behavior of foam is significantly different from that of gas in connected phase. In this study, the difference between foam flow and gas flow was characterized through displacement tests in the MSW columns. Resistance factor, which is defined as the ratio of steady pressure drop between foam displacement and gas displacement, is employed to characterize this difference. The effects of foam quality, void ratio, and particle size on resistance factor were studied. The unsaturated permeability curves of foams generated by leachate samples at different depths were measured. The leachate at the middle layer has low surface tension to produce strong foam, while the leachate at the top and bottom layers has high surface tension to produce weak foam. The unsaturated permeabilities of weak foam and strong foam were about 1 and 2 orders of magnitude smaller than that of gas, respectively. The reduction in waste void ratio decreased the resistance factor as the excessive shearing effect in small pores would cause the foam to collapse.

Unravelling the secrets of a landfill for municipal solid waste (MSW): Lipid-to-biodiesel production by the new strain Chlorella vulgaris DSAF isolated from leachates

Unravelling the secrets of a landfill for municipal solid waste (MSW): Lipid-to-biodiesel production by the new strain Chlorella vulgaris DSAF isolated from leachates

Mineral composition of the processed forming mixture of the Kryvyi Rih Mechanical Repair Plant

Currently, Ukraine and developed countries have developed and are constantly updating national waste management programs. Industrial waste as a raw material potential can replace primary sources of natural resources, significantly reduce resource consumption and help ensure the raw material independence of territories and individual countries. The spent molding compound of the Kryvyi Rih Mechanical Repair Plant is a multi-ton solid waste from foundry production. A part of the spent molding mixture is reused as a recyclable material, but the bulk of it is disposed of at municipal solid waste landfills. In this paper, the mineral composition of the spent molding compound is studied in detail, which reveals the possibilities of its reuse. Based on the results obtained, the mineral composition of the spent molding mixture was determined, and mineralogical recommendations were given for the technology of processing the spent mixture. Its involvement in reuse will make it possible to obtain conditioned reconstituted molding sands, free up part of the solid waste landfills, and reduce the negative technogenic load.

Exploring the geotechnical and microstructural properties of composite mixtures for landfill liner materials: an experimental investigation.

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.

Characterization of per- and polyfluoroalkyl substances (PFAS) and other constituents in MSW landfill leachate from Puerto Rico

Elevated per- and polyfluoroalkyl substance (PFAS) concentrations have been reported in municipal solid waste (MSW) landfill leachate with higher levels in wet and warmer subtropical climates. Information about landfill leachate characteristics is much more limited in tropical climates. In this study, 20 landfill leachate samples were collected from three MSW landfills on the tropical island of Puerto Rico and results were compared against landfills nationally and within Florida, USA. The samples collected in Puerto Rico underwent physical-chemical analysis, as well as a quantitative analysis of 92 PFAS. Samples described in this study include discrete leachate types, such as leachate, gas condensate, and leachate which has undergone on-site treatment (e.g., RO treatment, phytoremediation, lagoons). A total of 51 PFAS were detected above quantitation limits, including perfluorohexylphosphonic acid, a perfluoroalkyl acid (PFAA) which has not been reported previously in landfill leachate. ∑PFAS concentrations in this study (mean: 38,000 ng L−1), as well as concentrations of individual PFAS, are significantly higher than other reported MSW landfill leachate concentrations. The profiles of leachates collected from on-site treatment systems indicate possible transformation of precursor PFAS as a result of treatment processes – oxidizing conditions, for example, may facilitate aerobic transformation, increase the concentrations of PFAAs, and possibly increase the apparent ∑PFAS concentration. Extreme climate events, including rising temperatures and more frequent hurricanes, have placed additional strain on the solid waste management infrastructure on the island – adding complexity to an already challenging PFAS management issue. As concern grows over PFAS contamination in drinking water, these findings should inform solid waste and leachate management decisions in order to minimize PFAS emissions in island environments.

Identification of prevalent leachate percolation of municipal solid waste landfill: a case study in India

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.

Assessment of the Impact of Unauthorized Landfills of Solid Municipal Waste Located in the Arctic Zone of the Russian Federation on the Components of the Natural Environment

The natural, climatic and socio-economic conditions of the Arctic zone of the Russian Federation (AZRF) are considered. Factors of anthropogenic negative impact on the components of the natural environment are noted. It has been established that unauthorized municipal solid waste (MSW) dumps located in the Russian Arctic have a significant impact on the ecosystem. Contamination of soil, surface and groundwater near MSW dumps with substances of hazard classes I–IV has been recorded. It was revealed that the maximum content of pollutants in the components of the natural environment exceeds the established MPC/APC standards by 17 times.