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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Adapting, optimizing, and evaluating a model for the remediation of LNAPL in heterogeneous soil environments

Al Awar, Ziad. January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.
2

A Novel Microextraction Method for Determining the Presence of Pentachlorophenol in an Ongoing In-Situ Groundwater Remediation

Stratton, Julianna Nicole 12 August 2016 (has links)
Pentachlorophenol (penta) is a pollutant of concern worldwide. This study looks at a site that has been under remediation for the last 16 years due to penta contamination. The site has been air- and bio-sparged, phytoremediated and undergone in-situ chemical oxidation treatment in attempts to clean the ground water of penta. This thesis explores a novel microextraction method that has the promise of being more sensitive using less sample and fewer hazardous chemicals than conventional methods. Groundwater samples were extracted for phenolic compounds using a novel modified liquid microextraction protocol. Comparing our results with monitoring information from 2014, our method determined that penta is limited to a single monitoring well. However, our report was unable to determine exact quantitative results of penta concentration, due to loss of extraction solvent during the retrieval process.
3

Persulfate transport in two low-permeability soils

Merker, Marissa C. January 2010 (has links) (PDF)
Thesis (M.S. in civil engineering)--Washington State University, August 2010. / Title from PDF title page (viewed on July 23, 2010). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 15-17).
4

ASSESSING SUSTAINABLE REMEDIATION FRAMEWORKS USING SUSTAINABILITY DISCOURSE

2015 July 1900 (has links)
The remediation industry has grown exponentially in recent decades. International organizations of practitioners and remediation experts have developed several frameworks for integrating sustainability into remediation projects; however, there is no accepted definition or universal framework for sustainable remediation. Literature on sustainable remediation is only recently beginning to emerge, and there has been limited attention to how sustainability is best-integrated and operationalized in sustainable remediation frameworks and practices – or whether sustainability plays any meaningful role at all in sustainable remediation. This thesis examines the role of ‘sustainability’ in recently emerging sustainable remediation frameworks. More specifically, it presents the results of an analysis of how sustainability is defined, integrated and operationalized in sustainable remediation frameworks. Methods are based on a review of a sample of six leading remediation frameworks against a set of normative principles and criteria for sustainability integration adapted from sustainability assessments. Recommendations are made for improving the integration of sustainability in sustainable remediation frameworks, and how to better operationalize sustainability practices.
5

Bioremediation of contaminated riparian zones using mycorrhizal fungi an exploration of the feasibility of restoration through mycoremediation /

Jones, Gary K. January 1900 (has links) (PDF)
Thesis (M.E.S.)--Evergreen State College, 2009. / "April 2, 2009." Title from title screen (viewed 4/8/2010). Includes bibliographical references (p. 61-67).
6

Persulfate activation by organic compounds

Ocampo, Ana Maria. January 2009 (has links) (PDF)
Thesis (Ph. D.)--Washington State University, August 2009. / Title from PDF title page (viewed on Sept. 9, 2009). "Department of Civil and Environmental Engineering." Includes bibliographical references.
7

The influence of contaminant source materials on the aqueous dissolution of polycyclic aromatic hydrocarbons

Woolgar, Paula Jane January 1997 (has links)
No description available.
8

Modelling bioremediation of uranium contaminated aquifers

Rotter, Ben E. G. January 2008 (has links)
Radionuclide extraction, processing and storage have resulted in a legacy of radionuclide-contaminated groundwater aquifers worldwide. An emerging remediation technology for such sites is the in situ immobilisation of radionuclides via biostimulation of dissimilatory metal reducing bacteria. While this approach has been successfully demonstrated in experimental studies, advances in understanding and optimization of the technique are needed. Mass transfer processes in heterogeneous and structured porous media may significantly affect the geochemical and microbial processes taking place in contaminated sites, impacting remediation efficiency significantly. The objective of this work was to understand better how heterogeneous porous media may affect immobilisation efficiency through interactions with the dominant geochemical, microbial and transport processes. A biogeochemical reactive transport model was developed for uranium immobilisation by DMRB. Physical heterogeneity is conceptually represented by a two-region model. Simulations investigate the parameter sensitivities of the system over wide ranging geochemical, microbial and groundwater transport conditions. The simulations highlight the conditions under which optimal remediation occurs. The relative significance of regional microbial residence patterns, U(VI)-surface complexation, geochemical conditions such as mineralogy, and porous media characteristics such as porosity and regional mass transfer are identified. Additionally, low level radioactive waste disposal sites typically contain significant quantities of cellulose, whose hydrolysis can have a significant impact on the geochemical conditions in these sites. Those geochemical conditions, in turn, can affect radionuclide mobility and bioimmobilisation. To investigate the potentially critical role of cellulose, process-based predictive model was developed, which includes a novel approach to biomass transfer between a cellulose-bound biofilm and biomass in the bulk liquid. A sensitivity analysis of the system parameters revealed the significance of bacterial colonisation of cellulose particles by attachment through contact in solution. The thesis concludes that the processes involved in uranium bioimmobilisation are sensitive to regional residence characteristics, media porosity, surface complexation, microbial efficiency, and mass transfer under varying conditions. Careful characterisation of potential sites and use of a model that includes these processes in sufficient detail is therefore deemed necessary before the remediation effectiveness can be reliably predicted.
9

Field Trial of Residual LNAPL Recovery Using CO2-Supersaturated Water Injection in the Borden Aquifer

Nelson, Leif Carl January 2007 (has links)
The ability of supersaturated water injection (SWI) to recover non-aqueous phase liquids (NAPLs) was studied at the field scale as part of an ongoing program to evaluate its applicability to groundwater remediation. SWI uses Gas inFusionTM technology to efficiently dissolve gases into liquids at elevated pressures. SWI has been shown to both volatilize and mobilize residual NAPL ganglia (Li, 2004). During SWI pressurized water containing high concentrations of CO2 is injected into the subsurface below the zone of contamination. Once the injected water is in the aquifer the pressure drops substantially and the concentration of CO2 is no longer in equilibrium with the water and as a result CO2 bubbles nucleate. These bubbles then migrate upwards through the contaminated zone towards the water table. As they move they come into contact with residual NAPL ganglia and they either volatilize this NAPL, resulting in a bubble comprised of CO2 and gaseous NAPL, or mobilize this NAPL, resulting in a film of NAPL surrounding the bubble. In either case the bubbles continue to rise until they reach the water table at which point they are removed by a dual phase extraction system. In this work, a known amount of NAPL was emplaced below the water table at residual concentrations to represent a residual source of weathered gasoline. The source was created in a hydraulically isolated cell in an unconfined sand aquifer at CFB Borden, Ontario. After the source was emplaced SWI was used to remove as much of the contaminant mass as possible in 22.25 days of operation over three months. The goal of this project was to determine if SWI was capable of removing residual NAPL at a field site. It was successful in removing volatile NAPL but not non-volatile NAPL. 64% of the volatile compounds were removed but contaminant mass was still being removed when the system was shut down so with continued operation more mass would have been removed. There is no way of knowing how much more would have been removed had the project continued. These results indicate that continued development of the technology is warranted.
10

Computer-assisted cognitive remediation in patients with schizophrenia : effects on symptoms, cognition and psychosocial functioning

MacLeod, Joanne Louise January 2013 (has links)
Background: Cognitive remediation is a behavioural intervention that aims to improve cognitive functioning with the goal of durability and generalisation. Although evidence suggests that computer-assisted cognitive remediation (CACR) improves cognitive functioning in individuals with schizophrenia, it remains unclear whether these effects generalise and lead to improvements in clinical symptoms and psychosocial functioning. The current study aimed to investigate the effects of CACR on clinical symptoms, cognitive functioning and psychosocial functioning in individuals with schizophrenia or schizoaffective disorder. Method: A systematic review was performed using the quality assessment criteria defined by Scottish Intercollegiate Guidelines Network (SIGN 50) to investigate the effects of CACR on clinical symptoms in individuals with a diagnosis of schizophrenia or schizoaffective disorder. Additionally, a within subjects repeated measures design was used to investigate the effects of CACR on cognitive functioning, functional capacity and everyday social functioning. Results: There was some evidence to suggest that CACR improves clinical symptoms, but the majority of studies reviewed did not report a significant effect, and a number of methodological weaknesses were identified in the literature. Results of the experimental study revealed improvements in speed of processing, reasoning and problem solving and the overall composite score for cognition, but these improvements could not be attributed solely to the CACR intervention. No improvements in functional capacity or everyday social functioning were observed. Conclusions: Further, more rigorous research is required to develop a clearer understanding of the effects of CACR on clinical symptoms. The results of the experimental study support previous literature which has identified that a pure CACR intervention does not improve psychosocial functioning. The results are discussed in relation to the relevant literature.

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