Sulfate, nitrate, and certain trace elements are common groundwater contaminants observed at mining sites. Their source, fate, and remediation were investigated at a former uranium mining site. First, groundwater samples collected across the site were analyzed for geochemistry, stable isotopes, and trace elements. Then, two pilot-scale ethanol injection tests were conducted for biostimulation of nitrate and sulfate reduction. Groundwater was monitored in the test area before and after the tests. The results showed a mixing of two discrete sources of sulfate. Quantification of these two sources using two methods showed that sulfide-mineral oxidation of the mine tailings served as a steady but low-discharge source while sulfuric acid (applied during ore processing in the 1960s) served as a variable, strong source. It appears that sulfuric acid served as a sustained source of sulfate for approximately 40 years. This source may be from accumulation of sulfate salts (formed from sulfuric acid) in the source zone due to the arid climate of the site. Results showing correspondence of isotopic compositions of ammonium and nitrate confirmed the generation of nitrate via nitrification. Moreover, it was observed that ammonium concentration is closely related to concentrations of uranium and a series of other trace elements including chromium, selenium, vanadium, iron, and manganese. It is hypothesized that ammonium-nitrate transformation processes influence the disposition of the trace elements through mediation of redox potential, pH, and possibly aqueous complexation and solid-phase sorption. As for the biostimulation, sulfate reduction condition has been maintained for a period of approximately 3 years after a single input. Atypical fractionation behavior of the delta34S in sulfate was hypothesized to be caused by release of sulfate from sulfate minerals associated with the sediments. Elevated hydrogen sulfide concentrations were not observed until approximately four months after the start of the test. This behavior, in concert with the observed changes in aqueous iron and manganese species, suggests that hydrogen sulfide produced from sulfate reduction was precipitated, presumably in the form of iron sulfides, until the exhaustion of readily reducible iron oxides. Hydrogen sulfide produced thereafter appears to have been in part re-oxidized.

Upon request of the VPR and the thesis advisor this item has been made administrative access only until further notice. / Biodegradation of petroleum has been observed to be one of the most important factors that can alter reservoir chemistry. Biodegradation of petroleum has been connected to the generation of heavy oil at the expense of light hydrocarbon components. Generally, heavy oil is associated with the increasing in metal and sulfur content as well as viscosity. In addition, petroleum biodegradation will result in the production of certain metabolites that are implicated in forming emulsions and corrosion problems in the producing and refining facilities. However, identifying the microrganisms that catalyse this biodegradation is crucial to understanding their role in the hydrocarbons alteration. In this thesis, I addressed the connection between the petroleum biodegradation and the formation of light hydrocarbon components at the expense of heavy hydrocarbon components, and the increase in gas/oil ratio. A comparison between light, extra light, and medium sour crudes lends support to the hypothesis of light hydrocarbons formation through biodegradation of long chain oil components. The results suggested that there was no direct relationship between the relative density of oil and the level of biodegradation, but, there was a positive correlation between the level of biodegradation, the formation of light hydrocarbons, and an increase in the gas/oil ratio. As a first step in investigating this correlation, a metagenomics approach was used to identify and characterize the biodiversity in a European oil field. Extrapolation of the oilfield microbiome data based on an analysis of 200 species generated a hypothetical metabolic map that suggests a new model for petroleum formation and degradation that challenges the accepted dogma in which aerobic and anaerobic petroleum degradation is taking place in the hydrocarbons reservoir, as it is a matter of rate; where the aerobic petroleum degradation targets the short-chain hydrocarbons specifically methane and result in heavy oil generation; whereas the anaerobic petroleum degradation leads to form the gaseous components such as methane, carbon dioxide and hydrogen sulfide. Hence, the gaseous components have a direct impact on the oil density when they represent the majority of the oil field composition by making it more gaseous than liquid.

In this thesis, column experiments were conducted in order to determine the effect of irrigation with local groundwater on mobilization of lead and zinc in 50 years old sulfate-acid mine tailings. In addition, the influence of soluble oxalic acid, a common rhizosphere organic acid, was assessed by varying its concentration across an environmentally relevant range. In general, metal contaminant dissolution was not affected by the presence of oxalic acid. In both tailings, Zn mobilization was higher than Pb suggesting the presence of more kinetically labile Zn phases, regardless of the treatment used. Lead mobilization was also low because effluent solutions were near to equilibrium conditions with respect to gypsum, preventing Pb dissolution from Pb-sulfate minerals. Geochemical modeling also indicated that lead release was controlled by anglesite and plumbojarosite dissolution. Zinc release appears to be controlled by Zn-talc and goslarite.

This study utilizes new geochemical analyses of fluids (formation water and gas) collected predominately from Devonian organic-rich shales and reservoir sandstones from the northern Appalachian Basin margin to investigate basin scale hydrologic processes, water-rock reactions, microbial activity, and natural gas generation. Elemental and isotopic composition of co-produced formation waters and natural gas show that the majority of methane in Devonian organic-rich shales and reservoir sandstones is thermogenic in origin with localized accumulations of microbial gas. Microbial methanogenesis appears to be primarily limited by redox buffered conditions favoring microbial sulfate reduction. Thermal maturity (bioavailability) of shale organic matter and the paucity of formation waters may also explain the lack of extensive microbial methane accumulations. Iodine and strontium isotopes, coupled to elemental chemistry demonstrate basin scale fluid flow and clay mineral diagenesis. Evidence for this is based on anomalously high ¹²⁹I/I values sourced from uranium deposits (fissiogenic production of ¹²⁹I) at the structural front of the Appalachian Basin. Radiogenic ⁸⁷Sr/⁸⁶Sr (up to 0.7220), and depleted boron and potassium concentrations support smectite clay diagenesis at temperatures greater than 120 °C. The development of fissiogenic ¹²⁹I as a tracer of basin scale fluid flow is a novel application of iodine isotopes provided that the sources of cosmogenic and anthropogenic ¹²⁹I are reasonably well constrained. The anomalously high ¹²⁹I/I in Appalachian Basin brines may be alternatively explained by microbial fractionation based on a correlation with decreasing δ¹³C-DIC values and decreasing sulfate concentrations in the range of sulfate reduction. These results demonstrate that the microbial fractionation of iodine isotopes may be possible and an important consideration when interpreting ¹²⁹I/I, regardless of the source of ¹²⁹I. Results from this study have important implications for understanding the controls on and origins of natural gas production in sedimentary basins; tectonically and topographically driven basin scale fluid flow, including diagenetically induced waterrock reactions and mineral ore deposition related to orogenesis; and an improvement of the use of iodine isotopes for understanding large scale fluid flow, and possibly its use as a tracer of organic matter diagenesis and the distribution of radionuclides in the environment.

No description available.

Gas hydrate can precipitate in pore space of marine sediment when gas concentrations exceed solubility conditions within a gas hydrate stability zone (GHSZ). Here we present analytical expressions that relate the top of the GHSZ and the amount of gas hydrate within the GHSZ to the depth of the sulfate-methane transition (SMT). The expressions are strictly valid for steady-state systems in which (1) all gas is methane, (2) all methane enters the GHSZ from the base, and (3) no methane escapes the top through seafloor venting. These constraints mean that anaerobic oxidation of methane (AOM) is the only sink of gas, allowing a direct coupling of SMT depth to net methane flux. We also show that a basic gas hydrate saturation profile can be determined from the SMT depth via analytical expressions if site-specific parameters such as sedimentation rate, methane solubility and porosity are known. We evaluate our analytical model at gas hydrate bearing sites along the Cascadia margin where methane is mostly sourced from depth. The analytical expressions provide a fast and convenient method to calculate gas hydrate saturation for a given geologic setting.

A unique penetration instrument has been developed to evaluate the role of surfactants in kraft pulping process. This instrument can screen surfactants which can improve the wood impregnation more effectively and much faster than pilot-plant experiment. The role of surfactants in wood penetration has been explored. Surfactants can improve wood impregnation by dispersing the extractives in the wood structure and optimizing the interfacial properties between wood surface and kraft liquor. The addition of two blends of anionic and nonionic surfactants into kraft pulping process results in a significant reduction of the screen rejects and an increase of screened yield at the same delignification rate. / Six wood species were tested in this study including both non-resinous and resinous wood species. Both sapwood and heartwood of these species were tested. Surfactants were found to have no improvement on sapwood, but a significant improvement on heartwood. The critical micelle concentrations (CMC) of surfactants in kraft liquor were determined. The best dosages of surfactants based on CMC were also determined in this study.

The proteoglycan CD44 is a widely expressed cell surface receptor for the extracellular matrix glycosaminoglycan hyaluronan, and is involved in processes ranging from metastasis to wound healing. In the immune system, leukocyte activation induces hyaluronan binding through changes in CD44 post-translational modification, but these changes have not been well characterized. Here I identify chondroitin sulfate addition to CD44 as a negative regulator of hyaluronan binding. Chondroitin sulfate addition was analyzed by sulfate incorporation and Western blotting and determined to occur at serine 180 in human CD44 using site-directed mutagenesis. Mutation of serine 180 increased hyaluronan binding by both a CD44-immunoglobulin fusion protein expressed in HEK293 cells, and full-length CD44 expressed in murine L fibroblast cells. In bone marrow-derived macrophages, hyaluronan binding induced by the inflammatory cytokines tumor necrosis factor-α and interferon-γ corresponded with reduced chondroitin sulfate addition to CD44. Retroviral infection of CD44⁻/⁻ macrophages with mouse CD44 containing a mutation at serine 183, equivalent to serine 180 in human CD44, resulted in hyaluronan binding that was constitutively high and no longer enhanced by stimulation. These results demonstrate that hyaluronan binding by CD44 is regulated by chondroitin sulfate addition in macrophages. A functional consequence of altered chondroitin sulfate addition and increased hyaluronan binding was observed in Jurkat T cells, which became more susceptible to activation-induced cell death when transfected with mutant CD44. The extent of cell death was dependent upon both the hyaluronan binding ability of CD44 and the size of hyaluronan itself, with high molecular mass hyaluronan having a greater effect than intermediate or low molecular mass hyaluronan. The addition of hyaluronan to pre-activated Jurkat T cells induced rapid cell death independently of Fas and caspase activation, identifying a unique Fas-independent mechanism for inducing cell death in activated cells. Results were comparable in splenic T cells, where high hyaluronan binding correlated with increased phosphatidylserine exposure, and hyaluronan-dependent cell death occurred in a population of restimulated cells in the absence of Fas-dependent cell death. Together these results reveal a novel mechanism for regulating hyaluronan binding and demonstrate that altered chondroitin sulfate addition can affect CD44 function.

Sulfate is one of the most problematic ions present in reject brine in desalination systems due to its high potential of scale formation and membrane fouling; making it an obstacle in the application of zero liquid discharge. The ultra-high lime with aluminum process (UHLA) has shown to effectively remove sulfate. This research involves the study of sulfate removal from the nano-filtration unit in the zero liquid discharge system for inland desalination via a two-stage process using a calcium source to remove sulfate in the first stage and implementing the UHLA process in the second stage. The kinetics, equilibrium characteristics, and effects of different parameters on sulfate removal were studied. Kinetics of sulfate removal was studied on both stages of the process. The observation of fast kinetics in both stages indicated that removal kinetics is not a limitation for the application of the process. Equilibrium characteristics of the UHLA process were performed which revealed efficient sulfate removal at practical ranges of lime and aluminum doses. The effect of pH on sulfate removal in the process was studied. Results showed that sulfate removal in Stage 1 was independent of the pH of the solution while effective sulfate removal in Stage 2 was found to be above a pH of 11. The effect of initial sulfate concentrations on sulfate removal in Stage 1 was investigated and sulfate removal was mainly controlled by calcium sulfate solubility. The effect of initial chloride concentrations on sulfate removal in Stage 2 was evaluated and the results indicated that chloride has negligible effect on the removal of sulfate. Experiments concerning the effect of the recycle of calcium sulfate solids in Stage 1 showed an increase of the reaction rate. In contrast, the recycle of Stage 2 dry solids into Stage 2 revealed no effect on sulfate removal. An equilibrium model was developed to explain the equilibrium characteristics of Stage 2. It was found that a valid explanation for the chemistry of sulfate removal in Stage 2 was the formation of a solid solution consisting of ettringite and monosulfate. XRD analysis confirmed the formation of these solids.

Xylanase production from a Bacillus subtilis gene cloned into a strain of Escherichia coli was measured. Although this gene was expressed in E. coli at several temperatures, efficient normal xylanase secretion did not occur, the observed protein release apparently depending on cell leakage or lysis. Screening for a better microbial protein secretor free of cellulase selected B. cereus #259. The strain had wild plasmids that were hard to eliminate using acridine orange and elevated temperature curing techniques. While still bearing 5 wild plasmids, attempts to transform B. cereus #259 were unsuccessful using conventional methods and electroporation. Another strain, B. cereus #518, found to be free of wild plasmids, was then used. A bidirectional vector shuttle plasmid (pMK3) was employed to carry the cloned gene into this B. cereus strain. Transformation was carried out by high voltage electroporation. Xylanase production by the new B. cereus clone was similar to that from E. coli, but was shown to be continuously and normally secreted. The xylanase gene products from the E. coli and B. cereus hosts were shown to function identically. Both xylanases improved the delignification of unbleached softwood and hardwood kraft pulps, thus reducing the Cl$ sb2$ required to achieve a given degree of bleaching, without altering the physical properties of the fibers. Using a target kappa number lignin content) of 5, xylanase pretreatment of aspen kraft pulp led to a 22% saving of chlorine. Adsorbable organic halogens in the bleachery effluent were also lowered by more than 50%.