Academic literature on the topic 'Landfill cover layer'

The main purpose of selecting proper designs for landfills is to accommodate quantities of waste without having a negative effect on the surrounding environment and human health. The Babylon Governorate (province) in Iraq was taken as an example of an arid area with very shallow groundwater and where irregular waste disposal sites had developed that had not been subject to international standards when they were selected for landfill use. In the current study, the suggested design for landfills is a base liner and final cover system. In this suggested design, the final cover system allows for three scenarios. The first scenario considers an evapotranspiration soil cover (ET) (capillary barriers type), the second scenario is a modified cover design of “RCRA Subtitle D”, and the third scenario is a combination of the first and second scenarios. The HELP 3.95 D model was applied to the selected landfill sites in the governorate to check if there was any penetration of the leachate that might in future percolate from the landfill’s bottom barrier layer in arid areas. The results from the suggested landfill design showed that there was no leachate percolation from the bottom barrier layer using the second and third scenarios. For the first scenario, however, there was a small amount of leachate through the bottom barrier layer in the years 2013 and 2014.

To promote environmental protection and sustainability, the use of plants and recycled wastes in geotechnical construction such as landfill covers is recommended. A landfill cover field test was conducted at the Shenzhen Xiaping landfill site, located in a humid climatic region of China. The main objective was to validate the field performance of a novel vegetated three-layer landfill cover system using recycled construction waste without the need of geomembrane. Unsieved completely decomposed granite and coarsely crushed concrete was used for the top and intermediate layers while sieved completely decomposed granite was used as the lowest layer. One section was transplanted with Bermuda grass while the other section was left bare. To assess the landfill cover performance, pore-water pressure, volumetric water content, percolation, and atmospheric parameters were measured for a period of 13 months under natural climatic conditions. The cumulative rainfall depth was about 2950 mm over the entire monitoring period. During rainfall, the presence of grass led to lower pore-water pressure (or higher suction) and volumetric water content in the three-layer landfill cover system. At the end of monitoring, the cumulative percolation was about 27 and 20 mm for the bare and grass-covered landfill covers, respectively. It is evident that the vegetated three-layer landfill cover system using recycled concrete without geomembrane can be effective in minimizing percolation in humid climates.

The main components of landfill gas are methane and carbon dioxide. Emissions of methane, a strong greenhouse gas, can be minimized by in situ oxidation in the bioactive cover layer. Typically, organic-rich porous materials such as compost are used for this process. In this study, the material for a biocover was obtained from the same landfill by landfill mining. The objective was to study the spatial distribution of gases and the efficiency of methane degradation in the biocover. The methane and carbon dioxide emissions were measured at 29 measuring points six times on the surface and once at a depth of 0.5 m. The highest values of both gases from the surface were recorded in July 2015: 1.0% for CO2 and 2.1% for CH4. Deeper in the cover layer, higher values of methane concentration were recorded. The results showed that (a) methane from the waste deposit was entering the biocover, (b) the migration of methane to the atmosphere was low, (c) fluctuations in the composition of gases are seasonal, and (d) the trend in the concentration of CH4 over time was an overall decrease. The described cover design reduces the CH4 emissions in landfills using elements of circular economy—instead of wasting natural soils and synthetic liners for the construction of the final cover layer, functional waste-derived materials can be used.

Introduction. The process of municipal solid waste (further MSW) generation is inextricably linked with the life of humanity. Every day each person generates some, a small amount of garbage. As a result millions of tons of MSW are generated daily in the world which are unsuitable for further use and require disposal. There are various ways of handling MSW including their treatment, recycling and disposal. In Russian Federation the vast majority of MSW are currently located on the specially equipped facilities –– waste landfills. To date the most common waste management strategy remains their placement in a landfill. Waste landfills are arrays of stored waste and are special engineering structures designed for the safe isolation of their contents from the environment. Landfill includes gas exhaust and leachate drainage systems, liner and cover systems. The main component of this structure is waste itself. Mechanical stability of landfills should be provided at all stages of waste storage as well as after it complete filling to designed capacity and at post-closure stage. As the result of deformation of unstable waste, all landfill systems can be destroyed up to the collapse of garbage array leading to the significant environmental and other consequences. One of the most common problems leading to the various incidents at landfills is an incorrect assessment of their stability. MSW landfill is a complex multiphase system in which various interacting processes occur simultaneously. The main factor in the calculation and design of landfills is the forecast of their settlements. Studies by many authors have established that biological decomposition has a significant impact on the properties of MSW after which the waste is considered as the landfill soil with a particle size of up to 20 mm. Materials and methods. The paper presents the methodology and the results of numerical modeling of stress-strain state of the designed object “Waste Landfill”. The facility is an array of municipal solid waste of 38 meters high. Waste is stacked in the layers of 1.75 m thick. Each waste layer is covered by the loam cover of 0.25 m thick. Stress-strain state of municipal solid waste including biological creep was modelled using well-known “Soft-Soil-Creep model” (SSC-model). Results. The results of numerical simulation of stress-strain state of the waste pile at all stages of the filling and in the post-closure period are presented. An assessment of the increase in the capacity of the landfill due to the compaction and biological creep has been performed. Stability analysis of the landfill and potential failure mechanisms at different stages of filling and operation are presented. Conclusions. Numerical modeling of stress-strain state of the MSW array using the “Soft-Soil-Creep model” allows to analyze the stability of the waste pile at any stage of landfill filling and evaluate the increase in landfill capacity due to the waste settlement taking into account the mechanical creep and biocompression during layer-by-layer filling.

Landfill cover systems have to serve as a hydraulic barrier as well as a gas barrier. The ability of multilayered cover systems to mitigate landfill gas migration was assessed. A finite element model, SEEP/W®, was used to simulate the landfill cover system. It was found that gas advective flux through the single GCL barrier was highly dependent on the differential gas pressure across the cover system and the conditions of soils above the barrier layer. The change from wet to dry condition resulted in the increase of gas flux up to 3000 times. Gas flux variations were much lower for the case of a single CCL. The use of a geomembrane on top of a CCL or a GCL significantly increased the effectiveness of the barrier layer in mitigating gas migration, particularly in a dry climatic condition. Furthermore, the change of the cover conditions had less effect on gas flux through a composite cover system than gas flux through a single barrier cover system. For the effective control of landfill gas migration, the cover system must be maintained at the high moisture content conditions.

This study uses several approaches to examine whether calcium-containing aggregate such as dolostone is a suitable drainage material for landfill leachate-collection systems. The thermodynamic stability of carbonate drainage materials has been assessed using published leachate data from landfills in the United Kingdom and leachate sampled from four large landfill sites of variable age in southern Ontario. Electron-microbeam techniques have been used to check for dissolution in dolomitic stone exhumed from the drainage layer of the Keele Valley Landfill leachate-collection system and from experiments that simulated landfill conditions. The mineralogy of cover soils applied daily to the landfill has been compared to the drainage stone and detrital material occluding pore space in the leachate-collection system to evaluate their relative contributions to clogging. The data suggest that dissolution of dolomitic drainage stone is not significant and contributes little to the clogging of landfill leachate-collection systems. However, crystallization of secondary calcite occurs about the dolomitic stones and sizeable quantities of inorganic fines, including dolomite, were present within some samples of "clog material" exhumed from the Keele Valley collection system. Most of the dolomitic fines probably were generated during construction of the collection system; such creation of fines ought to be minimized in future landfill developments.Key words: leachate-collection system, landfills, clogging, mineralogy, leachate chemistry.

Landfills are complex systems which could potentially contaminate the environment. It should be prevented by providing impermeability during the landfill design. In that aim related regulations should be followed and adequate materials that provide impermeability should be used. The first part of the paper presents review of the current regulations, interpretations, and recommendations from U.S., EU and Republic of Serbia. Knowing that the Serbian regulation should fully follow related European Directive, in analyses some inadequate formulations and terms were observed related to the Directive Annex I, 3.2. Request of the Regulation that deals with the bottom of the landfill leakage is formulated differently than in Directive as well. Mentioned problems enable some design solutions which are not among the best available techniques. In the second part the paper presents comparative analysis of possible alternatives in impermeable layer design, both for the bottom and landfill cover. Some materials like clay, CCL, GCL might not be able to satisfy prescribed requirements. The longest lifetime and the lowest coefficient of permeability, as well as excellent mechanical, chemical and thermal stability, show the mixture of sand, bentonite and polymers (PEBSM).

Landfills come with a cover barrier which includes a compacted silty clay liner essential to safety on site. However this barrier encounters problems, especially those related to the differential settlement, which may cause stress in the clay layer leading to the development of cracks. Generally speaking, tensile stress damage and shearing are observed on the cap cover. Due to the weak mechanical performance of the clay layer it was proposed to add polypropylene fibre reinforcement. Direct tensile tests and compression tests under low confinement were carried out on unreinforced and reinforced soils. An improvement in soil resistance and in the brittleness index of fibre-reinforced clay was characterised. The proposed solution, technically feasible, enabled an optimization of the thickness of the mineral barrier.

A landfill is a large bioreactor, in the body of which landfill gases are generated due to anaerobic degradation of organic material. According to European legislation, the emission of methane, one of the landfill gases, should be kept to a minimum as methane is a greenhouse gas and has a significant impact on our climate. With large volumes, methane can be used for energy production, but if the collection is uneconomic, an attractive option would be to cover the landfill with a bioactive layer to degrade methane in-situ. In operational Uikala sanitary landfill, Estonia, where active gas collection system exists, it was found that uncaptured gas could be degraded in bioactive cover layer. To check whether such cover layer could be built from fine fraction after mechanical biological treatment (MBT), two experimental cells were constructed (0-20 mm and 0-40 mm fractions). The paper presents the design of experimental cells, a description of materials for construction and construction process, and preliminary results. Measurement system was installed in both cells: gas wells at eight depths and on three locations on surface. Three-level lysimeters were installed to determine water balance. Research is planned for two years with monthly gas sampling. The objective of the work is proving which of the MBT fractions, 0-20 or 0-40 mm, function better for methane degradation. Confirmation of the methane degradation efficiency in fine MBT fraction is important not only from the ecological point of view. The use of a fine fraction as a material for methane degradation layer would reduce the cost of processing this fraction and become a good example to a circular economy since the landfill would be recultivated using its own resources.

Current Indiana regulations regarding vegetative covers on multi-layer cap systems recommend a standard seeded turf as defined by the Indiana Department of Transportation. Although in its infancy, the use of native prairie grasses and forbs is beginning to generate interest as a viable vegetative cover. This creative project examines past influences that dictated the selection of vegetative covers, examines the use of native prairie grasses and forbs, and creates and applies a design "model" for an existing hazardous waste site located in Albany, Indiana.The goals of this creative project are to identify standard design guidelines for vegetative covers on hazardous waste and landfill multi-layer cap systems, evaluate standard guidelines and case studies of hazardous waste site vegetative covers, recommend changes to standard design guidelines, recommend an alternative vegetative cover using native prairie plants, apply new design guidelines to an existing hazardous waste site (Muncie Racetrack Site) using the alternative cover, and evaluate the results of the guidelines with the alternative cover.
Department of Landscape Architecture

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico
Nesta pesquisa, uma CÃlula Experimental (CE) de ResÃduos SÃlidos Urbanos (RSU) foi instalada numa Ãrea nÃo utilizada do Aterro SanitÃrio Metropolitano Oeste de Caucaia (ASMOC), RegiÃo Metropolitana de Fortaleza, com o objetivo de se estudar o comportamento de gramÃneas na sua superfÃcie, visando a reduÃÃo das emissÃes de CH4 e CO2 para a atmosfera e a produÃÃo de biomassa vegetal. As estimativas das emissÃes de gases foram realizadas por meio de ensaios com placa de fluxo estÃtico na cobertura convencional (branco) e nas coberturas cultivadas, alÃm das mediÃÃes feitas no dreno; todos em duas campanhas. Os cultivos de capim MombaÃa, Massai, Andropogon, Buffel e da grama Bermuda foram avaliados com relaÃÃo as caracterÃsticas morfogÃnicas, estruturais, produtivas e nutricionais. A Ãrea que recebeu a CE foi previamente estudada por meio do reconhecimento do perfil estratigrÃfico do subsolo e do nÃvel d‟Ãgua, caracterizaÃÃo dos solos em termos geofÃsicos (granulometria, limites de consistÃncia, compactaÃÃo Proctor Normal, permeabilidade à Ãgua) e quanto à fertilidade. Os RSU foram estudados quanto à composiÃÃo gravimÃtrica, densidade aparente, teor de umidade e seu lixiviado analisado do ponto de vista fÃsico-quÃmico. Os gases emitidos pelo dreno, na primeira campanha (1ÂC) foram compostos, em mÃdia, por 14,7% de CO2, 8,0% de CH4, 11,4% de O2 e 65,9% de outros gases. Na segunda campanha (2ÂC) houve um aumento na concentraÃÃo (%) dos dois principais gases de interesse (CO2: 0,3 vezes e CH4: 0,5 vezes) e reduÃÃo na concentraÃÃo dos demais (O2: 0,2 vezes e OG: 0,1 vezes): 19,0% de CO2, 11,8% de CH4, 8,7% de O2 e 60,4% de outros gases. Os gases emitidos pela cobertura (branco) foram (em %) menores que os emitidos pelo dreno, mostrando retenÃÃo: 1ÂC = 11,6% de CO2, 6,5% de CH4, 9,1% de O2 e 72,7% de outros gases; 2ÂC = 14,9% de CO2, 9,4% de CH4, 7,2% de O2 e 68,5% de outros gases. Em relaÃÃo aos fluxos mÃssicos houve aumento entre as campanhas (mÃdia): 2,5 x 10-3 e 3,6 x 10-3 g/m2.s de CH4 (1ÂC e 2ÂC, respectivamente), 1,2 x 10-2 e 1,5 x 10-2 g/m2.s de CO2 (1ÂC e 2ÂC). Os fluxos volumÃtricos foram (mÃdia): 4,0 x 10-6 e 5,7 x 10-6 m3/m2.s de CH4 (1ÂC e 2ÂC) e 7,0 x 10-6 e 8,8 x 10-6 m3/m2.s de CO2 (1ÂC e 2ÂC). Cabe observar que os fluxos estiveram dentro dos intervalos da literatura. Em relaÃÃo aos cultivos, observou-se que mesmo colocadas sobre solo tÃpico de aterro sanitÃrio e sem tratamento especial na cobertura ou no cultivo, as sementes dos quatro capins estudados e da grama Bermuda apresentaram germinaÃÃo dentro dos prazos biolÃgicos previstos. Assim, houve sobrevivÃncia dessas espÃcies sobre o solo do aterro sanitÃrio, porÃm com indicadores de desenvolvimento vegetal menores em relaÃÃo a literatura, contribuindo para isso o efeito negativo da extrema compactaÃÃo da cobertura e o baixo grau de fertilidade do solo. Cada cultivo teve uma capacidade diferente de impedir as emissÃes dos gases pela cobertura. Em ordem decrescente, observou-se (mÃdia): MombaÃa (2,6 e 3,8% de CH4 na 1ÂC/2ÂC; 4,6 e 6,0% de CO2 na 1ÂC/2ÂC), Massai (2,0 e 2,8% de CH4; 3,5 e 4,5% de CO2), Andropogon (1,1 e 1,5% de CH4; 1,9 e 2,5% de CO2), Bermuda (0,9 e 1,3% de CH4; 1,6 e 2,0% de CO2) e capim Buffel (0,4 e 0,6% de CH4; 0,5 e 0,6% de CO2). Os fluxos mÃssicos e volumÃtricos tambÃm foram menores no solo cultivado com capim MombaÃa e maiores no capim Buffel e isso manteve relaÃÃo com as principais caracterÃsticas morfogÃnicas, estruturais, produtivas e nutricionais utilizadas na avaliaÃÃo da sobrevivÃncia e desenvolvimento dos cultivos.
An Urban Solid Waste (USW) Experimental Cell (EC) was set up in an unused area of the West Metropolitan Landfill in Caucaia (ASMOC), in the Metropolitan Region of Fortaleza, with the aim of studying the behavior of different grasses planted on its cover layer in order to reduce atmospheric emissions of CO2 and CH4 and for the production of plant biomass. Gas emissions were tested with static flow plates on the normal cover layer (blank) and on the planted areas, in addition to the measurements taken on the landfill drainage. All measurements were made in two different campaigns. The morphogenesis, structural, productive and nutritional features of the Mombasa, Massai, Andropogon, Buffel and Bermuda grasses were evaluated. The area on which the EC was located was studied prior to the seeding, including a survey of the subsoil stratigraphic profile and groundwater levels, a geophysical soil characterization (grain size, Atterberg limits, normal Proctor compaction, water permeability) and fertility. The USW was studied for its gravimetric composition, density and moisture content and its leachate was analyzed from a physical and chemical perspective. The gases emitted by the drainage in the first campaign (C1) were composed on average by 14.7% CO2, 8.0% CH4, 11.4% O2, and 65.9% of other gases. In the second campaign (C2) there was an increase in the concentration (%) of the two main gases of interest (CO2: 0.3 times; CH4: 0.5 times) and a reduction in the concentration of the others (O2: 0.2 times, and other gases 0.1 times), with the following concentrations: CO2 19.0%, CH4 11.8%, O2 8.7%, and 60.4% of other gases. The gas emissions of the normal cover layer (blank) were lower than those of the drainage, showing a certain retention: C1: CO2 11.6%, CH4 6.5%, O2 9.1% and 72.7% of other gases; C2: CO2 14.9%, CH4 9.4%, O2 7.2% and 68.5% of other gases. Regarding the mass flows, there was an increase between the two campaigns (mean values): 2.5 x 10-3 and 3.6 x 10-3 g/m2.s of CH4 (C1 and C2, respectively), and 1.2 x 10-2 and 1.5 x 10-2 g/m2.s of CO2 (also for C1 and C2, respectively). The volumetric flows were the following (mean values): 4.0 x 10-6 and 5.7 x 10-6 m3/m2.s of CH4 (C1 and C2); and 7.0 x 10-6 and 8.8 x 10-6 m3/m2.s of CO2 (C1 and C2). The flows were within the ranges reported in the literature. Regarding the grass crops, it was observed that even though they were planted on a typical landfill soil without any special soil or cultivation treatment, the seeds of all five studied grasses germinated within the expected biological times. These species survived on the soil of the landfill yet presented smaller plant development indicators than those reported in the literature. The negative effect of an extreme soil compaction and low soil fertility contributed to such lower developmental results. Each crop showed a different ability to prevent gas emissions through the cover layer. We present them in descending order (mean values), namely: Mombasa (2.6% and 3.8% of CH4 in C1/C2, and 4.6% and 6.0% of CO2 in C1/ C2); Massai (2.0% and 2.8% of CH4, and 3.5% and 4.5% of CO2); Andropogon (1.1% and 1.5% of CH4, 1.9% and 2.5% of CO2); Bermuda (0.9% and 1.3% of CH4, 1.6% and 2.0% of CO2); and Buffel (0.4% and 0.6% of CH4, 0.5% and 0.6% of CO2). The volumetric and mass flows were lower in the soil planted with Mombasa grass and higher in that planted with Buffel. This was related to the main morphogenesis, structural, nutritional and productive features used in the assessment of crop survival and development.

Populiariausias atliekų valdymo metodas ne tik pasaulyje, bet ir Lietuvoje vis dar išlieka atliekų deponavimas sąvartynuose. Lietuvoje, 2009 metų duomenimis, sąvartynuose buvo pašalinta 90,6 % atliekų. Šiame darbe trumpai aptariama atliekų sąvartynų įrengimo, bei sąvartyno lauko uždengimo tvarka ir rekomendacijos. Aptariami keturiuose uždarytuose Kauno rajono sąvartynuose (Digrių, Gaižėnėlių, Miškinių ir Ilgakiemio) atlikti uždengiamojo sluoksnio būklės tyrimai. Remiantis gautais tyrimų duomenimis daromos išvados apie sąvartynų būklę. Gauti rezultatai rodo, jog ne visi sąvartynai rekultivuojami laikantis taisyklių ir rekomendacijų. Kadangi pastaraisiais dešimtmečiais labai susirūpinta švarios aplinkos išsaugojimu, ekologija ir aplinkos taršos mažinimu, aktualus klausimas išlieka tinkamas atliekų tvarkymas, sąvartynų tinklo optimizavimas (taip pat visiškas jų atsisakymas, dėl valstybių politikos kitaip tvarkyti atliekas, pavyzdžiui, jas deginant), Lietuvoje svarbus klausimas yra senų ir nebenaudojamų savartynų uždarymas. Reikia pasirinkti tinkamą sąvartyno uždarymo būdą, kadangi blogai rekultivuotas sąvartynas, gali sukelti didelę ekologinę katastrofą.
The most popular method of waste management not only in the world, but also in Lithuania, remains depositing waste in landfills. In Lithuania (according to the 2009 data) 90.6% of waste was deposited at the landfills. This work discusses the installation of the landfill, the procedures and recommendations of creating the final landfill covers. There was performed a research on four closed landfills in Kaunas district (Digriai, Gaižėnėliai, Miškiniai and Ilgakiemis) to find out the condition of landfill’s cover layer. According to the findings, conclusions about the condition of these landfills are made. The results show that not all landfills undergo recultivation in accordance with the rules and guidelines. Preservation of the clean environment, ecology and reduction of the environmental pollution is the major concern for the last decades and the most relevant question remains the proper waste management, optimization of the landfill network (as well as the complete abandonment of the landfills, because of different waste management policies, such as incineration). Still, Lithuania has to deal with old and disused landfills, so the proper way to close the landfill must be chosen, because poorly recultivated landfill can cause large ecological catastrophe.

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Capes
Uma das formas de tratamento de Resíduos Sólidos Urbanos (RSU) que mais se destaca são os aterros sanitários, que possui como vantagens, a facilidade de operação, menor custo quando comparado às outras técnicas (triagem, tratamento biológico, incineração, entre outras) e a existência de um plano de monitoramento contínuo. O aterro sanitário utiliza uma camada de cobertura final de solo compactado com a finalidade de isolar os resíduos do meio externo, minimizar a entrada de água para o interior do maciço sanitário, reduzir as emissões de gases para a atmosfera, evitar a proliferação de roedores e vetores de doença, entre outras. As Normas Brasileiras não regulamentam o tipo de solo a ser utilizado, nem técnicas de execução de camadas de coberturas de aterros, nem a forma de monitoramento, possuindo como única exigência o atendimento de um coeficiente mínimo de permeabilidade à água. Diante disso, este trabalho tem como objetivo analisar o desempenho do solo compactado utilizado na camada de cobertura final de um aterro de resíduos sólidos, tendo como campo experimental o Aterro Sanitário de Campina Grande/PB. Para isso foi realizada a caracterização física do solo utilizado na camada, verificação de seus parâmetros quanto à viabilidade para uso em aterros sanitários, análise físico-química e mineralógica, obtenção da curva de retenção de água no solo e análise dos pontos experimentais da curva aos ajustes propostos na literatura. Foi verificado o comportamento do solo frente aos processos de umedecimento/secagem e expansão/contração, observação da relação entre a umidade ótima de compactação e o ponto de entrada generalizada de ar (GAE), além da verificação da variação da umidade do solo em um perfil experimental da camada de cobertura por meio de sensores capacitivos. Os resultados demonstraram que, o solo possui permeabilidade à água admissível para uso em aterros sanitários segundo as normas nacionais e internacionais. O ajuste da curva de Van Genuchten aos pontos experimentais da curva de retenção atendeu às condições de concordância a partir dos parâmetros estatísticos analisados. A umidade ótima de compactação do solo possui valor próximo ao GAE, onde se inicia a dessaturação do solo, no qual o ar começa a entrar nos maiores poros formados pela drenagem da água e perda de umidade. Deve-se realizar a compactação do solo na energia proctor normal obedecendo à adição de água suficiente para atingir a umidade ótima, em um intervalo aceitável de ± 2%. Pode-se concluir que, o tipo de camada de cobertura final (solo argiloso compactado) utilizado é inadequado para a região do aterro devido às características climatológicas a que o solo está submetido e a ausência de proteção vegetal superficial. A aplicação da energia proctor normal para compactação do solo da camada de cobertura do aterro sanitário proporciona condições favoráveis à redução da permeabilidade à água do solo. A curva de retenção de água no solo da camada de cobertura do aterro sanitário apresenta comportamento unimodal e possui características de um solo argiloso. A utilização de sensores capacitivos se mostrou como uma técnica eficaz para aquisição automática da umidade do solo e verificação da sua variação ao longo do tempo, bem como, o monitoramento da sucção pela espessura da camada de cobertura final de solo compactado.
One of the forms of treatment of Municipal Solid Waste (MSW) is the landfill, which has the advantages of ease of operation, lower cost when compared to other techniques (sorting, biological treatment, incineration, among others) and the existence of a continuous monitoring plan. The landfill uses a final cover layer of compacted soil to isolate residues from the external environment, minimize the entry of water into the landfill, reduce the emission of gases into the atmosphere, prevent the proliferation of rodent and vectors of disease, among others. The Brazilian Regulations do not regulate the type of soil to be used, nor techniques for implementing layers of landfills, nor the form of monitoring, having as sole requirement the attendance of a minimum coefficient of water permeability. The objective of this work is to analyze the performance of the compacted soil used in the final cover layer of a landfill, with the Landfill Campina Grande/PB as an experimental field. The physical characterization of the soil used in the layer, verification of its parameters regarding the feasibility for use in landfills, physical-chemical and mineralogical analysis, obtaining the water retention curve in the soil and analysis of the experimental points of the curve were performed adjustments proposed in the literature. The behavior of the soil was verified in relation to the wetting/drying and swell/contraction processes, observation of the relation between the optimum compaction humidity and the Generalized Air Entry (GAE), besides the verification of soil moisture variation in one experimental profile of the cover layer by means of capacitive sensors. The results showed that the soil has permeability to water admissible for use in landfills according to national and international standards. The adjustment of the Van Genuchten curve to the experimental points of the retention curve met the conditions of agreement from the statistical parameters analyzed. The optimum soil compaction humidity has a value close to GAE, where soil desaturation begins, in which the air begins to enter the larger pores formed by water drainage and moisture loss. Soil compaction must be carried out in normal proctor energy by adding sufficient water to achieve optimum moisture, within an acceptable range of ± 2%. It can be concluded that the type of final cover layer (compacted clay soil) used is unsuitable for the landfill region due to the climatological characteristics to which the soil is subjected and the absence of surface vegetation protection. The application of normal proctor energy to soil compaction of the landfill cover layer provides favorable conditions for the reduction of soil water permeability. The water retention curve in the soil of the final cover layer of the landfill presents unimodal behavior and has characteristics of a clay soil. The use of capacitive sensors proved to be an effective technique for automatic acquisition of soil moisture and verification of its variation over time, as well as the monitoring of suction by the thickness of the final cover layer of compacted soil.

No Brasil, se espera ter até 2014, de acordo com o prazo da Política Nacional de Resíduos Sólidos, todos os lixões erradicados e os resíduos sólidos urbanos gerados depositados em aterros sanitários. Atualmente, os projetos de aterros sanitários dão oportunidade para um nicho de mercado, o da fonte de geração de energia. Um parâmetro de controle da poluição do ar causada pelos aterros sanitários são as chamadas camadas de cobertura. Nesse contexto, é de fundamental importância o estudo de camadas de cobertura de resíduos por ser um importante elemento de projeto para evitar ou minimizar a poluição do ar devido aos gases gerados em aterros sanitários de resíduos sólidos, já que é o elo existente entre o ambiente interno dos resíduos e a atmosfera. A presente pesquisa aborda o comportamento dos gases em relação à camada de cobertura existentes na CTR de Nova Iguaçu e no Lixão remediado de Seropédica. Foram realizados ensaios de Placa de Fluxo, medição de pressão e concentração dos gases no contato solo-resíduo e emissões dos gases pelos drenos, além das análises de solo in situ e em laboratório. Os ensaios foram realizados de outubro a novembro de 2012. Os resultados indicaram uma inexistência de fluxo de gases pela camada de cobertura, que possui 1,10 m de espessura, do lixão de Seropédica, sendo encontrado apenas fluxo nos drenos. Na CTR Nova Iguaçu, foi verificada que praticamente a inexistência de fluxo de gases com o sistema de gás ligado, mesmo possuindo uma camada de cobertura de 0,8 m.
In Brazil, according to the timeframe given by the National Policy of Solid Waste, by 2014, every dump will be eradicated and every municipal solid waste generated will be deposited in landfills. Currently, the landfill projects provide an opportunity for the market, which is a source of energy. A parameter of control of the air pollution caused by landfills is called cover layers. In this context, it is important the study of the cover layers to avoid or minimized the air pollution due to gases generated in landfills, which is the link between the solid waste and the atmosphere. This research addresses the behavior of the gases in relation to the cover layers on the CTR Nova Iguaçu and Dump of Seropédica. Six test trials of the Flux chamber, pressure measurement and concentration of gases in the soil-residue contact and emissions of gases through the drains, in addition to in situ soil analysis and laboratory analysis. The tests trials were performed from October, 2012 to November, 2012. The results indicated no gas flow through the cover layer, which has a thickness of 1.10 m, of the dump of Seropédica, where the gas flow was only encountered through the drains. In CTR Nova Iguaçu, the gas flow was almost inexistent, even having a cover layer of thickness of 0.8 m.

Esta pesquisa apresenta uma revisão bibliográfica sobre as emissões de metano em aterros sanitários, os conceitos de geração de gases em aterros sanitários, movimentações de gases em aterro, apresenta os métodos de medição de gases in situ, tipos de cobertura finais para aterros e a oxidação do metano na camada de cobertura. A pesquisa também tem como objetivo medir as emissões de gases e avaliar a infiltração das águas pluviais através da camada de cobertura do aterro sanitário da CTR Nova Iguaçu. As medições foram realizadas nos meses de julho a novembro de 2010, na camada de cobertura monolítica existente e em outra construída sobre uma barreira capilar. Sensores para medir temperatura e umidade foram instalados em profundidade nas duas camadas. Foram realizados ensaios de placa de fluxo para medir a composição dos gases e o fluxo através dos dois tipos de camadas, e avaliadas duas situações: com os poços de extração de gás ativos e desligados. Os sensores indicaram que em período de baixa pluviosidade, a barreira capilar apresenta uma eficácia superior à camada monolítica, e com a intensificação das chuvas, as umidades medidas nos dois tipos de camadas aumentam, e na barreira capilar o gradiente estabelecido entre os sensores diminui, indicando uma possível tendência à saturação desta barreira capilar. Porém, com a paralisação das chuvas, recupera e retoma sua condição inicial. Os resultados de medidas dos gases demostraram a eficiência do sistema de extração de gás quando ativado, resultando em emissões quase nulas de metano e gás carbônico nos dois tipos de camadas. No entanto, quando o sistema está desativado, as emissões através da camada monolítica são cerca de 3 vezes maiores do que através da barreira capilar.
This research presents a literature review on methane emissions from landfills, the concepts of landfill gas generation, the landfill internal gas flow, introduces the methods of measurement of gases "in situ", types of final landfill coverage and the methane oxidation in the cover layer. The research also purposes to measure greenhouse gas emissions and to evaluate the infiltration of rainwater through the landfill cover layer of the CTR Nova Iguaçu. Measurements were made in the months from July to November 2010, the existing monolithic cover layer and another built on a capillary barrier. Sensors to measure temperature and humidity were installed in two layers in depth. Plate assays were performed to measure the flow of the gas composition and flow through the two types of layers, and evaluated two situations with the gas extraction wells active and off. The sensors have indicated that in times of low rainfall, the capillary barrier has superior efficacy to the monolithic layer, and with the intensification of rain, the moisture content measured on two types of layers increase, the capillary barrier and the gradient established between sensors decreases, indicating a possible trend to saturation of capillary barrier. However, with the stoppage of rain, recovers and returns to its initial condition. The results of measurements of gases demonstrated the efficiency of extraction of gas when activated, resulting in near zero emissions of methane and carbon dioxide in the two types of layers. However, when the system is off, the emissions through the monolithic layer is about three times larger than through the capillary barrier.

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Funda??o de Amparo ? Pesquisa do Estado da Bahia - FAPEB
The water balance is an important aspect on development of a landfill project, and the choice of material for the cover layer will influence the generation of percolated liquids. Considering the composition and characteristics of cover layers, it becomes necessary the conventional material substitution. Therefore, this study compared the construction civil waste (CCW) to the soil from the university campus - UEFS in Feira de Santana/BA as used in evapotranspiration cover layer for landfill, using the water balance models Fenn et al. (1975) and S?o Mateus et al. (2012). The results showed that both materials have the same behavior for the Fenn et al. (1975) method, where the CCW generates less liquid than MSW to the ground. By the method of S?o Mateus et al. (2012), the CCW and the soil allow the passage of water to the MSW in different behaviors, and the soil promoted greater liquid infiltration, about 95.5% higher than the CCW. When the methods were compared, S?o Mateus et al. (2012) presented higher water infiltration to the MSW in the simulation with the soil, in relation to the method of Fenn et al. (1975), and smaller with the CCW, this occurs due to the distinction of the input parameters for the materials, highlighting the influence of the permeability coefficient in the water balance.
O balan?o h?drico ? parte importante no processo de elabora??o de um projeto de aterro sanit?rio, visto que a escolha do material para a camada de cobertura influenciar? na gera??o de l?quidos percolados. Tendo em vista a necessidade da utiliza??o de materiais para a composi??o das diversas camadas dos sistemas de cobertura, torna-se indispens?vel o estudo de materiais alternativos para a substitui??o dos materiais usados originalmente. Para tanto, este trabalho comparou o res?duo da constru??o civil (RCC) com o solo do campus universit?rio da UEFS em Feira de Santana/BA utilizados como camada de cobertura para aterro sanit?rio, utilizando os modelos de balan?o h?drico de Fenn et al. (1975) e S?o Mateus et al. (2012). Os resultados mostraram que, pelo m?todo de Fenn et al. (1975), ambos os materiais possuem comportamento semelhante, sendo que o RCC infiltrou menor quantidade de ?gua para o res?duo s?lido urbano (RSU) do que o solo. Pelo m?todo de S?o Mateus et al. (2012), o RCC e o solo permitem a passagem de ?gua para o RSU em comportamentos distintos, sendo que o solo promoveu maior infiltra??o de l?quidos, cerca de 95,5% maior do que o RCC. Quando comparados os m?todos, S?o Mateus et al. (2012) apresentou maior infiltra??o de ?gua para o RSU na simula??o com o solo, com rela??o ao m?todo de Fenn et al. (1975), e menor com o RCC, isto ocorre devido ? distin??o dos par?metros de entrada para os materiais, destacando-se a influ?ncia do coeficiente de permeabilidade no balan?o h?drico.

Thesis (M.S.)--University of Wisconsin--Madison, 2002.
Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 116-122).

In the first chapter we described several clusters of childhood cancers discovered by concerned residents of Woburn, Massachusetts, of Toms River, New Jersey, and of the Pelham Bay section of the Bronx, New York City. The residents in Pelham Bay blamed the cluster on a landfill nearby, in which hundreds of thousands of gallons of toxic chemicals, including waste oil sludges, metal plating wastes, lacquer, cyanides, ethyl benzene, toluene, and other organic solvents had been illegally dumped. This had been reported by an employee of the chemical company responsible, in testimony before a Congressional investigation of crime, and was never directly confirmed. Residents of the community had obtained a court order that stopped dumping in 1978, before the testimony about toxic wastes had been given. The story of this cancer cluster—both how it was discovered and what conclusions were reached about its causes—is typical of thousands of clusters reported each year to health authorities throughout the United States. After the alarm in Pelham Bay was sounded by the mother of a child with leukemia, ten years after dumping ceased, the New York City Department of Environmental Protection (NYCDEP) made measurements of hazardous chemicals in the air around the landfill, but found no significant amounts. The drinking water of the community came from the general New York City water supply system, so seepage from the landfill into the groundwater was not a possible route of exposure. It was concluded that by the time the measurements were made the landfill was no longer a threat to health. What the situation may have been in the past, during the time of dumping and just after, could no longer be known. After dumping had been stopped in 1978, the NYCDEP had covered the 150-foot-high mound of garbage, refuse, street sweepings, construction debris, and household and commercial waste, along with whatever may have been illegally dumped there, with a thin layer of soil. It was a hasty job, and it did not last. The soil cover cracked and eroded, washing away all the faster because of the steep slopes of the mound.

The storage yard’s leak-proof protection should be achieved by means of independent protective barriers in the form of geological barriers, artificial sealing layers, mineral soil liners and covers, as well as sidewall sealing. Some years ago, construction and exploitation of landfill sites in Poland took place without any guidelines and legal regulations. Landfills, especially situated in rural areas, were quite often constructed directly on the grounds, e.g. in former aggregate excavations, without any protection. Examples of the municipal landfills, located in the sites of adverse geological conditions were presented in this paper. The effect of existence or absence of geological barriers on the groundwater quality was carried out. In tested landfills, higher concentrations of groundwater pollution indicators were found in landfill monitoring wells located on the outlet of these waters, in comparison to the landfill monitoring wells located on their supply. In the case of the landfills situated directly on the soils of high hydraulic conductivity, the indicators of negative influence of deposited landfills increased even after the closing of the landfill sites. Subsurface water-bearing layer is a kind of “indicator” giving information about the harmful effect of landfills on the environment, and the need to take remedial actions.

The most significant element of the municipal landfill construction is leak-proof assurance which reduces the negative influence of waste on the environment. Mineral liners and covers are correctly built-in cohesive soil layers, with a coefficient of permeability less than 10−9 m/s. Recently, researchers have conducted investigations with the possibility of utilising fly ash as a mineral barrier material. A very important part in the selection of material for the barrier is determining its ability to deformation. Its destruction is initiated by the process of the formation and propagation of cracks caused by tensile stress. Tensile strength was determined for the compacted samples of fly ash and ash with the addition of sodium bentonite which improves plasticity of the ash, as well as for compacted clay, for comparison. Laboratory tests were performed using indirect method (Brazilian test) on disc-shaped samples, using a universal testing machine with a frame load range of ± 1 kN. It was found that sodium bentonite significantly affects the tensile strength of fly ash. The obtained values of deformation and tensile strength of compacted fly ash containing up to 5% bentonite have been compared to those obtained for the clay used in mineral sealing.