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Articles 31 - 60 of 164

Full-Text Articles in Environmental Engineering

Evaluating The Biotic Condition Of Restored Streams In Kentucky’S Inner Bluegrass Region, Charles Cole Crankshaw Jan 2021

Evaluating The Biotic Condition Of Restored Streams In Kentucky’S Inner Bluegrass Region, Charles Cole Crankshaw

Theses and Dissertations--Biosystems and Agricultural Engineering

Numerous stream restoration projects have been implemented in Kentucky’s Inner Bluegrass region to offset anthropogenic impacts. These projects range from full channel realignments to volunteer-led riparian installations. To assess the ability of said projects to restore stream habitat and biota, full restoration (n=12) and riparian (n=6) sites were compared to reference (n=6) and disturbed (n=12) sites using RBP and SVAP protocols, macroinvertebrate samples, and geomorphology. General trends for SVAP, RBP, and BI scores, starting with highest habitat or biotic quality, were reference sites, full and riparian restoration sites, then disturbed sites. The number of EPT taxa, another indicator of biological …


Development Of Novel Polymeric Materials For Their Application In Monitoring And Remediation Of Environmental Pollutants, Rishabh Shah Jan 2021

Development Of Novel Polymeric Materials For Their Application In Monitoring And Remediation Of Environmental Pollutants, Rishabh Shah

Theses and Dissertations--Chemical and Materials Engineering

Remediation of environmental pollutants from water is one of the major challenges in the 21st century. Utilizing novel polymeric materials to accomplish this challenge has garnered a lot of interest in recent times. Flexibility in synthesizing as well as functionalizing makes them attractive for their application in pollutant remediation. This work is based on development and characterization of novel crosslinked polymeric as well as linear polymeric materials from biphenyl-based monomers, biphenyl based crosslinker and a temperature responsive monomer (Nisopropylacrylamide (NIPAAm)) for their application in remediation of toxic pollutants such as polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs) and iron oxide nanoparticle …


Atmospheric Measurements With Unmanned Aerial Systems (Uas), Marcelo I. Guzman Nov 2020

Atmospheric Measurements With Unmanned Aerial Systems (Uas), Marcelo I. Guzman

Chemistry Faculty Publications

This Special Issue provides the first literature collection focused on the development and implementation of unmanned aircraft systems (UAS) and their integration with sensors for atmospheric measurements on Earth. The research covered in the Special Issue combines chemical, physical, and meteorological measurements performed in field campaigns as well as conceptual and laboratory work. Useful examples for the development of platforms and autonomous systems for environmental studies are provided, which demonstrate how careful the operation of sensors aboard UAS must be to gather information for remote sensing in the atmosphere. The work serves as a key collection of articles to introduce …


Fluvial Sediment Organic Matter Degradation Identified With Elemental And Isotopic Fate During Laboratory Incubation, Brenden Riddle Jan 2020

Fluvial Sediment Organic Matter Degradation Identified With Elemental And Isotopic Fate During Laboratory Incubation, Brenden Riddle

Theses and Dissertations--Civil Engineering

Fluvial sediment is well recognized as a critical factor in both carbon and nutrient budgets within stream systems. However, we find very few studies of reactivity and isotope enrichment for stream water from agricultural and urban streams and the class of substrate known as fluvial sediment organic matter. This study investigated the hypothesis that fluvial sediment is subject to degradation even though many previous studies have considered this class of substrate generally inert. Therefore we qualify that elemental and isotopic signatures of fluvial sediment organic matter should be considered potentially non-conservative when used in tracer studies. Methods applied to this …


Probabilistic Approach To Water, Sediment, And Nutrient Connectivity For Advancing Watershed Modelling, David Tyler Mahoney Jan 2020

Probabilistic Approach To Water, Sediment, And Nutrient Connectivity For Advancing Watershed Modelling, David Tyler Mahoney

Theses and Dissertations--Civil Engineering

The goal of this dissertation is to represent the spatial and temporal domains of water, sediment, and nutrient flux and pathways within fluvial and watershed settings. To complete this goal, we integrate connectivity theory into watershed model structures to simulate water, sediment, and nutrient movement at the fundamental unit they occur. Fluvial-based sediment and nutrient flux is an important driver of global sediment and nutrient budgets, and the quantification of which serves as an ongoing challenge to limnologists, engineers, and watershed managers. Watershed models have been richly developed over the past century, but are currently restrained by problems related to …


A Modeling Approach To Understanding Glyphosate Transport In The Belize River Watershed, Barbara Anmei Astmann Jan 2020

A Modeling Approach To Understanding Glyphosate Transport In The Belize River Watershed, Barbara Anmei Astmann

Theses and Dissertations--Civil Engineering

Glyphosate is the most widely used herbicide worldwide and is often transported from application areas to surface water when solubilized in runoff or sorbed to eroded sediment. There is evidence that suggests both glyphosate and its main metabolite aminomethylphosphonic acid (AMPA) may pose a risk to human health, as well as cause adverse effects in the environment. However, consistent monitoring data is still limited, especially in developing countries. Belize is a developing nation with agriculture being a major sector of its economy and is heavily reliant on glyphosate. The widespread use of glyphosate in Belize may be resulting in glyphosate …


Variance Decomposition Of Forecasted Water Budget And Sediment Processes Under Changing Climate In Fluvial And Fluviokarst Systems, Nabil Al Aamery Jan 2020

Variance Decomposition Of Forecasted Water Budget And Sediment Processes Under Changing Climate In Fluvial And Fluviokarst Systems, Nabil Al Aamery

Theses and Dissertations--Civil Engineering

Variance decomposition is the partitioning of different factors affecting the variance structure of a response variable. The present research focuses on future streamflow and sediment transport processes projections as the response variables. The authors propose using numerous climate factors and hydrological modeling factors that can cause any response variable to vary from historic to future conditions in any given watershed system. The climate modeling factors include global climate model, downscaling method, emission scenario, project phase, bias correction. The hydrological modeling factor includes hydrological model parametrization, and meteorological variable inclusion in the analysis. This research uses a wide spectrum of data, …


Investigation Into The Presence, Persistence, And Fate Of S. Aureus, And Its Mobile Genetic Elements, In Wastewater And The Surrounding Environment, Atena Amirsoleimani Jan 2020

Investigation Into The Presence, Persistence, And Fate Of S. Aureus, And Its Mobile Genetic Elements, In Wastewater And The Surrounding Environment, Atena Amirsoleimani

Theses and Dissertations--Civil Engineering

Currently, the world is engaged in a battle against very small parts of our environment that develop and share genes for resistance to multiple environmental conditions. Pathogenic infections caused by antibiotic-resistant bacteria have been impacting animal and human health and life. Increasing incidences of methicillin- resistant Staphylococcus aureus (MRSA) infections transmitted through the environment are rising faster than the discovery of new antibiotics. Multi-drug resistant S. aureus infections in healthy individuals without prior hospitalization have been increasing all around the world.

Many people carry S. aureus in their nose and on their skin, common niches for the bacteria to co-grow …


Soil Bulk Density Effects On Runoff Estimation, Colton Pugh Jan 2020

Soil Bulk Density Effects On Runoff Estimation, Colton Pugh

Theses and Dissertations--Biosystems and Agricultural Engineering

Urbanization has long been a major factor in the hydrology of surrounding areas. Engineers are commonly tasked with mitigating the extra runoff that urbanization brings with it. The NRCS Curve Number (CN) method is a commonly-used approach to predicting the amount of runoff that will be experienced from a given area. However, this method is known to be highly simplified in model of the processes involved. This study focused on determining the relationships between soil bulk density, simulated rainfall events, hydrologic soil group (HSG) and runoff estimation (specifically via the NRCS CN method). It was determined that soil bulk density …


Quantifying Nitrogen Fate In Karst Agroecosystem Streams Of Central Kentucky: Development And Application Of Numerical Modeling And Insight From High-Resolution Sensors, Nolan Lewis Bunnell Jan 2020

Quantifying Nitrogen Fate In Karst Agroecosystem Streams Of Central Kentucky: Development And Application Of Numerical Modeling And Insight From High-Resolution Sensors, Nolan Lewis Bunnell

Theses and Dissertations--Biosystems and Agricultural Engineering

In-stream fate of nutrients in karst agroecosystems remains poorly understood, despite the known impact of karst on water resources at local to global scales. In the Inner-Bluegrass region of central Kentucky, heterogeneity of karst maturity, flow pathways, and nutrient sources adds to the complexity of quantifying nutrient dynamics, thus requiring novel monitoring and modeling approaches. The significance of these streams is recognized given spring/surface water confluences have been identified as hotspots for biogeochemical transformations. In slow-moving streams high in dissolved inorganic nutrients (particularly dissolved inorganic nitrogen (DIN) and dissolved reactive phosphorus (DRP)), benthic and floating aquatic macrophytes are recognized to …


Using A Balloon-Launched Unmanned Glider To Validate Real-Time Wrf Modeling, Travis J. Schuyler, S. M. Iman Gohari, Gary Pundsack, Donald Berchoff, Marcelo I. Guzman Apr 2019

Using A Balloon-Launched Unmanned Glider To Validate Real-Time Wrf Modeling, Travis J. Schuyler, S. M. Iman Gohari, Gary Pundsack, Donald Berchoff, Marcelo I. Guzman

Chemistry Faculty Publications

The use of small unmanned aerial systems (sUAS) for meteorological measurements has expanded significantly in recent years. SUAS are efficient platforms for collecting data with high resolution in both space and time, providing opportunities for enhanced atmospheric sampling. Furthermore, advances in mesoscale weather research and forecasting (WRF) modeling and graphical processing unit (GPU) computing have enabled high resolution weather modeling. In this manuscript, a balloon-launched unmanned glider, complete with a suite of sensors to measure atmospheric temperature, pressure, and relative humidity, is deployed for validation of real-time weather models. This work demonstrates the usefulness of sUAS for validating and improving …


The Effects Of Reactant Concentration And Air Flow Rate In The Consumption Of Dissolved O2 During The Photochemistry Of Aqueous Pyruvic Acid, Alexis J. Eugene, Marcelo I. Guzman Mar 2019

The Effects Of Reactant Concentration And Air Flow Rate In The Consumption Of Dissolved O2 During The Photochemistry Of Aqueous Pyruvic Acid, Alexis J. Eugene, Marcelo I. Guzman

Chemistry Faculty Publications

The sunlight photochemistry of the organic chromophore pyruvic acid (PA) in water generates ketyl and acetyl radicals that contribute to the production and processing of atmospheric aerosols. The photochemical mechanism is highly sensitive to dissolved oxygen content, [O2(aq)], among other environmental conditions. Thus, herein we investigate the photolysis (λ ≥ 305 nm) of 10–200 mM PA at pH 1.0 in water covering the relevant range 0 ≤ [O2(aq)] ≤ 1.3 mM. The rapid consumption of dissolved oxygen by the intermediate photolytic radicals is monitored in real time with a dissolved oxygen electrode. …


Separation Of Unburned Carbon From Coal Conversion Ash: Development And Assessment Of A Dry Method, Charlotte J. Badenhorst, Nicola J. Wagner, Bruno R.V. Valentim, Karel S. Viljoen, Ana C. Santos, Alexandra Guedes Jan 2019

Separation Of Unburned Carbon From Coal Conversion Ash: Development And Assessment Of A Dry Method, Charlotte J. Badenhorst, Nicola J. Wagner, Bruno R.V. Valentim, Karel S. Viljoen, Ana C. Santos, Alexandra Guedes

Coal Combustion and Gasification Products Journal Archive

Unburned carbon found in coal conversion ash has the potential to be used in a variety of value-added applications. However, it is first necessary to separate the unburned carbon from the rest of the ash phases. This poses challenges due to the relatively low starting carbon-in-ash values (0.4 to 7.8 wt% reported for South African sources), and the high carbon grades (ideally ∼90 wt% carbon) and recoveries that need to be achieved. In this study a dry method for the separation of unburned carbon from coal ash was developed and assessed using fly, bottom, and gasification ash samples obtained from …


Use Of Ponded And Fresh Ashes From China For The Production Of Portland/Calcium Sulfoaluminate Clinkers, Tristana Y. Duvallet, Robert B. Jewell, Anne E. Oberlink, Thomas L. Robl, David Harris Jan 2019

Use Of Ponded And Fresh Ashes From China For The Production Of Portland/Calcium Sulfoaluminate Clinkers, Tristana Y. Duvallet, Robert B. Jewell, Anne E. Oberlink, Thomas L. Robl, David Harris

Coal Combustion and Gasification Products Journal Archive

This article summarizes the use of two fly ashes in the synthesis of Portland/calcium sulfoaluminate (OPC/CSA or A/CSA) clinkers. They are from the Shentou second power plant located in the Shanxi Province and from the Zhungeer power plant located in Inner Mongolia, China. The Zhungeer ash was collected dry, and the Shentou ash is from a pond. Their chemical compositions differ highly, especially the SiO2 and Al2O3 contents. The high contents of silica and alumina make both ashes candidates as a partial or total substitute for bauxite, an expensive source of alumina, in the production of OPC/CSA clinkers. These particular …


Investigation Of Atmospheric Effects On Vapor Intrusion Processes Using Modelling Approaches, Elham Shirazi Jan 2019

Investigation Of Atmospheric Effects On Vapor Intrusion Processes Using Modelling Approaches, Elham Shirazi

Theses and Dissertations--Civil Engineering

Most people in the United States (US) spend considerable amount of time indoors—about 90% of their time as compared to outdoors, which makes the US population vulnerable to adverse health effects of indoor air contaminants. Volatile organic compound (VOC) concentrations are well-known to be higher in indoor air than outdoor air. One source of VOC concentrations in indoor air that has gained considerable attention in public health and environmental regulatory communities is vapor intrusion. Vapor intrusion is the process by which subsurface vapors enter indoor spaces from contaminated soil and groundwater. It has been documented to cause indoor air contamination …


Conceptual Groundwater Remedial Alternatives At Coal Combustion Residuals Sites†, Herwig Goldemund, Jeffrey M. Ahrens Jan 2019

Conceptual Groundwater Remedial Alternatives At Coal Combustion Residuals Sites†, Herwig Goldemund, Jeffrey M. Ahrens

Coal Combustion and Gasification Products Journal Archive

Groundwater below many basins that have been used to store coal combustion residuals (CCRs) may have concentrations of certain inorganic constituents in excess of applicable regulatory standards. Given that many inorganic CCR constituents are also naturally occurring in the aquifer matrix, their detection may not always be indicative of a release from the CCR unit. Inorganics may be present at elevated levels in groundwater due to natural or background conditions, or due to changes to the aquifer geochemistry resulting from the presence of the CCR basin, which then mobilizes these naturally occurring constituents beneath the CCR unit. Care must be …


Fly Ash Composites, A Step Toward Pond Ash Composites, Kunigal N. Shivakumar, Wade H. Brown, Kazi A. Imran Jan 2019

Fly Ash Composites, A Step Toward Pond Ash Composites, Kunigal N. Shivakumar, Wade H. Brown, Kazi A. Imran

Coal Combustion and Gasification Products Journal Archive

The study demonstrated that ash composites made from polyurethane and fly ash are able to reduce leaching of coal ash inorganics to less than one-third of the U.S. Environmental Protection Agency’s maximum containment limit even after being exposed to an accelerated water circulation system for 14 months. Even if these ash blocks are broken, the composite is safe. The concept of encapsulation of fly ash into ash composite by using a polar polymer to bind the fine inorganic particles, as nature has done in the original unburned coal, makes the ash composite safe. The ash composites have compression and f …


In Situ Characterization Of Mixture Of Fly Ash And Fluidized Gas Desulfurization By-Product At Tennessee Valley Authority’S Gallatin Ash Stacking Facility†, David J. White, Pavana Vennapusa, Brendan Fitzpatrick, Jason F. Hill, Nicholas Mcclung Jan 2019

In Situ Characterization Of Mixture Of Fly Ash And Fluidized Gas Desulfurization By-Product At Tennessee Valley Authority’S Gallatin Ash Stacking Facility†, David J. White, Pavana Vennapusa, Brendan Fitzpatrick, Jason F. Hill, Nicholas Mcclung

Coal Combustion and Gasification Products Journal Archive

This article presents the results of field and laboratory testing performed on a new coal combustion product (CCP) derived from a mixture of fly ash and dry fluidized gas desulfurization by-product at the Tennessee Valley Authority’s Gallatin Fossil Plant in Gallatin, TN. Field testing included geospatial mapping using a vibratory smooth drum roller instrumented with a validated intelligent compaction (VIC) system and by field testing to characterize elastic modulus, shallow shear wave velocity, moisture content, dry density, and shear strength properties. Field testing was performed in areas where the CCP had been placed several days before testing and in areas …


Managing Springs Emanating From Coal Combustion Residual Disposal Impoundments, Mark L. Orzechowski, Daniel M. Tolmer Jan 2019

Managing Springs Emanating From Coal Combustion Residual Disposal Impoundments, Mark L. Orzechowski, Daniel M. Tolmer

Coal Combustion and Gasification Products Journal Archive

Affected springs emanating from coal combustion residual (CCR) disposal impoundments where “wet disposal” methods were employed is a typical issue that frequently needs to be addressed during operation and management of these facilities. Identifying potential effects on a spring is typically accomplished through regularly scheduled field reconnaissance and laboratory analyses. Analytical testing is performed to characterize the chemical constituents present in the spring water. The management approach employed for specific springs is developed on the basis of several factors, including chemical composition and flow rate of the spring water, regulatory requirements and discharge standards, available treatment technologies, facility operations, site …


Shear Strength Of Coal Combustion Product By Vane Shear, Wesley J. Herweynen, Christopher A. Bareither, Joseph Scalia Jan 2019

Shear Strength Of Coal Combustion Product By Vane Shear, Wesley J. Herweynen, Christopher A. Bareither, Joseph Scalia

Coal Combustion and Gasification Products Journal Archive

The objective of this study was to evaluate the shear strength of a coal combustion product (CCP) by using the vane shear test. A series of small-scale vane shear (SS-VS; diameter = 12.7 mm and height = 25.4 mm) and large-scale vane shear (LS-VS; diameter = 25 mm and height = 50 mm) laboratory tests were conducted. Undrained and drained strength envelopes were determined using consolidated undrained triaxial compression tests, and drained strength was checked via consolidated drained direct shear. In addition, effects of (1) rate of vane rotation, (2) time delay between vane insertion and beginning rotation, and (3) …


Mineralogy And Geochemistry Of Feed Coals And Combustion Residues From Tunçbilek And Seyitömer Coal-Fired Power Plants In Western Turkey, Ali Ihsan Karayigit, Ozlem Yigitler, Seda Iserli, Xavier Querol, Maria Mastalerz, Riza Gorkem Oskay, James C. Hower Jan 2019

Mineralogy And Geochemistry Of Feed Coals And Combustion Residues From Tunçbilek And Seyitömer Coal-Fired Power Plants In Western Turkey, Ali Ihsan Karayigit, Ozlem Yigitler, Seda Iserli, Xavier Querol, Maria Mastalerz, Riza Gorkem Oskay, James C. Hower

Coal Combustion and Gasification Products Journal Archive

This study focuses on the enrichment of elements in feed coal (FC) and combustion residues, namely, fly ash (FA) and bottom ash (BA) samples, picked up from the Tunçbilek and Seyitömer coal-fired power plants in western Turkey. The FCs in both plants have generally similar mineralogical compositions, although siderite and dolomite are more prominent in Tunçbilek and feldspar and pyrite are more abundant in Seyitömer. Minerals in the FA from both power plants are mainly quartz, hematite, magnetite, anhydrite, and mullite. Along with quartz, the Fe-oxides are dominant phases in the BA samples. Accessory minerals in the FCs, FAs, and …


Phaselous Vulgaris Growth Under The Influence Of Manufactured Coal Ash Aggregates, Sangchul Hwang, Imiraily Hernandez, Isomar Latorre, Sahid Rosado Jan 2019

Phaselous Vulgaris Growth Under The Influence Of Manufactured Coal Ash Aggregates, Sangchul Hwang, Imiraily Hernandez, Isomar Latorre, Sahid Rosado

Coal Combustion and Gasification Products Journal Archive

Manufactured coal ash aggregates (MAs) are a 2:1 (w/w) solidified composite of fly and bottom ash. The current study assessed the feasibility of beneficial utilization of MAs as a subsoil substitute for open-pit restoration to phyto-viable land. A series of indoor and outdoor experiments examined Phaselous vulgaris growth under the influence of MAs in the soil environment. With the MAs layer below the topsoil, P. vulgaris showed enhanced growth with respect to shoot height, leaf number, and leaf chlorophyll intensity. Similar growth enhancement was observed when the MAs were mixed with topsoil or applied as a micronutrient source over the …


Using The Conceptual Site Model To Efficiently And Effectively Implement Groundwater Monitoring And Corrective Action At Coal Combustion Residual Sites†, Carla Landrum, Jim Feild, Tim Glover, Alison Dunn Jan 2019

Using The Conceptual Site Model To Efficiently And Effectively Implement Groundwater Monitoring And Corrective Action At Coal Combustion Residual Sites†, Carla Landrum, Jim Feild, Tim Glover, Alison Dunn

Coal Combustion and Gasification Products Journal Archive

On 19 October 2015, the Disposal of Coal Combustion Residuals (CCRs) for Electric Utilities final rule (CCR Rule), issued by the U.S. Environmental Protection Agency (US EPA) under Subtitle D of the Recovery and Conservation Act (RCRA), became effective. The Groundwater Monitoring and Corrective Action subsections of the CCR Rule (40 CFR §§ 257.90–257.98) set out strict requirements for groundwater monitoring at the detection and assessment levels, followed by (if necessary) groundwater characterization in support of corrective measures assessment. Since the federal CCR Rule was implemented, the US EPA has proposed and finalized some amendments, and some states have proposed …


The Role Of Ash Mineralogy On Breakthrough Pressure And Contact Angle: A Statistical Evaluation, Jenberu L. Feyyisa, John L. Daniels Jan 2019

The Role Of Ash Mineralogy On Breakthrough Pressure And Contact Angle: A Statistical Evaluation, Jenberu L. Feyyisa, John L. Daniels

Coal Combustion and Gasification Products Journal Archive

One method to minimize contaminant leaching from coal fly ash (CFA) involves modifying its surface to become water repellent. Five types of CFA, CFA-1, CFA-2, CFA-3, CFA-5, and CFA-6, were modified by three organosilane (OS) products at different mix ratios. Multiple breakthrough pressure (BP) experiments were conducted for different samples at different mix ratios to identify the performance of the modified surface to resist a positive water entry pressure. The contribution of oxides and minerals in CFA to form a water-repellent surface were analyzed without considering OS effects. Results showed that semi-log–transformed regression models can effectively establish the relationship between …


South Africa’S Power Producer’S Revised Coal Ash Strategy And Implementation Progress, Kelley Reynolds-Clausen, Nico Singh Jan 2019

South Africa’S Power Producer’S Revised Coal Ash Strategy And Implementation Progress, Kelley Reynolds-Clausen, Nico Singh

Coal Combustion and Gasification Products Journal Archive

The South African electricity public utility Eskom has embarked on a process to increase utilisation of the ash produced through the electricity generation process at its coal-fired power stations. In the 2014–2015 financial year, 119.2 million tons of coal was consumed, producing 34.4 million tons (28.9%) of ash. About 7% of the Eskom ash is sold from 6 of the 13 coal-fired power stations. Many stations are currently running out of ash storage space, and expansion of the ash disposal facilities is required, which could affect security of supply because of limited ashing areas. Additionally, legislative requirements lead to extra …


Use Of Functionalized Bimetallic Membranes For Treatment Of Contaminated Groundwater At A Hazardous Waste Site In Kentucky, Lucy C. Pacholik Jan 2019

Use Of Functionalized Bimetallic Membranes For Treatment Of Contaminated Groundwater At A Hazardous Waste Site In Kentucky, Lucy C. Pacholik

Theses and Dissertations--Civil Engineering

Providing access to clean drinking water will continue to be a challenge for civil engineers for generations to come. Since many communities around the world rely on groundwater as a source of drinking water, remediation technologies must be implemented at sites where groundwater contamination exists due to years of mismanagement of hazardous waste. Using nanosized zero-valent metals such as iron and zinc embedded within and on the surface of functionalized (PAA) membrane filters has shown to be an effective dechlorination technique for contaminated groundwater. Introducing a noble metal such as Pd or Ni increases reaction rates by acting a catalyst …


Pathway Connectivity In An Epigenetic Fluviokarst System: Insight From A Numerical Modelling Study In Kentucky Usa, Ethan Adams Jan 2019

Pathway Connectivity In An Epigenetic Fluviokarst System: Insight From A Numerical Modelling Study In Kentucky Usa, Ethan Adams

Theses and Dissertations--Civil Engineering

Fluviokarst landscapes are dominated by both fluvial and karst features. Interpreting hydrologic pathways of fluviokarst can be confounded by the unknown connectivity of the various flow regimes. A combined discrete-continuum (CDC) hybrid numeric model for simulating the surface and subsurface hydrology and hydraulics in fluviokarst basins was formulated to investigate fluviokarst pathways. This model was applied to the Cane Run Royal Springs basin in Kentucky USA. A priori constraints on parameterization were avoided via multi-stage optimization utilizing Sobol sequencing and high performance computing. Modelling results provide evidence of hydrologic pathways dominated by fracture flow, epikarst transfer and runoff. Fractures in …


Decomposing A Watershed’S Nitrate Signal Using Spatial Sampling And Continuous Sensor Data, Evan Clare Jan 2019

Decomposing A Watershed’S Nitrate Signal Using Spatial Sampling And Continuous Sensor Data, Evan Clare

Theses and Dissertations--Civil Engineering

Watershed features, physiographic setting, geology, climate, and hydrologic processes combine to produce a time-variant nutrient concentration signal at the watershed outlet. Anthropogenic influences, such as increased agricultural pressures and urbanization, have increased overall nutrient loadings delivered to the fluvial network. The impact of such increased nutrient loadings on Kentucky’s drinking water remains a potential threat to the region.

By coupling spatial sampling of nitrate concentrations in surface water with contemporary nutrient and water quality sensor technology, a decomposition of the Upper South Elkhorn watershed’s nitrate signal and an estimation of source timing and loading in the watershed was completed. The …


Biological Selenium Control: Selenium Reduction By Shigella Fergusonii Strain Tb42616 And Pantoea Vagans Strain Ewb32213-2 In Bioreactor Systems, Yuxia Ji Jan 2019

Biological Selenium Control: Selenium Reduction By Shigella Fergusonii Strain Tb42616 And Pantoea Vagans Strain Ewb32213-2 In Bioreactor Systems, Yuxia Ji

Theses and Dissertations--Civil Engineering

Se(VI) and Se(IV), as the two major species of selenium in water, are toxic to aquatic lives and may cause adverse health effects to humans at high levels. Biological reduction of Se(VI) is a two-stage process first from Se(VI) to Se(IV) and then from Se(IV) to Se(0) with potential accumulation of the more toxic Se(IV) due to the slower rate of the second stage.

Selenium reduction was first evaluated with batch cultures of Shigella fergusonii strain TB42616 (TB) and Pantoea vagans strain EWB32213-2 (EWB) isolated in our laboratory from sludge and coal slurry sediment samples, respectively. In order to facilitate …


Synthesis, Characterization And Applications Of Reduced Graphene Oxide And Composite Membranes For Selective Separations And Removal Of Organic Contaminants, Ashish Aher Jan 2019

Synthesis, Characterization And Applications Of Reduced Graphene Oxide And Composite Membranes For Selective Separations And Removal Of Organic Contaminants, Ashish Aher

Theses and Dissertations--Chemical and Materials Engineering

Among the next generation materials being investigated for membrane development, partially reduced Graphene Oxide (rGO) has received increasing attention from the membrane community. rGO-based nanofiltration membranes have shown promising results in applications such as partial desalination, organic contaminant removal, gas-phase separations, and separations from solvent media. rGO offers a unique platform compared to common polymeric membranes since it can be used for separation applications in both aqueous and organic solvent media. An rGO-based platform could also be utilized to synthesize reactive membranes, giving rGO membranes the additional capability of reactively removing organic contaminants. This research focuses on the synthesis of …