Environmental Engineering Commons^™

Cross Photoreaction Of Glyoxylic And Pyruvic Acids In Model Aqueous Aerosol, Sha-Sha Xia, Alexis J. Eugene, Marcelo I. Guzman

Chemistry Faculty Publications

Aerosols of variable composition, size, and shape are associated with public health concerns as well as with light-particle interactions that play a role in the energy balance of the atmosphere. Photochemical reactions of 2-oxocarboxylic acids in the aqueous phase are now known to contribute to the total secondary organic aerosol (SOA) budget. This work explores the cross reaction of glyoxylic acid (GA) and pyruvic acid (PA) in water, the two most abundant 2-oxocarboxylic acids in the atmosphere, under solar irradiation and dark thermal aging steps. During irradiation, PA and GA are excited and initiate proton-coupled electron transfer or hydrogen abstraction …

The Role Of Dense Slurry In Achieving Zero Liquid Discharge, D.M. Timmons, Istvan Kovacsics

Coal Combustion and Gasification Products Journal Archive

The Coal Combustion Residual (CCR) and Effluent Limitations Guidelines (ELGs) rules pose significant technical and economic challenges for ash management and for treatment and discharge of flue gas desulfurization (FGD) wastewater at coal-fired power plants. Beneficial use is always a priority for ash, but only about half is being reused on a national basis, and the rest is destined for disposal. The U.S. Environmental Protection Agency identified biological treatment as the baseline treatment technology for FGD wastewater in the ELGs. However, it is becoming evident that bioreactors exhibit high capital and operating costs, occupy significant space, and are sensitive to …

Investigation Of Volatile Organic Compounds (Vocs) Detected At Vapor Intrusion Sites, Mohammadyousef Roghani

Theses and Dissertations--Civil Engineering

This dissertation investigates unexplained vapor intrusion field data sets that have been observed at hazardous waste sites, including: 1) non-linear soil gas concentration trends between the VOC source (i.e. contaminated groundwater plume) and the ground surface; and, 2) alternative pathways that serve as entry points for vapors to infiltrate into buildings and serve to increase VOC exposure risks as compared to the classic vapor intrusion model, which primarily considered foundation cracks as the route for vapor entry. The overall hypothesis of this research is that theoretical knowledge of fate and transport processes can be systematically applied to vapor intrusion field …

Compressibility Of Fly Ash Under Ko Loading: Strain Rate Effects In Constant Rate Of Strain Testing, Jaime A. Mercado, Luis G. Arboleda-Monsalve, Tarunjit S. Butalia, Pedro J. Amaya

Coal Combustion and Gasification Products Journal Archive

Coal combustion processes produce large volumes of fly ash. The compressibility of fly ash was studied using moist tamping and drypluviation methods to achieve different void ratios before subjecting the material to compressive oedometric Ko loading (i.e., zero lateral deformation throughout the test). The class F fly ash used in this research was produced at a Midwest U.S. power plant. The material was initially characterized with hydrometer and specific gravity tests, and maximum and minimum realizable void ratios were determined. The compressibility characteristics of the fly ash material were studied at four strain rates, 1%/h, 10%/h, 40%/h, and 100%/h, and …

Influence Of Flow Rate On Leachability, John L. Daniels, Gautham P. Das

Coal Combustion and Gasification Products Journal Archive

The leaching potential of coal fly ash is often approximated with laboratory-based methods that expose columns of compacted material to synthetic precipitation. While this procedure can simulate aspects of the field condition, it remains difficult to replicate site-specific thermodynamic and kinetic constraints on geochemical processes. This article explores one aspect that contributes to the field/laboratory disparity, namely, the influence of flow rate and intermittency. Seven column-based leaching experiments were conducted with the same ash but with different flow rates and intermittency (i.e., infiltration pulsing), and results were evaluated in terms of aqueous sodium, calcium, and chromium concentrations in the effluent. …

Kinetic And Thermodynamic Parameters For The Adsorption Of Methylene Blue Using Fly Ash Under Batch, Column, And Heap Leaching Configurations, J.H. Potgieter, S. Pearson, C. Pardesi

Coal Combustion and Gasification Products Journal Archive

In this article, the use of fly ash, a low-cost adsorbent, for the removal of a toxic cationic dye, methylene blue (MB), from aqueous solution has been investigated. Fly ash is a waste by-product generated from coal combustion. Contrary to many other reported investigations, the fly ash was not treated prior to the experiments for this investigation. The study was done in order to ascertain the viability of using the waste material to remove cationic dyes from wastewater. While MB adsorption has been described often in batch studies, batch, column, and heap leaching studies were carried out under the same …

Universal And Excavatable Controlled Low Strength Material Using High Loss On Ignition Fly Ash And Limestone Screenings†, James T. Locum, L.K. Crouch, Daniel Badoe

Coal Combustion and Gasification Products Journal Archive

Limestone screenings and high loss on ignition (LOI) fly ash are by-products that are stockpiling because of their unintentional production and the negative effects when utilized in portland cement concretes. The research objective was to investigate whether these by-products could produce controlled low strength materials (CLSMs) meeting the three types of Tennessee Department of Transportation (TDOT) 204.06 flowable fill specifications. TDOT defines these CLSMs as the following: general use, excavatable, and early strength. Each type is required to have an inverted slump flow of not less than 15 inches (38.1 cm) while meeting ASTM International D6024 at 24 hours. Because …

Assessment Of Watershed Nutrient Loads And Effectiveness Of Best Management Practices, Saeid Nazari

Theses and Dissertations--Civil Engineering

Several methods have been developed for use in estimating the water quality loads associated with urban and agricultural landuses and practices. These include the use of sophisticated computer models, typically based on using pollutant loading and runoff functions, regression equations, load export coefficients (LECs), and event mean concentrations (EMCs). This research has examined the feasibility of using a simple EMC approach with the Kentucky Nutrient Model (KYNM). The thesis includes an extensive literature review of EMCs and a synthesis of recommended values for a range of typical urban and agricultural landuses. The thesis also includes an extensive literature review of …

Preferential Pathways For Vapor Intrusion: Site Screening And Field Sampling Of Sewers To Assess Inhalation Exposure Risks, Evan James Willett

Theses and Dissertations--Civil Engineering

Hazardous waste sites and aging wastewater infrastructure are common in the United States. There are hundreds of thousands of contaminated sites and more than a million miles of sewer pipes. Populations living close to hazardous waste sites often suffer from increased risk of adverse health effects due to exposure to contaminated environmental media. Vapor intrusion is one process by which nearby populations can be exposed to volatile organic compounds (VOCs). Aging wastewater infrastructure is important for vapor intrusion site assessments because sewer pipes can serve as preferential vapor transport pathways. Near contaminated sites, pipe deterioration allows migration of contaminants into …

Numerical Modeling And Isotope Tracers To Investigate Karst Biogeochemistry And Transport Processes, Admin Husic

Theses and Dissertations--Civil Engineering

This dissertation investigated the physical and biogeochemical processes affecting the source, fate, and transport of sediment, carbon, and nitrogen within a highly-coupled fluviokarst system. Elemental and isotopic datasets were collected at surface and subsurface locations for both dissolved and particulate contaminant phases, new methodology regarding data collection was presented to the karst research community, an in-cave sediment transport model coupling physical transport with elemental and isotopic mass balances of carbon and nitrogen was formulated, pathway and process control on nitrate leaching from agricultural karst watersheds was assessed, and nitrate mobilization and fractionation were modeled using high frequency storm sampling and …

Investigation Of The Effectiveness Of An Integrated Flooded-Bed Dust Scrubber On A Longwall Shearer Through Laboratory Testing And Cfd Simulation, Sampurna N. Arya

Theses and Dissertations--Mining Engineering

Dust generation at an underground coal mine working face continues to be a health and safety issue. Prolonged exposure to high concentrations of airborne respirable dust can cause a debilitating and often fatal respiratory disease called Black Lung. In addition, the deposition of float dust in mine return airways poses a serious safety hazard if not sufficiently diluted with inert rock dust. A localized methane explosion can transition into a self-propagating dust explosion. Since dust is a byproduct of various mining activities, such as cutting and loading, crushing, and transportation, the dust-related issues cannot be totally eliminated. However, the adverse …

Pressure-Driven Stabilization Of Capacitive Deionization, Landon S. Caudill

Theses and Dissertations--Mechanical and Aerospace Engineering

The effects of system pressure on the performance stability of flow-through capacitive deionization (CDI) cells was investigated. Initial data showed that the highly porous carbon electrodes possessed air/oxygen in the micropores, and the increased system pressure boosts the gases solubility in saline solution and carries them out of the cell in the effluent. Upon applying a potential difference to the electrodes, capacitive-based ion adsorption occurs in competition with faradaic reactions that consume oxygen. Through the addition of backpressure, the rate of degradation decreases, allowing the cell to maintain its salt adsorption capacity (SAC) longer. The removal of oxygen from the …

Unmanned Aerial Systems For Monitoring Trace Tropospheric Gases, Travis J. Schuyler, Marcelo I. Guzman

Chemistry Faculty Publications

The emission of greenhouse gases (GHGs) has changed the composition of the atmosphere during the Anthropocene. Accurately documenting the sources and magnitude of GHGs emission is an important undertaking for discriminating the contributions of different processes to radiative forcing. Currently there is no mobile platform that is able to quantify trace gases at altitudes(UASs) can be deployed on-site in minutes and can support the payloads necessary to quantify trace gases. Therefore, current efforts combine the use of UASs available on the civilian market with inexpensively designed analytical systems for monitoring atmospheric trace gases. In this context, this perspective introduces the …

Oxidation Of Substituted Catechols At The Air-Water Interface: Production Of Carboxylic Acids, Quinones, And Polyphenols, Elizabeth A. Pillar, Marcelo I. Guzman

Chemistry Faculty Publications

Anthropogenic activities contribute benzene, toluene, and anisole to the environment, which in the atmosphere are converted into the respective phenols, cresols, and methoxyphenols by fast gas-phase reaction with hydroxyl radicals (HO(•)). Further processing of the latter species by HO(•) decreases their vapor pressure as a second hydroxyl group is incorporated to accelerate their oxidative aging at interfaces and in aqueous particles. This work shows how catechol, pyrogallol, 3-methylcatechol, 4-methylcatechol, and 3-methoxycatechol (all proxies for oxygenated aromatics derived from benzene, toluene, and anisole) react at the air-water interface with increasing O3(g) during τc ≈ 1 μs contact time and contrasts their …

Nitrate Radicals And Biogenic Volatile Organic Compounds: Oxidation, Mechanisms And Organic Aerosol, Nga Lee Ng, Steven S. Brown, Alexander T. Archibald, Elliot Atlas, Ronald C. Cohen, John N. Crowley, Douglas A. Day, Neil M. Donahue, Juliane L. Fry, Hendrik Fuchs, Robert J. Griffin, Marcelo I. Guzman, Hartmut Hermann, Alma Hodzic, Yoshiteru Iinuma, José L. Jimenez, Astrid Kiendler-Scharr, Ben H. Lee, Deborah J. Luecken, Jingqiu Mao, Robert Mclaren, Anke Mutzel, Hans D. Osthoff, Bin Ouyang, Benedicte Picquet-Varrault, Ulrich Platt, Havala O. T. Pye, Yinon Rudich, Rebecca H. Schwantes, Manabu Shiraiwa, Jochen Stutz, Joel A. Thornton, Andreas Tilgner, Brent J. Williams, Rahul A. Zaveri

Chemistry Faculty Publications

Oxidation of biogenic volatile organic compounds (BVOC) by the nitrate radical (NO₃) represents one of the important interactions between anthropogenic emissions related to combustion and natural emissions from the biosphere. This interaction has been recognized for more than 3 decades, during which time a large body of research has emerged from laboratory, field, and modeling studies. NO₃-BVOC reactions influence air quality, climate and visibility through regional and global budgets for reactive nitrogen (particularly organic nitrates), ozone, and organic aerosol. Despite its long history of research and the significance of this topic in atmospheric chemistry, a number …

Fate And Impacts Of Priority Pollutant Metals In Coal Fly Ash–Soil–Switchgrass Plant Mesocosms, Olushola M. Awoyemi, E. Kudjo Dzantor

Coal Combustion and Gasification Products Journal Archive

Coal fly ash (CFA) is a coal combustion by-product containing heavy metals (HMs) that can enter and accumulate in environmental matrices. The current study assessed the fate and effects of HMs contained in CFA on Armour silt loam (ASL) soil, switchgrass plant, and leachate. Soil impact indices compared levels of HMs in the CFA-soil admixtures to control soil (without CFA). These indices include contamination factor (*C*~f~), modified degree of contamination (m*C*~d~), and pollution load index (PLI). The ratio of the levels of HMs in switchgrass root and shoot tissues to their levels in the CFA-soil admixtures were used to determine …

Sediment Transport Modelling Using Dynamic (Dis)Connectivity Prediction For A Bedrock Controlled Catchment, David Tyler Mahoney

Theses and Dissertations--Civil Engineering

The (dis)connectivity of sediment, defined as the detachment and transport of sediment from source to sink between geomorphic zones, is a major control on sediment transport rates but has seldom taken precedence in sediment transport models that focus on assessment of sediment impacts on water supply. A watershed-scale sediment transport model was formulated that incorporates sediment (dis)connectivity knowledge and subroutines and predicts sediment flux through coupling with an excessive shear stress erosion equation. The intersecting probabilities of sediment supply, detachment, transport, and (dis)connectivity produce the probability of sediment connectivity for a watershed or region of a watershed. The integration of …

Geopolymerization Of Coal Ash To Produce Cementless Binders, Hamid Akbari, Robert Mensah-Biney, Jonathan Simms

Coal Combustion and Gasification Products Journal Archive

The main objective of this study was to evaluate geopolymer concrete made from coal combustion by-products, disposed of in landfills, as a potential substitute for the ordinary Portland cement (OPC), which is responsible for 5-8% of the total CO2 emissions in the world. In this study, a coal fly ash sample from the Carolinas was used in a chemical process known as geopolymerization to produce a “geopolymer” binder. The developed geopolymer binder could competently substitute the OPC binder in regular concrete applications. An experimental design program was conducted to optimize parameters of the geopolymerization affecting the strength of the final …

Groundwater Monitoring And Data Analysis Under The Coal Combustion Residuals Rule, Bruce Hensel

Coal Combustion and Gasification Products Journal Archive

No abstract provided.

Ponded And Landfilled Fly Ash As A Source Of Rare Earth Elements From A Kentucky Power Plant, James C. Hower, John G. Groppo, Kevin R. Henke, Uschi M. Graham, Madison M. Hood, Prakash Joshi, Dorin V. Preda

Coal Combustion and Gasification Products Journal Archive

Twenty samples, with one composite sample built out of the 20 individual samples, of ponded ash were collected at a Kentucky power plant. The coal feed throughout the history of the power plant was central eastern Kentucky low- to moderate-S high volatile A bituminous coal. The pond was in the process of being excavated, with the ash moved to a landfill on another company property. In spite of the long history of the pond and the expected variation in coal supply, and perhaps because of the mixing due to the excavation, there is little variation in ash-basis rare earth elements …

Rare Earth Element Distribution In Fly Ash Derived From The Fire Clay Coal, Kentucky, Madison M. Hood, Ross K. Taggart, Ryan C. Smith, Heileen Hsu-Kim, Kevin R. Henke, Uschi Graham, John G. Groppo, Jason M. Unrine, James C. Hower

Coal Combustion and Gasification Products Journal Archive

Fly ash was collected from individual mechanical and electrostatic precipitator (ESP) hoppers at a 130-MW pulverized-coal utility unit burning a southeastern Kentucky moderate- to high-S Pennsylvanian Fire Clay coal. The fly ash particle size is generally similar within each row of the mechanical and ESP hoppers, with the mean particle diameter decreasing from >36 μmin the mechanical hoppers to 6 μm in the last ESP row. Rare earth element (REE)–bearing phases occur within fine minerals and, possibly, as part of the fly ash glass phase. Transmission electron microscopy was used to identify Y-Ce-Nd-La–bearing regions within a glassy matrix. Y- and …

The Relative Impact Framework For Evaluating Coal Combustion Residual Surface Impoundment Closure Options: Applications And Lessons Learned, Ari S. Lewis, Andrew B. Bittner

Coal Combustion and Gasification Products Journal Archive

In response to the U.S. Environmental Protection Agency’s new rule regarding the disposal of coal combustion residuals (CCRs), many utilities need to re-examine their waste disposal practices and make decisions regarding if and how unlined surface impoundments (SIs) should be closed. The two primary options for closing SIs are in-place closure, with capping and engineering controls, and excavation of the CCR for transport to and re-disposal in a lined landfill. To help inform closure option decisions, we supported the Electric Power Research Institute’s development of a practical, science-based decision framework that comprehensively evaluates the potential impacts to human health and …

Tunable Nanocomposite Membranes For Water Remediation And Separations, Sebastián Hernández Sierra

Theses and Dissertations--Chemical and Materials Engineering

Nano-structured material fabrication using functionalized membranes with polyelectrolytes is a promising research field for water pollution, catalytic and mining applications. These responsive polymers react to external stimuli like temperature, pH, radiation, ionic strength or chemical composition. Such nanomaterials provide novel hybrid properties and can also be self-supported in addition to the membranes.

Polyelectrolytes (as hydrogels) have pH responsiveness. The hydrogel moieties gain or lose protons based on the pH, displaying swelling properties. These responsive materials can be exploited to synthesize metal nanoparticles in situ using their functional groups, or to immobilize other polyelectrolytes and biomolecules. Due to their properties, these …

Aqueous Photochemistry Of Glyoxylic Acid, Alexis J. Eugene, Sha-Sha Xia, Marcelo I. Guzman

Chemistry Faculty Publications

Aerosols affect climate change, the energy balance of the atmosphere, and public health due to their variable chemical composition, size, and shape. While the formation of secondary organic aerosols (SOA) from gas phase precursors is relatively well understood, studying aqueous chemical reactions contributing to the total SOA budget is the current focus of major attention. Field measurements have revealed that mono-, di-, and oxo-carboxylic acids are abundant species present in SOA and atmospheric waters. This work explores the fate of one of these 2-oxocarboxylic acids, glyoxylic acid, which can photogenerate reactive species under solar irradiation. Additionally, the dark thermal aging …

Characteristics And Composition Of Magnetic Concentrates Of Bottom Ash Samples From Two Types Of Thermal Power Plants In Odisha, India, Subir Kumar Das

Coal Combustion and Gasification Products Journal Archive

Aluminosilicate bottom ash samples were examined from a thermal power plant in Talcher (sample NT-BA) and in Sambalpur (sample HR-BA), Odisha, India, to determine magnetic particle morphology, internal structure, mineralogy, mineral chemistry, ash fusion temperature, chemical composition, and leaching characteristics. The Talcher plant has adopted pulverized coal combustion, whereas the Sambalpur plant uses circulating fluidized bed combustion boiler technology. For NT-BA, most magnetic particles were ideal solid spheres (ferrospheres) with diverse morphological features (smooth, granular, dendritic and skeletal, porous, spotted, polygonal, and hollow [magnetite cenospheres]). For HR-BA, magnetic particles were subspherical, oval, and angular and showed widely varying surface morphologies, …

Distribution Of Uranium And Other Radionuclides In Coal And Coal Combustion Products, With Discussion Of Occurrences Of Combustion Products In Kentucky Power Plants, James C. Hower, Shifeng Dai, Greta Eskenazy

Coal Combustion and Gasification Products Journal Archive

Uranium and thorium are part of the mineral assemblages within coals. Uranium can also occur in organic associations, particularly in low-rank coals. While the average U concentration in coals is 2.9 ppm for low-rank coals and 1.9 ppm for bituminous and higher rank coals, high concentrations are known from certain low-rank and thin coals and from coals in areas associated with U mineralization. No high-U coals are mined for power production in the United States. Uranium and Th in coal combustion products are found in amounts more or less in proportion to their concentrations in the feed coal. Not being …

Carbon Dioxide Adsorption Studies On Fly Ash Zeolites, Denitza Zgureva

Coal Combustion and Gasification Products Journal Archive

In this study, the potential of fly ash zeolites (FAZ) Linde (LTA) and faujasite (FAU) to adsorb carbon dioxide (CO2) was investigated in view of the results of implementation in postcombustion carbon-capture technologies. Adsorption isotherms of selected samples were measured at 273.15 K by a Micromeritics Tristar II 3020 surface analyzer. The highest adsorption capacity was obtained for FAZ with a FAU structure synthesized by a two-stage fusion hydrothermal process from fly ash (FA) that was composed of 65 wt% amorphous components. The adsorption capacity for this sample reached a value of 136.40 mg CO2/g FAZ at atmospheric pressure, a …

Analysis Of Scientific Investigations Related To Reclamation Of Surface Mining Control And Reclamation Act Permitted Coal Mines With Coal Combustion By-Products, Kimery C. Vories

Coal Combustion and Gasification Products Journal Archive

In the United states, the placement of coal combustion by-products (CCBs) (i.e., fly ash, bottom ash, boiler slag, flue gas desulfurization material, and fluidized bed combustion material) in coal mines has been an area of controversy. Federal and state governments, universities, the National Energy Technology Laboratory, and industrial research organizations have taken an active role in encouraging and promoting technological advances, research, and technology transfer related to the use of CCBs at coal mines. CCBs have been placed at Surface Mining Control and Reclamation Act of 1977 (SMCRA) permitted mines since 1977 to serve the following purposes: (1) a seal …

Coal Ash By-Product From Shanxi Province, China, For The Production Of Portland–Calcium Sulfoaluminate, Tristana Y. Duvallet, Thomas L. Robl, Kevin R. Henke, Yongmin Zhou, David Harris

Coal Combustion and Gasification Products Journal Archive

Twenty bulk samples were collected from ponded coal combustion ash in Shanxi Province, China, as part of an investigation of their beneficiation potential. The samples were shipped to the University of Kentucky, where they were chemically analyzed. The samples were highly consistent in chemistry, falling within the ASTM C-618 class F compositional range. The particle size of the ponded ash was relatively coarse, with only ,7% by weight on average, falling below 200 mesh (75 mm) particle size. The bulk of the material (.80%) was within 50 by 200 mesh (equivalent to 300 by 75 mm). X-ray diffraction investigation combined …

Effect Of Coal Fly Ash Leachate On The Bioluminescence Intensity Of Vibrio Fischeri, Shiro Ikeda, Irena Kostova, Hideaki Sekine, Yoshika Sekine

Coal Combustion and Gasification Products Journal Archive

Coal fly ash is a residue of coal-fired thermoelectric power plants (TPPs) and is mostly dumped in ash ponds or landfill sites, even though it potentially contains significant amounts of water-soluble hazardous contaminants. Bioassay using the bioluminescent bacterium *Vibrio fischeri* is known to be applicable for assessing the short-term and sublethal toxicity of complex mixtures without the need for precise chemical characterization. However, this type of bioassay is potentially adversely influenced by the pH-induced protein denaturation of cells. Because coal fly ash leachates often have alkaline or acidic properties, when applying the *V. fischeri*-based bioassay to the samples, we need …