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- Title
- Electrode Integration of Nanostructured Metal and Metal Oxide Materials Based on in-situ Growth Methods for Environmental Sensors.
- Creator
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Wang, Xiaochen, Cho, Hyoung Jin, Fang, Jiyu, Chen, Quanfang, Lee, Woo Hyoung, University of Central Florida
- Abstract / Description
-
In the past decades, increased human population and activities have introduced a large amount of pollutants into the environment. Various types of conventional analytical instruments were used for monitoring the emitted chemicals with low detection limit, high accuracy, and discrimination power. However, many of these methods are laboratory-based owing to sample collection, transportation, extraction, and purification steps. To make real-time on-site monitoring possible, miniaturized sensors...
Show moreIn the past decades, increased human population and activities have introduced a large amount of pollutants into the environment. Various types of conventional analytical instruments were used for monitoring the emitted chemicals with low detection limit, high accuracy, and discrimination power. However, many of these methods are laboratory-based owing to sample collection, transportation, extraction, and purification steps. To make real-time on-site monitoring possible, miniaturized sensors with various integrated elements were developed. One of the most well-known strategies is to utilize nanostructured materials with enhanced sensing properties for those devices. For a majority of the current state of art devices, the synthesis of nanostructured materials and device integration are done separately, that is, (")synthesis first and then integration(") approach which involves two separate process steps. However, this approach comes with some disadvantages such as misalignment, contamination, as well as disconnection between nanomaterials and electrodes.To overcome the aforementioned technical challenge, several synthesis methods were developed and validated for in-situ integration of nanostructured metal and metal oxide materials for environmental sensors in this work. The electroplating technique combined with photolithography was used to make the predefined metal electrodes. Then, with subsequent post-treatments, nanostructured metals and metal oxides could be produced in-situ and directly integrated in the electrodes without any extra transfer process steps.In the process of developing a phosphate sensor, nanofibrous Co electrodes were fabricated by pulsed electroplating of Co-Cu alloy and dealloying the Cu component. A linear potentiometric response to phosphate in the 10-5 to 10-2 M concentration range was obtained which validated the sensor's function. A mechanism based on mixed potential response was proposed to elucidate the Co electrode behavior in aqueous solutions with varying pH conditions and optimum pH ranges for working devices were proposed.In addition to the alloying and dealloying method, the template assisted electroplating method was also investigated. A nanoporous Co-Cu electrode fabricated by electroplating through a sacrificial glass fiber template was obtained. A linear amperometric response to phosphate with suppressed oxygen interference was achieved in a 10-5 to 10-2 M concentration range of phosphate. An analysis of the cyclic voltammetry characterization results provided a direction for further exploring an optimized electrode polarization potential range for suppressing oxygen interference while maintaining a good sensitivity to phosphate. Based on this result, we improved the fabrication process with another template: in-situ hydrothermally grown ZnO nanoflakes on the electrode surface, as a template for uniform nanostructured Co electroplating. The cyclic voltammetry characterization of the fabricated electrode showed an amperometric response in the range of 10-6 to 10-2 M of phosphate where the limit of detection (LOD) was enhanced compared with the previous work.For the flammable gas sensor development, the in-situ oxidation of Cu was utilized to form nanowires for sensing electrode fabrication. Multiple CuO nanowires were synthesized in-situ on the electroplated interdigitated Cu electrodes on a hotplate at 500 ? in air. The nanowires were successfully integrated as a sensing element into the device, forming bridges between two electrodes. The sensor's behavior was characterized by a current-voltage measurement. Simple processing parameters could be utilized for controlling the electrode morphologies and determining the characteristics of contacts - Schottky or Ohmic - at the electrode interface. A hypothesis was proposed to explain the transition phenomenon between Schottky and Ohmic contact modes, providing an important baseline for future device design and fabrication. Finally, the fabricated sensor was tested for a flammable gas detection using saturated ethanol vapor at room temperature, which implicates a low power consumption gas sensor without elevating the sensor temperature unlike traditional gas sensors.
Show less - Date Issued
- 2017
- Identifier
- CFE0007139, ucf:52312
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007139
- Title
- Electroplated micro- and nanoscale structures for emitters and sensors.
- Creator
-
Wang, Xiaochen, Cho, Hyoung, Fang, Jiyu, Chen, Quanfang, Lee, Woo Hyoung, University of Central Florida
- Abstract / Description
-
In the electroplating process, dissolved metal cations are reduced by electrical current to a form a coherent metal coating on an electrode. Therefore, electroplating is primarily applied to modify the surface properties of an object (e.g. abrasion and wear resistance, corrosion protection, lubricity, aesthetic qualities, etc.), but also be applied to build up high aspect ratio structures on undersized parts or to form devices by electroforming.Compared with other common MEMS ...
Show moreIn the electroplating process, dissolved metal cations are reduced by electrical current to a form a coherent metal coating on an electrode. Therefore, electroplating is primarily applied to modify the surface properties of an object (e.g. abrasion and wear resistance, corrosion protection, lubricity, aesthetic qualities, etc.), but also be applied to build up high aspect ratio structures on undersized parts or to form devices by electroforming.Compared with other common MEMS (microelectromechanical systems) metal device fabrication techniques, such as vapor depositions, electroplating has several outstanding advantages. First, the fabrication process is cost-efficient because electroplating process can be set up easily without complex and expensive facilities. Second, the fabrication condition of electroplating is less demanding and does not require high temperature or low pressure. Furthermore, the process is applicable to making various features consisting of nanometer to millimeter scale particles, wires, and films. Thus, in this thesis, based on the design requirements of electrospray emitters and environmental sensors, the electroplating method was chosen to fabricate micro- and nanoscale structures for such applications.Electrospray is an atomization technique by which an electrically conductive liquid through a small capillary is charged with high voltage (kV) and ejected to a ground electrode. To minimize the electric field edge effect of the emitter nozzles to get even electro-hydrodynamic pulling force on the liquid among the nozzles and minimize variation from one emitter to another, the device needs to have the viscous pressure drop across each nozzle dominant over the electro-hydrodynamic pulling force. Therefore, embedded structures that can create high flow impedance are desirable to achieve uniform feeding of low flow rate of liquid to each emitter.We designed and fabricated in-plane metallic electrospray devices with an embedded array of micropillars within a microchannel by photolithography and electroplating. The novelty of the proposed research lies in its embedded flow restriction structure, scalability, and ease of fabrication. The formation of jets as well as the flexing capability of the emitter was achieved. The other application of electroplating was demonstrated in the fabrication of environmental sensors. Utilizing a pulsed electroplating method, Co-Cu metal alloy films were prepared and Cu was selectively etched to fabricate nanoporous electrodes which could be used to measure both absolute levels and changes of phosphate concentration in aqueous environments. The formation of cobalt phosphate compound could be used for the detection. The increased surface area and relatively simple fabrication protocols make the proposed method attractive and promising for many environmental sensing applications.
Show less - Date Issued
- 2014
- Identifier
- CFE0005274, ucf:50548
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005274
- Title
- Assessment of a Surface Water Supply for Source and Treated Distribution System Quality.
- Creator
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Rodriguez, Angela, Duranceau, Steven, Lee, Woo Hyoung, Sadmani, A H M Anwar, University of Central Florida
- Abstract / Description
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This study focused on providing a source to tap assessment of surface water systems with respect to (i) the use of alternative biomonitoring tools, (ii) disinfection byproduct (DBP) formation and control, and (iii) corrosion control. In the first study component, two water systems were microbiologically evaluated using adenosine triphosphate (ATP) bioluminescence technology. It was determined that microbial ATP was useful as a surrogate for biomonitoring within a surface water system when...
Show moreThis study focused on providing a source to tap assessment of surface water systems with respect to (i) the use of alternative biomonitoring tools, (ii) disinfection byproduct (DBP) formation and control, and (iii) corrosion control. In the first study component, two water systems were microbiologically evaluated using adenosine triphosphate (ATP) bioluminescence technology. It was determined that microbial ATP was useful as a surrogate for biomonitoring within a surface water system when paired with traditional methods. Although microbial activity differed between distribution systems that used either chloramine or chlorine disinfectant, in both cases flowrate and season affected microbial ATP values. In the second study component, total trihalomethanes (TTHM) and haloacetic acids (HAA5) DBP formation and disinfectant stability was investigated using a novel DBP control process. The method relied on a combination of sulfate, ultraviolet light irradiation, pH, and aeration unit operations. Results indicate respective decreases in 7-day TTHM and HAA5 formation potentials of 36% - 57% and 20% - 47% for the surface waters investigated. In the third component of this work, a corrosion study assessed the effect of disinfectant chemical transitions on the corrosion rates of common distribution system metals. When a chlorine based disinfection system transitioned between chlorine and chloramine, mild steel corrosion increased by 0.45 mils per year (mpy) under chloramine and returned to baseline corrosion rates under chlorine. However, when a chloramine based disinfection system transitioned between chloramine and chlorine, mild steel corrosion increased in tandem with total chlorine levels. Unlike the chlorine system, the mild steel corrosion rates did not return to baseline under chloramine after exposure to 5 mg/L of total chlorine. Surface water systems should consider the use of ATP as a surrogate for biomonitoring, consider the novel treatment process for DBP formation control, and consider corrosion control in disinfectant decision-making activities.
Show less - Date Issued
- 2019
- Identifier
- CFE0007901, ucf:52751
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007901
- Title
- Characterization of Florida Landfills with Elevated Temperatures.
- Creator
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Joslyn, Ryan, Reinhart, Debra, Lee, Woo Hyoung, Randall, Andrew, University of Central Florida
- Abstract / Description
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The occurrence of elevated temperatures within landfills is a very challenging issue for landfill operators to detect and correct. Little is known regarding the causes of elevated temperatures (ETs) and the number of landfills currently operating under such conditions. Therefore, the goal of this research was to determine which landfills within Florida have been impacted by ETs, and to develop a more complete understanding of the factors that may lead to these landfills becoming elevated...
Show moreThe occurrence of elevated temperatures within landfills is a very challenging issue for landfill operators to detect and correct. Little is known regarding the causes of elevated temperatures (ETs) and the number of landfills currently operating under such conditions. Therefore, the goal of this research was to determine which landfills within Florida have been impacted by ETs, and to develop a more complete understanding of the factors that may lead to these landfills becoming elevated temperature landfills (ETLFs). Historical landfill gas wellhead data, waste deposition reports, and landfill site geometry were collected for 27 landfill cells through the FDEP OCULUS database and from landfill operators and owners. These data were evaluated to quantify the statistical characteristics that result in landfills becoming 'elevated' in temperature. Gas data included landfill gas temperatures, methane content, carbon dioxide content, and balance gas readings. Waste deposition information was gathered through solid waste reports for each landfill. Landfill site geometry was found through landfill permits, topographical landfill diagrams, and annual operation reports. Furthermore, landfill maps were created in ArcGIS to observe spatial distribution of ETs in landfills over time.Upon analysis of the landfill gas wellhead data, it was discovered that 74% of studied landfill cells had ET readings; regulatory limits specify a maximum allowable gas temperature of 55 degrees C (131 degrees F). When studying the solid waste reports, it was discovered that 37% of landfill cells contained MSW ash; of these cells, 90% of them are considered ETLFs. Regarding site geometry, it was found that ETLF cells are on-average double the site area and approximately 20 feet deeper than the average non-ETLF cell. Furthermore, results suggest that heat propagation in most landfills is limited; however, heat propagation is possible if gas wells are turned off for an extensive time period.
Show less - Date Issued
- 2019
- Identifier
- CFE0007471, ucf:52690
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007471
- Title
- Harmful Algal Bloom Mitigation using Recycle Concrete Aggregate coated with Fixed-Quat.
- Creator
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Ezeodurukwe, Ikenna, Lee, Woo Hyoung, Randall, Andrew, Sadmani, A H M Anwar, University of Central Florida
- Abstract / Description
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Human activities generate surplus nutrients which may lead to algal bloom events in water resources along with serious ecological problems and thus substantial economic losses. Particularly, harmful algal blooms (HABs) represent toxic cyanobacterial blooms which produce cyanotoxins. The primary concerns of HABs are the exposures to a wide variety of cyanotoxins via ingestion of contaminated drinking water, inhalation during recreational activities, and consumption of contaminated fish and...
Show moreHuman activities generate surplus nutrients which may lead to algal bloom events in water resources along with serious ecological problems and thus substantial economic losses. Particularly, harmful algal blooms (HABs) represent toxic cyanobacterial blooms which produce cyanotoxins. The primary concerns of HABs are the exposures to a wide variety of cyanotoxins via ingestion of contaminated drinking water, inhalation during recreational activities, and consumption of contaminated fish and shellfish. However, conventional physical and chemical methods are not always possible to efficiently handle these HABs events. It is urgent to develop viable and rapid solutions to control HABs in field and mitigate the effects of HABs in fresh water, particularly in those that serve as sources of drinking water supply.(&)nbsp;Quaternary ammonium compounds (Quats) represent a wide range of cationic compounds with different formulation that constitutes products for agriculture, domestic and medical and industry. As organic antimicrobial compounds, Quats can be used as alternatives to existing chemical-based technique for HABs control due to its less toxicity and its affinity to variety of surface. In this study, recycled concrete aggregate (RCA) from a regional construction and demolition (C(&)D) waste recycling facility was used as a sustainable and environmentally friendly substrate and coated with a composite of silica-quaternary ammonium compounds (Fixed-Quat).(&)nbsp;Then, the algistatic capabilities of imparting antimicrobial properties of Quats to the RCA surface, which involve the covalent attachment of the biocides to the surfaces (sol-gel technique), were evaluated with HABs-causing algal species, Microcystis aeruginosa. Chlorophyll-a was measured to determine the efficiency of HABs mitigation using Fixed-Quat coated RCA in terms of photosynthetic inactivation of the selected algae. OD660 and pH were measured as key parameters to monitor algal cell growth and cement hydration. Notably, a 61% reduction of chlorophyll-a within 6 hours and complete removal of chlorophyll-a within 8 hours were achieved, indicating that Fixed-Quat coated RCA would be efficient in growth inhibition of Microcystis aeruginosa. Overall, with an appropriate design for field application and further evaluations like lifetime of Quat coating and potential recovery of treated algae, the Fixed-Quat antimicrobial coated RCA would be a promising and sustainable(&)nbsp;alternative to conventional HABs mitigation methods in various aquatic systems.
Show less - Date Issued
- 2018
- Identifier
- CFE0007400, ucf:52066
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007400
- Title
- Evaluating the Integration of Chlorine Dioxide into a Coagulation, Sedimentation, and Filtration Process Treating Surface Water.
- Creator
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Coleman, Martin, Duranceau, Steven, Lee, Woo Hyoung, Sadmani, A H M Anwar, University of Central Florida
- Abstract / Description
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Methods of optimizing the coagulation, flocculation, sedimentation, and filtration (CSF) process at a conventional surface water treatment plant (WTP) were conducted to investigate opportunities for the reduction of disinfection by-product (DBP) precursor material. The research had two primary components: (1) optimize coagulant dosage and associated operating pH and (2) investigate pretreatment oxidation with chlorine dioxide (ClO2) and potassium permanganate (KMnO4). To accomplish the first...
Show moreMethods of optimizing the coagulation, flocculation, sedimentation, and filtration (CSF) process at a conventional surface water treatment plant (WTP) were conducted to investigate opportunities for the reduction of disinfection by-product (DBP) precursor material. The research had two primary components: (1) optimize coagulant dosage and associated operating pH and (2) investigate pretreatment oxidation with chlorine dioxide (ClO2) and potassium permanganate (KMnO4). To accomplish the first component, jar tests were conducted at various pH and aluminum sulfate (alum) dosages to model current and potential treatment conditions during the CSF process at a WTP. Isopleths were developed to examine the removal efficiencies of turbidity and natural organic matter (NOM). NOM is a DBP precursor material and was represented by non-purgeable dissolved organic carbon (DOC) throughout the research. Isopleths indicated that at pH 6.2 and a corresponding alum dosage of 20 mg/L (control condition), turbidity and DOC were reduced by 90 and 35 percent, respectively. However, at pH 5.5 and 30 mg/L alum dosage, turbidity removal decreased to 80 percent whereas, DOC removal improved to 50 percent. Jar testing was conducted to evaluate differences in the use of KMnO4 and ClO2 as a pretreatment chemical to observe the reduction of DBP precursor material (i.e., NOM), dissolved iron, and dissolved manganese. Addition of ClO2 was able to reduce total trihalomethanes and haloacetic acid formation potentials (168-hours) up to 40 percent and 15 percent, respectively, and was dependent on chlorine dioxide generation method, dosage, and raw water characteristics. Chlorine dioxide also was shown to remove iron and manganese at levels greater than 99 percent.
Show less - Date Issued
- 2018
- Identifier
- CFE0007396, ucf:52078
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007396
- Title
- Reducing Sulfuric Acid Pretreatment in a Nanofiltration Process Treating Surficial Groundwater.
- Creator
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Higgins, Carlyn, Duranceau, Steven, Lee, Woo Hyoung, Sadmani, A H M Anwar, University of Central Florida
- Abstract / Description
-
Nanofiltration (NF) is a pressure driven membrane process employed in drinking water treatment that requires pretreatment for reliable operation. The objective of this research was to determine if NF membranes can proficiently operate with a decreased or eliminated dose of sulfuric acid pretreatment. When used as pretreatment, sulfuric acid prevents calcium carbonate scaling on NF membranes, yet is costly, hazardous, and imparts high sulfate concentrations to NF feed and concentrate streams....
Show moreNanofiltration (NF) is a pressure driven membrane process employed in drinking water treatment that requires pretreatment for reliable operation. The objective of this research was to determine if NF membranes can proficiently operate with a decreased or eliminated dose of sulfuric acid pretreatment. When used as pretreatment, sulfuric acid prevents calcium carbonate scaling on NF membranes, yet is costly, hazardous, and imparts high sulfate concentrations to NF feed and concentrate streams. To conduct this research, a 0.324 million gallon per day (MGD) NF pilot plant was operated for 3,855 run-hours at a flux rate of 15 gallons per square foot-day. The NF pilot unit's process performance, productivity, and water quality were monitored while the sulfuric acid dose was gradually decreased, controlled by monitoring pH that ranged from pH 6.5 (80 mg/L sulfuric acid dose) to pH 7.0 (no sulfuric acid dose). NF pilot productivity, as measured by specific flux, was found to decline when sulfuric acid was eliminated by 2.33 percent, 9.61 percent, and 4.08 percent in the first stage, second stage, and total pilot system, respectively, with no distinguishable increase in pressure drop. Noticeable water quality trends include approximately 75 percent sulfate decrease in feed and concentrate streams, and 20 percent increase of calcium hardness and alkalinity in the permeate stream. After piloting, superimposed elemental imaging analysis revealed that the second stage, tail-end membrane surface was fouled with iron disulfide, calcium carbonate, clay, and natural organic matter. However, flux recovered to normal operating conditions after a membrane cleaning was performed. Results of the pilot study indicated that sulfuric acid could be eliminated from the full-scale NF pretreatment process; however, membrane cleaning frequencies could increase. If applied to the full-scale NF process, elimination of sulfuric acid pretreatment would reduce annual chemical costs by over $70,000.
Show less - Date Issued
- 2017
- Identifier
- CFE0007287, ucf:52148
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007287
- Title
- REMOTE SENSING WITH COMPUTATIONAL INTELLIGENCE MODELLING FOR MONITORING THE ECOSYSTEM STATE AND HYDRAULIC PATTERN IN A CONSTRUCTED WETLAND.
- Creator
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Mohiuddin, Golam, Chang, Ni-bin, Lee, Woo Hyoung, Wanielista, Martin, University of Central Florida
- Abstract / Description
-
Monitoring the heterogeneous aquatic environment such as the Stormwater Treatment Areas (STAs) located at the northeast of the Everglades is extremely important in understanding the land processes of the constructed wetland in its capacity to remove nutrient. Direct monitoring and measurements of ecosystem evolution and changing velocities at every single part of the STA are not always feasible. Integrated remote sensing, monitoring, and modeling technique can be a state-of-the-art tool to...
Show moreMonitoring the heterogeneous aquatic environment such as the Stormwater Treatment Areas (STAs) located at the northeast of the Everglades is extremely important in understanding the land processes of the constructed wetland in its capacity to remove nutrient. Direct monitoring and measurements of ecosystem evolution and changing velocities at every single part of the STA are not always feasible. Integrated remote sensing, monitoring, and modeling technique can be a state-of-the-art tool to estimate the spatial and temporal distributions of flow velocity regimes and ecological functioning in such dynamic aquatic environments. In this presentation, comparison between four computational intelligence models including Extreme Learning Machine (ELM), Genetic Programming (GP) and Artificial Neural Network (ANN) models were organized to holistically assess the flow velocity and direction as well as ecosystem states within a vegetative wetland area. First the local sensor network was established using Acoustic Doppler Velocimeter (ADV). Utilizing the local sensor data along with the help of external driving forces parameters, trained models of ELM, GP and ANN were developed, calibrated, validated, and compared to select the best computational capacity of velocity prediction over time. Besides, seasonal images collected by French satellite Pleiades have been analyzed to address the seasonality effect of plant species evolution and biomass changes in the constructed wetland. The key finding of this research is to characterize the interactions between geophysical and geochemical processes in this wetland system based on ground-based monitoring sensors and satellite images to discover insight of hydraulic residence time, plant species variation, and water quality and improve the overall understanding of possible nutrient removal in this constructed wetland.
Show less - Date Issued
- 2014
- Identifier
- CFE0005533, ucf:52864
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005533
- Title
- Integrating Spray Aeration and Granular Activated Carbon for Disinfection By-Product Control in a Potable Water System.
- Creator
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Rodriguez, Angela, Duranceau, Steven, Lee, Woo Hyoung, Sadmani, A H M Anwar, University of Central Florida
- Abstract / Description
-
Public water systems add disinfectants in water treatment to inactivate microbial pathogens. Chlorine, when used as a disinfectant, reacts with natural organic matter in the water to form trihalomethane (THM) and haloacetic acid (HAA5) disinfection by-products (DBPs), which are suspected carcinogens. The Safe Drinking Water Act's Disinfectant and Disinfection By-Product (D/DBP) Rules were promulgated by the U.S. Environmental Protection Agency to regulate the amount of DBPs in water systems....
Show morePublic water systems add disinfectants in water treatment to inactivate microbial pathogens. Chlorine, when used as a disinfectant, reacts with natural organic matter in the water to form trihalomethane (THM) and haloacetic acid (HAA5) disinfection by-products (DBPs), which are suspected carcinogens. The Safe Drinking Water Act's Disinfectant and Disinfection By-Product (D/DBP) Rules were promulgated by the U.S. Environmental Protection Agency to regulate the amount of DBPs in water systems. Regulatory compliance is based on maximum contaminant levels (MCL), measured as a locational running annual average (LRAA), for total THM (TTHM) and HAA5 of 80 (&)#181;g/L and 60 (&)#181;g/L, respectively. Regulated DBPs, if consumed in excess of EPA's MCL standard over many years, may increase chronic health risks. In order to comply with the D/DBP Rules, the County of Maui Department of Water Supply (DWS) adopted two DBP control technologies. A GridBee(&)#174; spray-aeration process was place into DWS's Lower Kula water system's Brooks ground storage tank in February of 2013. In March of 2015 the second DBP control technology, granular activated carbon (GAC), was integrated into DWS's Pi'iholo surface water treatment plant. To investigate the integration effectiveness of GAC and spray-aeration into a water system for DBP control, DBP data was gathered from the system between August of 2011 and August 2016, and analyzed relative to cost and performance.Prior to the spray aeration and GAC integration, it was found that TTHM levels at the LRAA compliance site ranged between 58.5 (&)#181;g/L and 125 (&)#181;g/L (at times exceeding the MCL). Additionally, HAA5 levels at the LRAA compliance site ranged between 21.2 and 52.0 (&)#181;g/L. The concerted efforts of the GAC and GridBee(&)#174; system was found to reduce LRAA TTHM and HAA5 concentrations to 38.5 (&)#181;g/L and 20.5 (&)#181;g/L, respectively, in the Lower Kula system. Hypothesis testing utilizing t-Tests confirmed that TTHMs levels were controlled by the spray aeration system and the GAC was responsible for controlling HAA5 formation. Although TTHM levels were reduced by 58 percent, and HAA5 levels by 48 percent, the estimated cumulative annual operation and maintenance (O(&)M) cost of the two systems was $1,036,000. In light of the cost analysis, total organic carbon (TOC)-based models for predicting LRAA TTHM and HAA5 levels were developed as equation (i) and (ii), respectively:(i) TTHM (&)#181;g/L = (32.5 x (TOC ppm)) + 5.59, (ii) HAA5 (&)#181;g/L = (8.37 x (TOC ppm)) + 12.4.The TTHM model yielded an R2 of 0.93, and the HAA5 model had an R2 of 0.52. F-Tests comparing predicted LRAA TTHM and HAA5 levels to actual LRAA TTHM and HAA5 levels determined no statistically-significant difference. With the knowledge of how the GAC and spray aerator controlled DBPs in the water system, a cost-effective and practical treatment operating parameter was developed. The parameter, Pi'iholo water plant filter effluent TOC content, can serve as an indicator that operators would use to alter DBP treatment process flow set points to achieve cost-effective treatment. Furthermore, the significant annual cost contribution by the GAC, coupled with HAA5 levels below DWS's MCLG, led to the recommendation of variable frequency drive (VFD) pumps for the GAC system. The addition of VFD pumps should reduce the frequency of carbon change outs while preserving adequate HAA5 control in the system.
Show less - Date Issued
- 2016
- Identifier
- CFE0006841, ucf:52881
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006841
- Title
- Treatment of Leachate Organic Matter through Sunlight Driven Processes.
- Creator
-
Lozinski, Duncan, Reinhart, Debra, Lee, Woo Hyoung, Bolyard, Stephanie, University of Central Florida
- Abstract / Description
-
The ability to manage leachate during post-closure care (PCC) of a landfill may be increasingly difficult as leachate organic matter (LOM) becomes recalcitrant when a landfill ages, requiring advanced and costly treatment technologies. This research investigated the ability to treat LOM through sunlight driven processes, with a focus on photolysis, to provide insight to landfill owners and operators on the potential of wetlands treatment as a means for reducing long-term risks and costs...
Show moreThe ability to manage leachate during post-closure care (PCC) of a landfill may be increasingly difficult as leachate organic matter (LOM) becomes recalcitrant when a landfill ages, requiring advanced and costly treatment technologies. This research investigated the ability to treat LOM through sunlight driven processes, with a focus on photolysis, to provide insight to landfill owners and operators on the potential of wetlands treatment as a means for reducing long-term risks and costs associated with leachate treatment during PCC. The study was completed in eight batch tests, where leachate was exposed to natural sunlight in central Florida for a period of 90 days. It was hypothesized that through photolytic reactions, in particular photolysis, high molecular weight recalcitrant LOM would be degraded to labile, low molecular weight material. To identify the treatment mechanisms, transformation processes were measured using ultraviolet-visible (UV-Vis) spectroscopy, fluorescence excitation-emission matrix spectroscopy (EEMs), size-exclusion chromatography (SEC), and chemical oxygen demand (COD) from the beginning to the end of the test period. Additionally, the ability for nitrogen species to become bioavailable when exposed to sunlight was evaluated for two of the leachate samples using solid-phase extraction (SPE) to fractionate recalcitrant dissolved organic nitrogen (rDON) and bioavailable dissolved organic nitrogen (bDON). Results suggest that treatment of LOM through sunlight driven processes is possible. Treatment is dependent upon the dilution of leachate and characteristics of the LOM. Dilution must be high enough to allow sunlight to penetrate the depth of the liquid. UV-Vis, EEMs, and SEC show that high molecular weight recalcitrant material is undergoing transformation into lower molecular weight material as a result of photolytic and likely biological reactions promoted by sunlight. The ability for nitrogen to become bioavailable when exposed to sunlight was shown to be dependent upon nitrogen concentrations in the sample.
Show less - Date Issued
- 2018
- Identifier
- CFE0007044, ucf:51987
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007044
- Title
- Electrochemical Microsensors for In Situ Monitoring of Chemical Compounds in Engineered and Natural Aquatic Systems.
- Creator
-
Church, Jared, Lee, Woo Hyoung, Randall, Andrew, Duranceau, Steven, University of Central Florida
- Abstract / Description
-
The adaption of needle-type electrochemical microsensor (or microelectrode) techniques to environmental science and engineering systems has transformed how we understand mass transport in biotic and abiotic processes. Their small tip diameter (5-20(&)#181;m) makes them a unique experimental tool for direct measurements of analytes with high spatial and temporal resolutions, providing a quantitative analysis of flux, diffusion, and reaction rate at a microscale that cannot be obtained using...
Show moreThe adaption of needle-type electrochemical microsensor (or microelectrode) techniques to environmental science and engineering systems has transformed how we understand mass transport in biotic and abiotic processes. Their small tip diameter (5-20(&)#181;m) makes them a unique experimental tool for direct measurements of analytes with high spatial and temporal resolutions, providing a quantitative analysis of flux, diffusion, and reaction rate at a microscale that cannot be obtained using conventional analytical tools. However, their applications have been primarily limited to understanding mass transport dynamics and kinetics in biofilms. With the advancement of sensor fabrication and utilization techniques, their potential applications can surpass conventional biofilm processes. In this dissertation, microsensors were utilized to elucidate mass transport and chemical reactions in multidisciplinary research areas including biological nutrient uptake, oily wastewater treatment, photocatalytic disinfection, and plant disease management, which have not yet explored using this emerging technology. The main objective of this work was to develop novel microsensors and use them for better understanding various natural and engineered aquatic systems. These include; 1) investigating localized photo-aeration and algal-bacterial symbiotic interaction in an advanced algal-bacterial biofilm process for nutrient removal from wastewater, 2) characterizing oil-in-water emulsions for better understanding bilge water emulsion stability, 3) evaluating sun-light driven photocatalytic reactions using a novel MoS2 nanofilm for water disinfection and microcystins-LR removal, 4) developing a zinc ion-selective microsensor and applying them for monitoring the transport of zinc in citrus trees, and 5) integrating heavy metal detection using anodic stripping voltammetry (ASV) in a microelectrode platform for plant applications.
Show less - Date Issued
- 2018
- Identifier
- CFE0007565, ucf:52576
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007565
- Title
- Using Fluorescence to Characterize Four Day Simulated Distribution System Trihalomethane Content in Florida Groundwaters.
- Creator
-
Ousley, Jonathan, Duranceau, Steven, Lee, Woo Hyoung, Sadmani, A H M Anwar, University of Central Florida
- Abstract / Description
-
The United States Environmental Protection Agency (USEPA) regulates public water systems and has established limits for certain disinfection by products (DBPs) that have been linked to health effects, such as bladder cancer. The regulation of DBPs, specifically total trihalomethanes (TTHMs) and haloacetic acids (HAAs), have encouraged water treatment professionals to assess the type and amount of organic precursors in their supplies. Three of the more common water quality parameters that are...
Show moreThe United States Environmental Protection Agency (USEPA) regulates public water systems and has established limits for certain disinfection by products (DBPs) that have been linked to health effects, such as bladder cancer. The regulation of DBPs, specifically total trihalomethanes (TTHMs) and haloacetic acids (HAAs), have encouraged water treatment professionals to assess the type and amount of organic precursors in their supplies. Three of the more common water quality parameters that are monitored as DBP surrogates include dissolved organic carbon (DOC), ultraviolet absorbance (UV254), and specific ultraviolet absorbance (SUVA). Although DOC, UV254, and SUVA have been effectively correlated to DBP formation, efforts to correlate fluorescence excitation emission matrices (FEEM) to DBP formation remains limited within the drinking water community. In this research, a fluorescence regional integration (FRI) approach was used to compare FEEM with DOC, UV254, and SUVA as an alternative surrogate for characterizing TTHMs for groundwater sources located in south central Florida. To quantitatively evaluate FEEM, DOC, UV254, and SUVA as TTHM precursor surrogate parameters, a statistical correlation analysis was employed. Thirteen groundwater samples were collected from various Central Florida groundwater wells in Lake County, Polk County, and Palm Beach County, and analyzed for FEEM, DOC, UV254, and SUVA prior to determining the four-day TTHM concentration using a simulated distribution system dosing procedure. The FRI method was then used to quantify FEEM by dividing the three-dimensional matrix into five distinct regions, each representing a unique organic constituent. The volume under each region was determined and used for the correlation analysis.It was determined that a combinations of regions III and V of the FEEM possessed a strong linear correlation to four day TTHM content (R2 = 0.95) as compared to DOC (R2 = 0.906), UV254 (R2= 0.84), SUVA (R2 = 0.640), and the individual regions of the FEEM. However, DOC showed the strongest correlation when a second order polynomial regression was used (R2 = 0.937). Results for the individual regions of the FEEM revealed four day simulated TTHM correlation coefficients of 0.25, 0.62, 0.86, 0.74, and 0.88 for regions I through V respectively. These values indicated that a combination of regions III and V, which represent the fulvic and humic-like organic fractions detected by FEEM respectively, was the most accurate four day simulated TTHM precursor surrogate parameter based on the groundwater supplies tested. These results reveal that although DOC is still one of the strongest surrogate parameters to TTHM formation, fluorescence has also shown to also be a potentially strong surrogate for groundwaters. The implications of these results signify that fluorescence monitoring could be a viable method of measuring organic content in groundwaters once the technology further develops.
Show less - Date Issued
- 2016
- Identifier
- CFE0006839, ucf:51782
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006839
- Title
- Control of Metal-Release and Tuberculation in a Silica-Laden Groundwater Distribution System on the Volcanic Island of Lana'i.
- Creator
-
Myers, Samantha, Duranceau, Steven, Sadmani, A H M Anwar, Lee, Woo Hyoung, University of Central Florida
- Abstract / Description
-
A corrosion control study for two distinct water distribution systems (WDS) has been completed for the Pulama Lana'i Water Company (Pulama). This project evaluated the use of chemical inhibitors to control corrosion and tuberculation within the Manele Bay WDS and the Lana'i City WDS. Pulama provides water to a population of 3,100 residents and is considering incorporating alternative water supplies in the future. Hence, knowing baseline corrosion rates within the WDS was desired.Several...
Show moreA corrosion control study for two distinct water distribution systems (WDS) has been completed for the Pulama Lana'i Water Company (Pulama). This project evaluated the use of chemical inhibitors to control corrosion and tuberculation within the Manele Bay WDS and the Lana'i City WDS. Pulama provides water to a population of 3,100 residents and is considering incorporating alternative water supplies in the future. Hence, knowing baseline corrosion rates within the WDS was desired.Several groundwater wells feed each of the WDS's; however, water quality between wells varies. Well water supplied to the WDS's is generally of high quality, therefore, the historical treatment method has been limited to disinfection prior to distribution. The distribution system consists of several materials of construction, which includes galvanized iron. Valves and pipes within the WDS were experiencing visible corrosion and tuberculation believed to be responsible for variable pressure drop throughout portions of the system.In this work, two corrosion racks, each consisting of two parallel loops, were designed, constructed, and installed at each site. One loop was maintained as a control while the other loop was used for testing alternative corrosion inhibitors. The racks utilized metal sample coupons and linear polarization resistance probes to provide data on corrosion rates of selected metals of interest.Results indicated that the water in Manele Bay experienced no noticeable change between the test loop and control loop when a corrosion inhibitor was added. A first experiment found the corrosion rates reached baseline steady(-)state at 4,000 operational hours. A second experiment found that the corrosion rates reached baseline steady(-)state at 2,200 operational hours. During these two experiments, the addition of a phosphate or silica(-)based inhibitor neither reduced nor increased the corrosion rates of mild steel, lead, and copper.Results from Lana'i City indicated that inhibitors offered little to no positive effect between the control condition and the test condition. During the first experiment, baseline corrosion was reached after 2,400 hours. The addition of a phosphate inhibitor did not reduce nor increase the corrosion rates of mild steel and lead. However, the corrosion rate of copper increased to 1.0mpy from 0.22mpy. The corrosion rate remained elevated after inhibitor feed was terminated. The second experiment reached baseline corrosion rates at 1,400 operational hours. The use of silica inhibitor neither reduced nor increased the corrosion rate of mil steel, lead, and copper.Since corrosion inhibitors were found to be ineffective, a valve exercise and replacement program for Pulama's assets was recommended. This program included: (1) developing a detailed asset inventory, (2) implementing operation and maintenance tasks, (3) forming a valve replacement plan, and (4) establishing long range financial planning. An opinion of probable replacement cost for 200 new valves was conceptually estimated to approximate 3.3 million dollars expended over a 20 year time frame.
Show less - Date Issued
- 2016
- Identifier
- CFE0006152, ucf:51152
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006152
- Title
- Dishwashing Water Recycling System and Related Water Quality Standards for Military Use.
- Creator
-
Church, Jared, Lee, Woo Hyoung, Randall, Andrew, Duranceau, Steven, University of Central Florida
- Abstract / Description
-
As the demand for reliable and safe water supplies increases, both water quality and available quantity are being challenged by population growth and climate change. Greywater reuse is becoming a common practice worldwide; however, in remote locations of limited water supply, such as those encountered in military installations, it is desirable to expand its classification to include dishwashing water to maximize the conservation of fresh water. Given that no standards for dishwashing...
Show moreAs the demand for reliable and safe water supplies increases, both water quality and available quantity are being challenged by population growth and climate change. Greywater reuse is becoming a common practice worldwide; however, in remote locations of limited water supply, such as those encountered in military installations, it is desirable to expand its classification to include dishwashing water to maximize the conservation of fresh water. Given that no standards for dishwashing greywater reuse by the military are currently available, the current study determined a specific set of water quality standards for dishwater recycling systems for U.S military field operations. A tentative water reuse standard for dishwashing water was developed based on federal and state regulations and guidelines for non-potable water, and the developed standard was cross-evaluated by monitoring water quality data from a full-scale dishwashing water recycling system using an innovative electrocoagulation and ultrafiltration process. A quantitative microbial risk assessment (QMRA) was also performed based on exposure scenarios derived from literature data. As a result, a specific set of dishwashing water reuse standards for field analysis (simple, but accurate) was finalized as follows: turbidity ((<)1 NTU), E. coli ((<)50 cfu mL-1), and pH (6(-)9). UV254 was recommended as a surrogate for organic contaminants (e.g., BOD5), but requires further calibration steps for validation. The developed specific water standard is the first for dishwashing water reuse and will be expected to ensure that water quality is safe for field operations, but not so stringent that design complexity, cost, and operational and maintenance requirements will not be feasible for field use. In addition the parameters can be monitored using simple equipment in a field setting with only modest training requirements and real-time or rapid sample turn-around. This standard may prove useful in future development of civilian guidelines.
Show less - Date Issued
- 2015
- Identifier
- CFE0005773, ucf:50061
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005773
- Title
- Study of the Formation and Control of Disinfection By-Products Originating from a Surface Water Supply on the Volcanic Island of Guam.
- Creator
-
Laberge, Erica, Duranceau, Steven, Randall, Andrew, Lee, Woo Hyoung, University of Central Florida
- Abstract / Description
-
Three oxidants have been evaluated for use as alternative chemical pretreatments for Fena Lake, a surface water that supplies the U.S. Navy's Public Water System (PWS) on the volcanic island of Guam. The study consisted of two investigative components. The first and primary component included a bench-scale evaluation to study the effects of different pre-oxidant chemicals on the formation of chlorinated disinfection by-products (DBPs). The second and ancillary component included a series of...
Show moreThree oxidants have been evaluated for use as alternative chemical pretreatments for Fena Lake, a surface water that supplies the U.S. Navy's Public Water System (PWS) on the volcanic island of Guam. The study consisted of two investigative components. The first and primary component included a bench-scale evaluation to study the effects of different pre-oxidant chemicals on the formation of chlorinated disinfection by-products (DBPs). The second and ancillary component included a series of water treatment and distribution system management studies that analyzed DBP formation within the treatment plant and water distribution system. The goal of this research was to reduce total trihalomethane (TTHM) and the five haloacetic acid (HAA5) formations in the PWS.In the primary component of the research, raw surface water from Fena Lake was collected by U.S. Navy personnel and shipped to University of Central Florida (UCF) laboratories for experimentation. Bench-scale tests that simulated the coagulation, flocculation, sedimentation and filtration (CSF) that comprises the Navy Water Treatment Plant (NWTP) were used to evaluate the use of two alternative pre-oxidants, potassium permanganate (KMnO4) and chlorine dioxide (ClO2) in lieu of gaseous chlorine (Cl2). The research assessed DBP formation by comparing several pretreatment scenarios, namely: (1) no pretreatment, (2) chlorine pretreatment, and (3) alternative oxidant pretreatment. KMnO4 pretreatment resulted in the lowest percent reduction of TTHMs and HAA5 relative to chlorine pretreatment, at 5.7% and 22.7%, respectively; however, this amount was still a reduction from the results demonstrated for the chlorine pretreatment condition. Without using a pre-oxidant, TTHM and HAA5 formation were reduced by 22.8% and 37.3%, respectively, relative to chlorine pretreatment. Chlorine dioxide demonstrated the greatest TTHM and HAA5 reduction relative to chlorine pretreatment at 34.4% and 53.3%, respectively.The second component of research consisted of a series of studies that evaluated distribution system operations and management alternatives to identify opportunities that could achieve DBP reduction within the PWS. Three concerns that were addressed were the NWTP's compliance with the U.S. Environmental Protection Agency's (USEPA's) Stage 2 Disinfectants/Disinfection By-Products (D/DBP) Rule, variable hydraulic detention times within a small subdivision in the distribution system, and severe weather. It was determined that: (1) A decision based on in-plant studies to cease prechlorination at the NWTP resulted in a decrease in TTHMs and HAA5s throughout the distribution system by 62% and 75%, respectively; (2) A fluoride tracer study led to the discovery of a valved pipeline responsible for elevated DBPs because of excessive water age that when exercised and managed resolved intermittent DBP spikes in the PWS; and (3) when the NWTP's ballasted floc clarifier (BFC) was operated in-series prior to the conventional CSF process during severe weather conditions the TTHM and HAA5 were below 39 ug/L and 29 ug/L, respectively, proving BFC in-series is a practical option for the plant during severe weather.
Show less - Date Issued
- 2014
- Identifier
- CFE0005515, ucf:50299
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005515
- Title
- Trihalomethane Removal and Re-Formation in Spray Aeration Processes Treating Disinfected Groundwater.
- Creator
-
Smith, Cassandra, Duranceau, Steven, Randall, Andrew, Lee, Woo Hyoung, University of Central Florida
- Abstract / Description
-
Historically, chlorination has been widely utilized as a primary and secondary disinfectant in municipal water supplies. Although chlorine disinfection is effective in inactivating pathogenic microbes, the use of chlorine creates the unintentional formation of regulated chemicals. On January 4, 2006, the United States Environmental Protection Agency (EPA) promulgated the Stage 2 Disinfectants/Disinfection by-product rule (DBPR) that focuses on public health protection by limiting exposure to...
Show moreHistorically, chlorination has been widely utilized as a primary and secondary disinfectant in municipal water supplies. Although chlorine disinfection is effective in inactivating pathogenic microbes, the use of chlorine creates the unintentional formation of regulated chemicals. On January 4, 2006, the United States Environmental Protection Agency (EPA) promulgated the Stage 2 Disinfectants/Disinfection by-product rule (DBPR) that focuses on public health protection by limiting exposure to four trihalomethanes (THM) and five haloacetic acids (HAA5), formed when chlorine is used for microbial pathogen control. This thesis examines post-aeration TTHM formation when employing spray-aeration processes to remove semi-volatile TTHMs from chlorinated potable water supplies.A bench scale air stripping unit was designed, constructed and operated to evaluate spray aeration for the removal of the four regulated trihalomethane (THM) species from potable drinking water including bromodichloromethane, bromoform, dibromochloromethane, chloroform. The study was conducted using finished bulk water samples collected from two different water treatment facilities (WTFs) located in Oviedo and Babson Park, Florida. Both treatment plants treat groundwater; however, Oviedo's Mitchell Hammock WTF (MHWTF) supply wells contain dissolved organic carbon and bromide DBP precursors whereas the Babson Park WTF #2 (BPWTF2) supply well contains dissolved organic carbon DBP precursors but is absent of bromide precursor. Three treatment scenarios were studied to monitor impacts on total trihalomethane (TTHM) removal and post-treatment (post-aeration) TTHM formation potential, including 1) no treatment (non-aerated control samples), 2) spray aeration via specially fabricated GridBee(&)#174; nozzle for laboratory-scale applications, 3) spray aeration via a commercially available manufactured BETE(&)#174; nozzle used for full-scale applications. Select water quality parameters, chlorine residual, and total trihalomethane concentrations were monitored throughout the study. The GridBee(&)#174; spray nozzle resulted in TTHM removals ranging from 45.2 (&)#177; 3.3% for the BPWTF2 samples, and 37.7 (&)#177; 3.1% for the MHWTF samples. The BETE(&)#174; spray nozzle removed 54.7(&)#177;3.9% and 48.1(&)#177;6.6% of total trihalomethanes for the Babson Park and Mitchell Hammock WTF samples, respectively. The lower percent removals at the MHWTF are attributed to the detectable presence of bromide and subsequent formation of hypobromous acid in the samples. Post spray aeration TTHM formation potentials were monitored and it was found that the MHWTF experienced significantly higher formation potentials, once again due to the presence of hypobromous acid which led to increases in overall TTHM formation over time in comparison with the Babson Park WTF #2 TTHM formation samples. In addition, chlorine residuals were maintained post spray aeration treatment, and initial chlorine residual and trihalomethane concentrations did not significantly impact overall spray nozzle performance. Among other findings, it was concluded that spray nozzle aeration is a feasible option for the Babson Park WTF #2 for TTHM compliance. For Oviedo's Mitchell Hammock WTF spray aeration was successful in removing TTHMs, however it was not effective in maintaining DBP rule compliance due to the excessive nature of DBP formation in the water samples. This study was not intended to serve as an assessment of varying nozzle technologies; rather, the focus was on the application of spray aerators for TTHM removal and post-formation in drinking water systems.
Show less - Date Issued
- 2015
- Identifier
- CFE0005715, ucf:50117
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005715
- Title
- An Improved Biosolid Gasifier Model.
- Creator
-
McLean, Hannah, Cooper, David, Randall, Andrew, Lee, Woo Hyoung, University of Central Florida
- Abstract / Description
-
As populations increase and cities become denser, the production of waste, both sewage sludge and food biomass, increases exponentially while disposal options for these wastes are limited. Landfills have minimal space for biosolids; countries are now banning ocean disposal methods for fear of the negative environmental impacts. Agricultural application of biosolids cannot keep up with the production rates because of the accumulation of heavy metals in the soils. Gasification can convert...
Show moreAs populations increase and cities become denser, the production of waste, both sewage sludge and food biomass, increases exponentially while disposal options for these wastes are limited. Landfills have minimal space for biosolids; countries are now banning ocean disposal methods for fear of the negative environmental impacts. Agricultural application of biosolids cannot keep up with the production rates because of the accumulation of heavy metals in the soils. Gasification can convert biosolids into a renewable energy source that can reduce the amount of waste heading to the landfills and reduce our dependence on fossil fuels. A recently published chemical kinetic computer model for a fluidized-bed sewage sludge gasifier (Champion, Cooper, Mackie, (&) Cairney, 2014) was improved in this work based on limited experimental results obtained from a bubbling fluidized-bed sewage sludge gasifier at the MaxWest facility in Sanford, Florida and published information from the technical literature. The gasifier processed sewage sludge from the communities surrounding Sanford and was operated at various air equivalence ratios and biosolid feed rates. The temperature profile inside of the gasifier was recorded over the span of four months, and an average profile was used in the base case scenario. The improved model gave reasonable predictions of the axial bed temperature profile, syngas composition, heating value of the syngas, gas flow rate, and carbon conversion. The model was validated by comparing the simulation temperature profile data with the measured temperature profile data. An overall heat loss coefficient was calculated for the gasification unit to provide a more accurate energy balance. Once the model was equipped with a heat loss coefficient, the output syngas temperature closely matched the operational data from the MaxWest facility.The model was exercised at a constant equivalence ratio at varying temperatures, and again using a constant temperature with varying equivalence ratios. The resulting syngas compositions from these exercises were compared to various literature sources. It was decided that some of the reactions kinetics needed to be adjusted so that the change in syngas concentration versus change in bed temperature would more closely match the literature. The reaction kinetics for the Water-Gas Shift and Boudouard reactions were modified back to their original values previously obtained from the literature.
Show less - Date Issued
- 2015
- Identifier
- CFE0005663, ucf:50199
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005663
- Title
- Functional Characterization of Green Sorption Media and Scaling of Pilot Studies for Copper Removal in Stormwater Runoff.
- Creator
-
Houmann, Cameron, Chang, Ni-bin, Wanielista, Martin, Lee, Woo Hyoung, University of Central Florida
- Abstract / Description
-
Green adsorption media with the inclusion of renewable and recycled materials can be applied as a stormwater best management practice for copper removal. A green adsorption media mixture composed of recycled tire chunk, expanded clay aggregate, and coconut coir was physicochemically evaluated for its potential use in an upflow media filter. The results found that the use of the green adsorption media mixture in isolation or the coconut coir with an expanded clay filtration chamber could be an...
Show moreGreen adsorption media with the inclusion of renewable and recycled materials can be applied as a stormwater best management practice for copper removal. A green adsorption media mixture composed of recycled tire chunk, expanded clay aggregate, and coconut coir was physicochemically evaluated for its potential use in an upflow media filter. The results found that the use of the green adsorption media mixture in isolation or the coconut coir with an expanded clay filtration chamber could be an effective and reliable stormwater best management practice for copper removal. A suite of tests were conducted on the media mixture and the individual media components including studies of isotherm, reaction kinetics, column adsorption and reaction kinetics. Batch adsorption tests revealed that the media and media mixture follow both the Freundlich and Langmuir isotherm models and that the coconut coir had the highest affinity for copper. A screening of desorbing agents revealed that hydrochloric acid has good potential for copper desorption, while batch tests for desorption with hydrochloric acid as the desorbing agent showed the data fit the Freundlich isotherm model. Reaction kinetics revealed that the adsorption reaction took less than 1 hour to reach equilibrium and that it followed pseudo-second order kinetics for the mixture and coconut. Desorption kinetic data had high correlation with the pseudo-second order model and revealed a rapid desorption reaction. Batch equilibrium data over 3 adsorption/desorption cycles found that the coconut coir and media mixture were the most resilient and demonstrated that they could be used through 3 or more adsorption/desorption cycles. The coconut coir also performed the best under dynamic conditions, having an equilibrium uptake of 1.63 mg?g-1, compared to 0.021 mg?g-1 at an influent concentration of 1.0 mg?L-1 and a hydraulic retention time of 30 minutes. A physical evaluation of the media found the macro-scale properties, such as particle size distribution and mass-volume relationships, and observed the micro-scale properties such as surface and pore microstructures, crystalline structures, and elemental composition. FE-SEM imaging found a strong correlation between the porosity of the micro pore structure and the adsorptive capacity. The equilibrium and dynamic adsorption testing results were confirmed by elemental analysis, which showed measureable quantities of copper in the coconut coir and media mixture after adsorption followed by partial desorption. A new scaling-up theory was developed through a joint consideration of the Damk(&)#246;hler and P(&)#233;clet numbers for a constant media particle size such that a balance between transport-controlled and reaction-controlled kinetics can be harmonized. A series of column breakthrough tests at varying hydraulic residence times revealed a clear peak adsorptive capacity for the media mixture at a Damk(&)#246;hler number of 2.7. The P(&)#233;clet numbers for the column breakthrough tests indicated that mechanical dispersion is an important effect that requires further consideration in the scaling-up process. However, perfect similitude of the Damk(&)#246;hler number cannot be maintained for a constant media particle size, and relaxation of hydrodynamic similitude through variation of the P(&)#233;clet number must occur.
Show less - Date Issued
- 2015
- Identifier
- CFE0005630, ucf:50205
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005630
- Title
- Evaluation of Iron and Manganese Control for a Volcanic Surface Water Supply Treated with Conventional Coagulation, Sedimentation and Filtration Processes.
- Creator
-
Hall, Christine, Duranceau, Steven, Lee, Woo Hyoung, Randall, Andrew, University of Central Florida
- Abstract / Description
-
A research project assessing the effectiveness of potassium permanganate (KMnO4) for the treatment of iron (Fe) and manganese (Mn) has been conducted by the University of Central Florida (UCF) on behalf of the United States Navy with regards to the water supply on the island of Guam, located in the Marianas Islands. The study consisted of three basic investigative components: one that examined the use of potassium permanganate for iron and manganese control for Fena Lake, a second that...
Show moreA research project assessing the effectiveness of potassium permanganate (KMnO4) for the treatment of iron (Fe) and manganese (Mn) has been conducted by the University of Central Florida (UCF) on behalf of the United States Navy with regards to the water supply on the island of Guam, located in the Marianas Islands. The study consisted of three basic investigative components: one that examined the use of potassium permanganate for iron and manganese control for Fena Lake, a second that examined the existing unit operations that comprised the Navy's water treatment plant (NWTP), and a third that examined iron and manganese field sampling analytical procedures.In the first and primary component of the research, surface water from Fena Lake located within the Naval Magazine in proximity of Santa Rita, Guam was collected at several different lake depths and initially analyzed for iron and manganese using inductively coupled plasma. Subsequent aliquots of Fena Lake collected at the various water depths were transferred to jars then dosed with varying amounts of potassium permanganate after which iron and manganese content was determined. The jars were covered to simulate actual lake to plant transfer conditions experienced at the Navy's on-island facilities. A portion of the jars was dosed with potassium permanganate prior to metals analysis in order to allow for comparisons of baseline conditions. To represent conventional treatment processes, the water samples were then coagulated with aluminum sulfate prior to filtration to remove the oxidized manganese and iron formed from the addition of the potassium permanganate. Coagulated aliquots were filtered and collected to evaluate residual dissolved iron and manganese content. Based on the results of the jar tests it was determined that manganese was reduced by 95% or greater and that iron was completely removed to below the analytical detection limit (0.001 mg/L). It was determined that the potassium permanganate dose required for oxidation of iron was 0.94 mg/mg iron and for manganese was 1.92 mg/mg manganese. It was also observed that when the jars containing aliquots that turned brown in color after potassium permanganate dosing meant that iron and manganese were present and were being oxidized; however, water samples that turned pink were found to be over-dosed with potassium permanganate. The pink water is an undesired characteristic and could result in customer complaints when distributed to the system.The second component of research focused on NWTP existing conditions. Water samples were collected after each key unit operation within the NWTP and analyzed for iron and manganese. This was to determine if pre-chlorination at Fena Lake was effective at removing iron and manganese that could be present in the source water. Analysis was conducted where pre-chlorination at Fena Lake was practiced as well as when no pretreatment was practiced prior to the NWTP. It was determined that the iron and manganese were not detected downstream of the coagulation unit operation within the NWTP even when pre-chlorination was not practiced. Consequently pre-chlorination of Fena Lake source water was not required for controlling iron and manganese under the conditions experienced in this study.A third study was also implemented to confirm that 0.1-micron filters are appropriate for use in preparing samples for analytical determination of iron and manganese analysis at various points within the NWTP. The filtration step is important to delineate between dissolved and suspended iron and manganese forms. Standard Methods 3120B recommends the use of 0.45-micron filters, although based on literature it has been shown that oxidized manganese particles may be smaller than a 0.45-micron pore size. Unless a coagulant was used, the oxidized manganese may not be fully removed via the 0.45-micron filter. To verify the effectiveness of using a 0.1-micron filter, a jar test was conducted to compare the use of a 0.1-micron filter, a 0.45-micron filter, and a 0.45-micron filter after the sample has been coagulated. It was found that the use of a 0.1-micron filter was superior to the use of 0.45-micron filters even with coagulant addition when directly comparing between dissolved and suspended iron and manganese forms. It is recommended that 0.1-microns be utilized in lieu of historically recommended 0.45-micron filters for sample preparation procedures.
Show less - Date Issued
- 2014
- Identifier
- CFE0005180, ucf:50655
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005180
- Title
- Metastable-State Photoacids: Synthesis, Properties, and Applications.
- Creator
-
Patel, Parth, Chumbimuni Torres, Karin, Hernandez, Florencio, Santra, Swadeshmukul, Beazley, Melanie, Lee, Woo Hyoung, University of Central Florida
- Abstract / Description
-
Reversible photochromic compounds have the ability to reversibly change its color when it absorbs photons of a particular wavelength. This process of color change is a consequence of structural changes within the compound, such as cis-trans photo-isomerization. Some examples of photochromic compounds are spiropyrans, spirooxazines, diarylethenes and azobenzenes. These compounds have been extensively studied for decades, and are used in various applications such as biomedicine, chemical...
Show moreReversible photochromic compounds have the ability to reversibly change its color when it absorbs photons of a particular wavelength. This process of color change is a consequence of structural changes within the compound, such as cis-trans photo-isomerization. Some examples of photochromic compounds are spiropyrans, spirooxazines, diarylethenes and azobenzenes. These compounds have been extensively studied for decades, and are used in various applications such as biomedicine, chemical sensors and harvesting solar energy. However, majority of photochromic compounds are initially activated by ultraviolet (UV) light. The use of UV light is harmful for biological applications and photo-degrade the compound over repeated use. To overcome these limitations, a new class of reversible photochromic compound was introduced, called metastable-state photoacid (mPAH). In brief, mPAH is a photochromic compound which can photo-dissociate its protons under visible light and can thermally re-capture the released protons efficiently in the dark. Based on this unique property, in this research, we (1) synthesized different mPAH, and (2) studied and characterized their physicochemical (acidity, kinetics, and optical) properties. Additionally, we (3) applied different visible light activated mPAHs towards light controllable polymeric-based ion-selective optodes for detection of calcium ions and sodium ions, and modulate fluorescence with pH. The research presented herein opens new avenues towards the synthesis of mPAH derivatives and could be applied to any proton-transfer process related applications which requires wireless controllability with high sensitivity.
Show less - Date Issued
- 2019
- Identifier
- CFE0007849, ucf:52769
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007849
