Engineering Commons^™

Bioremediation Of Chlorinated Ethenes: Ph Effects, Novel Dechlorinators And Decision-Making Tools, Yi Yang

Doctoral Dissertations

Chlorinated solvents have been widely used in different areas of modern society. Usage of these chlorinated solvents was not necessarily accompanied with proper handling and disposal of these hazardous compounds, which caused a variety of environmental problems and continues to affect human health. Remediation of chlorinated ethenes contaminated sites has high priority for state regulators and site owners. Among the available treatment technologies, bioremediation shows great promise as a cost-effective corrective strategy for a variety of environmental pollutants. Prerequisites are that the microbiology involved in contaminant degradation and geochemical factors, such as pH, are understood, so that bioremediation technologies can …

Potential Emissions And Exposures Of Toxic Organics From Storage Tanks For Chemical Additions In Hydraulic Fracturing: A Modeling Approach, Huan Chen

Doctoral Dissertations

Hydraulic fracturing has promoted the exploitation of natural gas in the United States (U.S.). However, the storing and emptying of chemical additives in hydraulic fracturing wells may pose adverse effects through inhalation exposures. Based on the information about hydraulic fracturing fluids, this study investigated: 1) water volumes used to mix chemical additives for making up the hydraulic fracturing fluids; 2) chemical species, concentrations and their degradability in the hydraulic fracturing fluids; 3) emissions of organics from chemical storage tanks; and 4) the occupational inhalation exposures by toxic and organic vapors.

Results shows for 80,047 wells fractured between 2008 and 2014 …

Long-Term Health Risk Of Climate Change Associated Surface Pm2.5 Concentration Variation: Multiple Accmip Model Data Under Different Emission Scenarios (Rcp26, 45, 60, 85) And Population Scenarios (Ssp1, Ssp2, Ssp3), Xiufen Zhu

Masters Theses

In this study, multiple models from Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) are utilized to derive the global burden of disease of chronic obstructive pulmonary disease (COPD), lung cancer (LNC), and lower respiratory infection (LRI) derived from surface PM_2.5 elevation. Various Representative Concentration Pathways and Shared Socio-economic Pathways scenarios are compared as well as various models to deduct the impact from various scenarios. The time series variation and seasonal variation are also illustrated in this study. Multi-model ensemble was conducted to reduce the deviation in model projection output.

Projection shows increase in the population normalized relative risk …

The Use Of Sodium Persulfate In Hydraulic Fracturing Fluids: A Degradation Study Based On Furfural, Katherine Elizabeth Manz

Masters Theses

Hydraulic fracturing has allowed natural gas to become a viable energy source via extraction of unconventional shale reserves, but this process requires an enormous amount of water. To ensure a productive fracture, a proprietary blend of chemical additives is added to the water. In this research, a hydraulic fracturing chemical additive – an enzyme breaking agent – is analyzed for organic components using gas chromatography mass spectrometry. The chemical changes that occur over the course of a fracture are also investigated using one model chemical found in the additive, furfural, in order to help assess the environmental risk that hydraulic …

Response Of Microbial Community Structure To Clay Flocculation Of Harmful Algal Blooms, Chunyi Chen

Doctoral Dissertations

Harmful algal blooms are cosmopolitan and can produce extremely dangerous toxins that can sicken or kill people and animals, and create dead zones in the water. The U.S. economic loss caused by algal blooms is $82 million every year. Clay-based flocculation techniques have been developed to mitigate algal blooms; however, the potential impacts on the microbial community are poorly understood. This dissertation includes multi-scale experiments (Jar, field, microcosms) to study the response of microbial community structure and function to clay flocculation of algal blooms.

Jar tests of removal of Microcystis aeruginosa by chitosan and two types of commercially available clays …