This study represents an analysis of comprehensive temperature and moisture content data collected from the anaerobic portion of a bioreactor landfill at the New River Regional Landfill, Florida, USA. The main focus of the study was the analysis of effects of the liquid injection on the temperature inside the landfill. When the leachate or groundwater at lower temperature than the landfilled waste is injected into the landfill, it has an initial cooling effect on the waste until the biological activity, enhanced by the additional moisture, releases heat. This cooling effect was tested in the study to determine whether it could be used to track moisture arrival as an alternative to moisture sensors. First of all, this hypothesis of cooling effect was tested at the injection wells by correlating temperature drops at the injection wells with known injection events. Then the temperature drop events were identified at monitoring locations where temperature and moisture sensors were co-located. The identification step at the monitoring wells was more difficult than in the case of the injection wells because the cooling effect at the injection well is more pronounced than at the monitoring sites, located 7.62 m away from the point of injection. From the analysis it was found out that, overall, the temperature drop at monitoring locations brought about by the injected liquid is a good criterion for tracking the moisture arrival, however only at the first arrival of moisture. Of all of the cases studied, temperature was able to indicate the moisture arrival for 85% of the times at the first injection as opposed to 36% overall. The difference was attributed to the stimulation of biological activity and subsequent heating of the injected liquid as it moves through the waste. Another focus of the research was the estimation of the waste quantity (volume) wetted from the injection. It was assumed that complete mixing takes places between injected liquid and the moisture already present in the waste and that the temperature of the injected liquid is the ambient temperature. According to the results, there was a significant gap between the expected and the actual wetted volume. The waste volume actually wetted was ≤ 1% to 9% of the total waste volume expected to be wetted. Also studied was the effect of ambient temperature on the waste temperature. It was observed that the ambient temperature has no effect on the global temperature inside a bioreactor landfill even at a shallow depth of 4.6 m. While analyzing the trend of waste temperature inside the landfill, liquid injection was found to lead to an increase in temperature.

With population growing every year, more and more people are looking for places to live. This can lead to construction of houses near and around landfills. As homes get closer to landfills, the odors these landfills produce become more of a problem, and lead to an increase in odor complaints. Modeling these odors and recommending odor buffer distances will help determine limits on how close to landfills new homes should be allowed. This should help reduce future odor complaints. To solve this problem one must accurately estimate odorous gas emissions from the landfill. Often odors can be indicated by methane emissions. A new technique using hundreds of ambient VOC concentrations, which are taken from landfills on a quarterly basis, was used to invert and solve the Gaussian dispersion equation for methane emissions. In this technique, Voronoi diagram theory was used to automatically locate numerous point sources for optimal positioning relative to receptors. The newly solved methane emission rates can now be input into a dispersion model, and the resulting methane concentrations used as surrogates for odors around the landfill. One of the most important steps in the analysis is to determine which model is best to use for odor modeling. There are many considerations that go into this decision, such as how much time it takes to run the model, how accurate the model is, and how easy the model is to use. Two current models CALPUFF and AERMOD were compared. In the modeling, methane was used as a surrogate for the odors. Since landfills handle many different combinations of waste, the type of odor may vary from landfill to landfill. In this test case, H2S was assumed to be the main contributor to the odor emitted from the landfill, and the H2S-to-methane ratio was used to estimate downwind H2S concentrations from the modeled methane concentrations. Once an air dispersion model is selected, it can be used to model odors and to develop a graphical screening method to show where these odors are most likely to occur and how strong they will be. This can be used to determine how close to a landfill homes can be built without having significant odor impacts bothering these new residents. Also, this tool can be used for improving landfill gas management. Several example scenarios include the possibility of not enough soil cover placed on the waste, leaks from an aging collection system, or cracks in the collection piping created by the settling of waste.

Current practices of landfill restoration can be characterised as anthropocentric, violent and unsuccessful gestures of purification and control, while they erase traces of planetary history and habitats generated by waste and dirt. The dominant notion of landfill restoration insists on a concept of humans as directors of geo-bio flow who are capable of controlling and reversing the dirty chaos they created. However, matter has its own agency and as any other form of life, waste flows; it may eventually spill, leak and reach our bodies and surroundings through water, air and geological strata. Focusing specifically on Fyli landfill in Athens, the project’s goal is the articulation of a design proposal that questions the current practices of landfilling and landfill aftercare seeking for a reconceptualization of ecological restoration that does not imply a clean, purified and beautiful landscape but generates acts or re-membering and adapting towards a symbiosis with our mess. But how urban design can create the conditions between the coexistence between landfill’s processes of contamination and deformation and human attachment to cleanliness and sameness?This is the research question that is investigated through the specific context of Fyli landfill, seeking a new story for restor[y]ing our relationship to waste.

No description available.

The failure of the Kettleman Hills landfill focused attention on the uncertainties associated with the use of limit equilibrium analyses for evaluation of the stability of slopes in which failure occurs along displacement-softening interfaces. Sliding on such interfaces can occur in a progressive manner with the result that the available interface strengths are reduced below their peak values. The amount of strength reduction depends on the magnitude of shear displacement, which varies from one location to another. Because the limit equilibrium method does not provide any information regarding the magnitudes of shear displacements along the sliding interface, it can only provide realistic assessments of stability where progressive failure effects are small, or where the degree of strength reduction due to progressive failure can be estimated independently. The objective of this research study was to develop procedures to study the phenomenon of progressive failure in lined landfills, and to use the results of these studies as a basis to provide guidance for performing limit equilibrium analyses. Progressive failure along liner interfaces was analyzed using the finite element method. Adaptation and application of the finite element method for this type of analysis was a principal focus of this study. Two new plasticity models for interface behavior, a displacement-softening model and a work-softening model, were developed to simulate strength reduction along liner interfaces. The work-softening model performs better than the displacement-softening model when applied to laboratory tests performed under conditions of changing normal stress. However, the differences in performance of the two models were not significant when applied to landfills. The displacement-softening model is computationally more efficient, and it was used in most of the analyses. Progressive failure effects were severe for all the cases that were analyzed in this study. Analyses of the Kettleman Hills failure showed that the average available shearing resistance at failure was only about 10 percent higher than the residual shearing resistance. Analyses of hypothetical Municipal Solid Waste landfills indicated that the average available shearing resistance would be about 6 percent to 14 percent greater than the residual shearing resistance. This means that a limit equilibrium factor of safety of 1.4 based on residual strengths would correspond to a factor of safety of 1.5 if progressive failure was taken into account. / Ph. D.

Cellulose to lignin ratio is one of the widely used indicators of degree of landfill stabilization. This ratio shows the amount of carbohydrate or cellulose consumed by anaerobes compared to relatively inert lignin. However, the method of lignin measurement contains an intrinsic error. Plastics are contained in the landfill samples and these are characterized as lignaceous materials due to their acid-insolubility. Lignin is typically measured as the organic residue that is acid insoluble but is combustible upon ignition. Additionally lignin may degrade under anaerobic, high temperature conditions associated with wet conditions in sediments and bioreactor landfills. In this study, it has been found that the typical measure of lignin, a gravimetric measure, also includes plastics, leading to erroneous measures of both lignin and the cellulose/lignin (C/L) ratio. Typically, 100% of the plastic will be measured as lignin. Since plastic amounts to approximately 10% of landfill contents, lignin measurements will be 10% greater than actual amounts. Laboratory reactors were set up with known amounts of paper and plastic. The degradation of the cellulose and lignin in paper was measured and compared to plastics, which was collected by hand and weighed. Ratios of cellulose to plastics and lignin to plastics were obtained. It was found, based on the cellulose to plastic ratio and lignin to plastic ration that lignin degrades under anaerobic conditions although at a much slower rate than cellulose. These findings indicate that the cellulose to lignin ratio cannot be used as the sole indicator of stabilization in the landfills. The inclusion of the biochemical methane potential test data along with C/L is thought to provide a better indication of landfill stabilization. / Master of Science

The biochemical methane potential (BMP) of a substance is a measure of the volume of methane gas produced per unit mass of that substance, through the process of anaerobic biodegradation. As the socio-economic consequences of climate change have become more apparent, the ability to predict the long-term cumulative environmental impact of various human activities has become more necessary. Landfills can be a substantial source of methane (a greenhouse gas) to the atmosphere, and consequently BMP is an important tool for predicting the potential cumulative long-term impacts of a landfill to the environment. From a strictly economic perspective, the practice of landfill methane extraction for industrial uses is becoming much more common. In this case, BMP is an important tool for predicting the economic feasibility of such a project. Current methods for determining the BMP of municipal solid wastes (MSW) are both time-consuming and inconsistent. A review of literature on the topic yields many different descriptions of the test, with large variations in sample sizes, incubation times, procedures, etc. Most of these methods also require expensive, and specialized equipment. This thesis describes a simple approach to the BMP test that might be carried out in a variety of laboratory settings, such as an on-site lab equipped with basic, simple, and inexpensive equipment. The method relies on a much larger than typical sample mass to produce large volumes of gas that are measured for composition multiple times over the course of the test. The volume and composition data is then used to produce a cumulative methane potential curve which can be fitted to a first-order decay model in order to predict an ultimate BMP value. The taking of multiple measurements on large volumes of gas, allows for the use of a portable field instrument called the GEMTM2000 to measure gas composition. By fitting the data to a curve in order to determine ultimate methane potential, individual measurement errors are averaged out and the final result has a precision similar to more traditional BMP methods, which rely on bulky and expensive gas chromatographs. Testing has been conducted on MSW samples from 3 separate sites. The method used involved comparatively large samples of waste (~200 g) and no limit was set on incubation time. The use of large waste samples produces large quantities of gas that must be collected and analyzed often. The method provided favourable results, consistent within acceptable limits of variability when compared with other BMP methods. There is even some evidence suggesting that the use of large waste samples improves the accuracy of the test, despite the use of equipment which provides less precise measurements of gas concentration. Given the long duration required for testing, the results were also evaluated for possible correlations between loss on ignition data and specific gravity measurements; two simple tests that can be conducted rapidly. Both data sets show a rough correlation with BMP, and may be used to quickly estimate ultimate BMP values, but the loss on ignition relationship provides the better correlation. Lastly, initial steps were taken in the development of what has been dubbed the Biochemical CO2 Potential (BCP) test, taking advantage of the relatively quicker rate of aerobic degradation. There are preliminary indications that the BCP method may be a viable alternative to the BMP, but the data set so far is small and further research is required to confirm that hypothesis.

Estudos recentes constataram a existência de processos que permitem a atenuação natural dos contaminantes presentes nos lixiviados. O adequado entendimento destes processos pode originar benefícios possíveis de serem aplicados em aterros antigos, novos ou naqueles que ainda serão concebidos. O presente estudo avaliou o comportamento e a atenuação de contaminantes dos líxiviados no solo, por meio de experimento desenvolvido em colunas de percolação e, para a avaliação da atenuação este teste é indicado por refletir as condições naturais e as características adsortivas do solo, propiciando uma melhor simulação da atenuação. O lixiviado e o solo utilizados neste experimento são provenientes do aterro sanitário de São Carlos - SP. O solo utilizado foi caracterizado quanto à composição física, química, biológica e mineralógica para verificar o transporte do percolado nas colunas e a interação solo-contaminante. Na área do aterro foram feitas perfurações, ensaios de condutividade hidráulica e avaliação da geologia local, para conhecimento das características físicas, químicas, biológicas, mineralógicas e geológicas do solo in situ. Este foi classificado como arenoso, apresentando características físicas e químicas que não se enquadram nos parâmetros adequados para sua utilização em áreas de disposição de resíduos sólidos urbanos, pois, a capacidade de troca de cátions, superfície específica, potencial hidrogeniônico e classe textural arenosa, evidenciam que este solo possui deficiente capacidade de retenção e imobilização de contaminantes. Além disso, pela observação in situ, constata-se que a área de disposição de resíduos sólidos de São Carlos esta situado sobre rochas da Formação Botucatu, sendo que a mineralogia do solo presente no local é composta de quartzo, caulinita, goethita, hematita, gibsita e ilita. O ensaio de condutividade hidráulica indicou que o solo presente na base do Aterro sanitário não atende a valor de permeabilidade exigida por norma, o que poderá permitir a infiltração de água da chuva, aumentando a produção do lixiviado e sua movimentação no perfil, podendo atingir as águas subterrâneas. Assim, foram traçadas curvas características do transporte de contaminantes nas amostras efluentes monitoradas durante o processo de percolação, coletadas a cada 0,25 volume de poros até atingir 10,0 volume de poros percolados. As curvas características do transporte de contaminantes traçadas apresentaram baixas concentrações de Chumbo, Cádmio, Ferro, Zinco, Manganês, Cálcio, Magnésio, Cobre, Cromo nas amostras fluentes. Já o Sódio, Potássio, Cloro, Níquel e Alumínio foram preferencialmente percolados com o lixiviado, evidenciando a variação da faixa de concentração de cada elemento no percolado. Os perfis de concentração dos metais pesados mostraram que existe uma frente de contaminação. As curvas de retenção de metais no solo mostraram que a preferência de sorção apresentada pelos solos nas colunas foi : Cobre > Cádmio > Cálcio > Zinco > Magnésio > Potássio > Manganês > Fósforo > Ferro > Níquel > Alumínio. Cujos valores retidos no solo das colunas podem estar evidenciando a capacidade deste solo em reter contaminantes.O solo em questão apresentou baixo potencial para retenção dos contaminantes presentes no lixiviado, classificado como arenoso e, com características químicas que não se enquadram nos parâmetros adequados para sua utilização em áreas de disposição de resíduos sólidos urbanos. / Recent studies had found the existence of processes that allow a natural attenuation of the leachates\'s cotaminants. An adequate understanding of these processes may originate benefits, that may be applied in ancient, new or to be created landfills. This work evaluated the contaminant\'s behavior and attenuation, contaminants existing in soil\'s leaching, throughout an experiment developed in percolation columns. This is the indicated examination for evaluate the attenuation, because it reflects soil\'s natural conditions and adsorptive characteristics, providing a better simulation of it\'s attenuation. The leachate and the soil used in this experiment came from Sao Carlos-SP landfill. The used soil has been characterized as its mineralogical\'s and physical chemical-biological\'s composition, looking for the percolated\'s transportation inside the columns, and for the interaction soil-contaminant. The landfill\'s area has been several times drilled, tested as it\'s hydraulic conductivity and assessment of local geology, in order to know the physical, chemical, biological, mineralogical and geological in situ soil\'s characteristics. This, has been classified as sandy, and, by presenting chemical characteristics that does not reach the adequated value for utilization on solid urban wastes, due to the values of CTC, SE, pH, and the textural sandy class, what shows a deficient buffering capacity in retaining and immobilisating contaminants. By observation in situ, has been found that Sao Carlos\'s solids disposal waste is located over rocks from the Botucatu formation, and the mineralogy of it is composed of quartz, caulinith, goethith, hematith, gibsith an ilith. The hydraulic conductivity test has indicated that the soil in the base of the sanitary landfill does not reaches the permeability values required by the standards, what may allow rain water\'s infiltration, and raises the amount of leachate and it\'s movement onto the ground, and even the leachete to reach the underground waters. So, has been drawn the characteristics curves of the contaminant\'s transportation in the effluents samples found during the percolation process, collected by every 0,25 VP until it reaches 10,0 VP percolated. The characteristical curves of the contaminant\'s transportation drawn showed low concentrations in the effluent samples of Lead, Cadmium, Iron, Zinc, Manganese, Calcium, Magnesium, Cooper, Chromium. Also, Sodium, Potassium, Chlorine, Nickel and Aluminium had been preferencially percolated within the leachate, what evidentiates the variation in the range of concentrations of every percolated element. The concentration profiles from heavy metal\'s had shown that there is a front of contamination. The retention curves from the soil\'s retaining metal showed that the preferency for the sorption was: Cooper > Cadmium > Calcium > Zinc > Magnesium > Potassium > Manganese > Phosphorus > Iron > Nickel > Aluminium, whose values may point the soil\'s ability in retaining contaminants. The studied soil has presented low potential in retain contaminants from the leachete, and is characterized as sandy, and it\'s chemical features shall not be framed according the standards parameters to be utilized in solid urban waste\'s disposal.

All processes in society produce waste. In nature, the waste is normally used as a resource for another process, but in human societies waste is often discarded. These discarded materials end up in places for depositing waste known as landfills. The increase in population, and humans’ tendency to improve their quality of life, has led to an increase in consumption of material. More material consumption means generating more waste, and more waste means bigger landfills. The increasing size of landfills has brought some other issues, such as increased land use and higher environmental impact. However in these landfills a lot of valuable materials are discarded and the concept of landfill mining (LFM) has been proposed in order to solve these issues and use landfills as a possible source of materials. Landfill mining is not yet a common practice, and the first barrier for this is the uncertainty of the amount and value of materials within landfills. The purpose of this study is to prospect the amount of metals in one specific landfill, in this case Gärstad landfill in Linköping, Sweden.  This is a first step to show the feasibility of landfill mining as an alternative way of extracting materials. The study is limited only to metals because they are one of the most important resources in today’s society. The theoretical background of the study is based on material flow analysis (MFA). Two approaches are used to study the materials in the landfill. The first is top-down which studies the flows of materials and the second is bottom-up which studies the stocks of material in the landfill. Based on these approaches the method was developed. First the system boundaries in time and space were defined. Then the amount of waste in landfill was estimated from the two mentioned approaches. In the end the metal content of the waste was estimated. Some criteria are also defined to compare the accessibility of the metals in the landfill. The results of this study show that there is a considerable amount of metals in the landfill, and that ash deposits resulting from incineration are the most interesting source of metals; with iron, aluminium, copper and zinc being the most abundant. The results are presented by type of waste, area of the landfill and accessibility in order to identify the hotspots. Later it is discussed that the method is cheap and fast but highly depends on previous data and available information. Also the metal content of the landfill is compared with natural ores. In the end the metal content of the landfill is evaluated and estimated to be around 3 billion SEK. It shows that aluminium, titanium and copper have the highest value money wise. As conclusion it was shown material flow analysis is a valid way to prospect landfills. But further cost-benefit analysis must be carried out to determine if landfill mining is justifiable. Also some recommendations are proposed to Tekniska Verken in order to facilitate future studies. The first is to develop a systematic way for landfilling different kind of waste and document them. Second is to include metals which have economic potential in the regular sampling from landfill. / Många processer i samhället generar avfall. I naturen används avfallet normalt som en resurs i en annan process, men i människliga samhällen kastas avfallet oftast bort. Bortkastat material hamnar förr eller senare oftast i deponier. Befolkningsökningen och människans tendens till att försöka förbättra sin livskvalitet har lett till en ökad materialkonsumtion. Högre konsumtion genererar mer avfall, och mer avfall kräver större deponier. Växande avfallsanläggningar leder i sin tur till ökad markanvändning och högre miljöpåverkan. I dessa anläggningar finns det emellertid stora mängder värdefullt material deponerat, och från dessa läcker både tungmetaller och metan ut, vilket är skadligt för miljön. Landfill Mining (LFM) har föreslagits som en lösning på dessa problem och avfallsanläggningarna används då även som en möjlig källa till material. Landfill mining är idag inte vanligt förekommande och det huvudsakliga hindret är de många osäkerheterna kring ett sådant projekt, till exempel; hur mycket material finns i deponierna och hur mycket är det värt? Syftet med den här studien är att uppskatta metallinnehållet i en specifik avfallsanläggning, i det här fallet Gärstad avfallsanläggning i Linköping. Detta är ett första steg i att utröna genomförbarheten av LFM som en alternativ resursbas. Studien är begränsad till metaller eftersom dessa håller på att ta slut i jordskorpan och det vore därför intressant att finna nya materialkällor till dessa. Den teoretiska bakgrunden till den här studien är baserad på materialflödesanalys (MFA). Två metoder har använts för att prospektera Gärstad. Dels top-down, som studerar flödet av material, dels bottom-up, som studerar materialförrådet i avfallsanläggningen. Avfallens totalmängd var uppskattad genom att beräkna flödet in och ut från anläggningen. Sedan använde vi tidigare gjorda provtagningar av avfallets metallmängder för att uppskatta metallinnehållet. Slutligen analyserades metallernas tillgänglighet baserad på typ av avfall, och om deponi delområdet var sluttäckt. Resultatet visar att det finns mycket metaller deponerat i Gärstad. Askan från avfallsförbränningen visade sig vara den avfallstyp med rikast metallinnehåll. Järn, aluminium, koppar och zink är de vanligaste förkommande metallerna. Metallkoncentrationen av avfallsanläggningen kan jämföras med naturliga malmer. Värdet av metallerna i Gärstad uppgår till cirka 3 miljarder. Dock är endast 30 % av metallerna tillgängliga med dagens teknik. De största värdena finns enligt följd i aluminium, titan och koppar. För att identifiera hotspots, redovisas resultatet enligt avfallstyp, lokalisering och tillgänglighet. MFA är ett fungerande prospekteringsverktyg för deponier. Metod är billig och snabb men beroende av att det finns tillgänglig data. Innan deponin transformeras till en gruva bör emellertid först en kostnad och nyttoanalys genomföras för att undersöka genomförbarheten vidare. Rekommendationer för att underlätta framtida utgrävningar är att utveckla ett systematiskt sätt att deponera olika typer av avfall och att dokumentera dem. De metaller som har ekonomisk potential bör dessutom inkluderas vid den normala provtagningen av deponerat avfall.

There are over 3,700 active and decommissioned municipal solid waste (MSW) landfill sites located in Ontario (MOE, 1991). Under current legislation, these landfill sites must be rehabilitated to a defined end use when decommissioned. In Ontario, the primary prescribed end use of closed landfills is typically agriculture, and that end use can lead to food-consumer concerns, due to the perceived risk of potential contamination from legacy materials found in landfills. Converting these sites to produce biomass-energy crops instead of food crops could mitigate that concern and also help to avoid the current controversy with bioenergy-crop production on high-capability agricultural land. In this study, a 3.5-year field program with subsequent verification and analysis investigated and developed rehabilitation prescriptions using locally obtained topsoil and soil-forming materials (subsoil) to develop anthropogenic soil profiles on top of a sealed landfill cover (clay cap). These prescriptions provided crop productivity at least as good as, and generally better than, local agricultural soils. Mixed forages and biomass-specific crops (warm season grasses) were grown on these soils in replicated plot trials to evaluate the efficacy of a range of soil treatments. Following establishment of technical feasibility for site rehabilitation, economic modeling was conducted to determine the feasibility of using these anthropogenic soils for the production of forage crops, biofuel feedstock, and simple energy products at a scale consistent with typical landfill sites in Ontario. An economic model was developed to aid proponents in selecting appropriate rehabilitation methods and to assess potential bioenergy-crop outputs for their site. This study demonstrated that while it is technically feasible to rehabilitate these waste sites to produce agricultural crops and/or biofuel feedstock, the scale of typical landfill sites makes it very difficult to compete, from an economic perspective, with conventional energy sources. However, the diverted incoming materials, such as leaf and yard waste, compostable biosolids, and paper mill waste, can be used in the development of manufactured soil profiles for rehabilitation, significantly reducing rehabilitation costs and facilitating more cost-competitive production of agricultural and biomass feedstock crops. / Niagara Waste Systems Limited, a division of Walker Industries Holdings Limited, MITACS