Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Physical Sciences and Mathematics (23)
- Environmental Sciences (16)
- Earth Sciences (9)
- Life Sciences (8)
- Chemistry (6)
-
- Geochemistry (6)
- Civil Engineering (5)
- Environmental Health and Protection (5)
- Hydrology (5)
- Environmental Indicators and Impact Assessment (4)
- Water Resource Management (4)
- Chemical Engineering (3)
- Environmental Chemistry (3)
- Environmental Monitoring (3)
- Nuclear Engineering (3)
- Other Civil and Environmental Engineering (3)
- Pharmacology, Toxicology and Environmental Health (3)
- Plant Sciences (3)
- Soil Science (3)
- Forest Sciences (2)
- Geological Engineering (2)
- Geology (2)
- Geotechnical Engineering (2)
- Mechanical Engineering (2)
- Oil, Gas, and Energy (2)
- Operations Research, Systems Engineering and Industrial Engineering (2)
- Physics (2)
- Keyword
-
- Bioremediation (8)
- Adsorption (6)
- Biodegradation (6)
- Plutonium (6)
- Sorption (6)
-
- TCE (6)
- Reductive dechlorination (5)
- Remediation (5)
- Wastewater (5)
- Groundwater (4)
- Life cycle assessment (4)
- PFAS (4)
- Transport (4)
- Uranium (4)
- Activated carbon (3)
- Anaerobic (3)
- Bioaugmentation (3)
- Desalination (3)
- Energy (3)
- FOG (3)
- Life Cycle Assessment (3)
- Modeling (3)
- Sustainability (3)
- Vadose zone (3)
- Water treatment (3)
- 1 (2)
- Abiotic (2)
- Actinide (2)
- Activated Carbon (2)
- Algae (2)
- Publication Year
- Publication
- Publication Type
Articles 121 - 150 of 172
Full-Text Articles in Environmental Engineering
Identification And Characterization Of Polychlorinated Biphenyl Dechlorinating Microorganisms From Lake Hartwell, Sc, Tess Brothersen
Identification And Characterization Of Polychlorinated Biphenyl Dechlorinating Microorganisms From Lake Hartwell, Sc, Tess Brothersen
All Dissertations
To date, all attempts to isolate PCB dechlorinators using traditional isolation techniques have failed. In addition, the study of PCB dechlorinating organisms has been hampered because researchers were unable to grow the organisms in sediment-free, defined media. Three microbial species capable of reductive dechlorination of polychlorinated biphenyls have been identified. These three species are from two phylogenetically distinct branches, Dehalococcoides (Bedard et al., 2007) and the DF-1/o-17 group (Wu et al., 2002a; Cutter et al., 2001). The three cultures from which polychlorinated biphenyl dechlorinators have been identified used similar strategies to 'wean' the microbes from the sediments. In this research, …
Evaluation Of Manganese Control In The Source Water And Microfiltration Plant Of A South Carolina Water Utility, Daniel Lewis
Evaluation Of Manganese Control In The Source Water And Microfiltration Plant Of A South Carolina Water Utility, Daniel Lewis
All Theses
Although present in most water supplies, manganese is a difficult-to-treat nuisance contaminant in drinking water. The US Environmental Protection Agency (EPA) has set a Secondary Maximum Contaminant Level (SMCL) of 0.05 mg/L but experts have recommended a goal of 0.02 mg/L or less to avoid chronic issues with the metal. This work is a report on manganese control for the Startex-Jackson-Wellford-Duncan (SJWD) Water District, a water utility in northwestern SC. Fourteen locations were sampled from June 2010 through October 2011. Manganese, iron, dissolved organic carbon, dissolved oxygen, and other relevant parameters were measured.
The lake-fed Middle Tyger River is the …
Biodegradation Kinetics For 1,2-Dichloroethane And Ethylene Dibromide In Anaerobic Enrichment Cultures Grown On Each Compound, Rong Yu
All Theses
1,2-Dichloroethane (DCA) and ethylene dibromide (EDB) are among the top 15 chlorinated aliphatic compounds on the Agency for Toxic Substances and Disease Registry's Priority List of Hazardous Substances. Co-contamination of groundwater with EDB and 1,2-DCA resulted mainly from environmental releases of leaded gasoline; these compounds were added as lead scavengers. A microcosm study by Henderson et al. with soil and groundwater from a site contaminated with leaded gasoline demonstrated anaerobic biodegradation of EDB at a higher rate, and to a greater extent, than 1,2-DCA. Both compounds were transformed mainly by dihaloelimination to ethene. The objectives of this study were to …
Effect Of Ultrasonic Vibration On The Mass Transfer Coefficient In A Sieve Plate Scrubber, Dinora Monroy Melendez
Effect Of Ultrasonic Vibration On The Mass Transfer Coefficient In A Sieve Plate Scrubber, Dinora Monroy Melendez
All Theses
The air pollution technique of wet scrubbers for fumes, mists and suspended dusts as part of a polluted gas stream has been study as well as used for industries for many decades. The sieve tray is the simplest type of these scrubbers. A laboratory-scale single-stage, sieve tray countercurrent wet scrubber has been designed to study the effect of ultrasonic vibrations on the rate of mass transfer. A 20 kHz ultrasound frequency was chosen for a high performance cavitation to enhance the mass transport between the gas and liquid phases. Various perforation diameters and weir heights were employed in order to …
Evaluation Of Tetrachloroethene Dechlorination Under Low Ph Conditions In Microcosms And Enrichment Cultures, Michael Hickey
Evaluation Of Tetrachloroethene Dechlorination Under Low Ph Conditions In Microcosms And Enrichment Cultures, Michael Hickey
All Theses
Chlorinated ethenes are among the most prevalent groundwater contaminants found at hazardous waste sites throughout the United States. Two such sites are the Statesville FCX OU3 Superfund Site in North Carolina and the C-area at the Savannah River Site (SRS) in Aiken, SC. Both sites are contaminated with two of the more common chlorinated ethenes; tetrachloroethene (PCE) and trichloroethene (TCE). Anaerobic biological reductive dechlorination is an increasingly common treatment option. There are two main concerns as to the feasibility of this approach. The first is if the microbes are present that are needed for carrying out complete reductive dechlorination of …
Determination Of Sorption Coefficients For Neptunium, Plutonium, Iodine, And Technetium In Engineered And Natural Systems Under Oxidizing And Reducing Conditions, Michael Lilley
All Theses
Plutonium, neptunium, technetium, and iodine present appreciable risks at nuclear waste disposal sites around the world due to their potential mobility. Sorption of each of these radionuclides is profoundly influenced by oxidation/ reduction reactions. Therefore, the mobility of each radionuclide may be greatly influenced by redox conditions of the natural or engineered system. The primary focus of this study was to determine distribution coefficients (Kd) for each radionuclide for engineered concrete and saltstone systems with varying amounts of reducing slag (a cement additive to create a reducing environment), and for iodide/iodate in natural sediments. Saltstones are a mixture …
Sensitivity Analysis Of Uranium Speciation Modeling In Groundwater Systems With A Focus On Mobility, Andrew Scott
Sensitivity Analysis Of Uranium Speciation Modeling In Groundwater Systems With A Focus On Mobility, Andrew Scott
All Dissertations
Uranium is an important natural resource used in production of nuclear reactor fuel and nuclear weapons. The mining and processing of uranium has left a legacy of environmental contamination that remains to be addressed. There has been considerable interest in manipulating the oxidation state of uranium in order to put it into an environmentally immobile form. Uranium forms two stable oxidation states in nature, uranium (IV) being much less soluble than uranium (VI), and therefore the preferred state with regard to limiting the potential exposure of man. One of the tools used in evaluating potential effects of manipulating the natural …
Modeling Greenhouse Gas Emissions From Conventional Wastewater Treatment Plants In South Carolina, Andrea Hicks
Modeling Greenhouse Gas Emissions From Conventional Wastewater Treatment Plants In South Carolina, Andrea Hicks
All Theses
Wastewater treatment is an essential part of life in the urbanized world. As global climate change becomes a more pressing issue, the greenhouse gas emissions created through wastewater treatment will become a more prominent concern. Tertiary treatment will likely be standard for wastewater treatment plants in the near future, and therefore must be included in a model of greenhouse gas emissions. Also, the geographic location of a WWTP will change the mix of power types (e.g., coal, nuclear, biomass) used to run the plant. Although GHG emissions from the waste sector are small compared to the emissions of the United …
Molecular Characterization Of Enrichment Cultures That Grow On Tetrachloroethene, 1,2 Dichloroethane And Ethylene Dibromide, Hari Shankar Peethambaram
Molecular Characterization Of Enrichment Cultures That Grow On Tetrachloroethene, 1,2 Dichloroethane And Ethylene Dibromide, Hari Shankar Peethambaram
All Theses
Halogenated aliphatic hydrocarbons are among the most common contaminants in soil and groundwater found at hazardous waste sites throughout the United States. Among them are tetrachloroethene (PCE), 1,2-dichloroethane (1,2-DCA) and ethylene dibromide (EDB). Organohalide respiration of each compound has been reported. However, considerably less information is known about EDB than PCE and 1,2-DCA, including the yield that occurs during growth with EDB as the sole TEA. The main objective of this project was to determine which types of chlororespiring microbes predominate during growth of enrichment cultures when PCE, 1,2-DCA and EDB served as the TEA, and what their yield is. …
Determining The Global Maximum Biofuel Production Potential Without Conflicting With Food And Feed Consumption, Watcharapol Pumkaew
Determining The Global Maximum Biofuel Production Potential Without Conflicting With Food And Feed Consumption, Watcharapol Pumkaew
All Theses
This study tries to resolve the competition between food and biofuel by balancing the allocation between food and feed areas and biofuel areas for the entire world. The maximum energy production is calculated by determining the theoretical amount of energy that can be grown, once food and feed consumption is taken into account, based on the assumption that unprotected grass and woody lands and forest lands can be converted into cultivated lands. The total optimum land area for biofuel energy, 4,926.49 Mha, consists of corn, rapeseed, sugar beet, sugar cane, and grasses. When considering energy conversion efficiency, the maximum energy …
Anaerobic Bio-Oxidation Of Vinyl Chloride And Ethene, Anthony Reid
Anaerobic Bio-Oxidation Of Vinyl Chloride And Ethene, Anthony Reid
All Theses
Tetrachloroethene and trichloroethene are among the most prevalent groundwater contaminants found at hazardous waste sites throughout the United States. Since implementing some of the common treatment methods to remediate these hazardous waste sites would exceed hundreds of billions of dollars, there is considerable interest in reducing costs while achieving remediation regulations. Under anaerobic conditions, these compounds can undergo reduction reactions known as reductive dechlorination. This occurs when an electron donor provides the reducing equivalents needed to replace the chlorine atoms with hydrogen atoms. The daughter products from higher chlorinated ethenes are ethene and ethane which can be used to document …
The Effects Of Physical Factors On The Adsorption Of Synthetic Organic Compounds By Activated Carbons And Activated Carbon Fibers, Hatice Kose
All Theses
Activated carbons (ACs) and activated carbon fibers (ACFs) have been extensively used for the removal of synthetic organic compounds (SOCs) that have been found to be toxic, carcinogenic, mutagenic or teratogenic. Adsorption of these compounds on ACs and ACFs are controlled by both physical factors and chemical interactions, which depend on the characteristics of the adsorbent (surface area, pore size distribution (PSD), and surface chemistry), the nature of the adsorbate (molecular weight and size, functional groups, polarity, solubility), and the condition of the background solution (pH, temperature, presence of competitive solutes, ionic strength). Since there are several mechanisms that can …
Plutonium - Humic Acid Stability Constant Determination And Subsequent Studies Examining Sorption In The Ternary Pu(Iv) - Humic Acid - Gibbsite System, Trevor Zimmerman
Plutonium - Humic Acid Stability Constant Determination And Subsequent Studies Examining Sorption In The Ternary Pu(Iv) - Humic Acid - Gibbsite System, Trevor Zimmerman
All Theses
Plutonium has been released to the environment through a variety of intentional and unintentional mechanisms, including atmospheric testing, disposition from weapons manufacturing processes, and subsurface disposal. Therefore, a thorough understanding of the chemical, physical, and biological processes affecting plutonium transport is imperative. It has been shown that humic acid (HA) (a refractory component of natural organic matter (NOM)) can effectively solubilize plutonium (Santschi et al., 2002). Increased solubility may result in enhanced subsurface transport, due to the higher concentration of Pu in the aqueous phase. In contrast, the formation of ternary surface complexes may hinder actinide transport. Solution pH is …
Energy And Nutrient Recovery From Anaerobic Treatment Of Organic Wastes, Christian-Dominik Henrich
Energy And Nutrient Recovery From Anaerobic Treatment Of Organic Wastes, Christian-Dominik Henrich
All Dissertations
The objective of the research was to develop a complete systems design and predictive model framework of a series of linked processes capable of providing treatment of landfill leachate while simultaneously recovering nutrients and bioenergy from the waste inputs. This proposed process includes an 'Ammonia Recovery Process' (ARP) consisting of: 1) ammonia de-sorption requiring leachate pH adjustment with lime or sodium hydroxide addition followed by, 2) ammonia re-absorption into a 6-molar sulfuric acid spray-tower followed by, 3) biological activated sludge treatment of soluble organic residuals (BOD) followed by, 4) high-rate algal post-treatment and finally, 5) an optional anaerobic digestion process …
Modeling Phosphate Adsorption For South Carolina Soils, Jesse Cannon
Modeling Phosphate Adsorption For South Carolina Soils, Jesse Cannon
All Theses
Eroded sediment and the pollutants it transports are problems in water bodies in South Carolina (SC) and the United States as a whole. Current regulations and engineering practice attempt to remedy this problem by trapping sediment according to settling velocity, and thus, particle size. However, relatively little is known about most eroded soils. In most cases, little experimental data are available to describe a soil's ability to adsorb a pollutant of interest. More-effective design tools are necessary if design engineers and regulators are to be successful in reducing the amount of sediment and sediment-bound pollutants in water bodies. This study …
Biodegradation And Bioremediation Of Hexachlorocyclohexane Isomers, Chlorinated Ethenes, Chlorinated Benzenes And Benzene, Vijaikrishnah Elango
Biodegradation And Bioremediation Of Hexachlorocyclohexane Isomers, Chlorinated Ethenes, Chlorinated Benzenes And Benzene, Vijaikrishnah Elango
All Dissertations
ABSTRACT
Groundwater at an industrial site is contaminated with γ -hexachlorocyclohexane (HCH) and α-HCH (i.e., lindane) (0.3-0.5 ppm). Other contaminants in the 1-15 ppm range include 1,2,4-trichlorobenezene (TCB), 1,2-dichlorobenzene (DCB), 1,3-DCB, 1,4-DCB, chlorobenzene (CB), benzene, trichloroethene (TCE) and cis-1,2-dichloroethene (cDCE). The aquifer consists of a shallow layer of soil over fractured dolomite, where most of the contaminant mass resides. The objective of this study was to compare 1) anaerobic reductive dechlorination of the polychlorinated contaminants, followed by aerobic biodegradation of the daughter products (mainly DCBs, CB, and benzene); and 2) aerobic biodegradation of α- and γ-HCH, TCB, DCBs, CB and …
Occurrence And Formation Of Disinfection By-Products In Indoor Swimming Pools Water, Amer Kanan
Occurrence And Formation Of Disinfection By-Products In Indoor Swimming Pools Water, Amer Kanan
All Dissertations
Chlorination is used to prevent the spread of waterborne infectious diseases from swimming pools. This required disinfection practice also results in the formation of undesirable disinfection by-products (DBPs) from the reactions of chlorine with the organic matter (released by swimmers or present in the filling water of the pool) and bromide. Some of these DBPs have important adverse public health effects; as a result their concentrations in drinking waters are regulated. Unfortunately, DBPs formation and control in swimming pools have not been studied and investigated to the same extent as their formation and control in drinking water.
The main objective …
The Formation And Control Of Iodinated Trihalomethanes In Drinking Water Treatment, Darryl Jones
The Formation And Control Of Iodinated Trihalomethanes In Drinking Water Treatment, Darryl Jones
All Theses
Ever since toxic disinfection by-products (DBPs) were discovered in the 1970s drinking water utilities have had to continue to develop treatment strategies to reduce the acute health risk from infectious pathogens in water, and at the same time limit the formation of disinfection by-products. The recent two stage (1998, 2006) D/DBP rule enacted by the Environmental Protection Agency (EPA) which sets limits of 80 µg/L for trihalomethanes (THMs) and 60 µg/L for haloacetic acids (HAAs) will likely put more pressure on utilities in the future to decrease their chorine contact time and follow that with ammonia addition to form monochloramine …
Biological Treatment To Remove Color And Toxicity Of Effluent From The Manufacturing Of Navipol Yellow Gr, Larry French
Biological Treatment To Remove Color And Toxicity Of Effluent From The Manufacturing Of Navipol Yellow Gr, Larry French
All Theses
Navipol Yellow GR is an organic solvent azo dye manufactured by Sunbelt Corp. in Rock Hill, SC. The effluent generated from the manufacturing of this dye is highly colored, toxic, and contains trace solvents consisting of mixed xylene isomers and ethyl benzene. Traditional wastewater treatment systems are unable to remove the color and toxicity from the effluent. This study investigated using a sequential anaerobic / aerobic treatment system to decrease color and toxicity of the dye effluent. The anaerobic phase used bacteria cultures of Pseudomonas aeruginosa, Bacillus subtilis, Enterococcus faecalis, or Enterobacter aerogenes to decrease the color of the dye. …
Probabilistic Remediation Evaluation Model For Chlorinated Solvents Considering Uncertainty, Hailian Liang
Probabilistic Remediation Evaluation Model For Chlorinated Solvents Considering Uncertainty, Hailian Liang
All Dissertations
The complex processes and expensive costs of source and plume remediation of dense, non-aqueous phase liquid (DNAPL) complicate the decision-making process for site remediation. Selection of remediation alternatives has been a big challenge due to the lack of tools that simultaneously evaluate the effectiveness of source and plume remediation and access the uncertainties in all major parameters. In this research, a new probabilistic remediation model, Probabilistic Remediation Evaluation Model for Chlorinated solvents sites (PREMChlor), has been developed. This is achieved through linking the analytical model REMChlor to a Monte Carlo modeling simulation package GoldSim via a FORTRAN Dynamic Link Library …
The Characterization, Isolation, And Fractionation Of Natural Organic Matter From Three Surface Waters, Olivia Orr
The Characterization, Isolation, And Fractionation Of Natural Organic Matter From Three Surface Waters, Olivia Orr
All Theses
The main objective of this study was to gain insight to the principles of isolation of natural organic matter (NOM) using reverse osmosis (RO) and subsequent fractionation using resin adsorption chromatography (RAC). Specifically, this study evaluated the RO and RAC methods for NOM characterization from three surface waters with varying physiochemical characteristics. Efficiency of RO was assessed by closing mass balances for dissolve organic carbon (DOC). Mass balances were also closed for dissolved nitrogen (DN), bromide (Br-), nitrate (NO3-), total calcium (Ca), total potassium (K), total manganese (Mn), total iron (Fe), total magnesium (Mg), total aluminum (Al), total copper (Cu), …
Leaching Of Dissolved Organic Carbon And Selected Inorganic Constituents From Scrap Tires, Meric Selbes
Leaching Of Dissolved Organic Carbon And Selected Inorganic Constituents From Scrap Tires, Meric Selbes
All Theses
An environmentally friendly method for the disposal of scrap tires is currently unavailable; as a result, ultimate disposal of used vehicle tires continues to be a major challenge around the world. In the United States (US), during the past two decades, scrap tires have been generated at the rate of approximately one tire per person per year (i.e., approximately 290 million new scrap tires every year). It is estimated that there are currently 2 billion tires stockpiled in the US. Due to various problems involved in the disposal of scrap tires, different alternatives for recycle and reuse have been examined; …
Modeling Nitrogen Loss From Regional Switchgrass Agriculture, Saumya Sarkar
Modeling Nitrogen Loss From Regional Switchgrass Agriculture, Saumya Sarkar
All Theses
A water quality modeling study was conducted to determine and compare nitrogen loss from agricultural systems growing switchgrass and cotton in the southeastern USA. The water quality impacts were modeled at the plot scale and at the watershed scale. The Soil and Water Assessment Tool (SWAT) was used to replicate field conditions observed at switchgrass research plots at Pee Dee Research and Educational Center at Florence, South Carolina. The plot scale modeling suggested that in the early years of growth there is significant nitrogen loss from switchgrass to streamflow and groundwater but they are significantly less as the switchgrass matures. …
Development Of Strategies For Enhanced In Situ Bioremediation Of High Concentrations Of Halogenated Methanes, Huifeng Shan
Development Of Strategies For Enhanced In Situ Bioremediation Of High Concentrations Of Halogenated Methanes, Huifeng Shan
All Dissertations
ABSTRACT
Bioremediation of high concentrations of halomethanes e.g., carbon tetrachloride (CT), trichlorofluoromethane (CFC-11) and chloroform (CF) has seldom been addressed before and remains highly challenging. A microcosm study was conducted to investigate bioremediation strategies for groundwater contaminated with CT (6 to 10 mg/L), CFC-11 (1 to 26 mg/L), CF (3-500 mg/L), and 1,1-dichloroethene (1,1-DCE; up to 9 mg/L) at a former industrial site in California. Biostimulation with corn syrup and catalytic amounts of vitamin B12 was demonstrated as a feasible remedial strategy and bioaugmentation with B12 represents the most promising bioremediation method of the ones studied. Halomethane transformation …
An Examination Of Confined Aquifer Gradient Behavior Under Pumping Conditions, Stefanie Fountain
An Examination Of Confined Aquifer Gradient Behavior Under Pumping Conditions, Stefanie Fountain
All Dissertations
Accurate and reliable estimates of groundwater flow and contaminant transport models are dependent on an understanding of the aquifer properties used to create the models. The borehole flowmeter has been used with increasing frequency at a variety of sites to produce high resolution vertical hydraulic conductivity (K(z)) distributions [Boggs et al. 1990; Rehfeldt et al. 1989b; Molz et al. 1989, Boman et al. 1997; Dinwiddie et al. 1999]. In theory, the validity of measurements obtained using borehole flowmeters is contingent on the hydraulic head gradients near the well at each discrete depth resulting from the pumping-induced flow having reached quasi-steady-state. …
Experimental And Modeling Studies For Optimizing Flocculant-Aided Sediment Retention Ponds, Byung Joon Lee
Experimental And Modeling Studies For Optimizing Flocculant-Aided Sediment Retention Ponds, Byung Joon Lee
All Dissertations
Attempts to control sediment-containing runoff and associated water quality problems have involved the establishment of many small to medium sediment retention ponds and the injection of nonionic and anionic polyacrylamide (PAM) flocculants to enhance colloid removal. However, to date use has been driven more by practicing engineers and trial-and-error approaches than by logical and consistent design approaches. Therefore, the purpose of this research was to optimize colloidal clay removal in PAM-aided sediment retention ponds by applying experimental and theoretical methodologies.
Initially, simple measurement techniques for the molecular weight (MW) and charge density (CD) of various PAMs were tested and their …
Effect Of Nitrification On Lead Corrosion In Chloraminated Distribution Systems, Michael Shade
Effect Of Nitrification On Lead Corrosion In Chloraminated Distribution Systems, Michael Shade
All Theses
Water treatment facilities have been shifting from using chlorination to chloramination as a primary disinfectant since 2004, when the EPA enacted the Disinfectants/Disinfection By-Products (D/DBP) Rule mandating the decrease of DBPs. After the switch to chloramination, an unexpected lead concentration increase was detected in the Washington, D. C., and Greenville, NC water systems. These increases may be associated with the switch from chlorination to chloramination. Decomposition of chloramines results in higher ammonia loading to drinking water distribution systems, which may increase nitrification. Nitrifying bacteria may facilitate lead corrosion via two mechanisms: use of nitrite or nitrate as an alternative electron …
Spatial Variability Of Radionuclide Distribution Coefficients At The Savannah River Site And The Sub-Surface Transport Implications, Kelly Grogan
All Theses
Distribution coefficients, Kd, were measured for a suite of gamma-emitting radionuclides in uncontaminated soils from the E-Area burial grounds at the Savannah River Site. The objectives of the study were to (1) characterize the spatial variability of Kd, (2) evaluate the effect of spatial variability on vadose zone transport, and (3) develop statistical models for predicting Kd from physical or chemical characteristics.
Equilibrium batch sorption tests were performed on 27 soil samples collected from depths ranging from 11 ft to 100 ft from the BGO-3A core with 241Am, 109Cd, 139Ce, 137Cs, 57Co, 60Co, 203Hg, 85Sr, and 88Y. Distribution coefficients were …
Laboratory Evaluation Of Polycyclic Aromatic Hydrocarbon Biodegradation At A Former Tar Plant Site, Mihika Baruah
Laboratory Evaluation Of Polycyclic Aromatic Hydrocarbon Biodegradation At A Former Tar Plant Site, Mihika Baruah
All Theses
A former tar plant site in the southeastern
U.S. is one of hundreds across the country that is contaminated with polycyclic
aromatic hydrocarbons (PAHs). The 2007
CERCLA Priority List of Hazardous Substances ranks PAHs as the eighth most
prominent hazardous substance at National Priority List sites. However, benzo(a)pyrene
is the only PAH that is regulated under the Safe Drinking Water Act, with a maximum
contaminant level of 0.2 µg/l. As with most sites, monitored natural
attenuation was the preferred bioremediation approach for this site, assuming
it could be shown that the PAHs were undergoing biodegradation. Field data from the site …
Exploration Of A Carbon Nanotube Anode Gas-Filled Radiation Detector, Landon Pruitt
Exploration Of A Carbon Nanotube Anode Gas-Filled Radiation Detector, Landon Pruitt
All Theses
The primary objective of this study was to design, test, and model the electrostatic field in a gas-filled radiation detector constructed with either a carbon nanotube (CNT) or a CNT array as the anode. Tungsten anodes of 500 to 4μm diameters were used to observe the gradual decrease in operating voltage with a decreasing anode diameter and estimate efficiencies of CNT anodes in a coaxial design. An electrostatic model (Maxwell 3D/2D) was used to model the resulting electric field associated with a single CNT in the coaxial configuration as well as to optimize the pitch (distance between individual CNTs in …