• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 332
  • 203
  • 36
  • 18
  • 10
  • 9
  • 8
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 702
  • 258
  • 218
  • 213
  • 196
  • 152
  • 141
  • 120
  • 118
  • 103
  • 91
  • 81
  • 71
  • 68
  • 66
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
371

Enhanced Biodegradation in Landfills

Shearer, Brad David 29 May 2001 (has links)
The objective of this paper is to evaluate the effectiveness of leachate recirculation and bioreactor landfills at enhancing biodegradation, and to optimize the operation of a bioreactor. Waste Management has been examining leachate recirculation landfills for several years. Samples of Municipal Solid Waste (MSW) from existing leachate recirculation (LR) landfills were collected and analyzed for several physical and biochemical properties. These parameters of interest were moisture content, pH, density, temperature, volatile solids, cellulose/lignin ratios, and biological methane potential (BMP). Leachate recirculation increased the dry density 55% faster and decreased the BMP 125% more rapidly. Moisture content was the biggest factor influencing overall degradation. Therefore, leachate reciculation effectively increases biodegradation of MSW in landfills. Waste Management built a pilot-scale bioreactor in Franklin, WI, which was sampled for one year. It contained a bioreactor side and a control side. The volatile solids, cellulose, and BMP degradation rates for the bioreactor were increased by 56%, 87%, and 271% versus the control, respectively. Moisture content was the biggest factor influencing overall degradation. The column study is designed to optimize three parameters under the control of an operator: moisture content, initial aeration period, and biosolids addition. The optimum moisture content is above 45%, but it is not safe to operate heavy equipment on refuse with greater than 45% moisture. Initial aeration did not speed up the overall degradation, but it did shorten the acidogenic phase. Finally, biosolids did not have a significant effect on degradation rates. The columns maintained an average temperature of 70oF. / Master of Science
372

Characteristics and Treatment of Landfill Leachate and Optimization of Leachate Oxidation with Fenton's Reagent

Gulati, Loveenia 17 June 2010 (has links)
The purpose of this study was to characterize the leachate from a landfill in Pennsylvania that had been pretreated by activated sludge and propose the most efficient treatment for this effluent. These samples had been pretreated in a sequencing batch reactor that also was operated to remove nitrogen by nitrification/denitrification. The SBR samples were found to have low BOD, high COD, high TOC and a very low BOD/COD ratio. These SBR decant samples have poor UV transmittance and hence quench UV light. Five treatment methods were evaluated, coagulation, ultrafiltration, combined coagulation/ultrafiltration, combined ultrafiltration/oxidation and combined filtration/fentons. These processes were tested for their ability to remove BOD and TOC and also to evaluate the improvement in UV transmittance. It was found that coagulation; Ultrafiltration and Ultrafiltration combined with coagulation do not work in improving the transmittance properties though there is a significant BOD and TOC removal with these processes. Ultrafiltration combined with oxidation was found to work the best in terms of TOC removal. In this study, four oxidants, KMnO?, H?O?, NaOCl and Fenton's reagent were used. It was observed that Fenton's reagent was capable of removing 90% TOC at a dose of 1g/L each of iron salt and hydrogen peroxide at a pH of 4.5. Since Fentons reagent was found to be the most effective method, hence, efforts were made to optimize the oxidation process with Fenton's. The two parameters which were studied were the initial pH and the chemical dosage. The initial pH was varied from a value of 2.5 to 6.5. The range of iron salt and peroxide dose used was from 0.05 to 0.1 g/L. Additional studies were conducted using samples filtered through a 0.45 um filter and oxidized with Fenton's reagent. The Fenton's process for oxidation of filtrates from the 0.45?m filter was also optimized with respect to pH and chemical dosage to determine the most economical operating conditions. The maximum transmittance of 57% was obtained for an iron dose of 0.075 g/L and a peroxide dose of 0.075 g/L at a pH of 4.5. This is in comparison to the transmittance of unoxidized 1K ultrafiltrate which was found to be 21.5%. There was a significant difference in the performance of 1K and 0.45um filtrates in terms of TOC removal and percentage transmittance. The oxidation process for improving the UV transmittance of leachate can therefore be economically optimized depending upon the desired efficiency by varying the operational parameters. / Master of Science
373

Treatment of Landfill leachates using anion exchange resins

Pathak, Sudhir Kumar 12 June 2013 (has links)
Landfill leachates are often discharged to wastewater treatment plants (WWTPs) but their highly varied composition makes their treatment in WWTPs difficult. Landfill leachates contain bio-refractory organic matter which easily passes the biological treatment processes at WWTPs and increases the organic matter in the effluent. Leachates also interfere with the UV disinfection process at treatment plants. Another concern is the presence of large amounts of bio-refractory organic nitrogen in the leachates which makes it difficult for WWTPs to meet the tightening total nitrogen requirements. Studies were conducted to evaluate the applicability of anion exchange resins to remove organic matter, UV quenching substance and organic nitrogen from landfill leachates. Leachate samples based on varying age and treatment methods were utilized. The anion exchange resins were found to work effectively for all studied leachates. The resins were found to remove more bio-refractory UV absorbing substances as compared to total organic carbon (TOC), suggesting that anion exchange resins could be employed for removal of UV absorbing substances. Multiple regenerations of the resin showed slight loss in the capacity to remove UV and organic carbon. Fractionation of leachate samples showed effective removal of humic acid (HA) fraction which is responsible for most of UV quenching. The resin was also found to effectively remove the bio-refractory hydrophilic (Hpi) fraction which tends to persist even after HA fraction has bio-degraded. Membrane filtration (1000 Da and 3000 Da Molecular weight cut off) in conjunction with ion exchange resins achieved better removal of organic matter and UV254 absorbing substances. In addition, this also significantly improved the performance of resins. Significant removal of organic nitrogen was also observed using anion exchange though it was less than both UV and TOC. Around 80% removal of organic nitrogen associated with bio-refractory Hpi fraction was achieved using anion exchange suggesting ion exchange as a viable alternative for removing organic nitrogen. / Master of Science
374

Estudo Experimental de Gases em Camadas de Cobertura no Aterro de Nova Iguaçu - RJ. / Experimental study of gases in cover layers of the landfill Nova Iguaçu - RJ.

Eduardo Gaiotto Marques da Silva 05 March 2011 (has links)
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.
375

Estudo Experimental de Gases em Camadas de Cobertura no Aterro de Nova Iguaçu - RJ. / Experimental study of gases in cover layers of the landfill Nova Iguaçu - RJ.

Eduardo Gaiotto Marques da Silva 05 March 2011 (has links)
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.
376

Sistema de filtração lenta no tratamento de percolado do aterro sanitario de Limeira-SP / Slow sand filter in the treatment of leachate of the sanitary landfill of Limeira -SP

Pelegrini, Nubia Natalia de Brito 17 February 2006 (has links)
Orientador: Jose Euclides Stipp Paterniani / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-06T12:32:37Z (GMT). No. of bitstreams: 1 Pelegrini_NubiaNataliadeBrito_M.pdf: 1010430 bytes, checksum: 1a5af5bc021dbf527427add6944a6e6d (MD5) Previous issue date: 2006 / Resumo: A disposição final de resíduos sólidos é uma prática que ainda traz sérios impactos ao meio ambiente. Nos aterros sanitários, os resíduos passam por processos físicos, químicos e biológicos de decomposição, gerando uma fração gasosa (composta principalmente por gases dióxido de carbono e metano) e uma fase líquida conhecida como chorume (ou percolado de aterro sanitário). O chorume de lixo é um líquido com elevado potencial poluente, os métodos convencionais utilizados em seu tratamento têm descartado-o com intensa coloração e alta toxicidade. Este trabalho teve como objetivo implantar em escala piloto um sistema de filtração lenta precedido de uma pré-filtração, apenas em manta sintética não tecida, para o tratamento de chorume de lixo ¿in natura¿, proveniente do aterro sanitário da cidade de Limeira-SP. O filtro lento foi constituído por um tanque cilíndrico de plástico tendo como meio filtrante areia e mantas sintéticas não tecidas. A taxa de filtração adotada durante os experimentos foi de 3 m3/m2.dia. O sistema de tratamento em estudo apresentou reduções consideráveis dos valores de alguns parâmetros de controle ambiental indicando a possibilidade do uso da filtração lenta para remediação de águas residuárias. As principais reduções obtidas referem-se a 40% de turbidez, 21% da coloração, 35% de dureza, 35% de carbono orgânico total (TOC) e reduções consideráveis de metais pesados (60% de cádmio, 30% de chumbo, 25% de cobre e 30% de cromo). Com relação à reutilização do chorume tratado em atividades agrícolas ainda são necessárias maiores reduções dos valores de parâmetros analíticos através da complementação com outras tecnologias de tratamento / Abstract: The final disposition of solids residues is a practice that still brings serious impacts to the environment. In sanitary landfill, the residues goes through physical, chemical and biological decomposition processes, generating into a gas phase (mainly composed by CH4 and CO2) and a liquid phase known as leachate. The waste leachate is a liquid with high pollutant potential. The conventional methods used in the treatment this residue have discarded him with intense coloration and high toxicity. This work had as objective implant in pilot scale a system of slow sand filtration preceded of a pré-filtration, only in non-woven synthetic fabrics, for the waste leachate treatment in natura, originating from the sanitary landfill of the city of Limeira-SP. The slow sand filter is constituted by a plastic cylindrical tank, sands and non-woven synthetic fabrics. The filtration rate adopted during the experiments it was of 3 m3/m2.dia. The treatment system in study presented considerable reductions of some values of environmental parameters control indicating the possibility of the use of the slow filtration for remediação of wastewaters. The main obtained reductions were 40% of turbidity, 21% of color, 35% of hardness, 35% of total organic carbon (TOC) and reductions considerably of heavy metals (60% of cadmium, 30% of lead, 25% of cupper and 30% of chrome). For the reuse of the treated leachate in agricultural activities are necessary larger reductions of some values of analytic parameters through the complementation with other treatment technologies. eywords: Landfill Leachate, Sanitary Landfill, Slow Sand Filtration, Reuse / Mestrado / Agua e Solo / Mestre em Engenharia Agrícola
377

Conversion of Landfill Gas to Liquid Hydrocarbon Fuels: Design and Feasibility Study

Kent, Ryan Alexander 24 March 2016 (has links)
This paper will discuss the conversion of gas produced from biomass into liquid fuel through the combination of naturally occurring processes, which occur in landfills and anaerobic digesters, and a gas-to-liquids (GTL) facility. Landfills and anaerobic digesters produce gases (LFG) that can be converted into syngas via a Tri-reforming process and then synthesized into man-made hydrocarbon mixtures using Fischer-Tropsch synthesis. Further processing allows for the separation into liquid hydrocarbon fuels such as diesel and gasoline, as well as other middle distillate fuels. Conversion of landfill gas into liquid fuels increases their energy density, ease of storage, and open market potential as a common “drop in” fuel. These steps not only allow for profitable avenues for landfill operators but potential methods to decrease greenhouse gas emissions. The objective of this paper is to present a preliminary design of an innovative facility which processes contaminated biogases and produces a valuable product. An economic analysis is performed to show feasibility for a facility under base case scenario. A sensitivity analysis is performed to show the effect of different cost scenarios on the breakeven price of fuel produced. Market scenarios are also presented in order to further analyze situations where certain product portions cannot be sold or facility downtime is increased. This facility is then compared to traditional mitigation options, such as flaring and electricity generation, to assess the effect each option has on cost, energy efficiency, and emissions reduction.
378

Assessment of Leachate Characteristics and Geotechnical Properties of Municipal Solid Waste Landfill

Naveen, B P January 2016 (has links) (PDF)
Solid Waste Management is one of the essential services provided by local bodies to keep the urban areas clean. Often it is poorly rendered as it is unscientific, out-dated and inefficient. With the rapid increase in population, livening standards, the generation rates of solid waste are increasing drastically. The landfill waste includes both organic and inorganic wastes as it is not often effectively segregated before disposal. The problem is acute in developing countries such as India. Bangalore city, with a population of about 10.18 million and more than 2000 industries, generates about 4,500 TPD of municipal solid waste. Of this Presently, various municipal solid waste processing units in Bangalore can handle only about 2100 TPD of waste. Mavallipura landfill developed and operated by M/s. Ramky Environmental Engineers, located 40 km away from Bangalore, is being used for disposing of about 1000 TPD, the installed capacity being only 600 TPD of waste. There are also a few dumps in around Bangalore due to historical reasons and insufficient capacity of various designated landfills. To reclaim the old dump sites/closed landfill sites for infrastructural development, it is necessary to know their geotechnical characteristics. Within the Landfill, the characteristics of the waste may change with depth due to degraded wastes as it has been dumped over a period of time. The physical parameters, chemical properties as well as the geotechnical behaviour of the waste change with depth. MSW is known to be a heterogeneous material of varying constituent types and dimensions, containing elements that degrade with time. To consider MSW as a geo-material to support the foundation of structures such as buildings and pavement, an analysis of the bearing capacity of the foundation and further long-term settlement of MSW is essential. The MSW samples are retrieved from a Mavallipura landfill site, Bangalore and analysed for important geotechnical properties such as compaction characteristics, shear strength, permeability, compressibility behaviour and dynamic properties of MSW using ultrasonic and cyclic triaxial tests. This research thus aims to provide valuable information about landfill sites for reclamation, closure and infrastructural development after the closure of landfills. Scanty data are available on the geotechnical properties of waste from landfill sites with varying degrees of degradation. This landfill site is selected as there is a huge environmental concern regarding the soil and groundwater contamination in the area and also can represent a typical landfill scenario in tropical regions. Quantification, quality assessment, consequent treatment and management of leachate have become a monstrous problem world over. In this context, the present study envisages to study the physicochemical and biological characterization of representative urban municipal landfill leachate and nearby water bodies and attempts to figure out relationships between the various parameters together with understanding the various processes for chemical transformations. The analysis shows intermediate leachate age (5-10 years) with higher nutrient levels i.e. 10,000 - 12,000 mg/l and ~2,000 - 3,000 mg/l of carbon (COD) and nitrogen (TKN) respectively. Elemental analysis and underlying mechanisms reveal chemical precipitation and co-precipitation as the vital processes in leachate pond systems resulting in accumulation of trace metals in these systems. The microbial analysis also correlated with specific factors relevant to redox environments that show a gradient in nature and the abundance of biotic diversity with a change in leachate environment. Finally, the quality and the contamination potential of the sampled leachate were performed with the help of potential leachate index (LPI) analysis and water quality index (WQI) analysis for surrounding water bodies (namely surface pond and open well) of Mavallipura landfill site. A geotechnical testing program has been drawn to evaluate the engineering properties of municipal solid waste samples retrieved from a landfill at Mavallipura at various depths through augur within the landfill dumped area. Laboratory studies included are composition, moisture content, particle size analysis, compaction, permeability, direct shear test, consolidation, triaxial compression test. For the laboratory tests, we had considered maximum particle sizes of less than 4.75 mm only. Standard Proctor Compaction tests yielded a maximum dry density of 7.0kN/m3 at 50% optimum moisture content. The permeability of MSW results shows in the range of 4x10-4 cm/sec. Compression index of MSW is 0.46980 and recompression index of MSW is 0.09454. Results obtained from the rectangular hyperbola method are compared with Casagrande and Taylor methods to prove that this method is reliable equally, and results are reasonably accurate. Based on direct shear tests, the MSW sample exhibited continuous strength gain with an increase in shear strain (16%) to define strength. The cohesion of MSW was 10kPa and friction angle is 34°. Based on the elastic constants results obtained from the direct shear test found to be very soft material. In the triaxial test, the MSW sample exhibited continuous strength gain with an increase in axial strain. The frictional component is increased due to sliding and rolling of fibrous particles over one another resulting in the development of apparent cohesion due to antiparticle bonds within the MSW material. Landfills are an integral part of waste management, and disastrous consequences can happen if seismic vulnerability of these landfills is not considered. Dynamic properties of MSW are required to perform seismic response analysis of MSW landfills, but there is no good understanding of the dynamic shear strength of MSW in literature. A comprehensive laboratory cyclic triaxial testing program has been taken up to determine the properties at different densities, confining pressures and shear strains. MSW degrades with time, and its shear modulus and damping are expected to vary with time and degradation. For the density of 6 kN/m3 the dynamic shear modulus values for MSW varied from 0.68 MPa to 5.38 MPa and damping ratio varied from 20% to 40% for MSW. For the density of 7 kN/m3 the dynamic shear modulus values for MSW varied from 1.8 MPa to 7.5 MPa and Damping ratio varied from 23% to 40% for MSW. For the density of 8kN/m3 dynamic shear modulus values for MSW varied from 2.46 MPa to 8.00MPa and damping ratio varied from 16% to 33% for MSW. Also, the ultrasonic testing method was used for determining the dynamic properties at low strains. The Ultrasonic test results indicated that with an increase in density of the sample and with decreased void ratio, the pulse propagation velocity (Vp) increases. With an increase in the density, the shear wave velocity and elastic constants (elastic modulus and shear modulus) increase. The elastic constant values obtained from the ultrasonic test are higher compared to values obtained from unconsolidated-undrained triaxial tests. Also, the carbon stored in the buried organic matter in Mavallipura landfill is estimated. Total organic carbon increases steeply with an increase in depth and is significantly high at a depth of 6 m. Subsurface properties cannot be specified but must be analysed through in-situ tests. The in-situ testing that are carried out in a landfill are boring, sampling, standard penetration test (SPT), dynamic cone penetration test (DCPT) and plate load tests (under static and cyclic condition). A correlation between corrected SPT ‘N’ values and measured using shear wave velocities has been developed for Mavallipura landfill site. Results show that the corrected SPT- N values increase with depth. Corrected N-values are used in the landfill design, so they are consistent with the design method, and correlations are useful. The results obtained from the dynamic cone penetration tests shows lower value when to compare with standard penetration test. The unit weight profile with depth ranged from a low unit weight of 2.48 kN/m3 near the surface to a highest value of approximately 9.02 kN/m3 at a depth of 6 m. The highest temperatures for landfills were reported at mid-waste elevations with temperatures decreasing near the top. The bearing pressure-settlement curves for plate size 75cm and 60cm presented similar behaviour while the plate size of 60cm curve presents a lesser settlement of 70mm, compared to with plate size of the 75cm curve with the settlement of 80mm and failure mode could be classified as punching shear. The cyclic plate load test with plate size of 60cm and 75cm were carried out on the soil cover. The elastic constants were found to be 73.87 and 96.84 kPa/mm and for 60 and 75cm plates respectively. Geophysical testing may not be as precise but has the benefit of covering large areas at small costs and sometimes can locate features that might be missing by conventional borings. Multichannel analysis of surface waves (MASW) is an indirect geophysical method used in the landfill for the characterization of the municipal solid waste site. The Mavallipura landfill was surveyed up to the length of about 35m at the top level. A series of one-dimensional and two-dimensional MASW surveys used active seismic sources such as sledgehammer (5kg) and propelled energy generator (PEG-40) was used. This hammer was instrumented with geophones to trigger record time. All the testing has been carried out with geophone spacing of 1m and recorded surface wave arrivals using the source to first receiver distance as 5m with recording length of 1000 millisecond and the recording sampling interval of 0.5 milliseconds (ms) were applied. Results shows that the PEG-40 hammer can generate the longest wavelength with a maximum depth of penetration. The shear wave velocity varies from 75 to 155 m/s with an increase in depth of about 27.5m. Based on the site characterization at the landfill site, it was found that the Mavallipura landfill site can be categorized as very loose, and it is still in a continued stage of degradation. Shear wave and P-wave velocity profile for eight major locations in the study area were determined and variation of waste material stiffness corresponding to the in-situ state with depth, was also evaluated. Also, MASW survey has been carried out to develop dispersion curve on another landfill site at Bhandewadi, Nagpur. MASW system consisting of 24 channels geode seismograph with 24 geophones of 4.5Hz capacity is used in this investigation. The seismic waves were created by sledgehammer with 30cmx 30cmx2cm size hammer plate with ten shots. These waves were captured by the geophones/receivers and further analyzed by inversion. The results indicated that near surface soils(less than 3m depth) approximately the to 5mm, and with 85% of dry weight basis of waste particles with sizes less than 10mm, the shear wave velocity varies from 75 to 140 m/s (frequency ranges from 30 to 23Hz). With the increase in 6.5m depth, the shear wave velocity ranged from 140 to 225m/s (frequency ranges 23 to 13Hz). Overall, the results of the study showed that seismic surveys have the potential to capture the changes in dynamic properties like shear wave velocity and Poisson’s ratio of the depth of MSW landfill to infer the extent of degradation and provide dynamic properties needed for seismic stability evaluations. Based on the in situ and laboratory results of this study and a review of the literature, the unit weight, shear wave velocity, strain-dependent normalized shear modulus reduction and material damping ratio relationships for Mavallipura landfill are developed and also validated using semi-empirical methods. Finally, seismic response analysis of Mavallipura landfill has been carried out using the computer programs like SHAKE 2000 and DEEPSOIL. Results show that the unit weight is increased with depth in response to the increase in overburden stress. The proposed material damping ratio and normalized shear modulus reduction curve lie close to the profile given in the literature for landfills composed of waste materials with 100% particles sized less than 20mm. Peak spectral acceleration at 5% damping value is 0.7g for 0.07 sec in SHAKE 2000 and peak spectral acceleration at 5% damping value is 0.63g for 0.04 sec in DEEPSOIL. Amplification ratio is 6.11 at 1.1l Hz in SHAKE2000 and 4.65 at 2.67Hz in DEEPSOIL. Peak ground acceleration (PGA) for the landfill site, it is observed PGA has decreased from 0.3g to 0.15g in DEEPSOIL and PGA has decreased from 0.33g to 0.15g in SHAKE2000. The studies presented in the thesis brought out the importance of characterization of municipal solid waste leachate regarding metabolism and treatment/degradation of Mavallipura landfill leachate. For municipal solid waste of with sizes ranging from 0.08 coefficient of permeability being about 10-4 cm/sec, the compression index was about 0.47. A more reliable method of calculating the coefficient of consolidation has been recommended. Correlations between shear wave velocity and SPT-N values has been developed for the Mavallipura landfill site. The results showed that the dynamic cone penetration tests values are lower than indicated by standard penetration tests. The cyclic plate load tests carried out with plate sizes of 75cm and 60cm showed that elastic constants of 96.84 kPa/mm and 73.87kPa/mm respectively. MSW properties evaluated in this thesis are compared with those of soft clays. The MSW properties showed higher values (strength and SBC) and lower values of compressibility, compared with those of soft clays. Thus foundation improvement on MSW is less challenging than foundations on soft soils. Also stabilization of MSW with other solid wastes such as fly ash can be considered as an economical option. Based on detailed studies the importance of unit weight, shear wave velocity, strain-dependent normalized shear modulus reduction and material damping ratio relationships for landfill waste have been developed. Based on the site characterization, the waste landfill has been categorized as very loose material, which is still in a degradation process. SHAKE2000 software shows higher PGA value comparing with DEEPSOIL.
379

Analysis of Groundwater Monitoring of Residential Wells In the Vicinity of Carbon Limestone Landfill, Poland Township, Mahoning County, Ohio

Alexander, Diana Marie January 2012 (has links)
No description available.
380

A comparison & contrast of Hong Kong and overseas practices in landfill gas management

Kam, Chung-hau, Brian., 甘忠校. January 1998 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Page generated in 0.052 seconds