The presence of coal tars in the subsurface associated with former manufactured gas plants (MGPs) offers a remediation challenge due to their complex chemical composition, dissolution behaviour and recalcitrant characteristics. A former MGP site in Clearwater Beach, Florida was characterized and bench-scale analyses were conducted to assess the potential for in situ chemical oxidation (ISCO) using persulfate to treat MGP residuals. Completion of a conceptual site model identified a homogeneous, silty sand aquifer, with an average hydraulic conductivity of approximately 2.3x10-3 cm/s and a groundwater flow rate of 2 cm/day in the direction of S20°E. Six source zones, three near the water table and three in the deep aquifer were estimated to have a total volume of 108 m3. A multi-level well transect was installed to monitor concentrations of dissolved compounds and to estimate mass discharge downgradient of the source zones over time. On average, the morphology of the aqueous concentrations remained consistent with time. A total mass discharge across the transect of 94 mg/day was estimated for site-specific compounds. Bench-scale tests were conducted on aquifer sediments and groundwater samples. The aquifer was determined to have a low buffering capacity, low chemical oxygen demand, and low natural oxidant interaction (NOI) with persulfate. Aqueous batch experiments identified the potential for iron (II) activated persulfate to reduce concentrations of BTEX and PAHs below method detection limits (MDLs). Unactivated persulfate was able to reduce BTEX concentrations to below MDLs after 14 days; however, the concentration of PAH compounds remained above MDLs after 14 days. Higher iron doses within the system were shown to be more effective in reducing BTEX and PAH compounds. Column experiments designed to mimic site conditions were used to evaluate the feasibility of persulfate treatment on impacted sediments from the Clearwater site. Two sets of column experiments were conducted: one using unactivated persulfate followed by alkaline activated persulfate; and one using iron (II) activated persulfate. On average, unactivated persulfate was able to reduce BTEX and PAH aqueous effluent concentrations by > 75% and 40%, respectively, after a total dose of 60 g/g soil. Two additional doses of alkaline activated persulfate (total persulfate dose of ~80g/g soil) in these columns were able to further reduce effluent BTEX and PAH concentrations by > 90% and > 75%, respectively. Iron (II) activated persulfate reduced effluent BTEX concentrations by > 70% and PAHs by > 65% after a total dose of 35 g/g soil. Average reductions in mass for BTEX and PAH compounds were approximately of 48% and 26% respectively in the iron (II) activated persulfate columns, and 24% and 10%, respectively in the alkaline activated persulfate columns. The potential for the ability to use in situ chemical oxidation using persulfate for the remediation of MGP residuals in the subsurface is evaluated using field measurements and bench-scale experimentation. The reductions observed in aqueous phase compounds in MGP groundwater as observed in the laboratory indicate the potential for reductions in groundwater concentrations at this and other contaminated former MGP sites. However, column experiments, indicating the inability for activated persulfate to reduce all identified compounds in the MGP NAPL suggest source treatment with activated persulfate would not reduce concentrations to below Florida Department of Environmental Protection natural attenuation concentrations.

Fenugreek (Trigonella foenum-graecum L.) is a single-cut, annual legume typically grown for seed. Fenugreek has potential as a forage because it maintains high quality throughout the growing season, and offers the benefits of a legume in a crop rotation. This work aimed to evaluate the growth of two fenugreek genotypes, AAFC F70 and CDC Quatro, in the central AB area over two growing seasons, and to evaluate fenugreek haylage degradation and digestion in dairy cows. In general, the two genotypes were similar in their growth patterns and fenugreek biomass yield was comparable to alfalfa in the same area. Plant quality was sufficient to be used for lactating dairy cows. The digestion studies revealed that while Quatro haylage was comparable to alfalfa haylage, F70 haylage was of lower quality and was not utilized to the same extent by dairy cows as the other two forage types. / Plant Science

Degradation of metals through atmospheric corrosion is a most important and costly phenomenon with significant effects on, e.g., the lifespan of industrial materials, the reliability of electronic components and military equipment, and the aesthetic appearance of our cultural heritage. Atmospheric corrosion is the result of the interaction between the metal and its atmospheric environment, and occurs in the presence of a thin aqueous adlayer. The common incorporation of pollutant species into this adlayer usually enhances the degradation process. During atmospheric corrosion indoors, low concentrations of organic atmospheric constituents, such as formic, acetic, propionic, butyric and oxalic acids, have found to play an accelerating role on a broad range of metals or their alloys, including lead, steel, nickel, copper, cadmium, magnesium and zinc. In this doctoral thesis the initial stages of the atmospheric corrosion of copper exposed to synthetic air, aiming at simulating representative indoor atmospheric environments, have been investigated both experimentally and through a computational method. The experiments have been based on a unique analytical setup in which a quartz crystal microbalance (QCM) was integrated with infrared reflection absorption spectroscopy (IRAS). This enabled the initial atmospheric corrosion of copper to be analyzed during ongoing corrosion in humidified air at room temperature and additions of 120 ppb (parts per volume billions) of acetic, formic or propionic acid. The main phases identified were copper (I) oxide (Cu2O) and various forms of copper carboxylate, and their amounts deduced with the different analytical techniques agree with a relative accuracy of 12% or better. Particular emphasis has been on the identification of different forms of copper (I) oxide generated during these exposures. An electrochemically based model has been proposed to describe how copper oxides, formed in the presence of acetic acid, are electrochemically reduced in neutral solution. The model includes the electrochemical reduction of copper (II) oxide (CuO), amorphous copper (I) oxide (Cu2O)am, intermediate copper (I) oxide (Cu2O)in, and crystalline copper (I) oxide (Cu2O)cr. A good agreement is obtained between the model and experimental data, which supports the idea of a reduction sequence which starts with copper (II) oxide and continues with the reduction of the three copper (I) oxides at more negative potentials. The quantified analytical data obtained in this doctoral study on corrosion products formed on copper, and corresponding data on zinc reported elsewhere, were used as the starting point to develop a computational model, GILDES, that describes the atmospheric corrosion processes involved. GILDES considers the whole interfacial regime in which all known chemical reactions have been considered which are assumed to govern the initial atmospheric corrosion of copper or zinc in the presence of carboxylic acids. The model includes two separate pathways, a proton-induced dissolution of cuprous ions or zinc ions followed by the formation of either copper (I) oxide or zinc (II) oxide, and a carboxylate-induced dissolution followed by the formation of either copper (II) carboxylate or zinc (II) carboxylate. The model succeeds to predict the two main phases in the corrosion products and a correct ranking of aggressiveness of the three acids for both copper and zinc. The ranking has been attributed to differences in acid dissociation constant and deposition velocity of the carboxylic acids investigated. / QC 20111114

Graduation date: 1994

Thesis (M.S.)--University of Adelaide, Dept. of Surgery, 2004. / "December 2003" Bibliography: leaves 82-99.

Ulm, Univ., Diss., 2008.

Thesis (M.Sc.). / Written for the Dept. of Natural Resource Sciences. Title from title page of PDF (viewed 2008/07/30). Includes bibliographical references.

Zugl.: Aachen, Techn. Hochsch., Diss., 2008.

Zugl.: Stuttgart, Univ., Diss., 2008

Thèse (M.Sc.)--Université Laval, 2008. / Bibliogr.: f. 32-36. Publié aussi en version électronique dans la Collection Mémoires et thèses électroniques.