Made available in DSpace on 2014-10-09T12:41:13Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:33Z (GMT). No. of bitstreams: 0 / Visando contribuir com o desenvolvimento de uma metodologia adequada ao Brasil para deposição de fontes seladas fora de uso, o presente estudo avaliou cenários de migração de radionuclídeos para fora de um repositório profundo tipo poço tubular. Considerou-se uma fratura anelar como caminho preferencial de fluxo da água subterrânea, que futuramente adentrará os poços, entrando em contato direto com as fontes. No futuro, fenômenos naturais e ação antrópica poderiam levar à degradação dos materiais que formam as barreiras artificiais do repositório e formar uma via preferencial de transporte e migração dos radioisótopos depositados. Haveria intrusão de água subterrânea e contato com as fontes seladas, corrosão e transporte dos radioisótopos para o ambiente acessível ao homem. A modelagem de transporte considerou percolação de água subterrânea numa fratura causada pelo descolamento entre o tubo de aço e a pasta de cimento, que separa o repositório do meio geológico. Foram simulados cenários de migração e o estudo poderá ser aproveitado na escolha de sítio e de novas técnicas para selagem. Diferentes gradientes hidráulicos e espessuras de fratura, entre outros parâmetros, influirão diretamente no fluxo pela fratura postulada que resultarão em diferentes tempos de trânsito até a biosfera. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

A study is made of the use of chemical analysis of groundwater samples to assess groundwater quality. Samples from forty-seven boreholes within and around ten landfill sites in the London Borough of Hounslow were analysed. Most of the landfill sites studied were filled prior to the implementation of the Control of Pollution Act 1974 and were not designed with environmental protection in mind. Boreholes were tested for methane, carbon dioxide and groundwater samples were analysed for electrical conductivity (EC), ammonium nitrogen (NI14-N), COD, TOC, Cl-, NO3, SO42-, Na+, K+, Ca2+, Ni2+, Cu2+, Pb2+, oxidation - reduction - potential (ORP) and pH. The first ten of these analytical parameters were considered for groundwater quality assessment and the most important selected for more detailed study namely CH4, C02, EC, NH4-N, COD and TOC. Pollution ratings are allocated on the basis of single pollutant analytical data and averaged for each of the bore hole samples. Goodness of fit values between the single analyte values and the average data were calculated and no set of single analyte data was found to provide good groundwater quality assessment. A series of formulae combining the six analyte parameters was considered and the data evaluated by goodness of fit calculations to provide an effective means of assessing groundwater quality. The ratings obtained from the best formula are compared with historical broad band classification of landfill sites and show how sites must be assessed on the basis of samples taken from within the site and not around the perimeter. The production of acetic acid in the acetogenic phase of landfill reactions will increase the leachability and mobility of many metal pollutants and particularly of lead. Studies on the leachability of lead in acetic acid media show how lead solubility is increased in acetic acid media by the formation of triacetatolead(II) species, Pb(CH3CO2)3-.

Permafrost temperatures were measured by the Geological Survey of Canada (GSC) in 1977-1981 at boreholes along a proposed pipeline route in the southern Yukon. Analysis of climate station records indicate that mean annual air temperatures in the region have since increased by 0.5-1.0˚C. Renewed interest in the pipeline and the need to develop adaptation strategies for existing highway infrastructure have meant that information on permafrost and geotechnical conditions must be updated. To accomplish this goal, a total of eight GSC boreholes ranging in depth from 5-9 m were located, unblocked of ice and instrumented with thermistor cables and data-loggers to permit renewed ground temperature monitoring. Manual temperature measurements were also taken at four other shallow boreholes. Electrical resistivity tomography (ERT) surveys were conducted at each site. MAGTs below 1 m at permafrost sites in the study area range from -0.2˚C to -1.5˚C with permafrost depths greater than 25 m. The permafrost at the study sites can be classified as sporadic discontinuous and extensive discontinuous. Ground temperatures indicate that permafrost can persist under warmer climatic conditions as long as it remains protected by its ecosystem properties. Thermal monitoring for 2011-2012 shows an average increase of 0.5-1.0˚C when compared to the original 1978-1981 ground temperatures. This slow rate of ground warming is mainly attributed to a combination of limited climate change, especially in the south of the study area, ground temperatures close to 0˚C, and the possible disturbance of sites from the removal of vegetation prior to the original measurements being made. ERT surveys conducted at most borehole sites show deeper thaw or taliks where the cleared cut-line used for geophysical work in the 1970s is crossed. These results indicate the impacts of climate change and environmental change in the study area over the past three decades. They appear to match the relatively slow rates of ground warming observed elsewhere in northern Canada where permafrost temperatures are close to 0˚C and where warming also requires changes in latent heat due to internal thaw. TTOP equilibrium modelling suggests that if climate change is responsible for the ground warming, most of the change can be attributed to the step-like MAAT increase that occurred between 1975-1976.

Vertical ground source heat pumps are established and still growing on the global market. The modelling of these systems is important for system design and optimization. This is an active field of research, and many models are often built into system simulation software such as TRNSYS. With the intention of having a better sensibility for existing TRNSYS tools, three different cases are simulated with several TRNSYS tools, so called Types. A Thermal Response Test, a large borehole field of an IKEA building complex in Sweden, as well as the Marine Corps Logistic Base in Albany, USA. The vertical ground heat exchanger types 203, 244, 243, 246, 451, 55a and 557b are used. Most of the simulations are investigated and evaluated by comparing them to measured data. The result shows that, for these specific cases, the DTS types 557a and 557b can underestimate the heat transfer early on due to a poor consideration of the thermal capacity inside the borehole. Depending on how the thermal resistance is calculated by a module, the fluid mean temperature simulation is affected by a constant throughout the simulation time. The simulation results indicate that the type 557b, where the borehole resistance is pre-set as an input and known from experimental data, is the most accurate of the types for groundwater filled boreholes. On short term, type 451 provides a good coherence with the measured data, with a relative deviation of 10.3 %. The borehole models that consider the borehole thermal capacity overestimate the short term heat transfer rate, whereas those that neglect the borehole capacity underestimate the short term thermal heat transfer on short term. Existing Types describe successfully the long term behaviour of large borehole fields. Serial versus parallel coupled BHE fields show relatively small differences in performance when simulated with type 557b for a specific study case.

In 2013, Stockholms Hamnar began a development project for Värtahamnen, one of Stockholms most important harbors, and also decided to build a new ferry terminal that is better suited to meet the increasing capacity demand. The new terminal will feature a borehole storage that will be used to cover the building’s heating and cooling demands. The boreholes have already been drilled and currently the construction of the building is being planned. The overall objective of this project is to study the new terminal and its borehole storage regarding certain input parameters (such as internal heat gains and the U-value of windows) that affect the building’s annual heating and cooling demands, as well as long-term temperature of the borehole storage. To do this, two modeling programs are used: IDA ICE and EED (Earth Energy Designer). The project focuses on three main parts. Part one is a sensitivity analysis of internal loads and construction specific parameters that shows how a variation in these affects the heating and cooling demands. To accomplish this, several models are created and simulated in IDA ICE. In part two, the long-term ground temperature is studied for two of the models analyzed in part one. This is done in both IDA (through a new borehole module) and EED, followed by a comparison of these results. The last part presents the possible amount of free cooling that can be taken from the ground. This estimation is made through simulations in EED, using altered load profiles of the two previously mentioned models. Additionally, this part covers the effects of a changed borehole configuration (number of boreholes, depth, layout, etc.). The results of the first part (the sensitivity analysis) show that there is a rather large variation in annual heating and cooling demands depending on what approach is used for estimating a reasonable amount of internal loads. One way to do this is to first determine the maximum possible load in each zone and then, when simulating the annual energy demand, reduce the total load in the whole building by a certain factor. Another approach is to, from the start of the building modeling, more accurately try to estimate the average amount of internal loads in each zone. In the second part, due to unbalanced load profiles for both analyzed models, the temperature of the borehole storage will increase over time if there is no limitation of the amount of cooling taken from the ground. The results of IDA generally agree with those of EED. In the last part of the project it is shown that a thermally more favorable borehole installation could increase the relative amount of free cooling from the ground, compared to the current installation.

This thesis investigates how architectural element analysis (AE) can be utilized to deconstruct the sedimentary architecture of glacial sedimentary successions, and its significance for paleoenvironmental reconstruction, understanding depositional histories, and providing insight to the hydrostratigraphy of glaciated terrains. The first component of this thesis explores the applicability of AEA to the local-scale analysis of a till succession exposed in outcrop sections in order to understand the significance of the bounding surface hierarchy and architectural elements in sediments deposited in a subglacial depositional environment. Fieldwork was conducted at two outcrop sites in north-central Illinois, U.S.A., which expose Late Wisconsin-age till of the Tiskilwa Formation, in order to test the local-scale applicability of AEA to the architectural analysis of a subglacial succession (Chapter 2). A major finding of this study was that fifth-order bounding surfaces delineate ‘element associations’ which can be mapped across the local study area, and utilized for detailed paleoenvironmental reconstruction of the ‘subglacial bed mosaic’ and local-scale reconstruction of the depositional history of the till sheet, including periods of separation and reattachment of the ice and its bed. The second part of this research explores AEA at Sólheimajökull (Iceland), specifically to test the validity of AEA for the analysis of glacial successions, and to better understand the environmental significance of unit contacts (bounding surfaces) and sedimentary geometries in a modern glacial landscape. Fieldwork was conducted at Sólheimajökull and basic principles of AEA and landsystems analysis were integrated in order to facilitate delineation of the sedimentary architecture and allostratigraphy of the Sólheimajökull landsystem (Chapter 3). Fifth-order surfaces delineate landsystem tract components, which can be utilized to characterize the heterogeneity and sedimentary architecture, delineate allostratigraphic units, and reconstruct the depositional hist¬ory of the Sólheimajökull landsystem. Data from Sólheimajökull (Chapter 3) and Illinois (Chapter 2) were utilized as a modern and outcrop analogue, respectively, to provide insight to the sedimentary architecture of subsurface Quaternary glacial deposits in Georgetown, southern Ontario (Canada; Chapter 4). Basic concepts of AEA were applied to the analysis of sediments recovered from fully-cored boreholes. A major finding of this study is that AEA can be effectively utilized for delineation of subsurface architectures from the analysis of core, and the hierarchies of bounding surfaces and units of AEA can be utilized to organize the sedimentary heterogeneity into a ‘nested’ architectural framework. The geometry and spatial relationship of architectural units (sixth-order surfaces) and architectural components (fifth-order surfaces) provides insight to the hydrostratigraphy of Georgetown. AEA, as utilized in this thesis, provides a systematic methodology with which to deconstruct glacial successions into their basic architectural building blocks at various scales of resolution. AEA enhances traditional facies models by facilitating site-specific delineation, visualization, and characterisation of the sedimentary geometry of facies associations, which in turn, allows direct comparison of sedimentary architectures at different study sites; this has significant implications for analogue selection for the purpose of reservoir analysis. The architectural framework of glacial deposits and its potential significance to hydrostratigraphic models (as discussed in this thesis) may help to facilitate communication and translation of data between the disciplines of ‘geology’ and ‘hydrogeology’. The results of this project can be utilized as a framework to better understand the sedimentary geometry and hydrostratigraphy of modern and Quaternary glacial deposits in southern Ontario, previously glaciated terrains elsewhere, and other modern glacial landsystems, and provide insight into other applications such as civial engineering projects, aggregate resources, placer mining exploration, and land use planning. / Thesis / Doctor of Philosophy (PhD)

Several CO2 transcritical booster systems in supermarkets use the potential of integrating geothermal storage, enabling subcooling during warm climate conditions as well as being a heat source during cold climate conditions. First of all, field measurements of one of these systems located in Sweden were analysed with particular focus on the heat-recovery performance. The best theoretical operational strategy was compared to the one really implemented and the differences in the annual energy usage were assessed through modelling. The results show that an alternative to the best theoretical operational strategy exists; heat can be extracted from the ground while low-temperature heat is rejected by the gas cooler. Such an alternative strategy has important technical advantages with a negligible increment of the energy usage. In the second part of this work, the benefits of geothermal subcooling were evaluated. Applying the BIN hours method, it was demonstrated that this system is expected to save on average roughly 5% of the total power consumption, in Stockholm’s climate. The models utilized for the winter and summer season were combined to find the relationship between geothermal storage size and annual energy savings. In this way, it was possible to calculate the present value of the operational savings for the study case. Furthermore, a general methodology for assessing the economic feasibility of this system solution is presented. Finally, several scenarios were investigated to produce parametric curves and to perform a sensitivity analysis. Comparing the results with the typical Swedish prices for boreholes, the cases where this system solution is economically justified were identified. These are supermarkets with a Heat Recovery Ratio (HRR) higher than the average. For examples, supermarkets supplying heat to the neighbouring buildings (considering the Stockholm’s climate, systems with an annual average HRR of at least 70%). Relying only on savings from subcooling was found to be not enough to justify a geothermal storage, a not-negligible amount of heat must be extracted in winter. Finally, some interesting concepts and alternatives to a geothermal integration are presented to point out relevant future work.

Rural water supply and sanitation in low and middle income countries face the same challenges now as in the 1970s. Despite massive efforts in providing communal “borehole with handpump” and “improved latrines” to improve the lives of millions of people, this traditional approach to development is failing to deliver long lasting improved services - even if for the last 40 years many attempts have been made to solve problems in the approach. The main research question is “Can low-income rural families pay for rural water supply and sanitation?” This thesis has analysed household poverty and costs on water and sanitation services in Mozambique and Ghana based on 3,049 surveys collected between 2009-2010 by the IRC International Water and Sanitation Centre WASHCost project. Evidence shows that even extreme poor households can and do pay for improved water and sanitation services. However, households prefer to pay for more expensive services to reduce the distance required to collect water instead of paying for the cheaper maintenance of communal (further away) sources. For sanitation, without targeted support towards the poorest, improved latrines might be unaffordable. Also, without follow up support, behaviour change and health impact will not be sustained. Small increases in the wealth of the poorest have a large impact on the services demanded in terms of quantity, distance and time spend as well as an increase in the level of capital and maintenance expenditure. Ultimately, the world now is not the same as in the 1970s and for achieving universal sustainable coverage for water and sanitation we need to rethink the failed traditional approach to development in low income countries with a deeper understanding of the market segmentation in the lowest quintile of the population and their real aspirations and demand.

Στο πεδίο κρατήρων του Κόλπου του Ελαιώνα, παρατηρήθηκε διαφυγή γλυκού νερού (Christodoulou et al., 2002). Προκειμένου να διαπιστωθεί αν ο παράκτιος υδροφόρος εκφορτίζεται στη θάλασσα, έγινε δειγματοληψία νερού σε πηγές και γεωτρήσεις στη χέρσο και πραγματοποιήθηκαν υδροχημικές και ισοτοπικές αναλύσεις. / Groundwater seepage was observed in the pockmark field in Eleonas Bay (Christodoulou et al., 2002). In order to find out if the coastal aquifer seeps through the seafloor, water samples were taken from springs and boreholes and hydrochemical and isotopic analyses took place.

Modern bottom-hole assemblies are equipped with various sensors which measure the geological and directional information of the borehole while drilling. It is very crucial to get the measured downhole information to the surface in real time in order to be able to monitor, steer and optimize the drilling process while drilling. The transmission of the information to the surface is most commonly carried out by coded pressure pulses (the technology called mud pulse telemetry) which propagate through the drilling mud inside the drill string towards the surface. However, hardly any specific experimental research on the hydraulic data transmission can be found in the literature. Moreover, it is essential to use a reliable model/simulation tool which can more accurately simulate the pressure pulse propagation in fluids inside drill strings under various drilling operation conditions in order to improve the performance of the data transmission process. The aims of this study are to develop and test a laboratory experimental setup, a simulation model and a novel method for detecting and decoding of measurement while drilling pressure pulse propagation in fluids inside drill strings. This thesis presents a laboratory experimental setup for investigating the process of data transmission in boreholes by mud pulse telemetry. The test facility includes a flow loop, a centrifugal pump, a positive mud pulser or alternatively a mud siren, pressure transducers at four different locations along the flow loop and a data collection system. Moreover, it includes an “actuator system” for the simulation of typical noise patterns created by the common duplex or triplex mud pumps. This laboratory setup with great capabilities opens the way for testing and developing new concepts for data transmission. A theoretical model using ANSYS CFX11 (Computational Fluid Dynamics (CFD) commercial code) was successfully developed to simulate dynamic pressure pulse transmission behavior in the fluid inside the flow loop. The collected laboratory data which simulate various data transmission processes in boreholes were used to verify and calibrate the theoretical method. A pretty good agreement is achieved between the predicted and measured pressure pulses at different locations along the flow loop for positive pulses with various durations using different flow rates and for continuous pressure pulses using different carrier frequencies. A novel approach (continuous wavelet transformation) for detecting and decoding the received continuous pressure pulses in a noisy environment was applied to various simulated drilling operation conditions for data transmission in boreholes in the laboratory. The concept was registered at the German Patent and Trade Mark Office (DPMA) for a patent in 2011. The results indicate that the continuous wavelet transformation can be used to clearly identify and better detect the continuous pressure pulse periods, frequencies and discontinuity positions in the time domain compared to the conventional method (Fourier transformation). This method will contribute to the possibility of transmitting the data at higher rates and over longer distances. A concept for developing an innovative pulser using electrical discharge or acoustic sources for inducing pulses keeping the drill strings fully open (eliminating the problem of plugging the pulser by pumped lost circulation materials) and without any mechanical moving parts (eliminating the failure related to the pulser moving parts) was also registered at the German Patent and Trade Mark Office (DPMA) for a patent in 2012. With this pulser, it is expected that it would be possible to transmit the data over longer distances and at higher rates. Realizing the concept of the new pulser and using continuous wavelet transformation for detecting and decoding the pulser signal are recommended for future work.