The possibility of utilisation of microbially induced calcium carbonate precipitation as a potential remedial technology for sequestering divalent metallic contaminants in subsurface environment was explored. Contamination by heavy metals and radionuclides is a significant environmental problem. Incorporating metals in calcium carbonate minerals is a mechanism that may offer long-term removal of metallic cations. Stimulating native ureolytic bacteria by supplying required nutrient and chemicals to create alkaline conditions suitable for calcium carbonate precipitation may accelerate biomineralisation processes in polluted soil. This study reports the ability of a bacterium in soils, Sporosarcina pasteurii, to remediate range of heavy metal and radionuclide (by using non-radioactive proxies) concentrations in aqueous solutions and particulate media by inducing urea hydrolysis and calcium carbonate precipitation. However, bacterial activity is limited by heavy metals toxicity and availability, hence, initially the minimal inhibitory concentration (MIC) of metals to bacterial activity was estimated, without the presence of a metal precipitation mechanism (only metals ions and nutrient broth). Metals inhibited bacteria in the following order Cd >Zn >Cu >Pb >Sr. The bacterial cells showed an improved growth and metal toxicity resistance in presence of urea containing medium over their presence in urea-free medium. Cd, Pb and Sr were fully removed, whilst Zn and Cu were partially removed by this technique. Removal of heavy metals was strongly correlated with full removal of calcium and high pH increase then white precipitate was produced, suggesting that urea hydrolysis by bacterial cells did play a role. Finally, it was explored the effects of ground conditions (transport and availability of heavy metals, preferential flow and heterogeneous hydraulic conductivity) on biomineralisation process in porous media in different sand fractions (fine, medium and coarse). High removal rates were achieved in porous media especially for cadmium and strontium. It is resulted that the heterogeneity of hydraulic conductivity plays a main role in distributing bacterial activity and subsequent precipitation processes in porous media. XRF, XRD, SEM and EDX spectrum tests for sand samples showed the presence of calcite and aragonite in precipitation crystals. The gained results demonstrate that microbially induce calcium carbonate technique is a means of sequestration of soluble heavy metals via co-precipitation with calcium carbonate precipitation that can be useful for divalent heavy metal and radionuclides bioremediation.

M.Sc. / The location of a solid waste landfill site is not only determined by the need of the local population of an area but also by minimum requirements imposed by the Department of Water Affairs and Forestry. These minimum requirements act as a method of environmental protection against pollution caused by landfill sites. The objective of this study is to explore the utilization of a geographical information system as an aid in selecting the best possible location for a new solid waste dumping site. It is possible to determine the most appropriate location for such a new waste dumping site by using the minimum requirements set forward by the Department of Water Affairs and Forestry as guidelines in the site selection process. The minimum requirements can be used to eliminate all those places that do not meet the necessary requirements. The remaining areas can all be considered as potential sites and must be investigated personally by the people responsible, in the local government. A need for a regional solid waste landfill site in the area of Howick, Hilton and Mpopomeni in the KwaZulu/Natal Midlands was identified and used as the basis for this study.

A review of literature on the subject of methane exploitation from landfill is presented in conjunction with the results of experiments concerning landfill gas extraction at the Grahamstown Landfill Site. A description of the LFG extraction system and the utilisation of LFG at the Grahamstown Landfill Site is included. Data concerning LFG enhancement parameters, LFG compositions and flow rates, refuse composition, LFG modelling, LFG pumping trials and the economics of LFG extraction and utilisation are presented. The indication is that LFG can be economically extracted and utilised as a heating fuel in South Africa.

Communities around the globe are confronted by environmental challenges such as waste management. These challenges are further aggravated by factors such the increasing volumes of waste, landfills that are running out of capacity and scarcity of suitable land to construct new landfill sites. The National Waste Management Strategy requires participation from all members of society including households, businesses, community organisations, nongovernmental organisations, parastatals and the three spheres of government, to promote practices that minimise the volumes of waste generated. The purpose of the research was to assess and investigate the current waste management practices at the Cape Peninsula University of Technology (CPUT), and recommend a waste management system. The research employed a quantitative approach, where participants were asked to complete a survey questionnaire. A literature review was conducted on waste management at higher learning institutions, with particular focus on the contribution that a university can make in alleviating some of the adverse effects of waste management. The outcome of the review highlighted some of the opportunities and barriers that can either disrupt or augment the process of implementing a waste management system. The results from the research revealed that CPUT does not conform to the hierarchy of waste management, and there is no waste management policy in place. The effect of this is that the stakeholders were not satisfied with the lack of leadership on waste related challenges. By developing a policy, providing leadership, conducting awareness campaigns and prioritising environmental challenges such responsible management waste, could improve the image of the institution in the eyes if its stakeholders.

Due to urbanization, industrialization and population increase, a substantial increase occurred in the number of vehicles and hence large numbers of end-of-use tires are being disposed every year. The vast majority of these tires are stockpiled or used as a fuel for combustion which, in both cases, affects the environment detrimentally. The use of tire rubber in cement-stabilized aggregate mixtures (CSAMs) will ensure beneficial use of large quantities of these waste materials, saving natural resources and may enhance the properties of CSAMs especially these related to brittleness and sensitivity to fatigue failure. Research was undertaken to investigate, at macro and mesoscale levels, the effect of both rubber and degree of stabilization and their combination on the behaviour of CSAMs in terms of the most influential pavement design properties under different static and dynamic modes of loading. These properties are strength, stiffness and fatigue. A range of testing equipment, methodologies and tools was developed, suggested and implemented to perform this investigation. Further investigation was also conducted to provide better understanding of the damage and failure mechanism through quantitative studying of the fractured surface, internal structure and surface cracking patterns under different testing modes. The results of this study revealed that the addition of rubber has a negative effect on the compaction efficiency, compressive, flexural and tensile strengths while the stiffness, under different testing modes, was slightly reduced. In addition, a tougher mixture was produced after rubber-modification which means a change from a brittle to a more ductile behaviour. This behaviour was observed through different stiffness modulus evaluation methods. On the other hand, increase in cementation level has resulted in an increase in both strength and stiffness for both reference and rubberized mixtures. However, the decrease in the mixtures’ strength due to rubberization was more obvious in highly cemented mixtures than the lightly cemented ones. On the other hand, a greater decline in the mixtures’ stiffness, due to rubber incorporation, was observed at low cement contents. This behaviour is related to the void-like behaviour which depends, to large extent, on the relative stiffness between rubber and surrounding matrix. Quantification of the fractured surfaces and cracking pattern utilizing the photogrammatry and fractal dimension concepts, respectively, revealed that the addition of rubber resulted in rougher and more tortuous cracks and increases disperse-ability of these cracks. This means the rubber-modification changed the cracking pattern which implies better load transfer through the cracks and less risk of reflection cracking. The investigation of the internal structure, at mesoscale level, showed that the cracks were propagated through the rubber particles at all investigated cementation levels. This contributed to a lengthening of the crack path and to the delaying of crack propagation by absorbing and relieving the stresses at the crack tip, especially at the microcrack level. The latter mechanisms are behind toughness and fatigue improvement. Evaluation of rubber distribution revealed uniform distribution and this decrease as rubber content increases. The results also indicated an improvement in the fatigue life for all rubber replacement levels. This was valid at all cementation levels. In terms of modulus degradability, rubberization of the cemented mixture has only a slight effect on this property while larger permanent deformation was accumulated after rubber inclusion. It was observed that the poorly cemented mixtures showed greater stiffness modulus degradation. Pavement analysis and design study showed that the decrease in the mixtures’ strength overshadowed any improvement due to both mitigation of mixtures’ stiffnesses or fatigue life enhancement. However, this is not the case for poor rubber mixtures where this mixture showed better behaviour than the reference mixtures.

No description available.

Made available in DSpace on 2016-05-02T13:54:16Z (GMT). No. of bitstreams: 1 OmarJoaodaMataDissertacao.pdf: 976126 bytes, checksum: 616780a10a223756893e1ab9f6ac26d1 (MD5) Previous issue date: 2012-06-05 / The purpose of this study was to measure biogas emission from a monitored landfill in the city of Betim, State of Minas Gerais, in southeast Brazil, and determine parameters for the application of mathematical models to evaluate methane production and the possible generation of energy for the specific Betim region. The study was conducted at the city sanitary landfill. With 500,000 inhabitants, and producing 300 tons of residues a day, Betim started to operate its sanitary landfill in 2002 and is expected to close it in 2012. The system of disposition and treatment of garbage includes the landfill, manure treatment ponds and a composting yard. It receives domestic and commercial waste from the city and the remains of pruning and weeding. The residues from pruning and weeding, restaurants and garbage trucks are transformed into organic matter on the composting yard. The gas consists of 50%-60% of methane generated by decomposition of the organic matter by bacteria, and also of carbon dioxide, hydrogen, oxygen, hydrogen sulphide, ammonia, carbon monoxide, water and small percentages of other elements. Several collections and analyses were carried out and compared with different measurement estimates of the biogas capturing system of sanitary landfills by different methods: World Bank WB; Intergovernmental Panel on Climate Change IPCC; and United States Environment Protection Agency USEPA, with the aim of finding parameters to evaluate the data obtained. The comparison of our data with the curves foreseen with the methods above, and the results provided by the laboratory, made it possible to validate the theoretical models. / O objetivo deste estudo foi medir a emissão de biogás a partir de um aterro monitorado na cidade de Betim, Estado de Minas Gerais, no sudeste do Brasil, e determinar parâmetros para a aplicação de modelos matemáticos para avaliar a produção de metano ea geração de energia possível para o Betim região específica. O estudo foi realizado no aterro sanitário da cidade. Com 500.000 habitantes, e produzindo 300 toneladas de resíduos por dia, Betim começou a operar seu aterro sanitário em 2002 e deverá ser concluída em 2012. O sistema de disposição e tratamento de lixo inclui o aterro sanitário, lagoas de tratamento de chorume e um pátio de compostagem. Ele recebe lixo doméstico e comercial da cidade e os restos de poda e capina. Os resíduos de poda e capina, restaurantes e caminhões de lixo são transformados em matéria orgânica no pátio de compostagem. O gás é constituído por 50% -60% de metano gerado pela decomposição da matéria orgânica por bactérias, e também de dióxido de carbono, oxigênio, hidrogênio, sulfureto de hidrogênio, amoníaco, monóxido de carbono, água e pequenas percentagens de outros elementos. Várias coleções e análises foram realizados e comparados com estimativas de medição diferentes das biogás captura sistema de aterros sanitários por meio de métodos diferentes: Banco Mundial - BM; Painel Intergovernamental sobre Mudança do Clima - IPCC, e Estados Unidos Agência de Proteção Ambiental - EPA, com o objetivo de encontrar parâmetros para avaliar os dados obtidos. A comparação dos nossos dados com as curvas previstas com os métodos acima, e os resultados fornecidos pelo laboratório, tornou possível para validar os modelos teóricos.

Dentre as várias técnicas de tratamento e disposição dos resíduos sólidos urbanos a disposição em aterros sanitários é a mais usada, devido ao baixo custo e relativa simplicidade operacional. No entanto, a falta de estudos para áreas adequadas é um dos principais fatores limitantes da aplicação desta técnica. É imprescindível o conhecimento dos atributos do meio-físico para avaliar as suas várias interações com o aterro sanitário. Essas interações e a variedade de atributos, dificultam a seleção do local adequado para a instalação do aterro sanitário. Diante disto, há a necessidade de uma metodologia que considere as interações, juntamente com os atributos, e se mostre eficaz na seleção do melhor local para o aterro. Propões-se aqui uma metodologia que considera 14 atributos do meio físico, referentes ao substrato rochoso, materiais inconsolidados, água e feições de relevo. Em vista da variedade de atributos, múltiplas alternativas possíveis e objetivos muitas vezes conflitantes, a serem considerados, foi aplicada a técnica de tomada de decisão denominada processo hierárquico analítico (PHA). O PHA divide um problema complexo em problemas mais simples na forma de uma hierarquia de decisão e, permitiu a obtenção do índice de adequabilidade (I.A.), que representa o valor numérico da adequabilidade de uma determinada áreas para a instalação de aterros sanitários, além de possibilitar a sua hierarquização em relação às áreas adjacentes. Esta metodologia foi aplicada na região de Araraquara, estado de São Paulo, limitada pelo paralelos 21º45\' e 22º00\' sul e meridianos 48º00\' minutos e 48º15\' minutos oeste Gr. O I.A. possibilitou o zoneamento e a classificação de unidades de combinação em favorável, moderada, severa e restritiva para a implantação de um aterro sanitário. A metodologia mostrou-se eficaz e permitiu comparar os 14 atributos de forma numérica, ao introduzir a ) técnica de tomada de decisão através do processo de hierarquia analítica. Desta forma, apresentou as vantagens de diminuir a subjetividade do processo de seleção e ponderar atributos inter-dependentes, direcionados ao objetivo de selecionar áreas para a implantação de um aterro sanitário. / Among several techniques for disposition and treatment of urban solid waste, sanitary landfill is the most employed, by their low cost and relative operational simplicity. However, the lack of research for suitable areas is one of the main problems to the application of this technique. It is necessary to know the attributes of the environment to assess their numerous interactions with the environment sanitary landfill. This interactions and the variety of the attributes becomes diffilcut the selection of the most suitable area to the installation of the sanitary landfill. A methodology to be effiecient in the selection of the best site to this facility, must consider the interactions and the attributes of the environment. This paper proposes a methodology which consider 14 attributes of the environment related to the rocky substrate, unconsolidated materials, water and relief. Because the variety of attributes, multiple possible alternatives and competing objectives to be consider was applied a decision support system (D.S.S.) technical named analytic hierachy process (AHP) which divides a complex problem in simpler ones in the form of a decision hierarchy. The use of AHP reaches the numerical suitability index (SI), of the areas to the installation of a sanitary landfill and becomes possible to hierarchy these areas. This methodology was applied in an area located in the Araraquara region, São Paulo state, limited by the parallels 21º45\' and 22º15\' south and meridians 48º00\' and 48º15\' West gr. The use of the suitability index (SI) permitted the zoning and ranking of the sub-areas and their classification in favorable, moderate, severe and restrictive to the installation of a sanitary landfill. The methodology to compare the 14 attributes in a numerical way by the use of the making decision technique applied to the AHP. By this way had the advantage of less subjectivity of the process of area selection and to weigh inter-dependents attributes, addressed to the objective of to select sites to the sanitary landfill.

This thessis deals with the realization options of automatic measuring device for infrared sensors used in sanitary electronic. The device is designed to work automatically and save all measured data to ERP system.

Dans le but de caractériser les conditions environnementales, hydrologiques et d’usage des sols, menant à la contamination d’un système karstique cette étude combine hydrogéologie et microbiologie environnementale. Les chroniques de température et d’hydrologie (pluviométrie, turbidité, conductivité) de l’hydrosystème karstique de Norville (SO Karst) des 5 dernières années ont été analysées pour trouver une corrélation entre les conditions hydrologiques menant au ruissellement sur le bassin versant et la contamination par E. coli de l’hydrosystème (eau et biofilms). Quinze campagnes de prélèvement d’eau à l’entrée (la perte) et la sortie (la source) du système et de biofilms ont été réalisées. La relation entre l’abondance et la diversité génétique (distribution des phylogroupes) des populations de E. coli circulant dans l’hydrosystème et les conditions hydrologiques et d’usage des sols a été étudiée. Un indicateur de contamination des eaux par E. coli (IndiCE) basé sur l’enregistrement de la température et la pluviométrie et corrélé avec la contamination d’eau de surface et sous terraine par E. coli d’un hydrosystème karstique, simple d’utilisation est proposé. Le rôle de réservoir de pathogène des biofilms karstiques, responsable de contamination secondaire, a été étudié en suivant l’occurrence de E. coli et des intégrons de classe 1 dans des biofilms formés à la source de l’hydrosystème karstique de Norville.Il a été montré en chemostat la capacité de E. coli à former des biofilms sur la craie en condition oligotrophique. In situ E. coli et les integrons de classe 1 peuvent s’associer à des biofilms autochtones sous forme cultivable transitoirement. L’ensemble de ces travaux de thèse a permis de mieux comprendre la dynamique de la contamination par E. coli des hydrosystèmes karstiques, dans l’eau et les biofilms. / In order to assess environmental conditions leading to contamination of a rural karstic hydrosystem this study combine hydrogeology, and environmental microbiology. We focused on a well-characterized chalk karstic hydrosystem (Norville, France) vulnerable to microbiological pollution, of the French national observatory network on karst (INSU/CNRS). Temperature and hydrological time series (pluviometry, turbidity and electrical conductivity) over the past 5 years were analysed in order to correlate hydrological condition leading to run-off on the watershed and E. coli contamination of the hydrosystem. Fifteen sampling campaigns of water and biofilms were carried out in different hydrological conditions, on the surficial watershed (i.e. the upstream part of the system) and at the spring downstream. That has been used to determine periods more subject to soil bacteria leaching and input in the hydrosystem. Finally, relationships between abundance and genetic diversity (phylogroup distribution) of E. coli population in the hydrosystem waters, hydrological conditions and land use were investigated. An hydrological indicator (IndiCE) based on the analysis of pluviometry, conductivity, turbidity and temperature time series has been constructed to assess the vulnerability of such karstic hydrosystem to E. coli contamination according to hydrological conditions. The role of karstic biofilm as pathogens reservoir and class 1 integrons, responsible of secondary contamination, has been studied recording E.coli occurrence in karstic biofilms sampled at Norville’s spring. It has been showed in reactor E. coli capacity to form biofilms on chalk in oligotrophic conditions. In situ cultivable E. coli and class 1 integrons can integrate autochthonous biofilms transiently. E. coli population structure in biofilms is significantly the same than in spring water. This thesis work allowed to a better understanding of E. coli contamination dynamic in water and biofilm of karstic hydrosystem.