Materials Science and Engineering Commons^™

Benefits Of Containerized Water Treatment Systems For Coal-Fired Power Plants, Andrew Vincent

World of Coal Ash Proceedings

Containerized systems deliver many of the same functional benefits as housing treatment equipment in permanent buildings, while significantly reducing engineering, construction, and installation costs. By containerizing a water treatment system, a substantial portion of fabrication, assembly, and testing can be completed in a controlled shop environment rather than in the field. This approach greatly reduces on-site labor requirements, mobilization duration, and overall installation complexity. Once delivered to site, containerized systems can be used as permanent installations. Alternatively, they offer the flexibility to be relocated within a plant or transferred between different sites as operational needs change. Multiple containerized systems can …

Rare Earth Element Distribution And Mineral Host In Coal Derived Ash From South African Power Stations, Sanki Biswas, Nicola Wagner, Oftense Moroeng

World of Coal Ash Proceedings

The global shift toward low-carbon energy systems, electric mobility, and digital technologies has sharply increased the demand for critical minerals, including rare earth elements (REY) vital for permanent magnets, batteries, wind turbines, photovoltaic cells, semiconductors, and modern defence applications. Coal by-products—particularly coal fly ash (CFA) and coal bottom ash (CBA)—are emerging as promising secondary sources of REY, but their economic viability depends on effective enrichment and extraction methods. South Africa’s coal-fired power plants generate nearly thirty million tonnes of coal-ash each year. This study investigates REY concentrations in CFA and CBA collected from five major power stations (PS-1 to PS-5) …

Lessons Learned From Managing Ash Pond Closure Waters, Danny Stephens, Tom Geeza, Phil Benson, Ashwin Ranna

World of Coal Ash Proceedings

The water management issues created by ash pond closure are complex and can create technology selection and operational management challenges. Ash dewatering activities produce highly variable effluents, depending on ash composition, aging, and dewatering and stormwater management techniques. Effluent limitations can also be highly variable, depending upon the size of the receiving body and the anticipated composition of the effluent stream. The user often faces competing risks: installing an unnecessarily complex and expensive treatment plant, being limited on closure activities by limitations in water treatment capabilities, or both. This paper presents several lessons learned from assessing ash closure water management …

Epri Ccp Beneficiation Research Update, Benjamin Gallagher, Patrick Webb

World of Coal Ash Proceedings

Coal combustion products (CCPs) are frequently utilized as supplementary materials in cement and concrete manufacturing. With an estimated 2 billion metric tons stored in repositories across the United States, interest in beneficial use has expanded beyond class F fly ash to include ponded and high-LOI ash. Beneficiation provides a critical pathway for managing CCP repositories, particularly under closure-by-removal strategies, and where ash sources have historically been difficult to process. Research conducted at EPRI’s Ash Beneficial Use Center (ABUC) examines the feasibility of processing these ash types into usable products and offers insights into repository variability and classification. Furthermore, the study …

Risk Evaluation Of Small Coal Combustion Residual Management Unit (Ccrmu) Fills, Andrew Bittner, John Kondziolka, Qian Zhang, Masoud Arshadi

World of Coal Ash Proceedings

US EPA expanded the scope of CCR regulations in 2024 to areas of historical CCR placement not regulated under the 2015 CCR rule, including CCR used as fill. US EPA presented new risk analyses specific to CCRMU fills and defined different regulations for CCRMU fills from 1 to 1,000 tons, noting uncertainty as to whether there was a size of CCRMU fill below which acceptable risks could be expected. This research fills US EPA's stated data gap by modeling and analyzing impacts from small CCRMU fills. Modeling was conducted using the same methods, models, and most of the same inputs …

Consolidation Modeling To Support Closure Planning Of An Upstream Raise Ccr Surface Impoundment Containing Fgd Material, Tanya Walkenbach, Craig Schuettpelz, Todd Stong, Shane Stockdill

World of Coal Ash Proceedings

Rainbow Energy Center’s (REC’s) Coal Creek Station has managed calcium sulfite flue gas desulfurization (FGD) material in composite-lined upstream raise surface impoundments since 2001. The upstream raise surface impoundment utilizes bottom ash (drainage zone) and fly ash (structural zone) produced at Coal Creek Station to contain the FGD placement. FGD material was hydraulically sluiced to the center of the 110-acre Upstream Raise 92 (UR92) coal combustion residual (CCR) unit between 2001 and 2021. The FGD was deposited to a maximum thickness of approximately 100 feet in the center of the unit. Significant consolidation of FGD material occurred with subsequent FGD …

Investigating The Performance Of Processed Stockpile Fly Ash For Low Carbon Concrete, Michael Mccarthy, Arfas Habeeb, Laszlo Csetenyi, Roderick Jones

World of Coal Ash Proceedings

Reducing embodied carbon in concrete has increasingly focused on clinker substitution through the use of supplementary cementitious materials (SCMs). However, the local availability of fly ash, a widely used SCM in the UK, offering benefits in this role, has reduced over the past decade, as coal-fired electricity generating plants have gradually been taken out of service. Attention has, therefore, increasingly focused on fly ash from stockpile and landfill sites to maintain supply, i.e., material not used following production and put into storage. Most UK fly ash originated from the burning of bituminous coal, producing low-lime siliceous material, which although undergoing …

Solar Solution For Closed Ccr Units And Adjacent Land, Chris Fairey

World of Coal Ash Proceedings

Solar Solution for Closed CCR Units and Adjacent Land Chris Fairey1, Kenny Hughes1 1Watershed Geo, 1125 Sanctuary Pkwy, Suite 180, Alpharetta, GA 30009 KEYWORDS: Solar, Racking, Brownfield, Greenfield, Slopes, PowerCap® ABSTRACT With the reduction in coal fired power generation, there is a consistent trend in the industry to supplement generation with solar power. The property located within and surrounding these decommissioned power plants offers a significant opportunity to create a renewable solar power asset. The PowerCap® Nail to Rail System, developed by Watershed Geo, is an advanced solar racking solution designed for sites that do not require environmental closure such …

Investigation Of A Historical Coal Combustion Residuals Management Unit (Ccrmu), Todd Stong, Shane Stockdill, Erin Hunter

World of Coal Ash Proceedings

Rainbow Energy Center’s (REC’s) Coal Creek Station has managed coal combustion residuals (CCR) in various engineered impoundments and landfills since plant operation began in 1978. Since then, waste containment methods have evolved resulting in significant changes to their CCR management practice. In the late 1980s and early 1990s REC closed several existing CCR units with natural soil liners and constructed several new CCR units with composite liner systems. One of the closed units was an area now referred to as North Section 16, an impoundment that received CCR including bottom ash, fly ash, and flue gas desulfurization material. North Section …

Transportation Logistics Panel, John Ward, Andrew Vollmer, Tracy Zea, Marci Jenks

World of Coal Ash Proceedings

As the industry shifts from freshly generated ash to harvested materials and advanced utilization, logistics is becoming one of the primary drivers of project success or failure. This moderated panel will explore how sourcing, transportation, and storage realities are changing — and what project teams most often underestimate when working with harvested coal ash. Panelists will discuss what breaks, what becomes more complex, and how logistics considerations are reshaping planning and development.

Abundances Of Elements In Global Coals, Shifeng Dai

World of Coal Ash Proceedings

The abundance of elements in coal is important not only because it provides a solid scientific and practical foundation for various geochemical comparisons, but also because it helps address broader questions in Earth Sciences. In this study, data on major and trace elements in global coals comprising hundreds of thousands of coal samples were compiled from peer-reviewed journal articles, books, various databases, dissertations, and technical reports. These data formed the basis for estimating element abundances in global coals presented in this study. All collected data were rigorously screened for reliability, and any records with questionable quality were excluded from the …

Optimization Of Remedial Strategies For Ccr Site Corrective Action Through Advanced Geochemical Modeling, Cole Mayer, Pj Nolan

World of Coal Ash Proceedings

The power industry is actively designing and implementing corrective measures for Coal Combustion Residuals (CCR). In many cases, these measures include active remedies such as pump and treat, in-situ injection, or reactive barriers, all of which demand a thorough understanding of the underlying geochemical system. Depending on the geochemical characteristics of an aquifer, different chemical reagents can achieve varying degrees of success or even be detrimental to the remediation of the site. Advanced geochemical modeling is an invaluable tool for developing a remedy that is optimized to the site-specific geological, hydrological, and geochemical environment. In the case study presented here, …

Application Of Stable Isotopes In An Alternative Source Demonstration, Alison O'Connor

World of Coal Ash Proceedings

Stable isotope analysis is commonly used in age dating, provenance studies and to differentiate between sources of groundwater. Multiple studies have shown that strontium and boron isotopic ratios can be successfully used in identifying CCR impacts to groundwater. This talk presents an applied case study using boron and strontium isotopes in conjunction with additional geochemical approaches in an alternative source demonstration. Boron and strontium isotopes were measured in both groundwater and CCR leachate over sampling events from 2019 to 2025. The data revealed that strontium and boron isotopic signatures in groundwater near the CCR unit differed significantly from both site-specific …

Alternative Cover Permitting And The Ccr Rule, Evan Andrews, Victor Damasceno

World of Coal Ash Proceedings

Federal rules (40 CFR Parts 9, 257 and 261) that regulate coal combustion residuals (CCR) created a significant demand associated with closure of coal ash management and storage facilities using liner systems. Timelines associated with these facility closures combined with substantial project scale and potential for future mining /reuse has driven the need for closure systems that perform beyond the prescriptive soil / geomembrane caps outlined in the federal regulations. As outlined in section 257.102 (d)(3)(i) of the CCR Rule, the standard cover system must include an infiltration layer of at least 18 inches of earthen material and an erosion …

Ccr Landfill Closure Challenges, Solutions And Innovation, Jay Mokotoff, Drew Browning, Steve Applegate

World of Coal Ash Proceedings

CCR landfills can present unique design and construction challenges for the industry when closing these units at the end of their life. In comparison to CCR surface impoundments, CCR landfills typically have greater flexibility under the CCR Rule for operations and beneficial use purposes and may not have defined closure dates which results in some of these closures extending further into the future. However, as coal burning plants continue to shudder, the closure of these landfills is rapidly approaching. This presentation will focus on the challenging site conditions, site specific considerations and potential solutions when designing and constructing the landfill …

Distinguishing Ccp From Nuclear Impacts In Groundwater, Lea Millet

World of Coal Ash Proceedings

As the energy transition from fossil fuels to other generation technologies continues, many companies worldwide are evaluating the feasibility of constructing nuclear power plants at sites previously used for coal-powered generation. Thermal power plant sites offer advantages for siting nuclear generation such as proximity to cooling water and grid connections; however existing impacts to groundwater from coal combustion product (CCP) management units may confound monitoring programs designed to detect impacts from nuclear operations. For example, boron and lithium may be present in waters associated with CCP management and nuclear power plant operations, and potassium that often has concentrations above background …

Engineering Granulometry To Optimize Performance Of Reclaimed Ash, Russell Hill

World of Coal Ash Proceedings

As utility production of fresh fly ash declines, the concrete industry is turning to reclaimed and beneficiated materials to maintain reliable SCM supply. This transition creates an opportunity not only to secure volumes but to engineer improved performance. The ReCinis™ beneficiation process enables this by providing controls that tune particle-size distribution (PSD), sphericity, packing behavior, surface area, and surface activation. Processing trials show that blends combining fine ground fractions with spherical, broad-graded hydrocyclone overflow (OF) materials can balance high reactivity with favorable rheology. Mechanochemical activation during grinding appears to increase reactivity beyond what surface-area metrics alone predict, likely through removal …

Sustainability And Waste Diversion At Tva Shawnee "Project Phoenix", Bryan Jacob, Shane Harris

World of Coal Ash Proceedings

An engineered turf closure system can serve as an ideal foundation for a solar energy system to be installed atop coal combustion residual (CCR) impoundments. This approach not only enables productive power generation during the post-closure period, it also preserves opportunities for recovery and beneficial use of CCR material in the future. “Project Phoenix” at TVA’s Shawnee Fossil Plant offers an illustrative example. This paper will cover the sustainability benefits of the companion ClosureTurf® and PowerCap® systems installed at that site as well as waste diversion activities undertaken during construction to recycle as much as practical and minimize waste destined …

Expert Perspectives On The U.S. Coal Combustion Products Market – Now, Then, And The Future, Mark Rokoff, David Cox, Walter Lemaire, John Ward

World of Coal Ash Proceedings

This panel discussion will explore the continued evolution of the U.S. coal combustion products market, with a focus on the impacts of dynamic regulatory and market forces. Invited expert panelists will share perspectives on developments over the past several years (building on discussions from WOCA 2022 and WOCA 2024), current conditions, and expected future trends—particularly those likely to shape the market between 2026 and 2030. The discussion will address the interrelated markets for engineering, construction, and beneficiation of ash from both operating and inactive plants. Panelists will offer perspectives relevant to the full coal ash industry, from owner/operator organizations to …

Demystifying Large Language Models: How Ai Is Transforming Data, Compliance, And Decision-Making In Coal Ash And Environmental Management, Scott Pfeiffer

World of Coal Ash Proceedings

The environmental and coal combustion residuals (CCR) industries generate vast amounts of information—from groundwater monitoring reports and RCRA documentation to closure plans and analytical data. Managing, interpreting, and communicating this information is a growing challenge for utilities, regulators, and consultants alike. Large Language Models (LLMs), such as OpenAI’s GPT architecture, represent a breakthrough in how organizations can interact with their technical data. These models use deep neural networks trained on billions of words to understand, summarize, and generate language with human-like accuracy. When securely adapted for enterprise use, LLMs can automate routine reporting, extract data from technical documents, generate regulatory …

Subsurface Delineation Of Coal Combustion Residuals Using Multiple Geophysical Methods, Eric Hageman, Adam Rak, Thomas Jordan, Kate Mckinley

World of Coal Ash Proceedings

Geophysical techniques provide alternative methods of Coal Combustion Residual (CCR) delineation and characterization to supplement more invasive boring programs used for beneficial reuse planning. A demonstration project was designed to characterize the electromagnetic and seismic stratigraphy of CCR material and test the effectiveness of three geophysical techniques: Electrical Resistivity Imaging (ERI), Transient Electromagnetic (TEM) induction, and Multi-channel Analysis of Surface Wave (MASW). The demonstration project was completed at a dry-stack CCR unit containing a variety of CCR ash, gypsum, and thin layers of drainage aggregate (limestone). During a single-day deployment, several geophysical survey tests were conducted in specific areas of …

Designing Enhanced Nonlinearity In Plasmonic Devices With Epsilon-Near-Zero Films, Kevin Tran Le

Electrical Engineering and Computer Science (MS) Theses

The growing demand for energy-efficient optical information processing motivates compact nonlinear photonic devices that can operate at low power. Silicon photonics is a mature platform for linear optical functions, but nonlinear operation remains challenging because of its weak Kerr response, two-photon absorption at telecommunication wavelengths, and limited compatibility with deeply subwavelength plasmonic confinement. This thesis computationally investigates epsilon-near-zero thin films integrated into plasmonic waveguide architectures as a route toward stronger light–matter interaction in compact nonlinear devices.

Two waveguide geometries are examined: a hybrid metal-insulator-metal plasmonic slab waveguide incorporating an ultrathin indium tin oxide epsilon-near-zero layer (5–50 nm), and a dielectric-loaded …

Adsorption Of Pfas On Bridged Functionalized Organosilica Materials, Elisha Lawerh Kabutey

Electronic Theses and Dissertations

PFAS are hazardous contaminants that have a devastating impact on human health and the environment. Their hazardous nature has led to the development of various adsorption methods for removing these contaminants from water sources. In this study, functionalized organosilica materials were synthesized from bis[3-(trimethoxysilyl)propyl] amine using the sol-gel method. The surface amino groups of the organosilica were converted into amine hydrochloride groups. Their adsorption properties were evaluated using salts of perfluorooctanoic acid, perfluorooctanesulfonic acid, and perfluorobutanesulfonic acid. Results showed excellent adsorption capacity of the materials. Adsorption of PFAS leads to particle agglomeration and flotation of the spent material. A column …

Engineering Silicone Magnetic Fluids For Localized Radiation Attenuation During Ocular Melanoma Brachytherapy, Zachary L. Caprow

All Dissertations

Ocular melanoma is commonly treated using plaque brachytherapy; however, radiation-induced damage to healthy ocular tissues frequently results in partial or complete vision loss. This work investigates the development of an injectable, magnetically responsive silicone magnetic fluid designed to localize adjacent to the tumor and attenuate low-energy gamma radiation during treatment.

The material system consists of iron oxide nanoparticles surface-functionalized with a siloxane polymer, in which the nanoparticles provide magnetic responsiveness and radiation attenuation, while the polymer coating ensures colloidal stability, injectability, and biocompatibility. A one-pot synthetic approach was developed wherein a functionalized siloxane polymer containing iron-affinitive groups was reacted with …

Molecular Catalysts For Electrochemical Nitrogen Activation Toward Sustainable Ammonia Synthesis, Jin-Xiu Han, Hao Xue, Xian-Biao Fu

Journal of Electrochemistry

Homogeneous electrocatalytic nitrogen reduction reaction (NRR) provides a powerful framework to interrogate molecular nitrogen-fixation pathways under mild conditions. By tuning the metal center, ligand architecture, and reaction medium, these systems enable capturing key intermediates and delivering mechanistic insight at the molecular-level resolution. Nevertheless, advances remain constrained by highly reduced operating potentials, intense competition from the hydrogen evolution reaction (HER), limited durability in turnover, and inadequate long-term stability.

In this review, we take electron delivery to the molecular active site as the guiding principle for organizing homogeneous electrochemical N₂ activation and transformation. We classify reported systems into direct electron transfer …

Water-Driven Solid Electrolyte Interphase Governs Continuous-Flow Ammonia Electrosynthesis, Peng-Bo Liu, Sheng-Liang Zhai, Ji Huang, Zhong-Shuo Zhang, Jie Zeng, Shao-Feng Li

Journal of Electrochemistry

Flow-cell architectures have emerged as a powerful platform for continuous and stable lithium-mediated nitrogen reduction (Li-NRR), enabling ambient-condition electrochemical ammonia synthesis and offering a promising alternative to Haber-Bosch processes. However, Li-NRR is exceptionally sensitive to trace water, and even minor variations in water content can profoundly alter interfacial chemistry. Here, we systematically investigate how initial water concentration affects Li-NRR performance in a continuous-flow cell. Excess water drives the formation of a thick solid electrolyte interphase (SEI) layer, which may impede nitrogen access to metallic lithium and hinder lithium-ion transport. As a result, the ammonia Faradaic efficiency collapses from ~61% to …

Insertion Of Noble Metal Free Cathodic Catalyst Layer With Fe-N-C Catalyst For Boosted Performance Of Pemfc, Shi Zhou, Muhammad Tariq, Asif Nadeem Tabish, Muhammad Salman, Fan-Di Ning, Muhammad Rayyan Tayyab, Ran-Ran Peng, Meng-Geng Hao, Wen-Mu Li, Xiao-Chun Zhou

Journal of Electrochemistry

Economical Fe-N-C catalysts are considered as promising alternatives to platinum group metal catalysts for proton exchange membrane fuel cells (PEMFCs). Despite exhibiting robust activity on rotating disk electrodes, their performance within membrane electrode assemblies often experiences limitations, such as decreased O₂ diffusion, high H₂O₂ formation, low proton conduction, and a lower electron transfer number. In this study, key factors, including proton transport, electron conduction, and gas diffusion within air-breathing PEMFCs, have been investigated by adjusting cathode catalyst layer (CCL) compositions. From the experimental results, the optimal peak power density was obtained when the loading of Fe-N-C …

A Comparative Study Of Tin Electrorefining In Molten Licl–Kcl–Cacl₂: Experimental Two-Electrode Current Control And Theoretical Three-Electrode Potential Control, Bryant Johnson, George Ankrah, Ander Fuller, Devin Rappleye

Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)

Molten salt electrorefining is a mature technology for metal recovery, yet conventional current‑controlled, two‑electrode operation provides limited electrochemical selectivity and restricted insight into electrode‑specific behavior. In this work, a simplified model is developed to compare current‑controlled two‑electrode electrorefining data with a potential‑controlled three‑electrode electrorefining simulation using tin in molten LiCl–KCl–CaCl₂ as a surrogate for plutonium processing. The model examines anodic and cathodic limitations under fixed‑potential operation and evaluates implications for selectivity, efficiency, and runtime relative to experimentally demonstrated two‑electrode performance. Results indicate that independent potential control enables operation closer to thermodynamic selectivity limits, with the potential to suppress impurity oxidation …

Growing Large Single And Multi-Crystals From Alum Powder, Owen Paulson, Mayra G. Aguilar, Owen T. Maloney, Kole C. Koehler

Research & Creative Achievement Day

Crystal growth science is used to replicate the growth of crystals that form in nature. Channels of hot fluid with concentrations of minerals created the crystals found as gemstones. At low concentrations, no crystal grows. At high concentrations, a multitude of crystals grow. At the ideal concentration, a single, clear crystal grows. Four solution concentrations were used to create seed crystals. Those Alum seed crystals were attached to a string and suspended in various concentrations of Alum solution to find concentrations that create no crystal, a single crystal, and a multi-crystal.

Growing Alum Crystals, Todd Carroll, Daniela Gutierrez Rubio, Kevin Dang, Samuel J. Whempner

Research & Creative Achievement Day

One of the easiest crystal growth experiments uses Alum powder to dissolve in water. The dissolved material slowly forms with seed crystals to create larger crystals. As the dissolved material is depleted, more is added to continue the crystal growth. Four different concentrations were used for seed crystal growth. Those crystals were attached to a string and hung in a bath of Alum solution. Different strategies were used to grow crystals and in some cases dissolve crystals.