Browsing by Subject "remediation"

Now showing 1 - 3 of 3
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    Enhanced Adsorption of Perfluoro Alkyl Substances in Groundwater; Development of a Novel In-Situ Groundwater Remediation Method
    (2019-03) Aly, Yousof
    Per- and poly- fluoro alkyl substances (PFAS) are a class of highly persistent, toxic and bio-accumulative anthropogenic chemicals. Due to their wide range of application including non-stick cookware, water and stain resistant coatings, chrome plating and aqueous film forming foams (AFFF), the potential exposure pathways for humans are numerous. AFFF use and subsequent release often leads to groundwater contamination, which poses a risk for human health. Currently, there is a wide array of remediation methods capable of treating PFAS contamination. These pump and treat methods, however, face many limitations including inhibitory costs, harmful byproducts, feasibility and ease of deployment. An in place (in-situ) remediation method holds the advantage of being more cost-effective, easier to deploy and cope with post remediation. Current in-situ PFAS remediation is limited. This thesis explores the amendment of a natural soil by two cationic coagulants (polydiallyldimethylammonium chloride [PDM] and poly(epichlorohydrin-dimethyl) amine [PA]) in order to increase adsorption, and thus retention, of PFAS in groundwater, and possibly sequestering a plume. PFAS adsorption onto natural soil was increased significantly based on batch and column tests. The increase in PFAS adsorption was not due solely to increases in organic matter from the addition of adsorption enhancers. Therefore, the mechanism of PFAS-enhancer interaction was explored. 19Fluorine-NMR spectra indicated that perfluoro carboxylates (PFCAs) were strongly bound in solution when in a solution of PA and PDM. The use of a PFOS ion specific electrode (ISE) found the same result. Given that this is a proposed in-situ remediation method; the long term behavior of PFAS-enhancer binding interactions is an important question that needs answering. Weathering and biodegradation by bacteria native to natural soil were not capable of degrading PA and PDM. However, activated sludge was able to degrade enhancers. There was little PFAS release detected indicating again that PFAS are strongly bound in solution and that this binding interaction potentially reduces bioavailability of enhancers when bound with PFAS.
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    Enhanced Sorption of Perfluoro-alkyl Substances (PFASs) onto Ottawa Sand
    (2016-02) Aly, Yousof
    Sorption to mineral surfaces is an important process in controlling the fate, mobility, and bioavailability of perfluoroalkyl substances (PFASs) in aquatic systems. Unlike other persistent organic pollutants, PFASs are highly water-soluble due to their hydrophilic head group and thus their solid-phase partitioning is limited under natural conditions. However, recent research has shown that sorption of PFASs to suspended solids in surface water can be enhanced by addition of cationic coagulants, through a combination of electrostatic and hydrophobic effects. Whether coagulant-enhanced sorption can be adapted for in situ remediation of PFAS-contaminated groundwater remains an open question. We investigated sorption of six PFASs at environmentally relevant concentrations in the presence of four cationic coagulants: polyaluminum chloride, polyamine, polydiallyldimethyl ammonium chloride (polyDADMAC), and a tannin-based cationic polymer. PFAS adsorption isotherms were determined on Ottawa sand and on aquifer material from a known PFAS-contaminated site. Preliminary results suggest that this method shows promise for in situ remediation of PFAS-contaminated groundwater.
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    Homo Mediaticus: Immigrants, Identity, and (Tele)Visual Media in Contemporary Francophone Literature
    (2016-09) Bates, Severine
    This dissertation examines the figure of the Immigrant in light of the practical and symbolic role played by the mass media, and especially television and its images, in the processes of identity construction and socialization, as problematized in several Francophone North African immigrant novels. It aims to shed light on the ways in which the figure of the Immigrant has been “mediated” in novels such as Tahar Ben Jelloun’s Les raisins de la galère, Youssouf Elalamy’s Les clandestins or Faiza Guène’s Kiffe kiffe demain. These novels fall mainly into three literary categories: Beur Literature, Banlieue literature and Illiterature (Hakim Abderrezak) which focuses on the phenomenon of clandestine migration (Hrig) in the Mediterranean basin. Products of what I call the “génération du visible,” these novels offer ground for reflection on the political, psychological, social, cultural and, ultimately, ontological effects of the media’s obsessive representations of this social category. Arguing for a new model of subjectivity for the Immigrant grounded on his relationship with the mass media, I posit that, in these novels and more generally in the collective imagination, the Immigrant—embodied by the Beur, Jeune de Banlieue or Harraga—emerges not only as a constructed figure of alterity and subalternity, but also as a Homo Mediaticus (Massimo Ragnedda) born from the interstices of images and discourses, and of the virtual and the real. I also contend that as a Homo Mediaticus, the Immigrant is both a product of media representation and a media user whose existence, subjectivity, and agency depend on his visibility (as object of the Gaze) and on the performative and meaningful act of “seeing” (as agent and user of technology). In novels like Faïza Guène’s Kiffe kiffe demain, the Immigrant's use of media technologies and of his imagination allows him to mediate his experiences in and with society, to control his “droit de regard,” and to create new identities that are more subversive and transcultural in nature than fixed or unique.