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Articles 61 - 90 of 108
Full-Text Articles in Water Resource Management
The Effects Of Orthophosphate As A Copper Corrosion Control Inhibitor In High Alkalinity Drinking Water Systems, Stephen Grace
The Effects Of Orthophosphate As A Copper Corrosion Control Inhibitor In High Alkalinity Drinking Water Systems, Stephen Grace
Theses and Dissertations
The purpose of this research was to investigate orthophosphate as a corrosion inhibitor for copper pipe in a high-alkalinity drinking water system. Specifically, this thesis sought to answer three research questions regarding the impact of orthophosphate treatment, the nature of the mechanism by which orthophosphate controls copper corrosion, and the value of equilibrium modeling in predicting orthophosphate’s effects. The research questions were answered through a comprehensive literature review and experimental methodology integrating laboratory jar tests, water sampling and analysis from a field investigation, qualitative solids analysis, and equilibrium model application. This study analyzed field data obtained over the course of …
Characterization Of Chlorinated Ethene Degradation In A Vertical Flow Constructed Wetland, James M. Waldron
Characterization Of Chlorinated Ethene Degradation In A Vertical Flow Constructed Wetland, James M. Waldron
Theses and Dissertations
Chlorinated solvents, including perchloroethene (PCE) and trichlorethene (TCE), are among the most common groundwater contaminants found in the United States. Once released into the environment, chlorinated solvents are extremely persistent and often require costly and lengthy remedial actions. The use of constructed wetlands has shown promise as an effective and less costly alternative for the treatment of chlorinated solvent contaminated groundwater. This study characterized and evaluated the concentration of chlorinated ethenes within a vertical flow constructed wetland, fed with PCE contaminated groundwater, at Wright-Patterson Air Force Base (WPAFB), Ohio. Chlorinated ethene concentrations were characterized within three distinct layers of the …
Using Value-Focused Thinking To Evaluate The Use Of Innovative Stormwater Management Technologies On Air Force Installations, Jeffrey T. Falcone
Using Value-Focused Thinking To Evaluate The Use Of Innovative Stormwater Management Technologies On Air Force Installations, Jeffrey T. Falcone
Theses and Dissertations
Stormwater runoff occurs naturally after every storm event; however, traditional development practices have created many impervious surfaces, such as buildings, parking lots, and streets that increase runoff volume and flow rate. Conventional stormwater management practices focus on collecting runoff into centralized channels and conveying it as quickly as possible to local bodies of water. This type of conveyance system decreases the opportunity for stormwater to naturally infiltrate back into the ground. It also prevents contaminants from being naturally filtered out of stormwater flows. As a result, centralized conveyance systems can cause flooding, erosion, and terrestrial and aquatic habitat degradation. Innovative …
A Multimetric Benthic Index For Georgia's Wadeable Streams, Amanda Lynn Middleton
A Multimetric Benthic Index For Georgia's Wadeable Streams, Amanda Lynn Middleton
Theses and Dissertations
Using an ecoregional approach, multimetric indices were developed to describe stream condition in each geographically distinct region of Georgia. Collected from predetermined reference and impaired condition streams, macroinvertebrate data were used to develop multimetric indices. Multimetric indices identified a range of stream conditions, as well as, the overall health of aquatic ecosystems. Based on multimetric indices, the Multimetric Rating System grouped streams according to overall stream condition. The Multimetric Rating System used multiple indices to describe various facets of stream condition. Therefore, it may be concluded that the Multimetric Rating System is a robust water management tool that may be …
Evaluation Of Microbial Diversity In Wetland Through Polymerase Chain Reaction (Pcr) And Restriction Fragment Length Polymorphism (Rflp), Gregory K. Joseph
Evaluation Of Microbial Diversity In Wetland Through Polymerase Chain Reaction (Pcr) And Restriction Fragment Length Polymorphism (Rflp), Gregory K. Joseph
Theses and Dissertations
The diversity of microbial communities in wetlands has not been fully measured. These communities may offer tools to naturally remediate sites polluted with chlorinated compounds. Polmerase Chain Reaction (PCR) and Restriction Fragment Length Polymorphism (RFLP) are genomic techniques that are capable of rapidly characterizing bacteria communities and can provide valuable information about the diversity of microbial communities.
Molecular Characterization Of Wetland Soil Bacterial Community In Constructed Mesocosms, Ethan C. Bishop
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 …
Investigation Of Copper Contamination And Corrosion Scale Mineralogy In Aging Drink Water Distributions Systems, Nadja F. Turek
Investigation Of Copper Contamination And Corrosion Scale Mineralogy In Aging Drink Water Distributions Systems, Nadja F. Turek
Theses and Dissertations
Research has shown higher levels of copper appear in drinking water conveyed through relatively new copper piping systems; older piping systems typically deliver lower copper levels in their drinking water. This research contributes field data from a real drinking water distribution system, providing a better understanding of this phenomenon, as it relates to treatment considerations and compliance with the Lead and Copper Rule. Copper pipes and copper levels were sampled from drinking water taps of 16 buildings with pipes ranging in age from less than 1 to 48 years. Water samples from each building were collected before and following a …
Modeling Study To Quantify The Benefits Of Groundwater Contaminant Source Remediation, David E. Wagner
Modeling Study To Quantify The Benefits Of Groundwater Contaminant Source Remediation, David E. Wagner
Theses and Dissertations
The purpose of this research was to quantify the benefits of groundwater contaminant source remediation by using a model to simulate how reduction of source mass was related to reduction of contaminant concentration at a receptor. This thesis sought to answer three research questions: (1) how are contaminant source mass reduction and reduction of mass flux leaving the source-zone related; (2) how can we quantify the effect of the important natural attenuation processes that act upon the dissolved contaminant as it travels from the source zone to downgradient receptors, and (3) under specified site conditions, what is the maximum contaminant …
Validation Of Methods To Measure Mass Flux Of A Groundwater Contaminant, Hyouk Yoon
Validation Of Methods To Measure Mass Flux Of A Groundwater Contaminant, Hyouk Yoon
Theses and Dissertations
In this study, flux measurements obtained using two methods are compared with known mass fluxes in a meso-scale three-dimensional artificial aquifer. One method, the tandem recirculating well (TRW) method, is applied using two different techniques. One technique is simple and inexpensive, only requiring measurement of heads, while the second technique requires conducting a tracer test. The second method, the integrated pump test (IPT) method, requires use of one or more pumping and observation wells in various configurations. The results of the experiments in the artificial aquifer show that the most expensive technique, the TRW method using tracers, provides the most …
Analysis Of Bacterial Population And Distribution In The Developing Strata Of A Constructed Wetland Used For Chlorinated Ethene Bioremediation, Milton J. Clausen Jr.
Analysis Of Bacterial Population And Distribution In The Developing Strata Of A Constructed Wetland Used For Chlorinated Ethene Bioremediation, Milton J. Clausen Jr.
Theses and Dissertations
Chlorinated hydrocarbons and their degradation products are among of the most common organic groundwater contaminates in the United States. These compounds attack the central nervous system in animals and can affect the photosynthesis of plants. These compounds are also resistant to degradation in the environment and, because of this, pose a risk to any ecosystem in which they are present. This study identified the dominant microbial species in a constructed treatment wetland at Wright-Patterson AFB, Dayton, Ohio using 16S rRNA gene sequence analysis. Samples were taken from three different depths and during each of the four seasons. These samples were …
Analysis Of Qa/Qc Protocols And Value Of Data To The Development Of Reference Criteria In The Georgia Ecoregions Project, Tracy Jo Ferring
Analysis Of Qa/Qc Protocols And Value Of Data To The Development Of Reference Criteria In The Georgia Ecoregions Project, Tracy Jo Ferring
Theses and Dissertations
The concept of Measurements Quality Objectives (MQOs), in bioassessment programs is a useful tool in evaluating the consistency of data and limiting variability and potential sources of measurement error. Typical evaluations of data repeatability and/or data quality center on the use of a series of calculations that quantify variability between measures. These calculations provided some indication of not only the quality of the data collected, but also acted as a measure of how representative the biological data were to each ecoregion. The evaluation of the Quality Control data for this project provides a framework for data users and water resource …
Modeling Groundwater Flow And Contaminant Transporting Fractured Aquifers, Jason M. Bordas
Modeling Groundwater Flow And Contaminant Transporting Fractured Aquifers, Jason M. Bordas
Theses and Dissertations
The hybrid discrete fracture network/equivalent porous medium (DFN/EPM) model was selected for analysis and application to simulate a contaminated site in this study. The DFN/EPM was selected because it appeared to have the potential to aid decision making by remedial project managers at contaminated DoD fractured aquifer sites. This model can use data that are typically available at a site while incorporating the important processes relevant to describing contaminant transport in a fractured medium. The model was applied to simulate the operation of a pump-and-treat remedial action at a trichloroethene-contaminated fractured aquifer at Pease AFB. The model was able to …
Validation Of An Innovative Groundwater Contaminant Flux Measurement Method, Seh J. Kim
Validation Of An Innovative Groundwater Contaminant Flux Measurement Method, Seh J. Kim
Theses and Dissertations
The ability to measure groundwater contaminant flux is increasingly being recognized as crucial in order to prioritize contaminated site cleanups, estimate the efficiency of remediation technologies, measure rates of natural attenuation, and apply proper source terms to model groundwater contaminant transport. An innovative mass flux measurement method using horizontal flow treatment wells (HFTWs) was developed recently to compensate for the disadvantages of other flux measurement methods that are being used. Flux measurement methods can be categorized as either point methods or integral methods. As the name suggests, point methods measure flux at a specific point or points in the subsurface. …
Modeling Application Of Hydrogen Release Compound To Effect In Situ Bioremediation Of Chlorinated Solvent-Contaminated Groundwater, Ryan C. Wood
Theses and Dissertations
This study investigates how application of Hydrogen Release Compound (HRC) might be implemented to remediate a site contaminated with tetrachloroethene (PCE) or its daughter products, under varying site conditions. The 3-D reactive transport model RT3D was coupled with a dual-Monod biodegradation submodel to simulate the effect of the hydrogen generated by HRC on accelerating the biodegradation of dissolved chlorinated solvents. Varying site conditions and injection well configurations were investigated to determine the effect of these environmental and design conditions on overall treatment efficiency. The model was applied to data obtained at a chlorinated solvent contaminated site at Vandenberg AFB, where …
Hydrogeologic Model Of A Leachate Plume In An Unconfined Coastal Plain Aquifer And Chemical Transport Mechanisms Of Metals And Dense Non-Aqueous Phase Liquids, Thomas Lindblad
Theses and Dissertations
Groundwater contamination is of increasing environmental concern as many aquifers across the globe have experienced a decrease in water quality in recent time. The growth of the world's population over the last couple of decades has caused a dramatic increase in the rate of groundwater use. One potential source of groundwater contamination is waste material in landfills. The 1 st Division Road Sanitary landfill at Fort Benning Military Reservation was studied to evaluate the potential effect on local groundwater and a leachate plume was recognized using data from 16 groundwater monitoring wells located around the facility. The study site is …
The Occurrence And Control Of Disinfection By-Products (Dbps) In Two Water Treatment Plants Utilizing The Same Source, Sam George Khoury
The Occurrence And Control Of Disinfection By-Products (Dbps) In Two Water Treatment Plants Utilizing The Same Source, Sam George Khoury
Theses and Dissertations
The influence of disinfection by-products (DBPs) on the operation and design of water treatment plants has been increasing since the early studies by Rook on trihalomethanes (THMs) (Stevens, 1977). Work conducted in the 1980s identified the existence of nonvolatile halogenated organics (non-THM organics), of which the majority produced by chlorination were haloacetic acids (HAAs), within the HAAs, dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) were the dominant members. Concern over potential health effect led the U.S. Environmental Protection Agency (USEPA) to set a maximum contaminant level (MCL) for total THMs and HAAs. The disinfectant/disinfection by-product rule (D-DBP Rule) currently proposed …
Modeling A Field Application Of In Situ Bioremediation Of Perchlorate-Contaminated Groundwater Using Horizontal Flow Treatment Wells (Hftws), Peter G. Chosa
Modeling A Field Application Of In Situ Bioremediation Of Perchlorate-Contaminated Groundwater Using Horizontal Flow Treatment Wells (Hftws), Peter G. Chosa
Theses and Dissertations
Perchlorate contaminated groundwater is rapidly becoming a significant environmental remediation issue for the Department of Defense. In this study, an existing numerical model that simulates the operation of a Horizontal Flow Treatment Well (HFTW) system to effect the in situ biodegradation of perchlorate through the addition of an electron donor is modified to include a submodel that describes bioclogging. Bioclogging restricts flow out of the HFTW due to the accumulation of biomass directly adjacent to the well. The modified model is then applied to an existing perchlorate contaminated site that will be used for an evaluation of the HFTW technology. …
Application Of Horizontal Flow Treatment Wells For In Situ Treatment Of Mtbe-Contaminated Groundwater, Preston F. Rufe
Application Of Horizontal Flow Treatment Wells For In Situ Treatment Of Mtbe-Contaminated Groundwater, Preston F. Rufe
Theses and Dissertations
This study utilized a three-dimensional numerical model to evaluate the potential application of HFTWs to manage MTBE-contaminated groundwater. HFTWs consist of two dual-screened treatment wells. One well operates in an upflow mode, with MTBE-contaminated water extracted from an aquifer through a screen in the deep portion of an aquifer and injected into the aquifer through a shallow well screen, while the adjacent well operates in a downflow mode, extracting water from the shallow zone of the aquifer and injecting it into the deep zone. As the MTBE-contaminated water flows through the wells, an electron acceptor and/or another electron donor is …
Characterization Of Chlorinated Solvent Degradation In A Constructed Wetland, Nathan D. Clemmer
Characterization Of Chlorinated Solvent Degradation In A Constructed Wetland, Nathan D. Clemmer
Theses and Dissertations
Widespread chlorinated ethene contamination of aquifers coupled with high costs of current treatment technologies demand innovative remediation solutions. Wetlands, maintaining anaerobic and aerobic zones promoting the complete degradation of chlorinated ethenes such as Tetrachloroethylene (PCE), could be the answer. This thesis characterized the chlorinated solvent contamination levels in three strata of an upward flow constructed wetland. Analysis of samples was accomplished by purge-and-trap gas chromatography. Water quality parameters, Dissolved Oxygen (DO), Oxidation Reduction Potential (ORP), pH, Conductivity, and Temperature, were also measured in monitoring wells with a water monitoring sonde. After removing data outliers caused by short-circuiting flow, PCE concentrations …
Optimizing An In Situ Bioremediation Technology To Manage Perchlorate-Contaminated Groundwater, Mark R. Knarr
Optimizing An In Situ Bioremediation Technology To Manage Perchlorate-Contaminated Groundwater, Mark R. Knarr
Theses and Dissertations
Combining horizontal flow treatment wells (HFTWs) with in situ biodegradation is an innovative approach with the potential to remediate perchlorate-contaminated groundwater. A technology model was recently developed that combines the groundwater flow induced by HFTWs with in situ biodegration processes that result from using the HFTWs to mix electron donor into perchlorate-contaminated groundwater. A field demonstration of this approach is planned to begin this year. In order to apply the technology in the field, project managers need to understand how contaminated site conditions and technology design parameters impact technology performance. One way to gain this understanding is to use the …
Analysis Of Anion Distributions In The Developing Strata Of A Constructed Wetland Used For Chlorinated Ethene Remediation, Joshua D. Kovacic
Analysis Of Anion Distributions In The Developing Strata Of A Constructed Wetland Used For Chlorinated Ethene Remediation, Joshua D. Kovacic
Theses and Dissertations
Perchloroethene (PCE), Trichloroethene (TCE) and their degradation products are among the most common organic groundwater contaminants in the United States. Constructed wetlands utilizing upward flow harbor reduction-oxidation conditions that have demonstrated the potential to promote both partial and total mineralization of PCE and TCE through the process of natural attenuation. Organic acid and inorganic anion concentrations are indicative of reduction-oxidation processes that drive chlorinated ethene degradation. These analytes were investigated to assess their development within three vertically stratified regions of a constructed wetland cell at Wright-Patterson Air Force Base fed by groundwater contaminated with PCE and TCE. Data collected during …
Modeling Catalytic Destruction Of Subsurface Contaminants In Recirculating Wells, Kerry J. Cadena
Modeling Catalytic Destruction Of Subsurface Contaminants In Recirculating Wells, Kerry J. Cadena
Theses and Dissertations
Groundwater and soil contamination is a significant problem throughout the nation, with approximately 300,000 to 400,000 sites affected (National Research Council, 1994). Examples of groundwater contaminants of special interest to DoD and AF installations include fuel hydrocarbons, chlorinated hydrocarbons, and nitroaromatic compounds. Traditional remediation technologies, which include pump-and-treat, permeable reactive barriers, and natural attenuation, have numerous drawbacks associated with them. These drawbacks have prompted researchers to look for innovative contamination clean-up methods. The technology investigated in this thesis, reticulating horizontal flow treatment wells (HFTWs) with in-well palladium (Pd) catalyst reactors, offers the potential for destruction of groundwater contaminants commonly found …
Palladium-Catalyzed Destruction Of Nitro Aromatic-Contaminated Groundwater, Dennis Landon Phillips
Palladium-Catalyzed Destruction Of Nitro Aromatic-Contaminated Groundwater, Dennis Landon Phillips
Theses and Dissertations
Of the over 17,000 DoD sites that potentially require remediation, sites containing soil and groundwater contaminated by energetic compounds are prevalent (Larson et al., 2001). Production of energetics such as 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5 - trinitro- 1,3,5 -triazine (RDX), and octahydro-1,3,5,7-tetranitro- 1,3,5,7-tetrasocine (HMX) for use in munitions has created a DoD-wide problem due to improper disposal techniques (Price et al., 2001), Nitro aromatic compounds (NACs) similar to those used in explosives can also be found in insecticides, herbicides, pharmaceuticals, dyes, plastics, and many other commonly used products. The natural breakdown of these contaminants creates byproducts such as amines, which are known …
A Comparison Of Modeling Approaches In Simulating Chlorinated Ethene Removal In A Constructed Wetland By A Microbial Consortia, Jason S. Campbell
A Comparison Of Modeling Approaches In Simulating Chlorinated Ethene Removal In A Constructed Wetland By A Microbial Consortia, Jason S. Campbell
Theses and Dissertations
The purpose of this study is to compare different approaches to modeling the reductive dechlorination of chlorinated ethenes in the anaerobic region of an upward flow constructed wetland by microbial consortia. A controlled simulation experiment that compares three different approaches to modeling the degradation of chlorinated ethenes in wetland environments is conducted and investigates how each of the modeling approaches affect simulation results. Concepts like microbial growth in the form of a biofilm and spatially varying contaminant concentrations bring the validity of the CSTR assumption into question. These concepts are incorporated into the different modeling approaches to evaluate the CSTR …
Application Of Horizontal Flow Treatment Wells For In Situ Treatment Of Perchlorate Contaminated Groundwater, Jeffrey C. Parr
Application Of Horizontal Flow Treatment Wells For In Situ Treatment Of Perchlorate Contaminated Groundwater, Jeffrey C. Parr
Theses and Dissertations
Groundwater contamination by perchlorate has recently been recognized as a significant environmental problem across the United States, and especially at Department of Defense facilities. In this study, a model is used to evaluate the potential of a innovative in situ bioremediation technology using Horizontal Flow Treatment Wells (HFTWs) to manage perchlorate-contaminated groundwater. The technology uses HFTWs to mix an electron donor into perchlorate-contaminated groundwater in order to promote reduction of the perchlorate by indigenous microorganisms in bioactive zones within the aquifer, as well as recirculate the contaminated water between treatment well pairs to achieve multiple passes of contaminated water through …
An Anion Characterization Of A Constructed Wetland Used For Chlorinated Ethene Remediation, Bradley M. Bugg
An Anion Characterization Of A Constructed Wetland Used For Chlorinated Ethene Remediation, Bradley M. Bugg
Theses and Dissertations
Chlorinated ethenes physical properties as well as its ubiquitous state at DOD installations makes it a priority for innovative remediation efforts. Current techniques are expensive and time consuming to maintain. Constructed wetlands suggest an inexpensive and operational alternative to conventional technologies. Sub-surface flow wetlands provide the anaerobic zones necessary to reduce the recalcitrant chlorinated solvents prior to anaerobic or aerobic mineralization of its daughter products. A vertical flow cell to include sequential sedimentary layers of two hydric soil lifts and a mix of hydric soil and woody compost was the subject of this investigation. This study focused on the statistical …
A Model For Palladium Catalyzed Destruction Of Chlorinated Ethenes In Contaminated Groundwater, Christopher M. Stoppel
A Model For Palladium Catalyzed Destruction Of Chlorinated Ethenes In Contaminated Groundwater, Christopher M. Stoppel
Theses and Dissertations
Groundwater contamination by chlorinated ethenes is a widespread environmental problem. Conventional remediation technologies have shortcomings that have prompted further research into the development of novel treatment technologies. A palladium/ alumina catalyst in the presence of dissolved molecular hydrogen (referred to hereafter as a PD/H2 system) has been demonstrated to rapidly destroy chlorinated ethene contaminated groundwater. First-order kinetics have been used to model chlorinated ethene destruction in a PD/H2 reactor. However, catalyst deactivation and regeneration are important processes that also need to be modeled in order to better understand their effect on treatment efficiency. This study presents a model …
Quantitative Validation Of A Model Of Chlorinated Ethene Natural Attenuation, Harold C. Young
Quantitative Validation Of A Model Of Chlorinated Ethene Natural Attenuation, Harold C. Young
Theses and Dissertations
Chlorinated ethenes are among the most prevalent groundwater contaminants at hazardous waste sites nationwide. In an attempt to manage the risks posed by these contaminants, while controlling costs, monitored natural attenuation (MNA) is being considered as a remediation strategy at many sites. MNA relies on naturally occurring physical, chemical, and biological processes in the subsurface to reduce the risk posed by the contamination. The implementation of MNA, however, requires a detailed understanding of these processes, and how they impact contamination at a particular site. One way to gain this understanding is through contaminant fate and transport modeling. In this study, …
Determining The Value Of Groundwater Contamination Source Removal: A Methodology, Benjamin C. Recker
Determining The Value Of Groundwater Contamination Source Removal: A Methodology, Benjamin C. Recker
Theses and Dissertations
Subsurface contamination by industrial chemicals is one of the most prevalent and costly environmental problems facing the United States government. This contamination problem must be managed to protect human health and the environment. Two basic strategies are used to deal with subsurface contamination: source removal and contaminant containment. While much cost and performance data are available for individual technologies associated with each of these strategies, there have been very few studies that have examined the benefits of implementing source removal technologies in order to reduce contaminant containment (and hopefully total) costs. This study examines the tradeoff between extent of source …
Modeling Chlorinated Ethene Removal In Constructed Wetlands: A System Dynamics Approach, Colby D. Hoefar
Modeling Chlorinated Ethene Removal In Constructed Wetlands: A System Dynamics Approach, Colby D. Hoefar
Theses and Dissertations
The purpose of this study is to gain understanding of the dynamics of the processes that degrade Perchloroethene (PCE) to ethylene, or carbon dioxide (CO2), within the confines of a constructed wetland. A system dynamics approach will be used. This model is focused on identifying and optimizing the naturally occurring processes in stratified wetland sediment that reduce mass, toxicity, mobility, volume or concentration of contaminants in groundwater. Contaminant fate and transport within a wetland system is extremely complex and the mechanisms that drive wetland behavior are dynamic. Confidence in the model was built through verification and testing. Reasonable …