Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xv, 160 p.; also includes graphics. Includes abstract and vita. Advisor: Warren A. Dick, Environmental Science Graduate Program. Includes bibliographical references (p. 135-160).

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

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This research addressed the question whether a constructed wetland system with phytoremediation could successfully uptake 1,4-Dioxane in groundwater and secondary effluent. It further addressed whether open pond storage could successfully treat wetland discharge. The project was located at the University of Arizona's Constructed Ecosystems Research Facility (CERF) in Tucson, Arizona. This two-year field study was motivated by previous laboratory studies which demonstrated the capability of plants to remediate the recalcitrant contaminant 1,4-Dioxane.The study was conducted in two open steel tanks configured to simulate constructed wetlands. The efficacy of 1,4-Dioxane uptake by cottonwood trees was tested in a side-by-side comparison utilizing planted and unplanted tanks. The sub-surface hydraulic conditions were fully characterized by bromide tracer studies. Six experiments were conducted, in which tapwater or secondary effluent was spiked with 5.2 mg/L 1,4-Dioxane and fed to the planted and unplanted (control) tank. The tank discharges were retained in separate open ponds to test if open pond storage would reduce 1,4-Dioxane content. Additional side experiments were conducted to examine the role of volatilization and UV degradation. Comparison of 1,4-Dioxane mass discharge from the planted and the control tank demonstrated an 18-48 percent uptake by the cottonwood trees. Mass balance assessments showed 1,4-Dioxane uptake efficiency was positively correlated to cottonwood transpiration rates in the planted tank. The open pond 1,4-Dioxane measurements demonstrated a 64-85 percent reduction in 1,4-Dioxane concentration due to volatilization during the initial 120 hours pond lapse time. Elimination of 1,4-Dioxane from the ponds followed first order kinetics. Field and laboratory side experiments demonstrated the potential for UV photo degradation of 1-4-Dioxane.

Salt-affected soils from point source brine contamination are common in the active oil field in SE Saskatchewan. A remediation process that included dewatering by sub-surface tile drains, application of surface amendments (calcium nitrate and straw), and growing forages has been successful but not previously examined. In a field study of two remediation sites, the changes in vegetation, soil salinity, and groundwater were assessed using geo-referenced electromagnetic (EM) maps (EM38h, EM38v, and EM31v), piezometers, and soil sampling. A laboratory soil core leaching experiment studied the effect of gypsum, calcium nitrate, and straw at various rates on the remediation of a brine-contaminated soil. All treatments including the control reduced the electrical conductivity (EC) to non-saline values (<4 dS m-1). The sodium adsorption ratio (SAR) was reduced to <13 with the high rates of gypsum and calcium nitrate. The fastest and most effective treatments were comprised of all rates of gypsum and the highest rate of calcium nitrate.

According to Environment Canada, across the country there are currently over 1400 abandoned gas station sites that are contaminated. Unbeknownst to local residents, many of these sites are undergoing remediation. Temporary interventions called remedial landscapes can be designed by landscape architects to communicate to the public the remediation activities, which are otherwise hidden from view. Environmental psychologists note that pro-environmental behaviour stems from increased awareness of environmental degradation. Furthermore, by presenting first hand information in the form of a landscape, people can make their own decisions concerning their role in unsustainable practices. This thesis posits that by experiencing remedial landscapes, people will change their environmental attitudes and or behaviours. Remedial landscapes also offer opportunities for public art and further exploration of alternative forms of remediation. It includes not only precedent studies of other remedial landscapes, but a public perception survey concerning a gas station undergoing remediation in Kerrisdale, Vancouver. The survey indicated that the remediation of contaminated sites is a community concern and that the remediation should be made more visible. Participants also agreed that the use of a designed landscape would be a viable tool for communicating the status of the site. This research informed a set of design guidelines for the Kerrisdale ‘test site.’ A remedial landscape has been designed using these guidelines and is included as part of the thesis.

A laboratory study was conducted to assess the relationship between degree of volatile organic compound (VOC) mass removal from soil and heating duration, initial dense non-aqueous phase liquid (DNAPL) saturation, and grain size. The relationship between post-remedy sampling temperature and VOC soil concentration was examined. Soil contained in glass jars was spiked with DNAPL phase tetrachloroethylene (PCE), saturated, and placed in an oven for a specified period of time. The soil temperature at the centre of each jar was monitored during heating. Upon removal from the oven, each jar was immediately capped with an air tight seal and placed into an ice bath until the soil temperature had cooled to the desired sampling temperature. The jar caps were subsequently removed and the soil was sampled using a coring tool and immersed into pre-weighed vials containing methanol. PCE in soil samples was quantified using purge-and-trap with gas chromatography/mass spectrometry. Soil temperature increased steadily from ambient until reaching a plateau at 89 ºC ± 4 ºC due to co-boiling of DNAPL phase PCE and water. A linear relationship was found between the length of the co-boiling plateau and the initial PCE saturation. Co-boiling continued until DNAPL phase PCE had been depleted, at which time the soil temperature increased to the boiling point of water and remained constant while remaining pore water was removed. PCE soil concentrations decreased rapidly in the early stages of heating, but leveled off between 9.0 and 19 ppb soon after the soil became dried out. Analysis of the sensitivity to initial PCE saturation data revealed that the concentration of PCE in post-remedy samples increased with increasing initial saturation. Results of the sensitivity to grain size tests showed a decreasing trend between PCE soil concentration and decreasing sand grain size while temperature at sampling was not found to affect the amount of PCE quantified post-thermal remedy. Soil temperature at the centre of each jar during cooling was measured and an analytical solution was fit to the recorded data. From this data, the thermal diffusivity of the soil was approximated and was found to range from 1.4 x 10-7 to 1.8 x 10-7 m2/s. / Thesis (Master, Civil Engineering) -- Queen's University, 2007-12-11 10:12:50.564

Soil remediation requires technologies to restore contaminated soil to a state that is environmentally acceptable. In most cases, while the soil can be remediated the contaminant itself cannot be reclaimed. Soil washing involves cleaning contaminated soil with a wash solution, generally an aqueous solution of a surfactant. It was proposed that using switchable surfactants for washing oil-contaminated soil will not only help remove the oil from soil, but also aid in the recovery of the oil contaminant from the wash mixture. Six surfactants were evaluated for their ability to wash Ottawa Sand artificially contaminated with North Sea crude oil. A water wash solution was used as a control. Two commercial surfactants, sodium dodecyl sulfate (SDS) and Triton X-100, and four switchable surfactants, N'-octyl-N,N-dimethylamidine (C8), sodium octyl 4-hydroxy-3-nitrobenzoate (SAS1), sodium 4-(octyoxy) benzoate (SAS2) and sodium laurate (SAS3) were studied. The surfactants were assessed based on their ability to remove oil from the sand and their ability to separate the crude oil from the wash mixture after CO2 treatment. Oil removal from sand was determined by gravimetric analysis. Oil content in the wash mixture was determined using Solid Phase Extraction and gravimetric analysis. It was determined that switchable surfactants are able to remove North Sea crude oil from sand as well or better than the commercial surfactants and have the added feature of oil separation and recovery from the wash mixture after CO2 treatment. / Thesis (Master, Chemistry) -- Queen's University, 2011-02-16 17:10:16.997

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