DSpace Repository :: Browsing by Author "Elliott, Mark"

Browsing by Author "Elliott, Mark"

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Associations between Perceptions of Drinking Water Service Delivery and Measured Drinking Water Quality in Rural Alabama
(MDPI, 2014) Wedgworth, Jessica C.; Brown, Joe; Johnson, Pauline; Olson, Julie B.; Elliott, Mark; Forehand, Rick; Stauber, Christine E.; University of Alabama Tuscaloosa; Georgia Institute of Technology; Georgia State University
Although small, rural water supplies may present elevated microbial risks to consumers in some settings, characterizing exposures through representative point-of-consumption sampling is logistically challenging. In order to evaluate the usefulness of consumer self-reported data in predicting measured water quality and risk factors for contamination, we compared matched consumer interview data with point-of-survey, household water quality and pressure data for 910 households served by 14 small water systems in rural Alabama. Participating households completed one survey that included detailed feedback on two key areas of water service conditions: delivery conditions (intermittent service and low water pressure) and general aesthetic characteristics (taste, odor and color), providing five condition values. Microbial water samples were taken at the point-of-use (from kitchen faucets) and as-delivered from the distribution network (from outside flame-sterilized taps, if available), where pressure was also measured. Water samples were analyzed for free and total chlorine, pH, turbidity, and presence of total coliforms and Escherichia coli. Of the 910 households surveyed, 35% of participants reported experiencing low water pressure, 15% reported intermittent service, and almost 20% reported aesthetic problems (taste, odor or color). Consumer-reported low pressure was associated with lower gauge-measured pressure at taps. While total coliforms (TC) were detected in 17% of outside tap samples and 12% of samples from kitchen faucets, no reported water service conditions or aesthetic characteristics were associated with presence of TC. We conclude that consumer-reported data were of limited utility in predicting potential microbial risks associated with small water supplies in this setting, although consumer feedback on low pressure-a risk factor for contamination-may be relatively reliable and therefore useful in future monitoring efforts.
Associations between Self-Reported Gastrointestinal Illness and Water System Characteristics in Community Water Supplies in Rural Alabama: A Cross-Sectional Study
(PLOS, 2016) Stauber, Christine E.; Wedgworth, Jessica C.; Johnson, Pauline; Olson, Julie B.; Ayers, Tracy; Elliott, Mark; Brown, Joe; Georgia State University; University of Alabama Tuscaloosa; Georgia Institute of Technology
Background Community water supplies in underserved areas of the United States may be associated with increased microbiological contamination and risk of gastrointestinal disease. Microbial and health risks affecting such systems have not been systematically characterized outside outbreak investigations. The objective of the study was to evaluate associations between self-reported gastrointestinal illnesses (GII) and household-level water supply characteristics. Methods We conducted a cross-sectional study of water quality, water supply characteristics, and GII in 906 households served by 14 small and medium-sized community water supplies in Alabama's underserved Black Belt region. Results We identified associations between respondent-reported water supply interruption and any symptoms of GII (adjusted odds ratio (aOR): 3.01, 95% confidence interval (CI) = 1.65-5.49), as well as low water pressure and any symptoms of GII (aOR: 4.51, 95% CI = 2.5-57.97). We also identified associations between measured water quality such as lack of total chlorine and any symptoms of GII (aOR: 5.73, 95% CI = 1.09-30.1), and detection of E. coli in water samples and increased reports of vomiting (aOR: 5.01, 95% CI = 1.62-15.52) or diarrhea (aOR: 7.75, 95% CI = 2.06-29.15). Conclusions Increased self-reported GII was associated with key water system characteristics as measured at the point of sampling in a cross-sectional study of small and medium water systems in rural Alabama in 2012 suggesting that these water supplies can contribute to endemic gastro-intestinal disease risks. Future studies should focus on further characterizing and managing microbial risks in systems facing similar challenges.
Autonomous engineering: a multi-scale GIS-based approach to green infrastructure design
(University of Alabama Libraries, 2019) Greer, Ashton Danielle; Graettinger, Andrew; University of Alabama Tuscaloosa
This dissertation presents a new method called “Autonomous Engineering” that incorporates geographic information systems (GIS) to automatically design green stormwater infrastructure. The Autonomous Engineering framework aims to increase the efficiency at which green infrastructure is designed, thus promoting increased implementation. Green infrastructure design is a unique challenge in that it is multi-scale; planning and design considerations must be made at both the site-level and the watershed level by analyzing various types of spatial data. This framework presents a methodology for designing green infrastructure based on a combination of remotely sensed watershed-scale data and ultra-high resolution site-level Light Detection and Ranging (LiDAR) data. First, watershed level data is analyzed to generate site recommendations and quantify runoff characteristics. Second, LiDAR data is processed using both deep learning and machine learning frameworks so that site-level spatial features can automatically be recognized and extracted and so that an ultra high resolution digital elevation model (DEM) is generated. Next, linear referencing techniques are used to analyze terrain and identify geometric design recommendations. The results are finalized in the form of custom design drawings and reports. This work has outcomes for improved green infrastructure design workflows as well as the spatial analysis of robust site-level data for other applications. Future work includes the extension of these methodologies to applications beyond green infrastructure.
Characterizing the Fate of Petroleum Biomarkers and Polycyclic Aromatic Hydrocarbons in Oil Spill Residues
(University of Alabama Libraries, 2022) Arekhi, Marieh; Terry, Leigh; Clement, Prabhakar; University of Alabama Tuscaloosa
The oil industry is one of the most important industries that support the energy demands of the modern world. Oil can enter the environment from different sources such as transportation, natural oil seeps, and accidental oil spills. Oil compounds are toxic (to varying extents) to coastal environments, and one of the main concerns of oil spills is releasing polycyclic aromatic hydrocarbons (PAHs) into the environment. PAHs are considered hazardous pollutants due to their toxicity, mutagenicity, and carcinogenicity and are classified as compounds with significant human health risks in the priority list of pollutants by USEPA. Thus, much attention has been focused on the source and fate of oil spill contamination in the environment and the natural processes by which the spilled oil is degraded, including photodegradation mediated by sunlight. The most common method for identifying an oil spill source is the chemical characterization of the spilled oil using petroleum biomarker fingerprints, which are geochemical organic compounds present in crude oils that can be related to their unique biological precursors. This dissertation focuses on three general research goals surrounding petroleum biomarkers and PAHs in oil spills. The first goal is to use petroleum biomarkers as oil spill fingerprinting methods and to complete an assessment of PAHs in the residues (tarmats) collected from the Persian Gulf shoreline remaining from the largest oil spill in history, the 1991 Gulf War oil spill. After an introduction in Chapter 1, Chapter 2 presents the results of a detailed field survey on the western shores of the Persian Gulf in Qatar and the chemical characterization dataset developed to investigate the source of the tarmats found in this area. The second goal is to characterize the fate of petroleum biomarkers over a 10-year period to validate their use for fingerprinting purposes in the residues (tarballs) of the 2010 Deepwater Horizon (DWH) oil spill in the Gulf of Mexico. For this purpose, Chapter 3 discusses the fate of three groups of petroleum biomarkers including terpanes, steranes, and triaromatic steranes in the DWH oil spill tarballs that have weathered in the Alabama coastal environment for over 10 years. The third goal is to characterize the efficiency of two types of low-cost LED light sources (full-spectrum and UV-A lights) for conducting laboratory-scale PAH photodegradation investigations, and Chapter 4 presents the results of this investigation. Finally, Chapter 5 summarizes the main findings of the studies conducted for this dissertation and discusses future research areas that are worth exploring in the context of oil spill pollution.
Climate-Related Hazards: A Method for Global Assessment of Urban and Rural Population Exposure to Cyclones, Droughts, and Floods
(MDPI, 2014) Christenson, Elizabeth; Elliott, Mark; Banerjee, Ovik; Hamrick, Laura; Bartram, Jamie; University of North Carolina; University of North Carolina Chapel Hill; University of Alabama Tuscaloosa
Global climate change (GCC) has led to increased focus on the occurrence of, and preparation for, climate-related extremes and hazards. Population exposure, the relative likelihood that a person in a given location was exposed to a given hazard event(s) in a given period of time, was the outcome for this analysis. Our objectives were to develop a method for estimating the population exposure at the country level to the climate-related hazards cyclone, drought, and flood; develop a method that readily allows the addition of better datasets to an automated model; differentiate population exposure of urban and rural populations; and calculate and present the results of exposure scores and ranking of countries based on the country-wide, urban, and rural population exposures to cyclone, drought, and flood. Gridded global datasets on cyclone, drought and flood occurrence as well as population density were combined and analysis was carried out using ArcGIS. Results presented include global maps of ranked country-level population exposure to cyclone, drought, flood and multiple hazards. Analyses by geography and human development index (HDI) are also included. The results and analyses of this exposure assessment have implications for country-level adaptation. It can also be used to help prioritize aid decisions and allocation of adaptation resources between countries and within a country. This model is designed to allow flexibility in applying cyclone, drought and flood exposure to a range of outcomes and adaptation measures.
Concentration-Discharge Responses of Water Quality Metrics to Hydrological Events in a Coastal Plain Forested Watershed
(University of Alabama Libraries, 2023) Ahmad, Sakinat Mojisola; Lu, Yuehan
Recent studies have continued to support the forecast that the Gulf Coast will experience more devastating storms in the coming years. This would enormously affect water quality, including material export from watersheds to downstream ecosystems. Also, streams in the southeastern United States are hot spots for organic carbon export, an important component in carbon budgeting and climate change prediction. To improve our understanding of stream water quality's response to storms, this study assessed the patterns of the concentration-discharge (C-Q) hysteresis during storms using high-resolution data of fluorescence Dissolved Organic Matter (fDOM), specific conductance, chlorophyll-a, Dissolved Oxygen, pH, and turbidity in a forested coastal plain stream in west central Alabama, United States. We employed wavelet analysis to assess how each water quality variable covaried with discharge while using Hysteresis and Flushing Index to evaluate solute transport patterns. Results show that source proximity and constituent availability collectively controlled the response sequence of water quality variables, with mechanisms varying across variables. For most storms, pH was exported first, followed by chlorophyll, turbidity, specific conductance, fDOM, and finally, dissolved oxygen. The mobilization mechanism, i.e., the export of hydrogen ions from adjacent sources, governed pH's response to storms. In contrast, the dilution mechanism seemed to dominate the response of chlorophyll-a, turbidity, and fDOM. Equal percentage of storms was governed by the mobilization mechanism and the dilution mechanism for specific conductance. Seasonal variation played a significant role in the hysteretic index of pH and chlorophyll-a, whereas antecedent discharge significantly impacted the Flushing Index of pH, chlorophyll-a, and turbidity. Dry period duration before a storm significantly increased the flushing of ions into the creek, as seen in the increased hysteresis index. These findings highlight the considerable influence of storms on stream biogeochemistry. However, different water quality components react differently, highlighting complexity in predicting how water quality will be affected by hydrological events and necessitating continuous, high-resolution monitoring.
Does Global Progress on Sanitation Really Lag behind Water? An Analysis of Global Progress on Community- and Household-Level Access to Safe Water and Sanitation
(PLOS, 2014) Cumming, Oliver; Elliott, Mark; Overbo, Alycia; Bartram, Jamie; University of London; London School of Hygiene & Tropical Medicine; University of Alabama Tuscaloosa; University of North Carolina; University of North Carolina Chapel Hill
Safe drinking water and sanitation are important determinants of human health and wellbeing and have recently been declared human rights by the international community. Increased access to both were included in the Millennium Development Goals under a single dedicated target for 2015. This target was reached in 2010 for water but sanitation will fall short; however, there is an important difference in the benchmarks used for assessing global access. For drinking water the benchmark is community-level access whilst for sanitation it is household-level access, so a pit latrine shared between households does not count toward the Millennium Development Goal (MDG) target. We estimated global progress for water and sanitation under two scenarios: with equivalent household-and community-level benchmarks. Our results demonstrate that the "sanitation deficit" is apparent only when household-level sanitation access is contrasted with community-level water access. When equivalent benchmarks are used for water and sanitation, the global deficit is as great for water as it is for sanitation, and sanitation progress in the MDG-period (1990-2015) outstrips that in water. As both drinking water and sanitation access yield greater benefits at the household-level than at the community-level, we conclude that any post-2015 goals should consider a household-level benchmark for both.
Environmental Application of Two- and Three-Dimensional Nanomaterials for Wastewater Treatment
(University of Alabama Libraries, 2022) Dadashi Firouzjaei, Mostafa; Elliott, Mark; University of Alabama Tuscaloosa
MXenes and metal-organic frameworks have become well-known materials among chemists, physicists, material scientists, and other field researchers, and they have attracted significant attention because of their novel chemical, magnetic, electronic, mechanical, and optical properties. Water pollution is one of the most significant challenges worldwide, and the application of novel two- and three-dimensional materials for wastewater treatment is of high importance.The first chapter of this work introduces the history, chemistry, properties, and applications of metal-organic frameworks and MXenes, two different groups of two- and three-dimensional materials. Chapter 2 of this work proposes two classes of novel silver-based metal azolate frameworks (MAF) to decorate polyamide (PA) forward osmosis membranes to improve numerous fouling and water transport aspects. Membranes functionalized with two concentrations of each MAF are compared with a pristine control material, with results that highlight their tunability and bio-inhibitory effects. These features improve the long-term water flux performance of the membranes, tested during 24 hours of accelerated biofouling and organic fouling conditions, and show lower than 10% and 20% decline in water flux. In the third chapter of this work, the surface functionalization of an ultrafiltration membrane obtained via UV-initiated grafting polymerization of acrylic acid (AA) and silver-containing metal-organic frameworks (Ag-MOFs) to achieve combined bactericidal and hydrophilic properties has been studied. The effectiveness of different modification pathways is evaluated, including Ag-MOFs blending into the AA solution followed by grafting and in-situ synthesis of Ag-MOFs over the surface of AA-grafted membranes, with the in-depth characterization of the resulting materials. In the final chapter, nanocomposites of graphene oxide (GO)-AgMOF and MXene-AgMOF were fabricated for the first time using a silver-based metal-organic framework (AgMOF) functionalized by the intercalation of graphene-oxide (GO) and MXene and investigated for the adsorption of cationic methylene blue (MB) and anionic orange G (OG) dyes. Very high adsorption efficiencies were observed for MB, with GO-AgMOF, MXene-AgMOF, and AgMOF able to remove 99.9%, 99%, and 98% of this dye from water at an initial concentration of 200 mg/L and an adsorbent mass of 0.01 g.
In Situ Ag-MOF Growth on Pre-Grafted Zwitterions Imparts Outstanding Antifouling Properties to Forward Osmosis Membranes
(American Chemical Society, 2020) Pejman, Mehdi; Firouzjaei, Mostafa Dadashi; Aktij, Sadegh Aghapour; Das, Parnab; Zolghadr, Ehsan; Jafarian, Hesam; Shamsabadi, Ahmad Arabi; Elliott, Mark; Sadrzadeh, Mohtada; Sangermano, Marco; Rahimpour, Ahmad; Tiraferri, Alberto; University of Alabama Tuscaloosa; Polytechnic University of Turin; Babol Noshirvani University of Technology; University of Alberta; Amirkabir University of Technology; University of Pennsylvania
In this study, a polyamide forward osmosis membrane was functionalized with zwitterions followed by the in situ growth of metal-organic frameworks with silver as a metal core (Ag-MOFs) to improve its antibacterial and antifouling activity. First, 3-bromopropionic acid was grafted onto the membrane surface after its activation with NN-diethylethylenediamine. Then, the in situ growth of Ag-MOFs was achieved by a simple membrane immersion sequentially in a silver nitrate solution and in a ligand solution (2-methylimidazole), exploiting the underlying zwitterions as binding sites for the metal. The successful membrane functionalization and the enhanced surface wettability were verified through an array of characterization techniques. When evaluated in forward osmosis tests, the modified membranes exhibited high performance and improved permeability compared to pristine membranes. Static antibacterial experiments, evaluated by confocal microscopy and colony-forming unit plate count, resulted in a 77% increase in the bacterial inhibition rate due to the activity of the Ag-MOFs. Microscopy micrographs of the Escherichia coli bacteria suggested the deterioration of the biological cells. The antifouling properties of the functionalized membranes translated into a significantly lower flux decline in forward osmosis filtrations. These modified surfaces displayed negligible depletion of silver ions over 30 days, confirming the stable immobilization of Ag-MOFs on their surface.
Investigation of E-coli and Virus Reductions Using Replicate, Bench-Scale Biosand Filter Columns and Two Filter Media
(MDPI, 2015) Elliott, Mark; Stauber, Christine E.; DiGiano, Francis A.; de Aceituno, Anna Fabiszewski; Sobsey, Mark D.; University of Alabama Tuscaloosa; Georgia State University; University of North Carolina; University of North Carolina Chapel Hill; Emory University; Rollins School Public Health
The biosand filter (BSF) is an intermittently operated, household-scale slow sand filter for which little data are available on the effect of sand composition on treatment performance. Therefore, bench-scale columns were prepared according to the then-current (2006-2007) guidance on BSF design and run in parallel to conduct two microbial challenge experiments of eight-week duration. Triplicate columns were loaded with Accusand silica or crushed granite to compare virus and E. coli reduction performance. Bench-scale experiments provided confirmation that increased schmutzdecke growth, as indicated by decline in filtration rate, is the primary factor causing increased E. coli reductions of up to 5-log10. However, reductions of challenge viruses improved only modestly with increased schmutzdecke growth. Filter media type (Accusand silica vs. crushed granite) did not influence reduction of E. coli bacteria. The granite media without backwashing yielded superior virus reductions when compared to Accusand. However, for columns in which the granite media was first backwashed (to yield a more consistent distribution of grains and remove the finest size fraction), virus reductions were not significantly greater than in columns with Accusand media. It was postulated that a decline in surface area with backwashing decreased the sites and surface area available for virus sorption and/or biofilm growth and thus decreased the extent of virus reduction. Additionally, backwashing caused preferential flow paths and deviation from plug flow; backwashing is not part of standard BSF field preparation and is not recommended for BSF column studies. Overall, virus reductions were modest and did not meet the 5- or 3-log10 World Health Organization performance targets.
Novel Time-Integrated Quantification of Sediment-Associated Fecal Indicator Bacteria in Rural Alabama Creek with Straight Pipes
(University of Alabama Libraries, 2024) Baroni, Corinne Maire; Elliott, Mark
In the Alabama Black Belt, widespread rural poverty, limited sewer access, and shrink-swell clays preclude the use of conventional septic systems, leading to both failing septic systems and discharge of raw sewage from homes through "straight pipes." The degree to which fecal microbes are associated with the suspended sediment load has important implications for contamination transport. Current state guidelines require periodic grab sampling to monitor surface water fecal contamination. While technically simple, grab samples alone are inadequate to monitor enteric pathogens in a body of water due to the highly variable nature of surface water microbes. We present the novel use of the bi-directional time-integrated mass sediment samplers (TIMS) as an accurate and efficient technology for capturing and monitoring fecal indicator organisms and the suspended sediment load. Made of PVC, the TIMS devices are low-cost, easy-to-use, and more effective than grab sampling, especially during periods of high precipitation. While these devices have been utilized for sediment capture in fluvial and estuarine settings, this is the first use of the bi-directional TIMS to characterize sediment-associated fecal microbes. Applied in three locations near known straight pipe usage, the TIMS devices captured significantly more E. coli as compared to grab sampling. This was more pronounced following initial flush precipitation events (i.e. heavy rain after a prolonged dry period) with results yielding an average of 111 times (>2-log10) more E. coli than grab sampling alone. Additionally, the attachment of fecal indicator bacteria to sediment was evaluated using a novel, simple two-step centrifugation-based isolation method. This isolation method was most effective at the 35 °C incubation temperature, which yielded an average of 38.7% sediment-associated E. coli across sampling sites.The results of this study indicate initial flush events are the most critical time to sample surface water for fecal contamination, which paves the way for improved surface water monitoring guidelines and better risk management. These novel methods allow for effective monitoring of the quality of in-situ derived surface water samples over time, providing a deeper understanding of sediment-microbial association and the role precipitation and fine-grained particles have on the fate and transport of fecal pathogens.
Planning for climate change: The need for mechanistic systems-based approaches to study climate change impacts on diarrheal diseases
(Elsevier, 2016) Mellor, Jonathan E.; Levy, Karen; Zimmerman, Julie; Elliott, Mark; Bartram, Jamie; Carlton, Elizabeth; Clasen, Thomas; Dillingham, Rebecca; Eisenberg, Joseph; Guerrant, Richard; Lantagne, Daniele; Mihelcic, James; Nelson, Kara; University of Connecticut; Emory University; Rollins School Public Health; Yale University; University of Alabama Tuscaloosa; University of North Carolina; University of North Carolina Chapel Hill; University of Colorado Anschutz Medical Campus; Colorado School of Public Health; Children's Hospital Colorado; University of Virginia; University of Michigan; Tufts University; University of South Florida; University of California Berkeley
Increased precipitation and temperature variability as well as extreme events related to climate change are predicted to affect the availability and quality of water globally. Already heavily burdened with diarrheal diseases due to poor access to water, sanitation and hygiene facilities, communities throughout the developing world lack the adaptive capacity to sufficiently respond to the additional adversity caused by climate change. Studies suggest that diarrhea rates are positively correlated with increased temperature, and show a complex relationship with precipitation. Although climate change will likely increase rates of diarrheal diseases on average, there is a poor mechanistic understanding of the underlying disease transmission processes and substantial uncertainty surrounding current estimates. This makes it difficult to recommend appropriate adaptation strategies. We review the relevant climate-related mechanisms behind transmission of diarrheal disease pathogens and argue that systems-based mechanistic approaches incorporating human, engineered and environmental components are urgently needed. We then review successful systems-based approaches used in other environmental health fields and detail one modeling framework to predict climate change impacts on diarrheal diseases and design adaptation strategies. (C) 2016 Elsevier B.V. All rights reserved.
Practical Tools for Disinfection Byproduct Mitigation in Drinking Water Utilities
(University of Alabama Libraries, 2023) Vines, Melanie; Terry, Leigh G
Drinking water treatment is crucial to protecting public health. The disinfection of drinking water with chlorine-based disinfectants prevents many waterborne illnesses and is widely considered to be one of the greatest public health advancements of the 20th century. However, these chlorine-based disinfectants react with organic matter and other constituents naturally present in source waters to create disinfection byproducts (DBPs), some of which pose a risk to public health. While over 600 DBPs have been identified, the classes of trihalomethanes (THMs) and haloacetic acids (HAAs) are regulated by the United States Environmental Protection Agency (USEPA) due to their prevalence and suspected carcinogenicity. While the Disinfectants and Disinfection Byproducts Rule has been in its current state since 2006, many utilities still struggle to stay in compliance.This dissertation focuses on three research goals surrounding the prevention and mitigation of DBPs, for which an introduction is given in Chapter 1. The first goal is to use fluorescence spectroscopy to evaluate organic matter removal via biological filtration (biofiltration) for drinking water treatment. Thus, Chapter 2 presents the results of a bench-scale biofiltration study which examined three source waters with varying organic matter character under different biofiltration operating parameters. The second goal is to determine the removal of pre-formed HAAs in a combined granular activated carbon (GAC) adsorbing filter and anthracite-based biological filter. For this purpose, Chapter 3 discusses the removal of HAAs from bromine-spiked tap water by the combined filter system. The third goal is to assess the efficacy of magnetic ion exchange (MIEX) treatment for removing DBP precursors. Chapter 4 presents the results from a comparison study between a pilot-scale conventional treatment train with MIEX pretreatment and a full-scale conventional treatment train without MIEX pretreatment. Finally, Chapter 5 summarizes the main conclusions of the studies conducted for this dissertation and discusses suggestions for future research for utilities to prevent and mitigate DBP formation.
Preventing cryptosporidiosis: the need for safe drinking water
(World Health Organization, 2013) Peletz, Rachel; Mahin, Thomas; Elliott, Mark; Montgomery, Margaret; Clasen, Thomas; University of London; London School of Hygiene & Tropical Medicine; University of Alabama Tuscaloosa; World Health Organization
Seasonal Characterization of Organic Matter and Evaluation of Ultrasonic Treatment for Algae Reduction, with Fluorescence Spectroscopy as an Analytical Tool
(University of Alabama Libraries, 2025) Bice, Remy; Terry, Leigh G.
Drinking water treatment is necessary to provide safe drinking water and protect public health. The Environmental Protection Agency (EPA) sets regulatory standards for the concentrations of organic matter within drinking water treatment plants (DWTPs). However, understanding the seasonal variations in the composition and concentration of organic matter is critical for optimizing treatment processes to enhance overall water quality management. This study employed a case-study approach to identify the seasonal characteristics of organic matter in surface waters and to evaluate the efficacy of ultrasonic techniques for reducing algal growth via fluorescence spectroscopy. The results indicated seasonal fluctuations, with summer exhibiting different organic matter components compared to spring, autumn, and winter, which demonstrated similar components, albeit with changes in fluorescence intensities. The analysis indicated that temperature and precipitation, contributing to changes in blend source water, had the greatest impact on organic matter characterization and algal growth. By establishing an integrated treatment framework that accounts for these seasonal dynamics, this research provides a comprehensive guideline for optimizing treatment strategies and ensuring the consistent delivery of high-quality drinking water.
Silver-Based Metal-Organic Frameworks for Microbial Mitigation
(University of Alabama Libraries, 2022) Zolghadr, Ehsan; Leclair, Patrick Pl; Elliott, Mark; University of Alabama Tuscaloosa
Metal-organic frameworks (MOFs) have recently emerged as promising materials for numerous antimicrobial applications due to their unique properties such as porosity, tunability, and high ion release rate. One of the applications is utilizing them as antimicrobial agents to tackle biofouling phenomena in membrane-based water purification through surface functionalization which is a promising approach to improve the biofouling resistance of polymeric membranes. The main body of this dissertation covers a novel ultrasonic-assisted technique to modify polyvinylidene fluoride (PVDF) microfiltration membranes by silver-based metal-organic frameworks (AgMOFs). Different morphological and characterization techniques were employed to indicate that the in-situ growth of AgMOFs was successful by this facile method. The AgMOFfunctionalized membrane also showed enhanced static antibacterial activities and dynamic biofouling resistance compared to those of the pristine membrane while in contact with the model bacteria, Escherichia coli and Staphylococcus aureus. Moreover, as a side study, AgMOF and its graphene oxide (GO)-decorated nanocomposite (GO AgMOF) are proposed as potential antimicrobial candidates for cancer treatment.
Social Media Analytics for Disaster Management: Hurricanes, Wildfires, and Climate Change
(University of Alabama Libraries, 2023) Karimiziarani, Mohammadsepehr; Moradkhani, Hamid
The increased frequency and intensity of natural disasters due to climate change pose significant challenges for disaster management. Social media platforms such as Twitter have emerged as critical tools for disseminating information during natural disasters. In this dissertation, I conduct a spatiotemporal social media data analysis of three different natural disaster cases to better understand the role of social media in effective disaster management.The first chapter proposes a Hazard Risk Awareness metric (HRA) to assess the risk awareness of communities exposed to natural disasters, based on identifying humanitarian topics of discussion in tweets posted by social media users in affected regions. The second chapter analyzes sentiment changes over time in different categories of disaster-related tweets, examining the relationship between the main topics of discussion and the main entities involved in disaster management. In chapter three, we explore the relationship between climate change and natural disasters based on social media users' posts during natural disasters.Finally, in chapter five, we present a novel approach to uncover more details on social response by performing emotion analysis and a sentiment classification based on emotions expressed in tweets. This dissertation contributes to the understanding of the role of social media in disaster management and provides insights into how social media can be used to enhance disaster management efforts.
Statistical Methods for Enhanced Coastal Flood Risk Assessment and Adaptation Planning
(University of Alabama Libraries, 2025) Sohrabi, Meraj; Moftakhari, Hamed
Extreme hydrometeorological events are becoming more severe and frequent due to climate change, highlighting the need to continuously expand our knowledge to protect lives and assets. Coastal areas are particularly vulnerable to multiple types of flooding while also being economically significant, making their protection even more critical. This study aims to analyze the connections and interactions between different types of flooding to develop a deeper understanding of these extreme events and helping to address the limitations of current engineering solutions. First, I conducted a frequency analysis of compound flood drivers to investigate the spatial and temporal distribution of these events along the U.S. coastline of the Gulf of Mexico, where various types of flooding can occur. Our findings indicate that rainfall is the dominant contributor to most flood events in this coastal system. This analysis provides valuable insights into how different types of flooding have contributed to flood events over the past 30 years and how their combinations and locations have changed across different seasons. Next, I established the relationship between intensity, duration, and frequency of elevated water levels caused by extreme events, emphasizing the importance of considering event duration in coastal flood protection infrastructure design. Traditionally, extreme water level analyses focus on questions such as how often and how high these events occur, but less attention has been given to how long they last—an equally critical factor in designing resilient coastal defenses. Finally, I examined hurricane events to explore the relationship between storm characteristics (i.e. intensity and trajectory) and on the associated flooding impacts. Gaining insight into this connection helps assess the expected risk of flooding and damage in areas projected to be impacted by the upcoming hurricanes. This, in turn, enables more efficient resource allocation for preparedness, facilitates faster response efforts, and improves estimates of potential damages.This dissertation advances coastal adaptation planning by providing a comprehensive suite of analytical tools and insights that address critical gaps in flood hazard assessment. Through detailed analysis of compound flooding, development of duration-based design curves, creation of an efficient hurricane scenario ranking system, and generation of probabilistic flood maps, this work equips coastal planners with practical methods to better understand and prepare for intensifying flood risks. These contributions are particularly timely as coastal communities face mounting challenges from climate change, offering decision-makers more robust and efficient approaches to assess vulnerabilities and design resilient infrastructure that accounts for the full complexity of coastal flooding mechanisms.
Synthesis and Modification of Reverse Osmosis Membranes for the Enhanced Separation of Small Neutral Molecules
(University of Alabama Libraries, 2023) Habib, Shahriar; Weinman, Steven
The focus of this dissertation is the modification and synthesis of reverse osmosis (RO) membranes for separating small, neutral molecules (SNMs) in water by using diamines and surfactants. While existing water treatment technologies such as coagulation, sedimentation, and filtration do well at treating large organic contaminants, SNMs, which can harm the environment and be toxic, such as urea and boric acid are still difficult to remove from water supplies. Because of its simple operation and minimal space requirements, RO has gained increased attention as a technique for removing SNMs from water. Despite excellent desalination performance, current RO membranes cannot reject SNMs sufficiently to produce potable water, especially at near-neutral pH levels, requiring the development of RO membranes with novel chemistries. Since IP reactions are fast and uncontrolled, the polyamide layer contains both network and aggregate free volume holes (pores). Because SNMs are not affected by the charge exclusion rejection mechanism that allows for high salt rejection, reducing the free volume to reduce the passage of SNMs through the membrane is needed. In this regard, the modification of RO membranes to increase the degree of cross-linking and altering the interfacial polymerization synthesis process of polyamide layers with new surfactants are ideal approaches. In this work, we modified polyamide layers of commercial RO membranes using m-phenylenediamine (MPD), numerous linear diamines, and a polyamine. The membranes were characterized using SEM, XPS, contact angle goniometry, and zeta potential. Membranes were performance tested for water permeance and NaCl, urea, and boric acid rejection using a dead-end stirred cell. We also investigated the effect of surfactants on MPD diffusion in the RO membrane synthesis process. We evaluated the MPD diffusion from a membrane support into n-dodecane in the presence of seven different surfactants and characterized the change in concentration of MPD into the organic phase when changing the surfactant, concentration of surfactant, and contact time. With the findings of these studies, we will be able to understand why surfactant addition, surface chemistry modification, and heat treatment affect the free volume, and further help us engineer RO membranes that can better separate SNMs.
The water purification robustness of metal-organic framework-polyamide nanocomposite thin films toward long term organic, inorganic, and bacterial contamination
(University of Alabama Libraries, 2020-12) Dadashi Firouzjaei, Mostafa; Elliott, Mark; University of Alabama Tuscaloosa
Forward osmosis (FO) is an osmotically driven process widely studied for water desalination, wastewater treatment, and water reuse, as well as dilution and concentration of aqueous streams. However, its application is still hampered by the lack of ideal draw solutes, high-performance membranes, and fouling/biofouling. Biofouling is particularly challenging when FO is applied for seawater desalination and wastewater treatment. Over the last decade, many attempts have been made to exploit advances in materials science to obtain membranes with anti-biofouling properties to prevent or to reduce the detrimental effects of this phenomenon. In this study, a polyamide FO membrane was functionalized with silver-based metal organic frameworks (Ag-MOFs) to improve its antibacterial and antifouling properties. The project has been carried out in three different phases using different types of Ag-MOFs with and without additives, with various fabrication methods for modification of the polyamide layer. All the membranes were fully characterized to confirm the successful functionalization of membranes. The results demonstrate that Ag-MOFs are robust antibacterial nanoparticles that can reduce membrane biofouling and organic fouling and stabilize long term water flux.

Browsing by Author "Elliott, Mark"

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