Engineering Commons^™

Fate And Transport Of Per- And Polyfluoroalkyl Substances (Pfas) At Aqueous Film Forming Foam (Afff) Discharge Sites: A Review, Jeffery T. Mcgarr, Eric G. Mbonimpa, Drew C. Mcavoy, Mohamad R. Soltanian

Faculty Publications

Per- and polyfluorinated alkyl substances (PFAS) are an environmentally persistent group of chemicals that can pose an imminent threat to human health through groundwater and surface water contamination. In this review, we evaluate the subsurface behavior of a variety of PFAS chemicals with a focus on aqueous film forming foam (AFFF) discharge sites. AFFF is the primary PFAS contamination risk at sites such as airports and military bases due to use as a fire extinguisher. Understanding the fate and transport of PFAS in the subsurface environment is a multifaceted issue. This review focuses on the role of adsorbent, adsorbate, and …

Removal Of Perfluorooctanoic Acid From Water Using Primitive, Conventional And Novel Carbonaceous Sorbent Materials, Christopher K. Brown

Theses and Dissertations

Polyfluoroalkyl Substances (PFAS), like perfluorooctanoic acid, have been used for the last 50 years in a wide variety of industrial processes and consumer-based products, including polymer additives, lubricants, fire retardants and suppressants, pesticides, and surfactants (Buck et al. 2015). The Department of Defense (DoD) has used PFAS-based Aqueous Film Forming Foam (AFFF) at fire training facilities and aircraft hangars. AFFF has contaminated approximately 600 sites classified as fire training facilities with PFAS (Huang, 2013).

This study focused on testing the most likely carbonaceous adsorbent compounds to remediate PFAS-contaminated sites on Air Force installations. Batch tests were performed to determine the …

Molecular Characterization Of Wetland Soil Bacterial Community In Constructed Mesocosms, Ethan C. Bishop

Theses and Dissertations

The use of wetlands to effectively remediate aquifers contaminated with chlorinated solvents is an emerging technique, which shows high promise. In order to better understand this process and test its legitimacy, a treatment wetland was constructed at Wright-Patterson AFB, Dayton, Ohio and, in a joint effort with Wright State University (WSU), has previously shown the effective removal of PCE. The purpose of this research was to characterize the soil bacterial community, pre-PCE injection, among three wetland plant species from the sedge family (Cyperaceae) within constructed wetland mesocosms and to identify any bacterial dominance. Carex comosa, Scirpus atrovirens, and Eleocharis erythropoda …

An Investigation Into Palladium-Catalyzed Reduction Of Perchlorate In Water, Eric G. Barney

Theses and Dissertations

In this study, application of a catalytic reactor to facilitate chemical reduction of perchlorate was investigated. Palladium-coated pellets were used as the catalyst, and formic acid was used as the reductant. Reactor performance was evaluated under a variety of operating conditions (influent pH, reductant concentration, residence time). Very little perchlorate reduction was observed under any operating condition. At best, approximately 8% perchlorate reduction was observed. This small reduction efficiency is clearly not sufficient for environmental treatment applications. Perchlorate strongly adsorbed to the catalyst at low pH (3 - 3.3). At higher pH (4 - 10), little adsorption was observed. This …

Optimal Sampling Of A Chemical Hazard Area, Jennifer R. Plourde

Theses and Dissertations

This thesis proposes a methodology for optimally sampling a chemical hazard area subsequent to a chemical weapons attack. The objective is to identify the maximum number of areas that no longer require protective gear for safe operations. We model the area as an undirected graph and employ network analysis techniques to provide a methodological framework for identifying an optimal sampling sequence within a fixed time limit. We propose four models that characterize the secondary vapor concentrations: i) static and deterministic, ii) static and stochastic, iii) dynamic and deterministic, and iv) dynamic and stochastic. Comparisons of the static cases and their …

In Situ Treatment Of Chlorinated Ethene-Contaminated Groundwater Using Horizontal Flow Treatment Wells, Derek R. Ferland

Theses and Dissertations

The limitations of conventional containment technologies for groundwater contaminated with chlorinated solvents have motivated development of innovative technologies to achieve national groundwater remediation objectives. One inn9vative technology that is currently under development involves metal reductants or catalysts to chemically destroy the dissolved chlorinated solvent. Models are important tools that can be used to help transition this technology to the field. Model studies can be used to gain understanding about the technology, help determine when the prospective technology might work for a given site, and design full-scale field applications.

Evaluation Of The Natural Biodegradation Of Aircraft Deicing Fluid Components In Soils, Laura M. Johnson

Theses and Dissertations

This research effort was conducted to analyze the biodegradation of propylene glycol (PG) and tolyltriazole in two different soil types; a sandy soil and a high clay soil. Both an automated respirometer and a high performance liquid chromatograph (H PLO) were used in the analysis. Two separate experiments were conducted. In the first experiment, one level of tolyltriazole was added to the soils to determine whether or not there was a difference in the biodegradation rates of tolyltriazole in the two soils. The respirometer results indicated that there was a significant difference between the respiration rates of the microorganisms in …

A Modeling Study For The Implementation Of In Situ Cometabolic Bioremediation Of Trichloroethylene-Contaminated Groundwater., John A. Christ

Theses and Dissertations

The limitations of conventional groundwater remediation technologies have led to the development of innovative technologies which may achieve national hazardous waste site remediation goals. Before an innovative technology can be implemented in the field, remedial project managers, regulators and other stakeholders require adequate modeling tools to help assess the applicability of the technology at a particular site. This modeling study investigates how an innovative technology, in situ cometabolic bioremediation, might be implemented to remediate a TCE-contaminated site, under different site conditions. A steady-state model is developed which couples an analytical expression to simulate the effect of flow between multiple pumping …

Modeling Trihalomethane Formation Potential From Wastewater Chlorination, Carol A. Mccormick

Theses and Dissertations

The deletion of federally mandated fecal coliform limits has led many states to review and modify their wastewater disinfection requirements. One issue in analyzing wastewater disinfection is the discharge of potentially carcinogenic halogenated organics formed during the chlorination process. This research investigates the formation of one class of the halogenated organics, the trihalomethanes. The applicability of using drinking water trihalomethane formation models for use with wastewater effluent is examined. Three models are compared for predictive capability by using measured trihalomethane values from previous research data. The results show that a previously developed model is applicable for use based on assumptions …