Typical Landfill Research Articles

Coal Ash Triggers an Elevated Temperature Landfill Development: Lessons from the Bristol Virginia Solid Waste Landfill Neighboring Community

Landfills for disposing of solid waste are designed, located, managed, and monitored facilities expected to comply with government regulations to prevent contamination of the surrounding environment. After the average life expectancy of a typical landfill (30 to 50 years), a large investment in the construction, operation, final closure, and 30-year monitoring of a new site is needed. In this case study, we provide a holistic explanation of the unexpected development of elevated temperature landfills (ETLFs), such as that in the city of Bristol (United States) on the border of the states of Virginia and Tennessee, including the initial role played by coal ash. Despite the increasing frequency of ETLF occurrence, there is limited knowledge available about their associated environmental problems. The study uses mixed (qualitative, quantitative, and mapping) methods to analyze (1) the levels of odoriferous reduced sulfur compounds, ammonia, and volatile organic compounds (VOCs) emitted, (2) the ratio of methane to carbon dioxide concentrations in five locations, which dropped from unity (normal landfill) to 0.565, (3) the location of gas well heads with gradients of elevated temperatures, and (4) the correlation of the filling rate (upward of ~12 m y−1) with depth for registered events depositing coal ash waste. The work identifies spatial patterns that support the conclusion that coal ash served as the initiator for an ETLF creation. The case of the city of Bristol constitutes an example of ETLFs with elevated temperatures above the regulatory United States Environmental Protection Agency (EPA) upper threshold (65 °C), having alongside low methane emissions, large production of leachate, land subsidence, and a large production of organic compounds. Such landfills suffer abnormal chemical reactions within the waste mass that reduce the life expectancy of the site. Residents in such communities suffer intolerable odors from fugitive emissions and poor air quality becomes prominent, affecting the well-being and economy of surrounding populations. Conclusive information available indicates that the Bristol landfill has been producing large amounts of leachate and hazardous gases under the high pressures and temperatures developed within the landfill. A lesson learned, which should be used to prevent this problem in the future, is that the early addition of coal ash into the landfill would have catalyzed the process of ETLF creation. The work considers the public health risks and socioeconomic problems of residents exposed to emissions from an ETLF and discusses the efforts needed to prevent further incidents in other locations.

Study on the water retention curve of shredded municipal solid waste considering the compressibility of specimens based on the centrifuge method.

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

MAP, PEOPLE, AND POLLUTANTS: LINKING SOCIOLEGAL-SPATIAL SCIENCE TO UNDERSTANDING WASTE MANAGEMENT IN SLEMAN REGENCY, INDONESIA

Indonesia’s waste management strategy promotes sustainable management and effective use of natural resources, as do many others. Due to a shortage of final processing sites (FPSs), ineffective solid waste management, and low environmental awareness, delivering information on ecologically friendly waste management has been difficult. Therefore, this research aims to locate typical landfills in highly populated metropolitan regions, explore solid waste management difficulties, and suggest feasible solutions. Sleman Regency, Province of the Special Region of Yogyakarta, was our focus while choosing an FPS location and assessing socioeconomic factors. We filter and classify quantitative and qualitative data from maps, observations, interviews, and document searches before using them in our mixed-methods approach. This study used sociolegal-spatial methods to improve waste management. The results show that geographical accuracy and comprehensiveness may be achieved within legal and institutional contexts. Trash reduction can be achieved if provincial, district/city, sub-district, and village administrations are compelled to adopt waste management policies and plans. These findings show that the government cannot accomplish its 2,030 waste elimination goal without systematic and long-term public infrastructure and village home socialisation.

Shrinkage and Consolidation Characteristics of Chitosan-Amended Soft Soil—A Sustainable Alternate Landfill Liner Material

Kuttanad is a region that lies in the southwest part of Kerala, India, and possesses soft soil, which imposes constraints on many civil engineering applications owing to low shear strength and high compressibility. Chemical stabilizers such as cement and lime have been extensively utilized in the past to address compressibility issues. However, future civilizations will be extremely dependent on the development of sustainable materials and practices such as the use of bio-enzymes, calcite precipitation methods, and biological materials as a result of escalating environmental concerns due to carbon emissions of conventional stabilizers. One such alternative is the utilization of biopolymers. The current study investigates the effect of chitosan (biopolymer extracted from shrimp shells) in improving the consolidation and shrinkage characteristics of these soft soils. The dosages adopted are 0.5%, 1%, 2%, and 4%. One-dimensional fixed ring consolidation tests indicate that consolidation characteristics are improved upon the addition of chitosan up to an optimum dosage of 2%. The coefficient of consolidation increases up to seven times that of untreated soil, indicating the acceleration of the consolidation process by incorporating chitosan. The shrinkage potential is reduced by 11% after amendment with 4% chitosan and all the treated samples exhibit zero signs of curling. Based on the findings from consolidation and shrinkage data, carbon emission assessments are carried out for a typical landfill liner amended with an optimum dosage of chitosan. In comparison to conventional stabilizers like cement and lime, the results indicate that chitosan minimized carbon emissions by 7.325 times and 8.754 times, respectively.

Performance of biocover in controlling methane emissions from landfill: A decade of full-scale investigation

Methane (CH4) emissions generated from waste management facilities represent a serious global warming concern. The objective of this study was to monitor a fully instrumented biocover capable of abating fugitive CH4 emissions from a closed landfill located at Kudjape, Saaremaa Island, Estonia. This investigation documented the alteration in the emission of CH4, carbon dioxide, and temperature fluctuation for a monitoring period of 10 years after the implementation of biocover. The fine fraction reclaimed from landfill mining along with natural mineral soil and sewage sludge compost in a proportion of 3:1:1 was used as a biocover substrate. CH4 emissions were monitored at the surface and from three locations at a regular depth of 25 cm up to 2 m inside the biocover layer. The measurements recorded from three gas monitoring wells present different scenarios of a typical landfill due to the heterogenous nature of waste and non-homogeneous distribution of landfill gas load to the methane-oxidation layer, namely, a) desired situation where a permanent reduction in CH4 concentration took place over time; b) hot-spot with an extremely high concentration of CH4 albeit consistent decrease over the years; c) a location with minimal initial concentration of CH4. Multivariate analysis showed that the CH4 concentration dynamics and parameters reflecting the CH4 oxidation process activity were different in biocover across the landfill. Based on data analysis results, the CH4 oxidation process stabilizes in biocover in 5–6 years after establishing the cover.

Degradation of biogas in a simulated landfill cover soil at laboratory scale: Compositional changes of main components and volatile organic compounds

A laboratory experiment lasting 28 days was run to simulate a typical landfill system and to investigate the compositional changes affecting the main components (CH4, CO2, and H2) and nonmethane volatile organic compounds from biogas generated by anaerobic digestion of food waste and passing through a soil column. Gas samples were periodically collected from both the digester headspace and the soil column at increasing distances from the biogas source. CH4 and H2 were efficiently degraded along the soil column. The isotopic values of δ13C measured in CH4 and CO2 from the soil column were relatively enriched in 13C compared to the biogas. Aromatics and alkanes were the most abundant groups in the biogas samples. Among these compounds, alkylated benzenes and long-chain C3+ alkanes were significantly degraded within the soil column, whereas benzene and short-chain alkanes were recalcitrant. Terpene and O-substituted compounds were relatively stable under oxidising conditions. Cyclic, alkene, S-substituted, and halogenated compounds, which exhibited minor amounts in the digester headspace, were virtually absent in the soil column. These results pointed out how many recalcitrant potentially toxic and polluting compounds tend to be relatively enriched along the soil column, claiming action to minimise diffuse landfill gas (LFG) emissions. The proposed experimental approach represents a reliable tool for investigating the attenuation capacities of landfill cover soils for LFG components and developing optimised covers by adopting proper soil treatments and operating conditions to improve their degradation efficiencies.

Identification of key surfactant in municipal solid waste leachate foaming and its influence mechanism

Serious foaming problems and the excessive consumption of defoamer have undoubtedly become one of the most critical problems that hinder municipal solid waste (MSW) leachate treatment efficiency and industry development. Since there is limited research penetrating the foaming mechanism and identification of the key surfactants, current defoaming and surfactant removal techniques lack pertinence and orientation. In this study, a foaming characterization device was developed and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC/MS/MS) was optimized to accurately identify the key surfactants affecting leachate foaming and offer a glimpse into their interaction mechanisms. This study collected leachate samples from 9 typical landfills and waste-to-energy facilities of various waste compositions, climatic conditions, ages, and geographical locations. The foaming problem of leachate was mainly centered on raw leachate and nanofiltration membrane concentrate (NFC). Fresh leachate performed with relatively low foaming capacity and foam stability, associated with low surfactant concentration. The pH value of the system was positively correlated with the concentration of anionic surfactants, indicating significant impacts on surfactant release in MSW. Since the distribution characteristics of linear alkylbenzene sulfonate (LAS) in leachate were consistent with the variety of foaming performances, LAS proved to be an indispensable surfactant in the leachate involved in this study, and its content proportion escalated to 92.87% in aged leachate.

Effects of perfluoroalkyl substances (PFAS) on antioxidant depletion from a high-density polyethylene geomembrane

To safely contain Per-and Polyfluoroalkyl substances (PFAS) in municipal solid waste landfills and contaminated soil monofills, it is necessary to understand how these substances interact with components of engineered systems designed to contain them. This paper examines the interaction between one of the most critical components of the system: a high-density polyethylene (HDPE) geomembrane. The same geomembrane is immersed in PFAS solution and synthetic municipal solid waste leachate containing PFAS for 2.5 years, and the effects of PFAS on antioxidant depletion time is examined. The geomembrane is incubated in ovens at 85-40 °C to obtain data for Arrhenius predictions at typical landfill temperatures. When exposed to PFAS solution alone, the antioxidant depletion times are smaller than when the same geomembrane is immersed in synthetic municipal solid waste leachate alone. The combination of the two has a synergistic effect which leads to an even greater reduction in antioxidant depletion time for this geomembrane, with results showing a 68% decrease in predicted antioxidant depletion time at a typical landfill temperature of 35 °C when PFAS is present in leachate. This study highlights the need to consider the potential impact of PFAS on the service life of geomembranes used to contain them.

Preparation and characterization of activated carbon modified by potassium for carbon dioxide/methane adsorption and separation

AbstractIn this study, potassium nitrate, which was confirmed feasible to improve the adsorption capacity of carbon dioxide and separation of carbon dioxide/methane mixture, was utilized to modify the commercial coconut shell activated carbon. Three parameters, including potassium ion concentration, modification temperature and modification time, were investigated. The best sample is obtained when impregnating in potassium nitrate solution of 0.1 mol L−1 at 55 °C for 12 h according to its adsorbed amount capacity and separation effect. The saturated adsorbed amount of carbon dioxide on the optimal sample reaches up to 12.25 mmol g−1. In addition, the selectivity for a binary mixture with volume ratio of 60/40, 50/50 and 40/60, which is considered in the range of typical landfill gas, are 6.86, 6.62 and 6.39, increasing by 45.9 %, 43.6 % and 41.4 %, respectively. The adsorbent obtained in this study is promising in the adsorption and separation of carbon dioxide and methane industrially. Moreover, the method of modifying by potassium ion provides a potential way in improving the property of the adsorbents.

The role of thermodiffusion in organic pollutant transport in landfill composite liner system

This paper presents a new analytical model for forecasting one-dimensional transient transport of organic pollutant in a typical landfill composite liner including a geomembrane (GMB), a geosynthetic clay liner (GCL) and a soil liner (SL). The model can consider the coupling effect of molecular diffusion, thermodiffusion, advection and linear adsorption processes. Zero concentration gradient condition is adopted at the bottom boundary. The separation of variables method and superposition principle are utilized to derive the solution. The solution is first validated against the results of experimental test and a numerical model. Then, the influence of thermodiffusion is investigated on pollutant migration in typical composite liner. The results reveal that thermodiffusion may significantly influence the pollutant migration. If the Soret coefficient exceeds 0.01 K−1, regardless of the combination conditions in terms of molecular diffusion, advection and adsorption, the influence of thermodiffusion generally cannot be ignored. The analytical model also can be utilized to design composite liner systems and to verify other numerical models.

The exposure risks associated with pathogens and antibiotic resistance genes in bioaerosol from municipal landfill and surrounding area

Pathogenic microbes with antibiotic resistance can thrive on municipal solid waste as nutrients and be aerosolized and transported to vicinities during waste disposal processes. However, the characterization of pathogenic bioaerosols and assessment of their exposure risks are lacking. Herein, particle size, concentration, activity, antibiotic resistance, and pathogenicity of airborne microorganisms were assessed in different sectors of a typical landfill. Results showed that active sector in downwind direction has the highest bioaerosol level (1234 CFU/m3), while residential area has the highest activity (14.82 mg/L). Botanical deodorizer from mist cannon can effectively remove bioaerosol. Most bioaerosols can be inhaled into respiratory system till bronchi with sizes ranging from 2.1−3.3 and 3.3−4.7 µm. Pathogenic bacteria (Bacilli, Bacillus, and Burkholderia-Paraburkholderia) and allergenic fungi (Aspergillus, Cladosporium, and Curvularia) prevailed in landfill. Although high abundance of microbial volatile organic compounds (mVOCs) producing bioaerosols were detected, these mVOCs contributed little to odor issues in landfill. Notably, surrounding areas have higher levels of antibiotic-resistance genes (ARGs) than inner landfill with tetC, acrB, acrF, mdtF, and bacA as dominant ones. Most ARGs were significantly correlated with bacterial community, while environmental parameters mainly influenced fungal prevalence. These findings can assist in reducing and preventing respiratory allergy or infection risks in occupational environments relating to waste management.

Investigation on characteristics of landfill leachate and feasibility study of low-temperature vacuum evaporation treatment

Leachate is characterized by poor biochemical properties and complex organic matter, which is potentially harmful to the surrounding environment. Low-temperature vacuum evaporation have been intensively studied for leachate treatment, but less attention was paid to monitoring the evolution of leachate organics. In order to analyze the component characteristics (especially organic matter) of typical landfill leachate and the feasibility of low-temperature vacuum evaporation process, fluorescence Excitation Emission Matrix (EEM) measurement coupling with Parallel Factor Analysis (PARAFAC) analysis and GC-MS was used to supplement the routine monitoring in order to reveal more insights into pollutants removal during the leachate treatment. The results showed that the main organic matter of landfill leachate was humic-like organic compounds, which accounted for 75–81%. The GC-MS showed that long-chain hydrocarbons, aromatic, aldehydes and esters compounds were abundant in the raw leachates. However, the humus and protein-based organic matter could be separated in a short time through low-temperature vacuum evaporation process, and the content of protein-based organic matter in condensate could be almost 100%, thus the biochemical properties were improved. The original CC, CO, C-N, C-O-C and other groups in the raw leachate were all disappeared after the low-temperature vacuum evaporation process, which was the essential reason for the transformation of fluorophores and improvement of biochemical properties.

Effect of landfill age on the physical and chemical characteristics of waste plastics/microplastics in a waste landfill sites

The landfills store a lot of waste plastics, thus it has been confirmed a main source for the occurrence of plastics/microplastic. Although there are some reports that microplastics (MPs) can generate in leachate and refuse samples from the landfill, it exist many blanks for the evolution of physical and chemical characteristics of waste plastics and microplastics with different landfill age. To explore the process that large pieces of plastic are fractured into microplastics, the waste plastics with landfill age from 7 to 30 years are surveyed from a typical landfill in Shanghai. The results show that PE and PP are the most common types of landfilling plastics, and their chemical composition also have changed due to the creation of CO and –OH. Moreover, the crystallinity is affected by plastic type and landfill age. The crystallinity of PP increased from 24.9% to 56.8%, but for PE, the crystallinity decreased from 55.6% to 20.8%. The mechanical properties of waste plastics were reduced significantly, which may be caused by changes in carbon-chain molecules. Al, Ti, Co, and other metal elements were detected on the plastic surface. The hydrophobic behavior of waste plastic is constantly decreasing (102.2°–80.1°) under long-term landfilling. By investigating the changes in the physical and chemical characteristics of waste plastics with different landfill age can shed light upon the process of environmental weathering of waste plastics. This provide theoretical guidance for reducing the transport of microplastics to the environment.

GIS and remote sensing coupled with analytical hierarchy process (AHP) for the selection of appropriate sites for landfills: a case study in the province of Ouarzazate, Morocco

The province of Ouarzazate has a population of 10,744 and is divided into 17 communes (15 rural communes and 2 urban communes), the majority of which have a population of less than 2000 people. Currently, more than 42% of the total population does not have access to a controlled landfill that meets all the socio-environmental criteria defined by Law 28-00 and its implementing regulations. The most typical landfills are located in small villages that resemble illegal dumps or dark areas close to the inhabitants. Moreover, in 2009, a controlled landfill was established near the city of Ouarzazate. Over time, urban extensions tend to move towards the site of the landfill following the development plans of the city, which influences the environmental life and health of the new population. Indeed, this landfill is considered to be located in the wrong place according to the results of our study; it does not meet all the main socio-environmental criteria. For these reasons, this study was conducted to identify appropriate landfill sites and waste transfer centers using geographic information systems (GIS) and remote sensing coupled with multi-criteria evaluation techniques such as AHP. Eleven criteria were selected, including distance to protected areas, wind direction, subsurface geology, lineament density, distance to surface water (river systems and dams), soil quality, distance to roads, elevation, and slope. The rasters of all the criteria were prepared, processed, and overlaid in the GIS environment by assigning each parameter its weight according to its importance. In the field, five sites have been provisionally selected, but only sites D and B have been given higher priority because of their geographical location, large surface area, geological imperviousness, zero risks, better soil quality, distance from any protection zone, any water point or hydrographic network, and their accessibility by provincial roads. These sites are located very close to the province’s waste hubs, which helps reduce the cost of transporting waste to the new landfill.

Coupled bio-hydro-thermo-mechanical interactions of landfilled MSW based on a multi-phase, multi-component numerical model

A clear understanding of long-term bio-hydro-thermo-mechanical (BHTM) behaviors of landfilled Municipal Solid Waste (MSW) is essential to better design and manage landfills, which requires the development of both analytical and numerical models that can represent typical behaviors of MSW. In this study, a novel multi-phase, multi-component numerical model, which incorporated the diffusion of landfill gas components, changes in the pH of leachate, and its solute migration as well as phase changes, was presented and adopted to investigate long-term coupled behaviors of MSW and the spatial and temporal variations of MSW properties. The numerical simulations were conducted on a typical landfill column and a landfill slope with relatively clear initial and boundary conditions to explore the coupled BHTM interactions of landfilled MSW. Based on the simulation results, the coupled mechanisms of MSW biodegradation, leachate and gas flows, MSW deformation, and heat transfer were revealed, and some significant insights on qualities of both leachate and landfill gas were also given. It has been found that the coupled model associated with its numerical code successfully predicted the long-term behaviors of landfilled MSW and qualities of leachate and landfill gas.

Investigation of microbial community structures in typical landfill cover soils of China

Investigation of microbial community structures in typical landfill cover soils of China

Investigation of microbial community structures in typical landfill cover soils of China

Investigation of microbial community structures in typical landfill cover soils of China

The problem of solid waste: origins, composition, disposal, recycling, and reusing

Solid waste disposal is a major challenge in many industrialized and developing nations, both in metropolitan regions as well as rural ones. The collection and disposal of municipal solid waste (MSW) is a serious issue facing metropolitan areas in many nations today. An effective MSW management strategy must satisfy all of these criteria: financial viability; technical feasibility; social and legal acceptability; and ecological friendliness. Small and large cities alike have a major difficulty in dealing with solid waste management.
 One of the current study topics is the valuation of food organic waste. Existing waste disposal methods include the typical landfill, incineration, composting, and other methods of handling solid waste. Composting and anaerobic digestion have traditionally been the most widely employed methods for the treatment and exploitation of the organic part of MSW (AD). The amount of organic solid waste (OSW) being generated globally is rising at an astronomical rate. Agricultural waste, domestic food waste, human and animal wastes, etc. comprise the majority of OSW. They're often used as animal feed, disposed of in landfills, or burnt. OAWs are made up of protein-, mineral-, and sugar-rich components that may be employed as substrates or raw materials in other processes.

Leachate from municipal solid waste landfills in a global perspective: Characteristics, influential factors and environmental risks

Landfilling is one of the most common measures for disposing municipal solid waste, while the environmental leakage of landfill leachate, a kind of wastewater with complex compositions and high-level pollutants, has become a crucial eco-environmental issue all over the world. Understanding the profiles of landfill leachate can be useful for promoting sustainable municipal solid waste management, however, there are very few studies at a global level because of data insufficiency. In this work, we established a global database on the physicochemical characteristics of landfill leachate from academic literature, including 1251 pieces of data from 236 provinces or cities in 51 countries. Concentrations of typical pollutants in landfill leachate were aggregated by different categories of countries, climate zones, and landfill ages. Correlations between typical leachate pollutants (chemical oxygen demand, biochemical oxygen demand after five days, ammonia nitrogen, sulfate, chloridion, potassium, cadmium, chromium, ferrum, nickel, and lead) and their influential factors (mean annual temperature, mean annual precipitation, landfill age, and the fraction of food waste) were analysed; and the environmental risks led by landfill leachate were assessed. Results showed that: (1) landfill leachate in developing countries at the dry temperature zone, as well as the moist and wet tropical zone, contained higher concentrations of chemical oxygen demand and biochemical oxygen demand after five days; (2) the percentage of food waste, as an influential factor, has a positive correlation with typical landfill leachate pollutants, with R2 varying from 0.07 to 0.18, indicating its high potential on transforming organic fraction in solid waste into leachate; (3) In regard to the environmental risk resulted from landfill leachate, the groundwater and surface water had greater risks than soil environment nearby the landfill. Besides, chemical oxygen demand, ammonia nitrogen, ferrum, chloridion and heavy metals, especially arsenic, cadmium, nickel, and manganese were dominating pollutants in groundwater and surface water. This work provides valuable data and parameters of global landfill leachate, which could be helpful to mitigate pollution from landfills and achieve the goals of sustainable municipal solid waste management.

Characterization and influence of odorous gases on the working surface of a typical landfill site: A case study in a Chinese megacity

Odor pollutants from a landfill can have serious impacts on the surrounding environment and nearby residents. Moreover, the variety and complexity of volatile organic compounds (VOCs) along with the landfill odor makes sampling and identifying compounds challenging. In this study, the authors monitored municipal solid waste (MSW)-related areas, sludge-related areas and waste coverage with the most malodorous compounds. In terms of all 120 VOCs, 67 malodorous VOCs with significant variations were categorized into six classes of compounds under all test conditions. Among the concentration characteristics, Site B concentrations were the highest. For the odor index (OI), the OI values of Site B were higher than those on other sites. The organic sulfides, organic acids and amine were the major malodorous pollutants emitted from landfill and influenced the residential area. Through a coefficient of divergence analysis, the CDjk values of Sites A (0.66) and B (0.69) were lower than others, indicating the effects of odor emission on the surrounding residential area were slightly more severe than on the other sites because of the meteorological condition during the study period. The results of this study can provide essential information to enhance understanding the actual odor emission intensity and characteristics of landfill and the migration, transportation and influence of odorant emissions on the working surface of the landfill.