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Mercury (Hg) is distributed globally through atmospheric transport. The broad range of environmental conditions will lead to various possible speciation of mercury, which will ultimately affect the toxicity and transport of mercury. Hg toxicity, transport and speciation have been widely studied. However, information about effects of Hg speciation on its environmental behavior in unsaturated porous media and on its removal from wastewater stream is still limited. The present work contributes towards understanding the impact of Hg speciation on both the transport of Hg species in unsaturated porous media (e.g., surface soil) and removal of Hg species in wastewater streams. This knowledge is necessary to assess the possible environmental risks of Hg in the environment, where different Hg species can exist and have different properties and impacts on water quality and ecosystems. The first objective of this research was to determine the effect of Hg speciation on its retention in partially saturated soils. The retention of Hg species in model porous media and in real soil was assessed in column breakthrough experiments. Deposition (retention) rates for each Hg species were calculated to evaluate the influence of Hg speciation, porous medium composition and influent solution on the mobility of Hg species in porous media. This study provided information about the relative retention of each Hg species in soils, and identified natural-organic-matter-bound Hg as the most mobile Hg species and that with the greatest potential for vertical migration to groundwater. The second objective of this research was to determine how Hg speciation affects its ability to be removed from water via adsorption by activated carbon and organoclay. The effects of Hg speciation, water quality parameters and adsorbent type on the removal of Hg were compared to explore the potential removal efficacy and mechanism. The result indicated Hg removal efficacy was influenced by Hg speciation differently depending on the solution conditions. Therefore, using total dissolved Hg(II) to predict Hg removal efficacy may not provide a reliable estimate of adsorption. Organoclay was shown to have a highly reactive surface and the highest adsorption capacity per unit specific surface area among the tested adsorbents. The third objective was to determine the Hg speciation in produced water from an oil production well, and to study the influence of Hg speciation on its removal from produced water by adsorbents. Mercury species in a produced water sample were identified as mainly particulate species and hydrophobic species. The removal of the amended Hg species in produced water was measured to evaluate the impact of Hg speciation on its removal. This study showed that produced water composition affected Hg speciation and formed hydrophobic Hg was more difficult to remove than initially added hydrophilic Hg species in produced water.

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Extraction of oil and gas in Utah’s Uintah Basin results in large quantities of wastewater, or produced water, with nutrients and residual organic chemical that represent a significant resource for producing energy-related and value-added products. Produced water was obtained as a biomass producing nutrient source from industries operating in Utah’s Uintah Basin. Within the Uintah Basin (defined as Uintah and Duchesne Counties within Utah) approximately 93 million barrels of water were produced in 2013 while only 11% of the water was disposed of through evaporation, with the national average at 2%. The rest is reinjected into the subsurface. The goal of this project was to design a system that utilizes produced water as a nutrient source for growing microalgae biomass in a biofilm form using a Rotating Algal Biofilm Reactor (RABR). The biomass would then be harvested and converted into biocrude oil using hydrothermal liquefaction (HTL). The objectives were to (1) cultivate biomass on produced water, (2) optimize the reactor to reduce energy costs to operate while increasing biomass productivity, and (3) increase feedstock quality for HTL. The RABR was constructed out of polystyrene disks, and experimentation was carried out to optimize rotational speed of the reactor. Two strains of algal biomass were identified as biofilm formers and grown using produced water as the nutrient source. The biomass was then utilized as a HTL feedstock that gave an average yield of 34.5% ash free dry weight.

Microfiltration is one of the most important processes in membrane sciences that can be used for separating drops/particles above 1 ??m. Depth microfiltration membranes retain drops/particles inside the surface of the membrane, the process is expensive and membranes quickly become fouled. On the other hand, surface microfiltration membranes stop drops/particles on the surface of the membrane and the process is less fouling. Higher permeate flux and lower trans-membrane pressure is obtained with a shear enhanced microfiltration technique. Production of specific size of drops and stability of the drops are very important in testing the microfiltration of crude oil drops/water emulsions. Oil drops from 1-15 ??m were produced with a food blender, operated at its highest speed for the duration of 12 mins. In addition, vegetable oil drops were stabilised with 1% polyvinyl alcohol (PVA), Tween 20 and gum Arabic, stability was assessed on the basis of consistency in the size distribution and number of drops in each sample analysed at 30 mins interval. A slotted pore Nickel membrane with the slot width and slot length of 4 and 400 ??m respectively has been used in the filtration experiments. The slot width to the slot length ratio (aspect ratio) of the used membrane is 100. Vibrating the membrane at various frequencies created shear rates of different intensities on the surface of the membrane. Membrane with a tubular configuration is preferred over the flat sheet because it is easy to control in-case of membrane oscillations both at lab and industrial scale. Besides this, a tubular membrane configuration provides a smaller footprint as compared to the flat sheet. The influence of applied shear rate on slots/pore blocking has been studied. Applying shear rate to the membrane reduced the blocking of the slots of the membrane; and reduction of slots blocking is a function of the applied shear rate. At higher shear rate, lower blocking of the slots of the membrane was verified by obtaining lower trans-membrane pressure for constant rate filtration. The experiments are in reasonable agreement with the theoretical blocking model. Divergence of the experimental data from the theory may be due to involvement of deforming drops in the process. During microfiltration of oil drops, the drops deform when passing through the slots or pores of the membrane. Different surfactants provided different interfacial tensions between the oil and water interface. The influence of interfacial tension on deformation of drops through the slots was studied. The higher the interfacial tension then the lower would be the deformation of drops through the slots. A mathematical model was developed based on static and drag forces acting on the drops while passing the membrane. The model predicts 100% cut-off of drops through the membrane. Satisfactory agreement of the model with the experiments shows that the concept of static and drag force can be successfully applied to the filtration of deformable drops through the slotted pore membranes. Due to the applied shear rate, inertial lift migration velocities of the drops away from the surface of the membrane were created. Inertial lift velocities are linear functions of the applied shear rate. A mathematical model was modified based on inertial lift migration velocities. The critical radius of the drops is the one above which drops cannot pass through the surface of the membrane into the permeate due to the applied shear rate and back transport. The model is used as a starting point and is an acceptable agreement with the experiment. The model can be used to predict the 100% cut-off value for oil drops filtration and a linear fit between this value and the origin on a graph of grade (or rejection) efficiency and drop size to slot width ratio was used to predict the total concentration of dispersed oil left after filtration. Hence, it is shown how it is possible to predict oil discharge concentrations when using slotted filters.

Orientador: Roberto Sartori Filho / Banca: João Carlos Pinheiro Ferreira / Banca: Margot Alves Nunes Dode / Resumo: Objetivou-se com o presente estudo avaliar a criotorerância de mórulas e blastocistos produzidos in vivo de doadoras da raça Sindi e Nelore (Bos indicus) e Holandês Preto e Branco (HPB - Bos taurus). No Experimento 1, 24 fêmeas lactantes e não lactantes da raça Sindi foram superovuladas com 100 mg de FSH suíno com protocolos em que as duas últimas aplicações de FSH foram substituídas ou não por 300 UI de eCG. Sete dias após a indução da ovulação, os embriões foram colhidos e avaliados quanto ao estágio de desenvolvimento embrionário e grau de qualidade. Dois terços dos embriões foram destinados à criopreservação, dos quais metade foi congelada pelo método convencional, com curva de resfriamento de -0,5ºC/min e a outra metade foi vitrificada pela técnica de Cryotop. Em seguida, foram descongelados e transferidos para receptoras sincronizadas, de maneira contemporânea aos embriões frescos. No Experimento 2, 31 fêmeas da raça Nelore foram superovuladas com 133 mg de FSH suíno e os dois terços dos embriões colhidos foram criopreservados e transferidos semelhantemente ao Experimento 1. No Experimento 3, 67 vacas lactantes e novilhas da raça HPB foram superovuladas com 500 e 300 UI de FSH suíno, respectivamente, e após a colheita dos embriões foram adotados os mesmos procedimentos realizados nos Experimentos 1 e 2. Os resultados foram analisados por modelos lineares generalizados e estão apresentados na forma de média dos quadrados mínimos ± erro padrão. Nos Experimentos 1 e 2, os embriões transferidos a fresco apresentaram maior taxa de concepção aos 30 dias do que os vitrificados e congelados (54,8±7,4a, 17,7±7,3b e 19,5±6,6%b; respectivamente; P 0,0013) na raça Sindi (n=231 embriões) e (46,0±6,1a; 31,2±5,4b e 28,1±5,3%b; respectivamente, P 0,04) na raça Nelore (n=297 embriões). O estágio de desenvolvimento embrionário parece não... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this study was to evaluate the cryotolerance of morulae and blastocysts produced in vivo in Sindhi and Nelore (Bos indicus) and Holstein (Bos taurus) donnors. In Experiment 1, 24 lactating and non-lactating Sindhi donnors were superovulated with 100 mg porcine FSH with protocols in which the last two FSH treatments were replaced or not by 300 IU eCG. Embryos were collected 7 days after ovulation induction and embryo development and quality degree were accessed. Two thirds of the embryos were cryopreserved, by the conventional freezing or Cryotop method. After that, embryos were thawed and transferred to synchronized recipients, simultaneously to fresh embryos. In Experiment 2, 31 Nelore cows were superovulated with 133 mg porcine FSH and two thirds of the embryos were cryopreserved and transferred similarly to Experiment 1. In Experiment 3, 67 Holstein lactating dairy cows and heifers were superovulated with 500 and 300 IU pFSH, respectively, and the same procedures were performed as in Experiments 1 and 2. Results were analyzed using generalized linear models and are presented as least squares means ± standard error. In Experiments 1 and 2, fresh embryos had a higher conception rate at Day 30 than those vitrified and frozen (54.8±7.4a, 17.7±7.3b and 19.5±6.6%b; respectively; P 0.0013) in Sindhi donnors (n=231 embryos) and (46.0±6.1a; 31.2±5.4b and 28.1±5.3%b; respectively; P 0.04) in Nelore donors (n = 297 embryos). Embryo developmental stage seems to have not influenced conception rates of Zebu embryos, especially cryopreserved ones. Finnaly, in Experiment 3, conception rates of fresh and cryopreserved embryos were similar (37.4±12.3, 24.5±11.3 and 21.0±9.5%; respectively, P>0.15) and also no difference was detected for the cryotolerance of morulae versus blastocysts (P>0.10) / Mestre

Synthetic membranes have a high separation efficiency, small footprint, low energy consumption and ease of operation, making them an attractive alternative to traditional separation operations. For this reason, membranes have been extensively studied for the treatment and recycling of bitumen-containing wastewaters. Such wastewaters include petroleum produced water, residual pipeline cleaning solutions and contaminated water from oil spills. Ceramic membranes are preferred in these applications over polymeric membranes because they are highly resistant to solvents and can be operated at high temperatures over a wide range of pH. Fine clays and silicates, coated with bitumen, are significant foulants for membrane filtration systems. These foulants possess acidic, basic and amphoteric groups, leading to the presence of both positive and negative surface charges. Ceramic membranes in aqueous media have a pH dependent surface charge. It was hypothesized that these surface charges are responsible for the high fouling of ceramic membranes that is observed when treating wastewaters containing bituminous fines. The overall objective of this research was to reduce fouling and increase the lifetime of ceramic membranes in treating oil sands produced water; an example of a wastewater containing bituminous fines. This goal was achieved through the surface modification of the ceramic membrane’s selective layer, as well as by the implementation of a novel in-place steam regeneration technique. All membrane filtration tests were performed with field samples of oil sands produced water that were supplied to CanmetMINING (NRCan) by three Canadian oil sands companies. Organosilanes are silicon-based monomers that can possess a wide array of chemical functionality due to their organic moieties. They are capable of reacting with oxide surfaces, and have seen extensive use as surface modification agents for ceramic membranes in various applications. To maintain desirable hydrophilic properties without surface charges, highly hydrophilic and non-ionic polyethylene oxide (PEO) based organosilanes were identified. These PEO-silanes were then used to modify ceramic membranes of several different selective layer materials, and the thermal stability of the silane layer was studied using FTIR, SEM, zeta potential and contact angle measurements. The modification procedure with PEO-silanes was first applied to lab-scale membrane disks, and subsequently to commercial scale multilumen membrane tubes that were tested in a pilot-scale system at CanmetMINING. Results obtained from both sets of experiments were promising and demonstrate that ceramic membranes can be surface modified in a way that successfully renders them fouling resistant to the bituminous fines present in these wastewaters. Upon surface modification, foulants were more readily released from the membrane surface, resulting in an enhanced flux and separation performance. A novel steam regeneration technique was also applied as a means of bituminous fouling alleviation. This technique was tested in the CanmetMINING pilot-scale system and consisted of periodically injecting steam into the membrane lumen feed channels during operation. Direct steam injection rapidly heated foulant cake layers, and water droplets in the saturated steam caused surface abrasions that ultimately resulted in the scouring of bitumen away from the membrane surface. Membrane fluxes when steam regeneration was active were up to 4 times higher when compared to tests where only traditional permeate backflushing was used. The fouling remediation techniques developed in this work have broad potential applicability in ceramic membrane filtration systems aimed at treating all wastewaters containing bituminous compounds, such as process waters in general and contaminated water from oil spills.

Unconventional natural gas extraction from the Marcellus Shale requires millions of gallons of water to fracture shale and release natural gas from the formation. This process produces water with high levels of total dissolved solids (TDS); and, efforts to recycle these fluids has stimulated microbial growth in produced water. The objective of this study was to analyze the ionic composition of and characterize microorganisms from Marcellus produced water samples. A semi-synthetic culture medium was designed with high TDS to enrich for halophilic microbes, which yielded robust cultures that were able to grow over a wide range of salinities. DNA extracted from aerobic cultures was used for 16s rDNA clone libraries and Automated Ribosomal Intergenic Spacer Analysis (ARISA). ARISA and 16S gene sequencing revealed differences in bacterial composition between Marcellus and freshwater samples. Sequencing of 16S gene indicated the presence of Halomonas, Thalassospira and other genera related to halophilic and petroleum degrading species. / Bayer School of Natural and Environmental Sciences / Environmental Science and Management (ESM) / MS / Thesis

Food consumption trends change continuously. A noticeable trend in Sweden and the western world is consumers’ need for knowledge about the food they consume and where it originates from. Moreover, consumers appreciate food products produced close to home. The interest towards locally produced food has lately increased amongst today’s consumer, as has many researchers’ interest in the topic.  The purpose with this dissertation is to investigate how and if product-specific attributes attached to a locally produced food product, like Price, Quality, Brand and Organically produced can lead to that consumers’ are loyal towards a region. A deductive research approach is applied for this dissertation. Based on the theories of consumer loyalty, and by regarding current food trends, the theory of regional loyalty as a concept is developed. The product-specific attributes Brand, Price, Quality and Organic are examined and tested. A model and hypotheses are developed in order to understand the relationship better. By using a quantitative method and conducting a questionnaire, the consumer’s attitudes were examined. The research was conducted in themunicipalityofKristianstadand 130 questionnaires were handed out outside the biggest grocery stores in town. The findings indicate that there is a positive correlation between the variables attached to locally produced food products and regional loyalty. The results show that all these attributes are related to regional loyalty except of price, regardless of age, income or current occupation. According to the authors’ knowledge, since no study has been conducted on regional loyalty or product-specific attributes affecting this, the results of this dissertation will bring new knowledge to this area of research. The results may also be useful for executives when marketing locally produced food products.

The constantly growing demand for energy and the consequent depletion of fossil fuels have led to a drive for energy that is environmentally friendly, efficient and sustainable. A viable source with the most potential of adhering to the criteria is nuclear-produced hydrogen. The hybrid sulphur cycle (HyS) is the proposed electrothermochemical process that can produce the energy carrier, hydrogen. The HyS consists of two unit operations, namely the electrolyzer and the decomposition reactor, that decomposes water into hydrogen and oxygen. A techno-economic evaluation of the technology is needed to prove the commercial potential of the cycle. This research project focuses on determining the hybrid sulphur cycle’s recommended operating parameter range that will support economic viability whilst maintaining a high efficiency. This is done by comparing the results of an evaluation of four case studies, all operating under different conditions. The technical evaluation of the research project is executed using the engineering tool Aspen PlusTM. The models used to achieve accurate results were OLI Mixed Solvent Electrolyte, oleum data package for use with Aspen PlusTM, which provides an accurate representation of the H2SO4 properties, and ELECNRTL to provide an accurate representation of H2SO4 at high temperature conditions. This evaluation provides insight into the efficiency of the process as well as the operating conditions that deliver the highest efficiency. The economic evaluation of the research project determines the hydrogen production costs for various operating conditions. These evaluations provide a recommended operating parameter range for the HyS to obtain high efficiency and economic viability. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2010.