Landfill Research Articles

Assessing the stability of slopes in municipal solid waste landfills

Assessing the stability of slopes in municipal solid waste landfills

Evaluation of the Activity of a Municipal Waste Landfill Site in the Operational and Non-Operational Sectors Based on Landfill Gas Productivity

This research identifies the productivity of landfill gas actively captured at a municipal waste landfill site with a waste mass exceeding 1 million Mg from sectors in the operational and non-operational phases, considering meteorological conditions. Based on the analysis of landfill gas, including emissions and composition (CH4, CO2, O2, and other gases), the processes occurring demonstrate the impact of the decomposition of deposited waste on the activity of the deposit. With average monthly gas emissions exceeding 960,000 m3, the average content of CH4 (30–63%) and CO2 (18–42%) and the varied content of O2 (0.3–9.8%) in individual sectors of the landfill site were significant. The statistically significant relationship between CH4, CO2, and landfill gas emissions exhibited a noticeable decrease in methane content. Despite the abandonment of waste storage, a high correlation is present between the emission level and methane content (0.59) and carbon dioxide (0.50). In the operational part of the landfill, this relationship is also statistically significant but to a lesser extent; Spearman’s R-value was 0.42 for methane and 0.36 for carbon dioxide. The operational and post-operational phases of the municipal waste landfill demonstrated a noticeable impact from the amount of precipitation, relative humidity, and air temperature, on landfill gas productivity. The generally progressive decline in the activity of the waste deposit, which reflects a decreasing trend in the methane content of approximately 2% annually in the total composition of landfill gas, as well as the share below 50%, indicates the need only to utilise landfill without producing energy.

Pathways and contributions of sulfate reducing-bacteria to arsenic cycling in landfills

Sulfate-reducing bacteria (SRB) are generally found in sanitary landfills and play a role in sulfur (S) and metal/metalloid geochemical cycling. In this study, we investigated the influence of SRB on arsenic (As) metabolic pathways in refuse-derived cultures. The results indicated that SRB promote As(III) methylation and are beneficial for controlling As levels. Heterotrophic and autotrophic SRB showed significant differences during As cycling. In heterotrophic SRB cultures, the As methylation rate increased with As(III) concentration in the medium and reached a peak (85.1%) in cultures containing 25 mg L−1 As(III). Moreover, 4.0–12.6% of SO42− was reduced to S2−, which then reacted with As(III) to form realgar (AsS). In contrast, autotrophic SRB oxidized As(III) to less toxic As(V) under anaerobic conditions. Heterotrophic arsM-harboring SRB, such as Desulfosporosinus, Desulfocurvibacter, and Desulfotomaculum, express As-related genes and are considered key genera for As methylation in landfills. Thiobacillus are the main autotrophic SRB in landfills and can derive energy by oxidizing sulfur compounds and metal(loid)s. These results suggest that different types of SRB drive As methylation, redox reaction, and mineral formation in landfills. These study findings have implications for the management of As pollutants in landfills and other contaminated environments.

Identification of potential landfill site suitability for urban solid waste disposal of Balurghat Municipality of Dakshin Dinajpur District using GIS and multi-criteria decision-making approach

The production of urban solid waste is one of the most dangerous environmental health risks on the planet. By selecting suitable landfill sites, it is possible to resolve the issue of health risks and environmental pollution driven by the unscientific disposal of solid waste. The current research is centered on determining suitable landfill locations for solid waste disposal within the Balurghat municipality through the integration of Geographic Information System (GIS) and Multi-Criteria Decision-Making (MCDM) approach. Ten factors were taken into consideration according to their weightage including elevation (0.022), Lithology (0.027), Slope (0.032), Land use and land cover LULC (0.040), Depth of water (0.057), Population density (0.075), Distance from sensitive places (0.107), Distance from road (0.154), Distance from river (0.205) and Land value (0.282). After conducting thorough field visits, an analytical hierarchy process (AHP) under the MCDM approach using GIS reveals acceptable sites that were noted and referenced. Final results are validated through a receiver operating characteristic (ROC) curve using randomly selected 80 potential landfill-suitable site location points with higher accuracy, and a total of 93% of the area under the curve (AUC) has been found worthy to validate the spatial result. The present investigation revealed that only 0.65% of land is very highly suitable, 31.06% of land is highly suitable, 52.54% of land is moderately suitable and 14.74% of land is not suitable for landfilling in Balurghat Municipal area and surroundings respectively. The highly suitable site belongs to the Mamna, Katna, Kuaran, Amtali, Noksha, Bannapara, and Malancha villages of the study area which is a very negligible area. So, the planners should adopt alternative strategies like source minimization, composting, sanitary landfills and awareness programmes for sustainable solid waste management. Hence, the Balurghat Municipality administration, urban planners, and administrative authorities stand to gain valuable insights from the findings of this study as they endeavour to enhance the management of urban solid waste in the area.

Employing Plant Parasitic Nematodes as an Indicator for Assessing Advancements in Landfill Remediation

This research concentrated on the soil nematode communities inhabiting a reclaimed municipal waste landfill situated in Giedlarowa, southeastern Poland. The landfill, which was layered with natural soil in 2008 and cultivated with grass, served as the primary focus of the study. Samples for analysis were taken four times (October 2020 (Pf1), March 2021 (Pf2), October 2021 (Pf3), and March 2022 (Pf4)), with each time comprising three repetitions. The analysis was conducted employing microscopic examination, which enabled the identification of up to five trophic groups and species of plant-parasitic nematodes. During the assessment of nematode activity in the initial and subsequent growing seasons, it was found that Pratylenchus crenatus emerged as the predominant species among herbivorous nematodes in the plant-parasitic nematode (PPNs) community. Criconemoides informis, another nematode species, held a significant rank as well; their population during the third growing season formed the most substantial group among the PPN organisms dwelling in the soil. Nevertheless, interesting results were also obtained by populations of nematodes of the genus Hemicyclophora and Loofia, which were characterized by high densities. The analyzed soil environment showcased a C:N ratio spanning from 0.69 to 3.13. Furthermore, the soil samples exhibited variations in phosphorus content (P2O5), ranging from 4.02 mg/100 g to 10.09 mg/100 g. Criconemoides informis, Longidorus attenuates, Mesocriconema spp., and Bitylenchus maximus exhibited a positive correlation with soil mineral levels of calcium (Ca) and magnesium (Mg).

Enhancing biomethanation performance through co-digestion of diverse organic wastes: a comprehensive study on substrate optimization, inoculum selection, and microbial community analysis.

A blend of organic municipal solid waste, slaughterhouse waste, fecal sludge, and landfill leachate was selected in different mixing ratios to formulate the best substrate mixture for biomethanation. Individual substrates were characterized, and the mixing ratio was optimized with the help of a response surface methodology tool to a value of 1:1:1:1 (with a C/N ratio of 28±0.769 and total volatile fatty acid (VFA) concentration of 2500±10.53 mg/L) to improve the overall biomethanation. The optimized blend (C/N ratio: 28.6, VFA: 2538 mg/L) was characterized for physicochemical, biological, and microbial properties and subjected to anaerobic digestion in lab-scale reactors of 1000 mL capacity with and without the addition of inoculum. The biogas yield of individual substrates and blends was ascertained separately. The observed cumulative biogas yield over 21 days from the non-inoculated substrates varied between 142±1.95 mL (24.6±0.3 ml/gVS) and 1974.5±21.72 mL (270.4±3.1 ml/gVS). In comparison, the addition of external inoculation at a 5% rate (w/w) of the substrate uplifted the minimum and maximum cumulative gas yield values to 203±9.9 mL (35.0±1.6 mL/gVS) and 3394±13.4 mL (315.3±1.2 mL/gVS), respectively. The inoculum procured from the Defence Research and Development Organisation (DRDO) was screened in advance, considering factors such as maximizing VFA production and consumption rate, biogas yield, and digestate quality. A similar outcome regarding biogas yield and digestate quality was observed for the equivalent blend. The cumulative gas yield increased from 2673±14.5 mL (373.7±2.2 mL/gVS) to 4284±111.02 mL (391.47±20.02 mL/gVS) over 21 days post-application of a similar dosage of DRDO inoculum. The 16S rRNA genomic analysis revealed that the predominant bacterial population belonged to the phylum Firmicutes, with the majority falling within the orders Clostridiales and Lactobacillales. Ultimately, the study advocates the potential of the blend mentioned above for biomethanation and concomitant enrichment of both biogas yield and digestate quality.

Assessing of Manual Sorting in Municipal Solid Waste: A Study Case in São Paulo City

The dependence of political factors and the lack of integrated municipal waste (MSW) management in metropolitan regions of developing countries turn selective collection and circular economy great challenges to be implemented. This paper presents the characterization of the selective household MSW sent to a manual sorting plant located in the central area of the São Paulo City, aiming to assess the real rejects that are going to sanitary landfill after sorting process. Six sampling campaigns were carried out at the input and output of the sorting process during a year (2016 to 2017). The results show that the materials from the selective collection destined to the plant already arrive with 13.8 % of rejects. In addition, there are about 49.8 % of dry and recycled materials after the sorting process, half of them without commercial value, technical recycling solution available or non-identified. This study shown that, independent of the efficiency and social problems in the totally manual sorting process, which was higher than the local Materials Recovery Facilities, the lack of recycling industries and the presence of dry, but not recyclable materials, as composite packaging, non-identified plastics, Styrofoam and electronics difficult the profitability of this kind of plant.

Management of pharmaceutical waste in the Babylon Governorate

Globally, a massive amount of expired or leftover medications accumulates each year because of pharmaceutical overprescription, combined with overproduction. This pharmaceutical waste poses environmental, economic, and so-cial/ethical challenges. The objective of this study is to understand societal behavior regarding the disposal of medi¬cations in the Babylon Governorate and develop a prototype of a knowledge-based system that promotes proper disposal of pharmaceutical waste. A two-phase cross-sectional study was carried out. The first phase involved inter¬viewing pharmacists, while the second phase targeted the general population. A visit to Aljiumhori Hospital was made in order to assess the pharmaceutical waste disposal methods. The study found that most pharmacists (70%) and people (59.2%) prefer throwing expired medicine in the trash can. Moreover, 64.4% of the people participating in our study believe that placing unused drugs in special containers in each region is the best disposal method. Additionally, 48.2% of households are unaware of the environmental and health consequences of this waste. Pharmaceutical waste disposal in the Babylon Governorate is poorly managed. The absence of processes separating medical waste from general waste and the use of sanitary landfills as the sole method of disposal can pose serious environmental and public health risks. One can only address this issue with proper waste management, staff training, and protocol adherence.

Toxic heavy metals in a landfill environment (Vientiane, Laos): Fish species and associated health risk assessment

Leachates from municipal landfills introduce toxic heavy metals into water, causing bioaccumulation. This study assesses metal levels and potential human health risks associated with consuming Anabas testudineus and Channa striata. Inductively coupled plasma mass spectrometry detected Cd, Cu, Cr, Ni, Pb, and Zn in both fish species. Leachate metal concentrations meet international discharge standards, Cd, Cr, and Pb in the fish exceed the international accepted values. Gastrointestinal tract+liver samples show significant variation between species, particularly in Cd and Pb. EDI, THQ/HI, and TR for the both species fall below TDIs, lower than the limit of 1, and within the acceptable range of the US-EPA permissible limit, respectively. Fish consumption appears safe regarding carcinogenic risk, but exceeding metal limits could impact heavy metals accumulation in the local food chain. Raising public awareness is crucial, and governmental agencies and environmental organizations should enhance waste treatment technologies and enact relevant health legislation.

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.

Water balance estimation for an ordinary solid waste sanitary landfill in Costa Rica

To assess the necessity of treatment systems for leachate generated by ordinary solid waste deposited in a sanitary fill, accurate estimation of the leachate and gas amount produced during biodegradation process is essential. Climatic conditions at the site significantly influence leachate generation; therefore, accurate estimation of rainfall, temperature, solar radiation, and infiltration into the fill is imperative. In this study, we analyzed the water balance of the Miramar landfill in Costa Rica, assessed the amount of leachate produced using various methodologies, and then compared these findings with the field data to identify the best methodology for specific environmental conditions. To comprehensively analyze landfill behavior, as well as the leachate and gases generated from waste decomposition, determining the hydraulic properties of the materials inside the cells is necessary. These properties must consider variables such as the types of materials present at the site, age of the ordinary waste, and their densities. The hydraulic properties of the materials were obtained from various laboratory tests, which included determining the soil–water characteristic curve necessary for assessing unsaturated conditions in the solid waste. These properties are compared with the results of studies conducted in other landfills to validate the current methodology and the obtained results, which can be used for conducting studies on leachate generation or slope stability analysis for sanitary landfill slopes. The amount of leachate generated was estimated using the methodology proposed by Delgado A. (2018). Additionally, the Hydrologic Evaluation of Landfill Performance model (HELP V 4.0) was employed, demonstrating superior estimation compared to recorded field data. The HELP V 4.0 model facilitated the incorporation of different material layers and thicknesses, weather information at the site, slopes, and drainage conditions.

Case Study of Calculating Carbon Credits for Municipal Solid Waste Incineration Power Generation

By replacing landfilling with municipal solid waste incineration, the emission of greenhouse gases (GHGs) generated by sanitary landfilling is avoided. Simultaneously, the thermal energy generated by waste incineration is utilized for power generation, replacing an equivalent amount of electricity generated from fossil fuels, thereby reducing greenhouse gas emissions. Taking a certain municipal solid waste incineration project as an example, relevant methodologies ACM0022 and CM-072-V01 are applied, and simulated calculations of Certified Emission Reductions (CCER) are conducted through national verification. Combined with the current carbon trading prices, additional value-added benefits are calculated, providing a reference for exploring growth opportunities for waste incineration power plants and achieving carbon peak and neutrality targets for the power plants.

Nitrogen-Rich Sewage Sludge Mineralized Quickly, Improving Lettuce Nutrition and Yield, with Reduced Risk of Heavy Metal Contamination of Soil and Plant Tissues

Sewage sludge should primarily find use in agriculture, reducing the quantity directed towards alternative disposal methods like incineration or deposition in municipal landfills. This study evaluated the agronomic value and the risk of soil and plant tissue contamination with heavy metals in sewage sludge obtained from two wastewater treatment plants (WWTP). The experiment was arranged as a 2 × 5 factorial (two sewage sludges, five sanitation treatments), involving lettuce cultivation in pots over two growing cycles. The two sewage sludges were sourced from the WWTPs of Gelfa and Viana do Castelo and underwent five sanitation and stabilization treatments (40% and 20% calcium oxide, 40% and 20% calcium hydroxide, and untreated sewage sludge). The Gelfa sewage sludge, characterized by a higher initial nitrogen (N) concentration, resulted in greater dry-matter yield (DMY) (12.4 and 8.6 g plant−1 for the first and second growing cycles, respectively) compared to that from Viana do Castelo (11.0 and 8.1 g plant−1), with N release likely being a major factor influencing crop productivity. The high N concentration and the low carbon (C)/N ratio of sewage sludge led to rapid mineralization of the organic substrate, which additionally led to a higher release of other important nutrients, such as phosphorus (P) and boron (B), making them available for plant uptake. Alkalizing treatments further stimulated sewage sludge mineralization, increasing soil pH and exchangeable calcium (Ca), thereby enhancing Ca availability for plants, and indicating a preference for use in acidic soils. Cationic micronutrients were minimally affected by the sewage sludge and their treatments. The concentrations of heavy metals in the sewage sludge, soils, and lettuce tissues were all below internationally established threshold limits. This study highlighted the high fertilizing value of these sewage sludges, supplying N, P, and B to plants, while demonstrating a low risk of environmental contamination with heavy metals. Nevertheless, the safe use of sewage sludge by farmers depends on monitoring other risks, such as toxic organic compounds, which were not evaluated in this study.

Sustainable Space Transformation Design Strategies for Post-Landfill Closure

This study explores strategies for promoting sustainable development in urban public spaces by focusing on transforming and reusing closed landfill sites. Using landscape regeneration theory and the genius loci principle from architectural phenomenology, this research investigates spatial redesign techniques to facilitate the sustainable utilization of these sites. Through the analysis of three representative case studies and the specific application of these strategies to the Zhangjiawan Landfill site in Xining City, Qinghai Province, northwest China, this study elucidates practical approaches for spatial function transformation, constructing community networks, and heritage preservation and cultural continuity. From an urban macro-planning perspective, the post-closure design of the Zhangjiawan Municipal Landfill emphasizes organic linkages with adjacent city parks, fostering community integration and enhancing recreational opportunities for residents. The transformed area facilitates social interaction and cultivates a harmonious community atmosphere by repurposing the site to incorporate community farms, cultural centers, and outdoor sports facilities. Moreover, integrating leisure spaces, cultural exhibitions, and ecological restoration initiatives contributes to ecosystem rehabilitation while providing residents with leisure, social engagement, and cultural enrichment spaces. This research demonstrates how effective spatial transformation can promote environmental education, heritage preservation, and urban functionality in redeveloping closed landfill sites. The theoretical insights and practical design strategies presented contribute to advancing sustainable practices in urban planning and public space utilization.

Investigating potential protease activity of psychrotrophic bacteria from a municipal landfill for solid waste management

Investigating potential protease activity of psychrotrophic bacteria from a municipal landfill for solid waste management

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.

Geophysical exploration to assess leachate percolation and aquifer protectivity within hydrogeological units at a major open dump in Eket, Nigeria

Leachate contamination was investigated with geo-electrical methodologies at a major open dump in Eket, Southern Nigeria. The open dump is heavily polluted, degrades the environment, and has released toxins into the atmosphere. To model leachate percolation, vertical electrical soundings (VES) and electrical resistivity tomography (ERT) surveys, constrained by well lithological information, were undertaken at the site. The field equipment used for the geo-electrical investigations was the ABEM Terrameter SAS 1000 and its accessories. WINRESIST software was employed to process the sounding data and RES2DINV was employed to generate 2D tomograms indicating subsurface heterogeneity. Results obtained from sounding data showed that the subsurface had three lithological units (motley topsoil, fine sand and coarse sand), with coarse sand being the main hydrogeological unit comprising water-bearing formations. The first layer’s resistivity ranged from 84.9 – 625.4 Ωm with a mean of 360.4 Ωm; the second layer’s resistivity ranged from 7.5 – 1008.1 Ωm with a mean of 142.9 Ωm, and the third layer’s resistivity values ranged from 11.6 – 745.6 with a mean of 205.5 Ωm. The 2D resistivity tomograms indicated that leachate had percolated into groundwater resources. This is concerning as groundwater is the major water resource within the area. Measures of the Dar-Zarrouk indices and electrical reflection co-efficient indicated that the highly heterogenous region had moderate aquifer protective capacity and moderate aquifer potentiality. To mitigate contamination at the site, sanitary landfills, phyto-remediation, impermeable liners, or impermeable earth materials should be employed to diminish the rate of leachate percolation.

Green flocculation for sustainable remediation of municipal landfill leachate using Parkia biglobosa extract: optimization, mechanistic insights and implication for design

Green flocculation for sustainable remediation of municipal landfill leachate using Parkia biglobosa extract: optimization, mechanistic insights and implication for design

Bibliometric Aspects of Scientific Publications on the Circular Economy and Landfill

Objective: This article aims to identify the trends of scientific publications on sanitary landfills in the context of the circular economy as an instrument for urban solid waste management. Theoretical framework: The theoretical basis of this research sought to discuss the theme of circular economy and its relationship with solid waste management in different contexts of countries. Method: The methodology of this study was based on the bibliometric search in the Web of Science database from the keywords ("landfill" AND "environmental impact" OR "solid waste" AND "circular economy"), followed by the statistical analysis of the results and generation of graphs and tables in the bibliometrix application, qualitative analysis of the most cited articles and the methods used for 30 selected articles on waste management and circular economy was also carried out. Results and conclusion: The results identified 667 publications between the years 2008 and 2021, presenting a scientific growth and important contribution of the authors to studies on the circular economy applied to solid waste management in world countries. In view of the results, he realized that the circular economy contributes to the management of solid waste by establishing strategies in the countries to minimize the impacts and disposal of waste in landfills and insert the criteria of reuse, recycling and reinsertion of a product in the production chain. Research implications: The bibliometric research allows the creation of a reliable database of scientific publications, whose state-of-the-art on the circular economy applied to solid waste management allows the identification of the main practices applied in different countries worldwide. Originality/value: The study applies different methods to analyze the field of studies of the circular economy applied to landfills, in order to highlight the importance of the theme in the world scenario, as well as the innovations and strategies already executed. This article sought to present scientific trends, from which new research can be developed in different countries that seek to adopt sustainable alternatives for solid waste management.

Application of selected groundwater quality indices in anthropogenically transformed areas

Correctly assessing the impact of waste landfills on groundwater quality requires the development and use of comprehensive tools that consider the content of individual components in water, as well as those relating to the hydrochemical background. The article presents a comparative analysis of selected water quality indices used around the world to assess the environmental threat caused by sources of pollution. The paper includes the following indicators: Water Quality Index, Landfill Water Pollution Index, Nemerow Pollution Index, Backman Index, Canadian Water Quality Index, Horizontal Ratio, Enrichment Factor and Fuzzy Water Quality. Attention was paid to the values of individual indices, their applicability in municipal and industrial waste landfills, and limitations in their use. A literature review has proven that some indices, such as the Landfill Water Pollution Index and Nemerow Pollution Index, are used very often as they provide reliable results. Index methods help conduct rational water management, complement groundwater quality monitoring, and serve as a tool for making decisions in various water protection areas.