The United States Environmental Protection Agency regulates the lead and copper content of a public water system's finished water at the consumer's tap, through the Safe Drinking Water Act's Lead and Copper Rule (LCR), promulgated in 1991. This rule was recently changed through the LCR Revisions (LCRR), that took effect in 2021. The more stringent requirements of the LCRR motivated the City of Sarasota, Florida (City), to work with the University of Central Florida (UCF) on a study of the municipality's finished water corrosivity. Initially, this evaluation investigated the City's existing finished water corrosivity using linear polarization resistance (LPR) measurements and gravimetric coupon analysis at the pilot-scale, during which four phosphate-based inhibitors were tested for corrosion control. Based on the initial screening results, the City challenged UCF to derive a cost-effective, bench-scale method that could mimic distribution system conditions and be used to assess treatment technology infrastructure changes on finished water corrosivity. A modified corrosion jar test was developed that compared metal release of a high and low total dissolved solids water. The modified bench-scale method that omitted the effects of zero headspace using a sealed environment was found to be an improvement over conventional jar testing techniques. The results of the bench-scale experiments demonstrated the effectiveness and reproducibility of the modified method, as confirmed through analyses of variance. The modified bench-scale method simulated distribution system metal release, using first-order kinetic models, with R2 values of up to 0.98, demonstrating its beneficial use as a cost-effective alternative to otherwise more complicated pipe loop studies.

Microcystins (MCs) are toxins produced by cyanobacteria commonly found in harmful algal blooms (HAB) occurring in many surface waters. Due to their toxicity to humans and other organisms, the World Health Organization (WHO) set a guideline of 1 µg/L for microcystin-leucine-arginine (MC-LR) in drinking water. However, current analytical techniques for the detection of MC-LR such as liquid chromatography-mass spectrometry (LC-MS) and enzyme-linked immunosorbent assay (ELISA) are costly, bulky, time-consuming, and mostly conducted in a laboratory, requiring highly trained personnel. Therefore, an analytical method that can be used in the field for rapid determination is essential. In this study, an Anti-MC-LR/MC-LR/Cysteamine coated screen-printed carbon electrode (SPCE) biosensor was newly developed to detect MC-LR, bioelectrochemically, in water. The functionalization of the electrode surface was examined using scanning electron microscopy-energy dispersive X-Ray spectroscopy (SEM-EDX) and X-Ray photoelectron spectroscopy (XPS). The sensor performance was evaluated by electrochemical impedance spectroscopy (EIS), obtaining a linear working range of MC-LR concentrations between 0.1 and 100 µg/L with a limit of detection (LOD) of 0.69 ng/L. Natural water samples experiencing HABs were then collected and analyzed using the developed biosensor and validated using ELISA, demonstrating the excellent performance of the biosensor with a relative standard deviation (RSD) of 0.65%. The interference and selectivity tests showed a minimal error and RSD values against other common MCs and possible coexisting ions found in water, suggesting high selectivity and low sensitivity of the biosensor. The biosensor showed acceptable functionality with a shelf life of up to 12 weeks. Overall, the Anti-MC-LR/MC-LR/Cysteamine/SPCE biosensors can be an innovative solution with characteristics that allow for in situ, low-cost, and easy-to-use capabilities which are essential for developing an overarching and integrated "smart" environmental management system.

The production of clean water is emphasized under the United Nations goals for sustainable development (SDGs), enlightening the acute need of developing new sustainable technologies in all disciplines. SDGs have urged all engineers in the 21st century to mitigate pollution of drinking water sources and prevent all receiving waterbodies from the impact of agriculture discharge, wastewater effluent, and stormwater runoff. Current water matrix constituents of concern include traditional pollutants (i.e., total nitrogen and total phosphate), natural organic matters (i.e., total organic carbon (TOC), tannic acid), heavy metals (i.e., copper, calcium), and harmful algae toxins (i.e., microcystin), as well as contaminants of emerging concern (i.e., Per- and polyfluoroalkyl substances (PFAS), pharmaceuticals, endocrine disrupting chemicals, personal care products). This study presents the most recent development of a suite of in situ cost-effective, scalable, and fit-for-purpose specialty adsorbents to simultaneously remove PFAS, TOC, total nitrogen, total phosphate, and microcystin through synergistic effect of different specialty ingredients. It is also aimed to clarify physiochemical removal mechanisms for the removal of color (tannic acid), nutrients (phosphate and nitrate), contaminants of emerging concern (PFAS) and algal toxins (Microcystin LR). The originality of these specialty adsorbents with chemical, molecular, and even microbial insights falls within the sustainable nature of specialty ingredients and wide availability tailored for scalable applications in any landscape.

Ultraviolet advanced oxidation processes were compared using sodium perborate (UV/NaBO3 AOP) or hydrogen peroxide (UV/H2O2 AOP) for 1,4-dioxane removal from tertiary wastewater effluent. Both UV/H2O2 and UV/NaBO3 AOPs were also tested with the addition of acetic acid. Results revealed that sodium perborate performed similarly to hydrogen peroxide – the UV/NaBO3 AOP with 6 milligrams per liter (mg/L) as H2O2 resulted in 43.9 percent 1,4-dioxane removal, while an equivalent UV/H2O2 AOP showed 42.8 percent removal. Although the oxidants performed similarly, NaBO3 is an average of 3.3 times more expensive than H2O2. However, the solid form of NaBO3 can provide a major benefit to remote and mobile operations. Unlike H2O2 solution, which degrades over time and requires repeated costly shipments, NaBO3 is a convenient source of H2O2, and a long-term supply can be shipped at once and mixed into solution as needed. Additionally, acetic acid addition increased 1,4-dioxane removal by 5.7 percent in an UV/H2O2 AOP. It is proposed that the UV irradiation of acetic acid produced the acetoxyl radical, which cohesively works with the hydroxyl radical, produced via H2O2 irradiation, to enhance 1,4-dioxane degradation in a combined, novel UV/H2O2/acetic acid AOP. Other UV-AOP observations relate to a decrease of up to 29 percent in total dissolved solids (TDS), an inverse relationship between TDS and turbidity removals, and degradation of organic matter. Despite organic matter changes, the UV/NaBO3 AOP did not reduce trihalomethane formation due to the increased chlorine demand from hydrogen peroxide residual. Additionally, new insights into limitations of H2O2 residual test methods are included.

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Understanding the groundwater flow in karst aquifers and the effect of best management practices (BMPs) on nitrate decrease in spring discharge is critical for effective management and protection of karst water resources. However, the control on the conduit network's impacts on spring discharge and nitrate concentration is not fully understood, and the cumulative effects of BMP on reducing nitrate in karst groundwater systems have not been evaluated at the basin scale. In this dissertation, a coupled Conduit Flow Process (CFPv2) and Conduit Mass Three-Dimensional (CMT3D) model was applied to evaluate the biosorption-activated media (BAM)-based BMP on nitrate removal in Silver Springs in Florida. It is found that the effect of BMP by implementing BAM blanket filters in twenty-six stormwater retention basins is limited; whereas, for implementing BAM blanket filters in 50% of the urban area, the nitrate-N concentration in spring discharge would be decreased by 10.7% in a normal hydrologic year. The controls on the contribution of conduit flow to spring discharge are evaluated. For aquifer with turbulent flow in a single conduit, the effects of three dimensionless numbers (Reynolds number, relative surface roughness, and hydraulic conductivity ratio) and recharge on conduit flow contribution are quantified. Moreover, the effects of conduit geometry and density on conduit flow contribution are evaluated for conduit networks. Finally, the prediction of long-term average discharge in ungauged basins is assessed for improving recharge estimation.

The use of ultraviolet (UV) light and chlorine dioxide (ClO2) as an advanced oxidation process (AOP) has been investigated at the bench-scale to understand the effects of their use on disinfection by-product (DBP) formation potential (FP) in chlorinated groundwater (GW) and surface water (SW) supplies. Two GWs and two SWs of varying qualities were subject to a series of AOP treatment sequences at the bench scale: sodium hypochlorite, to serve as a baseline; ClO2-Cl2, UV-Cl2, and UV-ClO2-Cl2. In these treatment sequences, Cl2 is used as a primary and secondary disinfectant. Several water quality parameters were measured throughout the experiments, including chlorite (ClO2-) and chlorate (ClO3-) when ClO2 was used for process testing. Total trihalomethane (TTHM) FP curves were developed for each experiment along with the 7-day haloacetic acid (HAA) FP. The treatment sequence UV-ClO2 followed by Cl2 addition for GW supplies was shown to remove between 8 and 35 percent of the TTHM FP as compared to little to no change in formation potential with UV treatment alone followed by Cl2 addition. The SW supplies resulted in reductions between 16 and 27 percent for the treatment sequence UV-ClO2 followed by Cl2, approximately double the reduction from ClO2 alone followed by Cl2. GW treatment using the UV-ClO2 AOP followed by Cl2 was found to increase HAA formation, in one case by almost 50 percent compared to the baseline HAA concentrations. The research indicated the reduction of DBP FP AOP effectiveness to reduce DBP formation was highly dependent on the specific source water type and quality.

Wet detention ponds are used for stormwater treatment across the United States and reduce most pollutants by at least 60%, but only remove 30% of total nitrogen. Floating Treatment Wetlands (FTWs) are an emerging technology that uses aquatic plants suspended in the pelagic zone to remove nitrogen through vegetative assimilation and microbial denitrification. A before-after field experiment evaluated nitrogen removal in a an existing pond in Orlando, FL, retrofitted with BioHaven® FTWs planted with the aquatic macrophytes Juncus effusus (Soft Rush) and Pontederia cordata (Pickerelweed). Surface water samples were used to compare the nitrogen removal performance of the pond under both storm and non-storm conditions during a pre-analysis phase (control) to post-analysis after FTW deployment. The evaluation revealed similar TN removals in non-storm conditions during pre-analysis and post-analysis periods (-1% and -3%, respectively). During storm conditions, there was a negative TN removal of -26% in the preanalysis compared to the positive 29% removal post-analysis. In addition, nitrogen concentrations for organic-nitrogen, ammonia/ammonium, and nitrites/nitrates were used as input for calibrating and validating a system dynamics model to predict multiple, interacting nitrogen species' transformation and translocation across the abiotic and biotic components of water, sediment, plants, and atmosphere. The validated model created in STELLA v.9.4.1 was used to simulate alternative designs to achieve maximum nitrogen removal based on the treatment efficiency in the evaluation. Simulations predicted 60% FTW coverage at the experimental planting density (22 per m2) could achieve maximum nitrogen removal. Alternatively, similar nitrogen removal could be achieved at only 15% FTW coverage by increasing plant density. The model can be used as a lowcost tool for designing FTW technology applications and monitoring nitrogen transport.

Ichetucknee Springs System is in north central Florida, under the jurisdiction of the Suwannee River Water Management District (SRWMD). The Ichetucknee River is one of the most pristine spring-fed rivers in Florida and became a state park in 1970. Over 400,000 people visited the Ichetucknee Springs State Park in 2016. From that total, over 130,000 people came during the tubing season alone (Memorial Day to Labor Day). During the tubing season, only 750 visitors per day are allowed to launch from the North Launch, near the Ichetucknee Head Spring. The park enforces visitor usage of the river during these time frames to protect the integrity of the aquatic vegetation and aquatic organisms in the northern portion of the River. The objective of this study is to evaluate the response of water quality from the Head Spring to the seasonal changes in visitor numbers to the Park. Water quality parameters were continuously monitored and recorded by a SRWMD station using a YSI EXO2 and SUNA nitrate sensor: temperature, turbidity, pH, specific conductivity, dissolved oxygen content, and nitrates (NO2+NO3). Water quality data from April 2015 to September 2017 was reviewed and processed into max daily values that were compared to daily visitor counts. Results from the statistical analysis indicate there is a significant difference in turbidity from the Head Spring during the tubing season and outside the tubing season (Kruskal-Wallis, p < 0.001), which results from higher visitor counts during the weekends of the tubing season. However, due to inconsistency of water quality readings and equipment damage, some data were lost or outside the range of monitoring capabilities; which may have resulted in decreased correlation between water quality and daily visitor counts. Continued evaluation of water quality by continuous monitoring is warranted as it can assist the SRWMD and Ichetucknee Springs State Park Staff better monitor and evaluate the health of the Ichetucknee Springs System.