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Articles 151 - 172 of 172
Full-Text Articles in Environmental Engineering
Scale-Up And Characterization Of An Enrichment Culture For Bioaugmentation Of The P-Area Chlorinated Ethene Plume At The Savannah River Site, Ashley Eaddy
All Theses
Bioaugmentation has become an increasingly popular remediation strategy for groundwater sites contaminated with chlorinated solvents. When biostimulation is not an option due to the lack of necessary microorganisms required for dechlorination of the contaminants, bioaugmentation is an attractive option for remediation. The P-Area groundwater plumes at the Savannah River Site (SRS) are just such a case. The P-Area site is contaminated with tetrachloroethene (PCE), trichloroethene (TCE), and cis-dichloroethene (cDCE), and no dechlorination past cDCE is occurring. A similar site, the C-Area site, is near one of the P-Area site's source zones but displays complete reduction of TCE to ethene. …
Microcosm Evaluation Of Vinyl Chloride Bio-Oxidation Under Anaerobic Conditions, Jessica High
Microcosm Evaluation Of Vinyl Chloride Bio-Oxidation Under Anaerobic Conditions, Jessica High
All Theses
The vast majority of hazardous waste sites in the US have groundwater contaminated with halogenated organic solvents, primarily tetrachloroethene (PCE) and trichloroethene (TCE). Because the cost to remediate these sites is projected to exceed hundreds of billions of dollars, there is considerable interest in utilizing bioremediation as a low-cost remedy. Under anaerobic conditions, the best characterized biodegradation pathway for chlorinated ethenes is reductive dechlorination, whereby an electron donor such as hydrogen provides the reducing equivalents needed to replace chlorine atoms with hydrogen atoms. The ultimate daughter products from chlorinated ethenes are non-hazardous ethene and ethane, a process easily documented with …
Fecal Coliform Source Identification Using Chemical Tracers, Nicole Fahrenfeld
Fecal Coliform Source Identification Using Chemical Tracers, Nicole Fahrenfeld
All Theses
Fecal sterols and fluorinated whitening agents (FWA) were used as chemical tracers for fecal coliform source tracking in Cane and Little Cane creeks in Walhalla, SC. Fecal sterols were quantifiable in both stream sediments and suspended particulates using an extraction, clean-up, and analytical method modified from Isobe et al. (2002) with a N,O-Bis(trimethylsilyl)trifluoroacetamide (BSTFA) derivatization scheme. Only human sterol source identification ratios were able to be calculated using the chosen sterol suite. Human fecal signatures were seen in both the sediment and the water column at various points along both creeks, indicating human fecal pollution is contributing to the fecal …
Development Of A Colorimetric Test For Quantification Of Uranium In Drinking Water, Amy Ratliff
Development Of A Colorimetric Test For Quantification Of Uranium In Drinking Water, Amy Ratliff
All Theses
A new method was developed for the determination of uranium in groundwater above 30µg/L (30ppb). This concentration is the maximum contaminant level (MCL) for uranium in drinking water, which was set in December 2003 by the US EPA under the provisions of the Safe Drinking Water Act. The method is rapid and requires little technical training to conduct, allowing it to be used by consumers, in the laboratory, or in the field. The two-step technique involves preconcentrating uranium using a U/TEVA-2 extraction chromatographic resin followed by complexation with a pyridylazo indicator dye, Br-PADAP. At neutral pH, a counter ion is …
Storm Water Export Of Nitrogen, Phosphorous, And Carbon From Developing Catchments In The Upper Piedmont Physiographic Province, Laura Reid
All Theses
Impacts on water quality caused by land use change from forests and pastures to housing subdivisions were evaluated in catchments undergoing active development in the upper Piedmont physiographic province of South Carolina. Specific attention was focused on the export of nitrogen, phosphorus and carbon from these catchments during storm events. Three catchments with varying stages of development were compared to categorize the effects of land disturbance. Storm events occurring within a four year period of 2004 through 2007 were studied for changes in water quality within catchment streams. Due to the potential large input of surface runoff to streams following …
Anaerobic Biodegradation Of Ethylene Dibromide And 1,2-Dichloroethane In The Presence Of Fuel Hydrocarbons, James Henderson
Anaerobic Biodegradation Of Ethylene Dibromide And 1,2-Dichloroethane In The Presence Of Fuel Hydrocarbons, James Henderson
All Dissertations
Field evidence from underground storage tank (UST) sites where leaded gasoline leaked indicates the lead scavengers 1,2-dibromoethane (ethylene dibromide, or EDB) and 1,2-dichloroethane (1,2-DCA) may be present in groundwater at levels that pose unacceptable risk. These compounds are seldom tested for at UST sites. Although dehalogenation of EDB and 1,2-DCA is known to occur, the effect of fuel hydrocarbons on their biodegradability under anaerobic conditions is poorly understood. Microcosms (2 L glass bottles) were prepared with soil and groundwater from a UST site in Clemson, South Carolina, using samples collected from the source (containing residual fuel) and less contaminated downgradient …
The Formation Of Halonitromethanes In Wastewater Treatment Plant Effluents, Jesse Addison
The Formation Of Halonitromethanes In Wastewater Treatment Plant Effluents, Jesse Addison
All Theses
Disinfection by-products (DBPs) have been a water treatment concern since their discovery in the 1970's. Today, only eleven drinking water DBPs are regulated by the Environmental Protection Agency (EPA). However, over 500 DBPs have been identified in drinking waters with advances in analytical methods within the last two decades. Halonitromethanes (HNMs) were among the fifty-plus unregulated high-priority DBPs that were monitored for and detected in drinking waters in a recent nationwide occurrence study funded by EPA. The toxicology studies conducted in recent years showed that HNMs are one of the most cytotoxic and genotoxic classes among the emerging DBPs, and …
Laboratory Evaluation Of Chlorinated Ethene Transformation Processes In Fractured Sandstone, Ramona Darlington
Laboratory Evaluation Of Chlorinated Ethene Transformation Processes In Fractured Sandstone, Ramona Darlington
All Dissertations
A fractured sandstone aquifer at an industrial site in southern California is contaminated with trichloroethene (TCE) to depths in excess of 244 m. Field monitoring data suggest that TCE is undergoing reduction to cis-DCE and that additional attenuation is occurring. However, vinyl chloride (VC) and ethene have not been detected in significant amounts, so that if transformation is occurring, a process other than reductive dechlorination must be responsible. The overall objective of this study was to evaluate the occurrence of biotic and abiotic transformation processes at this site for TCE, cis-DCE and VC. Anaerobic microcosms were constructed with site groundwater …
Bacterial Auto-Aggregation And Co-Aggregation In Activated Sludge, Fei Chen
Bacterial Auto-Aggregation And Co-Aggregation In Activated Sludge, Fei Chen
All Theses
Microbial auto-aggregation and co-aggregation, leading to biofilm or floc formation, widely occur in natural systems. This study was conducted to investigate the extent of bacterial auto-aggregation and co-aggregation in activated sludge and their contributions in activated sludge floc formation. In this study, an activated sludge sample was separated into a supernatant part (planktonic community) and a sediment part (floc community) by centrifugation at 650_g for 2 minutes. 197 strains were isolated from both communities. These isolates belong to 18 phylotypes based on molecular identifications. Similar phylogenetic distributions of these isolates were observed in planktonic and floc communities, suggesting a similar …
Metalloporphyrin Catalyzed Degradation Of Pce: Effects Of Reductants, Buffers And Cosolvent Concentration, Sowmya Suryanarayanan
Metalloporphyrin Catalyzed Degradation Of Pce: Effects Of Reductants, Buffers And Cosolvent Concentration, Sowmya Suryanarayanan
All Theses
Reductive dechlorination of chlorinated organic contaminants using metalloporphyrins as catalysts may be an effective approach to treat widespread contamination. However, most previous studies have examined water-soluble rather than insoluble metalloporphyrins despite the fact that the latter category makes up the largest fraction found in nature. Recent studies have shown that addition of different cosolvents to water can activate otherwise non-reactive metalloporphyrin catalysts and facilitate the reduction of tetrachloroethylene (PCE), presumably by the mere process of making the otherwise insoluble metalloporphyrins dissolve in solution. Therefore, solubility has been advanced as a key factor in the ability of metalloporphyrins to catalyze organic …
Laboratory Evaluation Of Microbial Aggregation In Activated Sludge, Xiaoling Liu
Laboratory Evaluation Of Microbial Aggregation In Activated Sludge, Xiaoling Liu
All Theses
Microbial aggregation was investigated in this study using the activated sludge process as a model system, the performance of which is highly dependent on effective bioaggregation. This research includes two experiments. First, four laboratory-scale activated sludge sequencing batch reactors (SBRs) were constructed in order to evaluate the effect of solids retention time (SRT) on microbial aggregation. These SBRs were operated at SRT of 4, 8, 16, and 32 days, respectively, fed with a protein-based synthetic wastewater, and monitored over a period of 268 days for performance and sludge settling characteristics including soluble COD in the effluent (sCOD), sludge volume index …
Cosolvent Effects On The Reductive Dechlorination Of Tetrachloroethylene Catalyzed By Iron Tetraphenyl Porphyrin Chloride, Lavanya Ramasubramanian
Cosolvent Effects On The Reductive Dechlorination Of Tetrachloroethylene Catalyzed By Iron Tetraphenyl Porphyrin Chloride, Lavanya Ramasubramanian
All Theses
Abiotic electron transfer mediated reductive dechlorination reactions have been studied extensively in the past decade. Porphyrins and metalloporphyrins are common electron transfer mediators used. Past studies have shown that some metalloporphyrins play a key role in increasing the rate of reaction in the presence of cosolvents. There have also been suggestions that organic cosolvents enhance the rate of reduction by increasing the solubility of metalloporphyrins.
The primary objective of this project was to examine the effect of cosolvents on the metalloporphyrin-catalyzed reductive dechlorination of tetrachloroethylene (PCE). Subsequently, experiments were also conducted to test the hypothesis that metalloporphyrin solubility is linked …
Achiral And Chiral Analysis Of Polychlorinated Biphenyls (Pcbs) In The Aquatic And Riparian Food Webs In Twelve Mile Creek, South Carolina., Viet Dang
All Theses
Polychlorinated biphenyls (PCBs) contamination in the Twelve Mile Creek arm of Lake Hartwell, South Carolina, has been an issue for decades. Lake Hartwell, which is a reservoir located on the border between the states of South Carolina and Georgia, was contaminated with an estimated 440,000 pounds of PCBs. PCBs were released from the Sangamo-Weston capacitor plant located on Town Creek, which feeds into Twelve Mile Creek and ultimately Lake Hartwell. The Twelve Mile Creek tributary connecting the Sangamo-Weston plant to Lake Hartwell has had little attention. Understanding PCBs contamination in the aquatic and riparian food webs of Twelve Mile Creek …
Development And Evaluation Of An Enrichment Culture For Bioaugmentation Of The P-Area Chlorinated Ethene Plume At The Savannah River Site, Elizabeth Wood
Development And Evaluation Of An Enrichment Culture For Bioaugmentation Of The P-Area Chlorinated Ethene Plume At The Savannah River Site, Elizabeth Wood
All Theses
The Twin Lakes chlorinated ethene plume at the Department of Energy's
Savannah River Site (SRS) emerges in a wetland in which trichloroethene (TCE) is
completely reduced to ethene and ethane. Novel strains of Dehalococcoides have been
detected from the wetland area. The objectives of this study were 1) to develop an
enrichment culture capable of completely dechlorinating TCE and tetrachloroethene
(PCE) to ethene using samples from the wetland; 2) to evaluate the use of lactate,
emulsified vegetable oil and corn syrup as possible electron donors for biostimulation of
the P-area chlorinated ethene plume at SRS that is not undergoing natural …
Approaches To Mitigate The Impact Of Dissolved Organic Matter On The Adsorption Of Synthetic Organic Contaminants By Activated Carbon, Abhishek Yadav
Approaches To Mitigate The Impact Of Dissolved Organic Matter On The Adsorption Of Synthetic Organic Contaminants By Activated Carbon, Abhishek Yadav
All Theses
The main objective of this study was to conduct a systematic investigation of various approaches to mitigate the competition of dissolved organic matter (DOM) on the adsorption of synthetic organic contaminants (SOCs) by activated carbons. TCE and atrazine were selected as the target SOCs because they are known to adsorb in different pore size regions. TCE adsorbs in the primary micropore region (i.e., <10 ) which is inaccessible to the majority of the DOM components, while atrazine adsorbs in the secondary micropore region (i.e., 10-20 ) which is partially accessible to some DOM components. The adsorbents used in this study consisted of four activated carbons (OLC, CRC, F400He, and HD4000ST) and one activated carbon fiber (ACF: ACF10). All sorbents were basic and hydrophobic in nature and represented a set of activated carbons with gradually widening pore size distribution, from the extremely microporous carbons (ACF10 and OLC) to carbons with some amount of mesopores (CRC and F400He) and finally a predominantly mesoporous (HD4000ST) carbon.
Isotherms were performed as single solute and after preloading with a dissolved organic matter (5 mg DOC/L and 20 mg DOC/L) for both TCE and atrazine and using the five activated carbons. Single solute isotherm results showed …
Characterization Of The Ibc Technologies Superlig¨ 620 Solid Phase Extraction Resin With Applications For Automated Process Monitoring, John Clements
Characterization Of The Ibc Technologies Superlig¨ 620 Solid Phase Extraction Resin With Applications For Automated Process Monitoring, John Clements
All Theses
Characterization of the IBC Advanced Technologies SuperLig¨ 620 solid phase extraction resin was performed in order to develop an automated strontium-90 process monitor. The main focus was on strontium separation from barium, with the goal of developing an automated separation process for strontium-90 in Hanford high-level tank wastes. High-level waste tanks contain significant cesium-137 activities, of which barium daughters are of great concern as interferences to strontium quantification. A number of complexants were studied in a series of batch distribution coefficient experiments, as SuperLig¨ 620 was not previously known to elute strontium in typical mineral acids. The optimal separation was …
Application Of Classical Versus Bayesian Statistical Methods To On-Line Radiological Monitoring, Amy Attardo
Application Of Classical Versus Bayesian Statistical Methods To On-Line Radiological Monitoring, Amy Attardo
All Theses
The on-line monitoring for illicit radioactive material with a minimum number of false detections is a critical need for homeland security. The primary objectives of this work were to apply both Bayesian and classical statistical process control chart techniques to the on-line monitoring of radiological data and to then compare the Type I and Type II error incidence rates. Two versions of the cumulative sum (CUSUM) and Shiryayev-Roberts (S-R) procedures known as total reset and alarm reset methods were developed. The best method in terms of Type I errors was the S-R total reset method. In terms of Type II …
Modeling Long-Term Plutonium Transport In The Savannah River Site Vadose Zone, Deniz Demirkanli
Modeling Long-Term Plutonium Transport In The Savannah River Site Vadose Zone, Deniz Demirkanli
All Dissertations
Improved understanding of flow and radionuclide transport in vadose zone sediments is fundamental to future planning involving radioactive materials. Long-term experiments were conducted at the Savannah River Site (SRS), where a series of lysimeters containing sources of different Pu oxidation states were placed in the shallow subsurface and exposed to the environment for 2 to 11 years. After the experiments, Pu activity concentrations were measured along vertical cores. The distributions were anomalous in nature, with irregular downward migration and unexpected upward migration. Previous studies suggested that surface-mediated, oxidation/reduction (redox) reactions may be responsible for the anomalies. This hypothesis is tested …
A Comparison Of The Zns(Ag) Scintillation Detector To The Silicon Semiconductor Detector For Quantification Of Alpha Radioactivity In Aqueous Solutions, Jennifer Foster
A Comparison Of The Zns(Ag) Scintillation Detector To The Silicon Semiconductor Detector For Quantification Of Alpha Radioactivity In Aqueous Solutions, Jennifer Foster
All Theses
A ZnS(Ag) detector was successfully used in the direct detection of alpha particles from aqueous solutions and the results were compared to the passivated ion implanted planar silicon (PIPS) continuous air monitor (CAM) detector. The ZnS(Ag) detector is recommended for on-line detection of gross alpha radioactivity from high-level liquid waste process streams; however, the detector suffers from limitations due to variations in detection efficiency with alpha energies. The beta and gamma interference did not significantly spillover into the alpha region of interest of the ZnS(Ag) detector which provided absolute detection efficiencies of 7.19 ± 0.13%, 5.37 ± 0.02%, and 4.21 …
Controlling Steam Flood Migration With Air Injection Wells, Rex Hodges
Controlling Steam Flood Migration With Air Injection Wells, Rex Hodges
All Dissertations
Steam flooding is an aggressive remediation technology for removing volatile organic chemical (VOC) sources that slowly dissolve into passing groundwater. Plume concentrations can be reduced, accelerating cleanup, and decreasing plume management costs. Steam injected in wells surrounding the source spreads outward and develops into a front that drives contamination to a system of groundwater pumping wells in the saturated zone and soil vapor extraction wells in the vadose zone. The process can be modeled with the non-isothermal multi-phase flow simulator T2VOC to include operation designs and factors at individual sites.
A pilot field-scale test at the Savannah River Site (SRS) …
Predicting The Future Fate Of Pcbs In Lake Hartwell, Alan W. Elzerman, Kevin J. Farley, Frank M. Dunnivant, Craig Cooper
Predicting The Future Fate Of Pcbs In Lake Hartwell, Alan W. Elzerman, Kevin J. Farley, Frank M. Dunnivant, Craig Cooper
Publications
No abstract provided.
Pcbs And Related Compounds In Lake Hartwell, Alan W. Elzerman, Frank M. Dunnivant, Geoffrey G. Germann
Pcbs And Related Compounds In Lake Hartwell, Alan W. Elzerman, Frank M. Dunnivant, Geoffrey G. Germann
Publications
No abstract provided.