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- Title
- Evaluation of an On-Line Device to Monitor Scale Formation in a Brackish Water Reverse Osmosis Membrane Process.
- Creator
-
Roque, Jennifer, Duranceau, Steven, Randall, Andrew, Zhang, Husen, University of Central Florida
- Abstract / Description
-
A modified two-element membrane pressure vessel assembly has been used to monitor process operational changes in a full-scale reverse osmosis (RO) water treatment plant (WTP). This study evaluated the effectiveness of the assembly as an on-line monitoring device intended to detect scale formation conditions when connected to an operating RO process train. This study was implemented to support the requirements of a larger University of Central Florida (UCF) research project ongoing at the city...
Show moreA modified two-element membrane pressure vessel assembly has been used to monitor process operational changes in a full-scale reverse osmosis (RO) water treatment plant (WTP). This study evaluated the effectiveness of the assembly as an on-line monitoring device intended to detect scale formation conditions when connected to an operating RO process train. This study was implemented to support the requirements of a larger University of Central Florida (UCF) research project ongoing at the city of Sarasota's Public Works and Utilities (City) water treatment facilities located in Sarasota, Florida. During the time-frame of this study, the City was in the process of eliminating their sulfuric acid feed from the pretreatment system of their existing 4.5 million gallon per day (MGD) RO membrane process. The City was motivated to eliminate its dependence on sulfuric acid to reduce operating costs as well as reduce operation health and safety risks associated with the use of the acid as a pretreatment chemical. Because the City was concerned with secondary process impacts associated with acid elimination, additional measures were desired in order to protect the full-scale process.This thesis reports on the design, fabrication and installation of a third-stage two membrane element pressure vessel (")canary(") sentinel monitoring device (Canary), its effectiveness as an on-line scaling monitor during full-scale acid elimination, and presents the results of the study. The Canary sentinel device was controlled using the normalized specific flux of the two membrane elements fed by a portion of the second stage concentrate of one of the City's full-scale RO process skids. Although the Canary demonstrated the ability to detect changes in an RO process operation, scaling did not occur under the conditions evaluated in this study. An autopsy of one of the Canary elements revealed that no scaling had occurred during the acid elimination process. Therefore, the Canary was found to be useful in its function as a sentinel, even though no scaling was detected by the device after acid elimination at the City's full-scale plant had been accomplished.
Show less - Date Issued
- 2012
- Identifier
- CFE0004433, ucf:49353
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004433
- Title
- Evaluating Corrosion Control Alternatives for a Reverse Osmosis, Nanofiltration and Anion-Exchange Blended Water Supply.
- Creator
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Wilder, Rebecca, Duranceau, Steven, Randall, Andrew, Zhang, Husen, University of Central Florida
- Abstract / Description
-
The research reported herein describes the study activities performed by University of Central Florida (UCF) on behalf of the Town of Jupiter Water Utilities (Town). The Town recently changed its water treatment operations from a combination of reverse osmosis (RO), lime softening (LS) and anion-exchange (IX) to a combination of RO, IX and nanofiltration (NF). Although this treatment change provided enhanced water to the surrounding community in terms of better contaminant removal and reduced...
Show moreThe research reported herein describes the study activities performed by University of Central Florida (UCF) on behalf of the Town of Jupiter Water Utilities (Town). The Town recently changed its water treatment operations from a combination of reverse osmosis (RO), lime softening (LS) and anion-exchange (IX) to a combination of RO, IX and nanofiltration (NF). Although this treatment change provided enhanced water to the surrounding community in terms of better contaminant removal and reduced DBP formation potential, integration of the NF process altered finished water quality parameters including pH, alkalinity and hardness. There was concern that these changes could result in secondary impacts related to accelerated corrosion of distribution system components and subsequent regulatory compliance. In addition, replacement of the LS process altered the in-plant blending operations by creating an unstable intermediate blend composed of RO and IX waters. There were concerns that this intermediate blend was affecting the integrity of in-plant hydraulic conveyance components.UCF developed a corrosion monitoring study to assess the potential impacts related to internal corrosion, water quality and regulatory compliance after integrating NF into the existing water supply. The intended purpose was to further highlight the complexities of corrosion, describe a unique approach to corrosion monitoring as well as offer various recommendations for corrosion control in a system that relies on a blended water supply. Research was conducted in three phases to address the in-plant and distribution system corrosion issues separately and identify appropriate corrosion control treatment alternatives. The three test phases included: a baseline conditions assessment to compare corrosion of the intermediate RO-IX blend with the finished water blend (RO-IX-NF); an in-plant corrosion control evaluation; and a distribution system corrosion control evaluation.A test apparatus was constructed and operated at the Town's facilities to monitor corrosion activity of mild steel, copper and lead solder metal components. The test apparatus consisted of looped PVC pipe segments housed with electrochemical probes and metal coupons to monitor corrosion rates of the metallic components. Electrochemical probes containing metal electrodes were used to obtain instantaneous corrosion rates by means of the Linear Polarization Resistance (LPR) technique while the metal coupons were gravimetrically evaluated for weight loss. The electrochemical probes permitted daily monitoring of each metal's corrosion rates while metal coupons were analyzed at the conclusion of testing and used for comparison. Different test waters flowed through the corrosion rack according to each test phase and relative corrosion rates were compared to evaluate corrosion control techniques.Study findings indicated that the intermediate blend was more corrosive, in general, then the final blend; however, research also indicated that the final blend of water was increasing lead and copper concentrations within the distribution system. An orthophosphate corrosion inhibitor was evaluated for in-plant corrosion control. The inhibitor's performance was assessed by comparing mild steel corrosion rates with and without the chemical. In addition, secondary impacts related to introduction of the chemical were evaluated by pre-corroding the metallic components prior to the introduction of the inhibitor. Results indicated that the inhibitor marginally decreased corrosion rates and increased the turbidity of the water supply. Based on these observations, it was concluded that the inhibitor was not a viable solution for in-plant corrosion control. To resolve in-plant corrosion issues, recommendations were made for modification of in-plant blending operations to eliminate the corrosive intermediate blend from the process allowing the RO, IX and NF treated waters to be blended in a common location. The effectiveness of a poly/ortho blended phosphate chemical inhibitor was evaluated for reducing lead and copper corrosion to resolve distribution corrosion issues. A 50/50 poly/ortho blend was selected because of its analogous use in similar municipal water facilities. Metallic corrosion rates, particularly lead and copper, were compared with and without the inhibitor to assess the performance of the chemical. Like the previous test phase, the metallic components were pre-corroded prior to the chemical's introduction to determine if secondary impacts could result from its presence. Results indicated that lead and copper corrosion rates were lower in the presence of the inhibitor, and secondary impacts related to increased turbidity were not observed for this chemical. Based on these results, it was recommended that a poly/ortho blended phosphate be used to decrease lead and copper corrosion within the Town's distribution system.
Show less - Date Issued
- 2012
- Identifier
- CFE0004460, ucf:49349
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004460
- Title
- Fate of Coated Zinc Oxide in Municipal Solid Waste Landfills.
- Creator
-
Bolyard, Stephanie, Reinhart, Debra, Santra, Swadeshmukul, Randall, Andrew, University of Central Florida
- Abstract / Description
-
Given the increase in nanomaterial (NM) use in consumer products and the large fraction of waste placed in landfills worldwide, the probability of these products reaching municipal solid waste (MSW) landfills at the end of their useful life is high. Since nanotechnology use is still in its early stages, there are currently no regulations pertaining to the disposal of NMs and their fate in MSW landfills is still unknown. Understanding the fate of NMs in MSW landfills is vital to ensure the...
Show moreGiven the increase in nanomaterial (NM) use in consumer products and the large fraction of waste placed in landfills worldwide, the probability of these products reaching municipal solid waste (MSW) landfills at the end of their useful life is high. Since nanotechnology use is still in its early stages, there are currently no regulations pertaining to the disposal of NMs and their fate in MSW landfills is still unknown. Understanding the fate of NMs in MSW landfills is vital to ensure the proper handling of these novel materials from cradle to grave; such research will provide information on how these NMs can be safely introduced into the environment. This research seeks to understand the fate of NMs within waste environments by examining the interactions between NMs and landfill leachate components. The primary focus of this thesis is the effect of Zinc Oxide (ZnO) on biological landfill processes, solids aggregation, and chemical speciation of Zn in landfill leachate following the addition of crystalline, nano-sized ZnO coated with triethoxycaprylylsilane. This research (1) observed the effects of coated ZnO on five-day biochemical oxygen demand (BOD5) and biochemical methane potential (BMP), (2) examined effects of solids aggregation on the fate of ZnO, (3) quantified the concentration of Zinc (Zn) by size fractions, and (4) modeled the chemical speciation of Zn in landfill leachate using Visual MINTEQ.No change in dissolved Zn was observed after coated ZnO was exposed to (")middle-aged(") leachate. Upon exposure to (")mature(") leachate there was an increase in dissolved Zn assumed to be a result of the dissociation of ZnO. Solids data supported the aggregation of particles in both middle aged and mature leachate. There was an increase in the Zn concentration in leachate fractions greater than 1500 nm presumably due to the dispersion of normally insoluble ZnO nanoparticles (NPs) following the interaction with humic acids (HA). ZnO did not inhibit anaerobic or aerobic processes in either middle aged or mature leachate, presumably due to the relatively low concentration of dissolved ionic Zn. Despite the observation of increased dissociation upon exposure to mature leachate, the presence of dissolved organic matter (DOM) may have hindered the ability for dissolved ionic Zn to become bioavailable. Fractionation, BOD5 and BMP tests, and chemical speciation modeling provided insight on the mobility of ZnO in landfills and the absence of inhibitory effects on landfill processes. Aggregation of ZnO NPs may prevent movement through traditional containment systems (i.e. geomembrane liners) due to the increased particle size. However, the increased dispersion suggests that ZnO NPs will be transported out of the landfill in the leachate, however biological treatment of leachate should be unaffected by the presence of ZnO. The bioavailability of Zn was not substantially affected by the presence of ZnO due to affinity of dissolved Zn for DOM. However, due to the heterogeneity of landfill leachate and the utilization of different NM coatings, it is challenging to predict the overall mobility of other NMs in a landfill.
Show less - Date Issued
- 2012
- Identifier
- CFE0004264, ucf:49509
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004264
- Title
- Turbidity Removal Efficiency and Toxicity Issues Associated with the Chitosan-Based Dual Bio-Polymer Systems.
- Creator
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Hernandez, Rylee, Chopra, Manoj, Wanielista, Martin, Randall, Andrew, University of Central Florida
- Abstract / Description
-
Stormwater runoff can be a great concern in the State of Florida due to the impact the quality of the runoff water can have on the natural water bodies. Stormwater runoff can carry pollutants and sediments which can cause both physical and biological risks in an aquatic ecosystem such as a lake, river, or pond. Polymers, namely the chitosan-based dual polymer system, can be used remove the sediment from this runoff to ensure the safety of the state's water bodies. Three soils are used in this...
Show moreStormwater runoff can be a great concern in the State of Florida due to the impact the quality of the runoff water can have on the natural water bodies. Stormwater runoff can carry pollutants and sediments which can cause both physical and biological risks in an aquatic ecosystem such as a lake, river, or pond. Polymers, namely the chitosan-based dual polymer system, can be used remove the sediment from this runoff to ensure the safety of the state's water bodies. Three soils are used in this testing: AASTO soil classifications A-3(sandy soil) and A-2-4 (silty-sand), and a soil with a fine-grained limerock component. An optimum dose of the chitosan-based dual polymer system is first determined using jar testing. The optimum dose is the dose that reduces the final turbidity to 29 NTUS or below and creates significant flocs. The under dose and over dose are calculated based on the optimum dose. Using these dosages, field scale tests are conducted using two different treatment methods: a semi-passive treatment method and a passive treatment method. Whole effluent toxicity and residual chitosan tests are then conducted on the effluent from the field scale treatment methods. The passive treatment method is the best field scale treatment method when using the silty-sand and the soil with a fine-grained limerock component. The semi-passive treatment method is the best field scale treatment method when using the sandy soil. The passive treatment method with the silty-sand achieves a final turbidity of 123.9 NTUS (88.45% removal). The passive treatment method with the soil with a fine-grained limerock component achieves a final turbidity of 132 NTUS (83.86% removal). The semi-passive treatment method with the sandy soil achieves a final turbidity of 31.43 NTUS (82.04% removal). There is only significant toxicity associated with the tests using the effluent from the passive treatment method with the soil with a fine-grained limerock component which only uses the cationic polymer.
Show less - Date Issued
- 2012
- Identifier
- CFE0004301, ucf:49482
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004301
- Title
- Application of Landfill Treatment Approaches for the Stabilization of Municipal Solid Waste.
- Creator
-
Bolyard, Stephanie, Reinhart, Debra, Santra, Swadeshmukul, Randall, Andrew, University of Central Florida
- Abstract / Description
-
This research focused on the fundamental requirements of stabilizing a mature landfill using three treatment approaches as well as the implications of discharging leachate organic matter (LOM) to wastewater treatment plants (WWTPs). Three treatment approaches aimed at removing releasable carbon and nitrogen from mature landfills including flushing with clean water, leachate recirculation with ex-situ chemical oxidation, and leachate recirculation with ex-situ chemical oxidation and in-situ...
Show moreThis research focused on the fundamental requirements of stabilizing a mature landfill using three treatment approaches as well as the implications of discharging leachate organic matter (LOM) to wastewater treatment plants (WWTPs). Three treatment approaches aimed at removing releasable carbon and nitrogen from mature landfills including flushing with clean water, leachate recirculation with ex-situ chemical oxidation, and leachate recirculation with ex-situ chemical oxidation and in-situ aeration were evaluated. After extensive treatment of the waste in the flushing bioreactor (FB) scenarios, the overall biodegradable fraction was reduced relative to mature waste. Leachate quality improved for all FBs but through different mechanisms. Flushing was the most effective approach at removing biodegradable components and improving leachate quality. A mass balance on carbon and nitrogen revealed that a significant fraction still remained in the waste. Solid waste and leachate samples from the anaerobic bioreactors and FBs were characterized using Fourier Transform Infrared (FTIR) to provide a better understanding of changes in waste characteristics when waste transitions from mature to stabilized. Organic functional groups associated with aliphatic methylene were present in leachate and solid waste samples during the early stages of anaerobic degradation and disappeared once these wastes underwent treatment. Once the waste was stabilized, the FTIR spectra of leachate and solid waste were dominated by inorganic functional groups (carboxylic acid/carbonate group, carbonate, quartz, and clay minerals). Leachate is commonly co-treated with domestic wastewater due to the cost and complexity of on-site treatment. The organic constituents in leachate can be problematic for WWTPs as their recalcitrant components pass through conventional treatment processes, impacting effluent quality. Twelve leachates where characterized for total nitrogen (TN) and dissolved organic nitrogen (DON). The average concentration of TN and DON in leachate was 1,160 and 40.7 mg/L, respectively. Leachates were fractionated based on hydrophobic (recalcitrant; rDON) and hydrophilic (bioavailable; bDON) properties. The average concentrations of bDON and rDON were 16.5 and 18.4 mg/L, respectively. Multiple leachate and wastewater co-treatment simulations were carried out to assess the treatment of leachate nitrogen at historic nitrogen removal levels of four WWTPs and the effects on wastewater effluent quality for four WWTPs. The effluent quality exceeded typical TN limits of 3 to 10 mg/L at leachate volumetric contributions of 10%. The maximum calculated pass through concentrations of rDON and DON at 10% volumetric contribution for the twelve leachates was 4.77 and 9.71 mg/L, respectively. The effects of LOM on wastewater effluent quality was further evaluated in the field. Results showed that leachate detection for each field study could be determined using UV254 nm absorbance. DON and dissolved organic carbon (DOC) concentrations increased at significant levels in leachate-impacted wastewater samples. The DON decreased through the treatment train, suggesting that this parameter was effectively removed, while DOC persisted. DOC pass through coincided with an increase in color and UV254 nm absorption. In effluents, the UV254 nm transmittance was just below the minimum 65% disinfection requirement at dilutions greater than 1%. Leachate-impacted wastewater showed a higher concentration of humic-like peaks during fluorescence measurements than wastewater without leachate.
Show less - Date Issued
- 2016
- Identifier
- CFE0006076, ucf:50959
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006076
- Title
- Development of a Chemical Kinetic Model for a Fluidized-bed Sewage Sludge Gasifier.
- Creator
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Champion, Wyatt, Cooper, Charles, Mackie, Kevin, Randall, Andrew, University of Central Florida
- Abstract / Description
-
As the need for both sustainable energy production and waste minimization increases, the gasification of biomass becomes an increasingly important process. What would otherwise be considered waste can now be used as fuel, and the benefits of volume reduction through gasification are seen in the increased lifespan of landfills. Fluidized-bed gasification is a particularly robust technology, and allows for the conversion of most types of waste biomass.Within a fluidized-bed gasifier, thermal...
Show moreAs the need for both sustainable energy production and waste minimization increases, the gasification of biomass becomes an increasingly important process. What would otherwise be considered waste can now be used as fuel, and the benefits of volume reduction through gasification are seen in the increased lifespan of landfills. Fluidized-bed gasification is a particularly robust technology, and allows for the conversion of most types of waste biomass.Within a fluidized-bed gasifier, thermal medium (sand) is heated to operating temperature (around 1350(&)deg;F) and begins to fluidize due to the rapid expansion of air entering the bottom of the reactor. This fluidization allows for excellent heat transfer and contact between gases and solids, and prevents localized (")hot spots(") within the gasifier, thereby reducing the occurrence of ash agglomeration within the gasifier. Solids enter the middle of the gasifier and are rapidly dried and devolatilized, and the products of this step are subsequently oxidized and then reduced in the remainder of the gasifier. A syngas composed mainly of N2, H2O, CO2, CO, CH4, and H2 exits the top of the gasifier.A computer model was developed to predict the syngas composition and flow rate, as well as ash composition and mass flow rate from a fluidized-bed gasifier. A review of the literature was performed to determine the most appropriate modeling approach. A chemical kinetic model was chosen, and developed in MATLAB using the Newton-Raphson method to solve sets of 18 simultaneous equations. These equations account for mass and energy balances throughout the gasifier. The chemical kinetic rate expressions for these reactions were sourced from the literature, and some values modified to better fit the predicted gas composition to literature data.
Show less - Date Issued
- 2013
- Identifier
- CFE0005089, ucf:50746
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005089
- Title
- Assessment, Optimization, and Enhancement of Ultrafiltration (UF) Membrane Processes in Potable Water Treatment.
- Creator
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Boyd, Christopher, Duranceau, Steven, Cooper, Charles, Randall, Andrew, University of Central Florida
- Abstract / Description
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This dissertation reports on research related to ultrafiltration (UF) membranes in drinking water applications. A pilot-scale investigation identified seasonal surface water quality impacts on UF performance and resulted in the development of a dynamic chemically enhanced backwash protocol for fouling management. Subsequent analysis of UF process data revealed limitations with the use of specific flux, transmembrane pressure (TMP), and other normalization techniques for assessing UF process...
Show moreThis dissertation reports on research related to ultrafiltration (UF) membranes in drinking water applications. A pilot-scale investigation identified seasonal surface water quality impacts on UF performance and resulted in the development of a dynamic chemically enhanced backwash protocol for fouling management. Subsequent analysis of UF process data revealed limitations with the use of specific flux, transmembrane pressure (TMP), and other normalization techniques for assessing UF process fouling. A new TMP balance approach is presented that identifies the pressure contribution of membrane fouling and structural changes, enables direct process performance comparisons at different operating fluxes, and distinguishes between physically and chemically unresolved fouling. In addition to the TMP balance, a five component optimization approach is presented for the systematic improvement of UF processes on the basis of TMP variations. Terms are defined for assessing process event performance, a new process utilization term is presented to benchmark UF productivity, and new measures for evaluating maintenance procedures are discussed. Using these tools, a correlation between process utilization and operating pressures was established and a sustainable process utilization of 93.5% was achieved. UF process capabilities may be further enhanced by pre-coating media onto the membrane surface. Silicon dioxide (SiO2) and powdered activated carbon (PAC) are evaluated as pre-coating materials, and the applicability of the TMP balance for assessing pre-coated membrane performance is demonstrated. The first use of SiO2 as a support layer for PAC in a membrane pre-coating application is presented at the laboratory-scale. SiO2-PAC pre-coatings successfully reduced physically unresolved fouling and enhanced UF membrane organics removal capabilities.
Show less - Date Issued
- 2013
- Identifier
- CFE0005088, ucf:50758
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005088
- Title
- Bioremediation of a Trichloroethene DNAPL Source Zone Utilizing a Partitioning Electron Donor - Field Implementation.
- Creator
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Bartlett, Joseph, Randall, Andrew, Reinhart, Debra, Wang, Dingbao, Daprato, Rebecca, University of Central Florida
- Abstract / Description
-
Trichloroethene (TCE) is a chlorinated volatile organic compound (CVOC) that can be found in industrial and household products. It is typically used as a solvent or degreaser. TCE can have detrimental health impacts and is known to be carcinogenic to humans. Federal and state regulatory drivers determine the need to assess and remediate soil and groundwater contaminated with CVOCs. There are many different methods for remediation; however, bioremediation has the ability to breakdown TCE all...
Show moreTrichloroethene (TCE) is a chlorinated volatile organic compound (CVOC) that can be found in industrial and household products. It is typically used as a solvent or degreaser. TCE can have detrimental health impacts and is known to be carcinogenic to humans. Federal and state regulatory drivers determine the need to assess and remediate soil and groundwater contaminated with CVOCs. There are many different methods for remediation; however, bioremediation has the ability to breakdown TCE all the way to harmless gasses (ethene and ethane). Bioremediation requires dechlorinating microbes (indigenous or augmented), electron donor (food source), and an electron acceptor (CVOCs). Electron donors are typically injected into the target area and are distributed naturally throughout the subsurface. A partitioning electron donor (PED) has the ability to partition from the dissolved phase into low permeability zones and/or dense non-aqueous phase liquids (DNAPLs) (i.e. source zones), and then be slowly released and readily metabolized at the DNAPL:water interface. This thesis summarizes the first field scale PED implementation with the main research objective of evaluating whether utilizing a PED for bioremediation of a TCE source zone is achievable. Based on laboratory studies, n-butyl acetate (nBA) was selected as the PED for application in a TCE source area, selected at Cape Canaveral Air Force Station's Launch Complex 34, identified as Hot Spot 1. Hot Spot 1 has a zone of high concentration TCE in a low permeability clay layer at a depth of approximately 40 feet below land surface (ft BLS). Implementation included the recirculation of groundwater above and below the clay layer without PED injection for comparative analysis (baseline flux), then with PED injection in, above, and below the clay layer (system operation phase). The groundwater was recirculated using a solar powered recirculation system, which consisted of a pair of extraction wells in the center of the treatment area, screened above and below the low permeability layer, and a set of five peripheral injection well pairs, similarly screened, used to create an inward hydraulic gradient and promote horizontal flow across the top and base of the clay layer. Groundwater concentrations in the treatment area were monitored using three monitoring well clusters (each with six depth intervals ranging from 23 to 61 ft BLS) and existing monitoring wells in the treatment area. The groundwater recirculation system was operated, without addition of PED, for approximately four weeks to establish the baseline flux condition. PED was then introduced to the subsurface by injecting 34,000 gallons of a solution containing nBA (3,000 mg/L) and conservative tracers (bromide and/or iodide) using direct push technology (DPT) at 20 locations from approximately 23 to 62 ft BLS. Confirmation sampling (DPT groundwater and monitoring well sampling) was conducted to assess the PED distribution after injection activities. The recirculation system remained off after PED injection for approximately four weeks to allow the PED to partition into the DNAPL and to facilitate the acclimation and establishment of biomass within the treatment area. The recirculation system was then restarted and operated for approximately one year. Groundwater sampling was performed regularly to assess mass flux and microbial reductive dechlorination. PED amendment was successfully injected above, in, and below the low permeability layer, as evidenced by positive detections of nBA from soil and groundwater sampling within the treatment area immediately following the injection event. The implementation was also successful in reducing contaminant mass from both soil and groundwater.CVOC mass removed during the baseline flux phase (pre-PED injection; 14 March 2011 to 18 April 2011) was calculated based on groundwater sampling data and totaled 14 pounds (lbs). All of the mass removed during the baseline flux phase was from the high permeability layer, indicating that mass removed was dissolved phase mass above and below the clay layer. Mass removal was likely a result of extraction and dilution from operation of the recirculation system. The mass removal rate during the baseline flux phase was approximately 0.40 pounds per day (lbs/day).CVOC mass removed during the system operation phase (post-PED injection; 9 August 2011 to 11 September 2012) was calculated based on groundwater and soil sampling data and totaled 110 lbs. Of the 110 lbs removed, 78 lbs of CVOC mass was removed from the high permeability layer and 32 lbs was removed from the low permeability layer, indicating that not only dissolved phase mass in the high permeability layer was removed, but source zone material sorbed into the low permeability layer was removed as well. Mass removed from the low permeability layer was likely a result degredation (ie. reductive dechlorination) at and around the DNAPL:water interface. The mass removal rate during the system operation phase was approximately 0.28 lbs/day. The higher rate of removal during the baseline flux phase is likely due to the initial removal of a significant amount of dissolved phase CVOCs and not the mass sorbed into the low permeability layer.In general, TCE and cis-1,2-dichloroethene (cDCE) concentrations decreased during the baseline flux phase with no increase in vinyl chloride (VC) concentration, indicating removal via extraction and dilution and not reductive dechlorination. Following the PED injection, TCE and cDCE concentrations generally decreased with increases observed in VC concentrations, indicative of reductive dechlorination. Ethene concentration was monitored to assess complete dechlorination from TCE to ethene. Average ethene concentration detected in samples collected from treatment zone monitoring wells increased from 52.8 micrograms per liter (?g/L) (pre-injection; April 2011) to 408 ?g/L (September 2012), indicating complete dechlorination of CVOCs was occurring. In addition, dechlorinating microbial biomass increased significantly, as evidenced by increases in average Dhc (dechlorinating microbial culture) and vcrA (specific gene of culture responsible for breaking down VC through to ethene) concentrations detected in samples collected from treatment zone monitoring wells; Dhc increased from 8.5x106 gene copies/L (pre-injection; April 2011) to 5.0x107 gene copies/L (September 2012) and vcrA increased from 5.0x103 gene copies/L (April 2011) to 6.8x107 gene copies/L (September 2012).TOC concentration was shown to generally increase following the injection activities, then decrease through the system operation period, indicating the electron donor was successfully injected into the subsurface, and was being utilized by the indigenous dechlorinating microbial population. Remaining TOC at the site was minimal, with an average TOC concentration of 21 mg/L (September 2012) detected in samples collected from treatment zone monitoring wells, decreasing from 250 mg/L (August 2011) just following injection. If reductive dechlorination were to continue to occur, more electron donor would be needed.The reduction of CVOC concentrations at the site are likely due to reductive dechlorination as a result of the PED amendment injection, as evidenced by: (i) the production of daughter products relative to the degradation of TCE; (ii) the production of ethene; (iii) the production of dechlorinating microbial mass; and (iv) the reduction of electron donor.Although effective, nBA was utilized and depleted quicker than an industry electron donor would be expected to last, depleting within 12 months, as opposed to two to three years. Based on this alone, it appears that nBA would not be a good candidate for full scale implementation at this or other sites; however, to provide a true comparative analysis, side-by-side test plots would be recommended at the site, one utilizing nBA and one utilizing a standard substrate. This would ensure both electron donor options are being subjected to the same geophysical and geochemical settings and the same or similar contaminant concentrations.
Show less - Date Issued
- 2016
- Identifier
- CFE0006439, ucf:51457
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006439
- Title
- Biological Nutrient Removal (BNR) Process Optimization and Recovery of Embedded Energy Using Biodiesel By-product.
- Creator
-
Salamah, Sultan, Randall, Andrew, Duranceau, Steven, Chopra, Manoj, University of Central Florida
- Abstract / Description
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Enhanced biological phosphorus removal (EBPR) as well as biological nitrogen removal require a carbon source to be carried out. Volatile fatty acid (VFAs) (mainly acetic and propionic acids) are the major driving force for EBPR. Many domestic wastewaters have an insufficient amount of VFAs. However, carbon sources such as acetic and propionic acids can be produced using primary solids fermentation process. Due to the cost of VFA production, an external carbon source can be added to the...
Show moreEnhanced biological phosphorus removal (EBPR) as well as biological nitrogen removal require a carbon source to be carried out. Volatile fatty acid (VFAs) (mainly acetic and propionic acids) are the major driving force for EBPR. Many domestic wastewaters have an insufficient amount of VFAs. However, carbon sources such as acetic and propionic acids can be produced using primary solids fermentation process. Due to the cost of VFA production, an external carbon source can be added to the biological nutrient removal (BNR) system that can be fermented to provide the desired VFAs. Glycerol (biodiesel by-product) offers a solution to reduce carbon addition cost if can be fermented to acetic and propionic acid or can be used directly as an external carbon substrate for EBPR and denitrification. Using glycerol in wastewater treatment can also offset the biodiesel plant disposal cost and reduce the BNR chemical cost. The main objective of this study was to optimize the prefermentation process and optimize the BNR system using glycerol as an external carbon source. In this work, Optimization of the prefermentation process using glycerol, mixing, and hydrogen gas addition was evaluated. EBPR performance within an A2O-BNR system was evaluated using either a direct glycerol method to the anaerobic zone or by co-fermentation with primary solids. Also, optimization of the nitrogen removal (specifically denitrification) efficiency of a 5-stage BardenphoTM BNR system using either a direct glycerol method to the second anoxic zone or by co-fermentation with primary solids was evaluated. It was found in this study that glycerol was an efficient external carbon substrate for EBPR as well as biological nitrogen removal. The prefermentation experiment showed that glycerol co-fermentation with primary solids produced significantly higher (p(<)0.05) VFAs than primary solids fermentation alone, even more than the possible value from the added glycerol (427 mg-COD/L). The increased VFAs imply that the glycerol addition stimulated additional fermentation of primary solids. Lowering the prefermenter mixing energy (50 to 7 rpm) resulted in a significant increase in VFAs production (80%). Also, purging the headspace of the prefermenter with hydrogen gas did not lead to more VFAs, but significantly (p(<)0.05) increased the propionic acid to acetic acid ratio by 41%. In the A2O-BNR pilot plant experiment, it was found that glycerol is a suitable renewable external substrate to drive enhanced EBPR as well as denitrification. The results from both locations of glycerol addition (direct vs. fermented) were beneficial to the BNR system. Both systems had similar effluent quality and achieved total nitrogen (TN) and total phosphorus (TP) removals up to 86% and 92% respectively. The 5-stage BardenphoTM BNR experiment investigated the location of glycerol addition (direct vs. fermented) on the performance of denitrification in the second anoxic zone and the overall performance. The results from both systems were that glycerol was beneficial to the BNR system and had virtually similar effluent quality. Both systems achieve complete denitrification and excellent removal of TN and TP up to 95% and 89% respectively. Also, the pilot that received fermented glycerol had significantly higher VFAs loading and lower observed yield. The side-stream prefermenter effluent flowing to the second anoxic reactor did not cause high effluent ammonia (NH3) concentration. In summary, the location at which glycerol was added did not affect effluent quality for nitrogen and phosphorus. However, glycerol addition and mixing energy did impact prefermenter performance and effluent quality.
Show less - Date Issued
- 2017
- Identifier
- CFE0006788, ucf:51826
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006788
- Title
- Near-road Dispersion Modeling of Mobile Source Air Toxics (MSATs) in Florida.
- Creator
-
Westerlund, Kurt, Cooper, Charles, Radwan, Ahmed, Randall, Andrew, Hall, Steven, University of Central Florida
- Abstract / Description
-
There is a growing public concern that emissions of mobile source air toxics (MSATs) from motor vehicles may pose a threat to human health. At present, no state or federal agencies require dispersion modeling of these compounds, but many agencies are concerned about potential future requirements. Current air pollution professionals are familiar with Federal Highway Administration (FHWA) and U.S. Environmental Protection Agency (EPA) requirements for dispersion modeling to produce predicted...
Show moreThere is a growing public concern that emissions of mobile source air toxics (MSATs) from motor vehicles may pose a threat to human health. At present, no state or federal agencies require dispersion modeling of these compounds, but many agencies are concerned about potential future requirements. Current air pollution professionals are familiar with Federal Highway Administration (FHWA) and U.S. Environmental Protection Agency (EPA) requirements for dispersion modeling to produce predicted concentrations for comparison with appropriate standards. This research examined a method in which the potential near-road concentrations of MSATs were calculated. It was believed that by assessing MSATs in much the same way that are used for other pollutants, the model and methods developed in this research could become a standard for those quantifying MSAT concentrations near-roadways.This dissertation reports on the results from short-term (1-hour) and long-term (annual average) MSATs dispersion modeling that has been conducted on seven intersections and seven freeway segments in the state of Florida. To accomplish the modeling, the CAL3QHC model was modified to handle individual MSAT emissions input data and to predict the concentrations of several MSATs around these roadway facilities. Additionally, since the CAL3MSAT model is DOS based and not user-friendly, time was invested to develop a Windows(&)#174; graphical user interface (GUI). Real-world data (traffic volumes and site geometry) were gathered, worst-case meteorology was selected, mobile source emission factors (EFs) were obtained from MOVES2010a, and worst-case modeling was conducted. Based on a literature search, maximum acceptable concentrations (MACs) were proposed for comparison with the modeled results, for both a short-term (1-hour) averaging time and a long-term (1-year) averaging time.Results from this CAL3MSAT modeling study indicate that for all of the intersections and freeway segments, the worst-case 1-hour modeled concentrations of the MSATs were several orders of magnitude below the proposed short-term MACs. The worst-case 1-year modeled concentrations were of the same order of magnitude as the proposed long-term MACs.The 1-year concentrations were first developed by applying a persistence factor to the worst-case 1-hour concentrations. In the interest of comparing the predicted concentrations from the CAL3MSAT persistence factor approach to other dispersion models, two EPA regulatory models (CAL3QHCR and AERMOD) with the ability to account for yearly meteorology, traffic, and signal timing were used. Both hourly and annual MSAT concentrations were predicted at one large urban intersection and compared for the three different dispersion models. The short-term 1-hour results from CAL3MSAT were higher than those predicted by the two other models due to the worst-case assumptions. Similarly, results indicate that the CAL3MSAT persistence factor approach predicted a worst-case annual average concentration on the same order of magnitude as the two other more refined models. This indicated that the CAL3MSAT model might be useful as a worst-case screening approach.
Show less - Date Issued
- 2013
- Identifier
- CFE0004772, ucf:49804
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004772
- Title
- Evaluation of The Biodegradability and Toxicity of PCA and mPCA.
- Creator
-
Rueda, Juan, Randall, Andrew, Duranceau, Steven, Yestrebsky, Cherie, University of Central Florida
- Abstract / Description
-
The main types of hypergolic propellants used at Kennedy Space Center (KSC) are hydrazine (HZ) and monomethylhydrazine (MMH). HZ and MMH are classified as hazardous materials and they are also known to be potentially carcinogenic to humans; therefore, handling these substances and their waste is strictly regulated. The wastes streams from HZ and MMH have been estimated to be the main hazardous wastes streams at KSC. Currently at KSC these wastes are first neutralized using citric acid and...
Show moreThe main types of hypergolic propellants used at Kennedy Space Center (KSC) are hydrazine (HZ) and monomethylhydrazine (MMH). HZ and MMH are classified as hazardous materials and they are also known to be potentially carcinogenic to humans; therefore, handling these substances and their waste is strictly regulated. The wastes streams from HZ and MMH have been estimated to be the main hazardous wastes streams at KSC. Currently at KSC these wastes are first neutralized using citric acid and then they are transported on public roads for incineration as hazardous materials. A new method using alpha ketoglutaric acid (AKGA) was proposed to treat HZ and MMH wastes. From the reaction of AKGA with HZ and MMH two stable products are formed, 1,4,5,6-tetrahydro-6-oxo-3-pyridazinecarboxylic acid (PCA) and l-methyl-1,4,5,6-tetrahydro-6-oxo-3-pyridazinecarboxylic acid (mPCA), respectively.The cost of purchasing AKGA is greater than the cost of purchasing citric acid; thus, AKGA can only become a cost effective alternative for the treatment of HZ and MMH wastes if the products of the reactions (PCA and mPCA) can be safely disposed of into the sewage system without affecting the treatment efficiency and effluent quality of the wastewater treatment plant (WWTP). In this research mPCA and PCA were analyzed for acute toxicity using fish and crustaceans as well as their effect on the wastewater treatment efficiency and viability using AS microbes, and their biodegradability by AS organisms. Acute toxicity on fish and crustaceans was investigated according to the methods for acute toxicity by USEPA (USEPA Method EPA-821-R-02-012) using Ceriodaphnia dubia (96 hours) and Pimephales promelas (96 hours) as the test organisms. The effect of mPCA and PCA in the treatment efficiency and viability were estimated from respiration inhibition tests (USEPA Method OCSPP 850.3300) and heterotrophic plate counts (HPCs). Lastly, the biodegradability of mPCA and PCA was assessed using the Closed Bottle Test (USEPA Method OPPTS 835.3110). For mPCA, the 96 hours LC50 for C. dubia was estimated at 0.77 (&)#177; 0.06 g/L (with a 95% confidence level) and the NOEC was estimated at 0.5 g/L. For P. promelas, the LC50 was above 1.5 g/L but it was noticed that mPCA had an effect on their behavior. Abnormal behavior observed included loss of equilibrium and curved spine. The NOEC on the fish was estimated at 0.75 g/L. PCA did not exhibit a significant mortality on fish or crustaceans. The LC50 of PCA in P. promelas and C. dubia was (>) 1.5 g/L and the NOEC was 1.5 g/L for both organisms. An Inhibitory effect on the heterotrophic respiration of activated sludge organisms was not observed after exposing them for 180-min to PCA and mPCA at concentrations of up to 1.5 g/L compared to the blank controls. Overall the impact of PCA and mPCA on total respiration rates was small, and only observed at 1,500 mg/L if at all. The difference was apparently caused by inhibition of nitrification rather than heterotrophic inhibition. However due to the variability observed in the measurements of the replicates, it is not possible to firmly conclude that PCA or mPCA at 1,500 mg/L was inhibitory to nitrification.Based on the results from the HPCs, mPCA and PCA did not affect the viability of heterotrophic organisms at 750 mg/L. In the BOD-like closed bottle test using a diluted activated sludge mixed liquor sample, the AS microorganisms were capable of biodegrading up to 67% of a 2 mg/L concentration of PCA (with respect to its theoretical oxygen demand, or ThOD) in 28 days. No biodegradation was observed in the samples containing 2 and 5 mg/L of mPCA after 28 days of incubation using a diluted activated sludge mixed liquor sample as inoculum.The results of this study show that mPCA is more toxic than PCA to Ceriodaphnia dubia and Pimephales promelas. However neither mPCA nor PCA had an effect on the heterotrophic respiration of an AS mixed liquor sample at 1.5 g/L and there was probably no significant inhibition of the nitrification respiration. Samples of PCA and mPCA at 2 and 5 mg/L could not be completely degraded (with respect to their total theoretical oxygen demand) by dilute AS biomass during a 28 day incubation period. mPCA did not show significant degradation in the two different biodegradation tests performed.
Show less - Date Issued
- 2013
- Identifier
- CFE0004744, ucf:49779
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004744
- Title
- A Comparison of Aluminum and Iron-based Coagulants for Treatment of Surface Water in Sarasota County, Florida.
- Creator
-
Yonge, David, Duranceau, Steven, Randall, Andrew, Cooper, Charles, University of Central Florida
- Abstract / Description
-
In this research, five different coagulants were evaluated to determine their effectiveness at removing turbidity, color and dissolved organic carbon (DOC) from a surface water in Sarasota County, Florida. Bench-scale jar tests that simulated conventional coagulation, flocculation, and sedimentation processes were used. Iron-based coagulants (ferric chloride and ferric sulfate) and aluminum-based coagulants (aluminum sulfate, polyaluminum chloride (PACl) and aluminum chlorohydrate (ACH)) were...
Show moreIn this research, five different coagulants were evaluated to determine their effectiveness at removing turbidity, color and dissolved organic carbon (DOC) from a surface water in Sarasota County, Florida. Bench-scale jar tests that simulated conventional coagulation, flocculation, and sedimentation processes were used. Iron-based coagulants (ferric chloride and ferric sulfate) and aluminum-based coagulants (aluminum sulfate, polyaluminum chloride (PACl) and aluminum chlorohydrate (ACH)) were used to treat a highly organic surface water supply (DOC ranging between 10 and 30 mg/L), known as the Cow Pen Slough, located within central Sarasota County, Florida. Isopleths depicting DOC and color removal efficiencies as a function of both pH and coagulant dose were developed and evaluated. Ferric chloride and ACH were observed to obtain the highest DOC (85% and 70%, respectively) and color (98% and 97%, respectively) removals at the lowest dose concentrations (120 mg/L and 100 mg/L, respectively). Ferric sulfate was effective at DOC removal but required a higher concentration of coagulant and was the least effective coagulant at removing color. The traditional iron-based coagulants and alum had low turbidity removals and they were often observed to add turbidity to the water. PACl and ACH had similar percent removals for color and turbidity achieving consistent percent removals of 95% and 45%, respectively, but PACl was less effective than ACH at removing organics. Sludge settling curves, dose-sludge production ratios, and settling velocities were determined at optimum DOC removal conditions for each coagulant. Ferric chloride was found to have the highest sludge settling rate but also produced the largest sludge quantities. Total trihalomethane formation potential (THMFP) was measured for the water treated with ferric chloride and ACH. As with DOC removal, ferric chloride yielded a higher percent reduction with respect to THMFP.
Show less - Date Issued
- 2012
- Identifier
- CFE0004621, ucf:49936
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004621
- Title
- Mathematical Modeling of Carbon Removal in the A-Stage Activated Sludge System.
- Creator
-
Nogaj, Thomas, Randall, Andrew, Duranceau, Steven, Chopra, Manoj, Jimenez, Jose, University of Central Florida
- Abstract / Description
-
This research developed a dynamic activated sludge model (ASM) to better describe the overall removal of organic substrate, quantified as chemical oxygen demand (COD), from A-stage high rate activated sludge (HRAS) systems. This dynamic computer model is based on a modified ASM1 (Henze et al., 2000) model. It was determined early in the project that influent soluble COD, which is normally represented by a single state variable in ASM1, had to be subdivided into two state variables (SBs and...
Show moreThis research developed a dynamic activated sludge model (ASM) to better describe the overall removal of organic substrate, quantified as chemical oxygen demand (COD), from A-stage high rate activated sludge (HRAS) systems. This dynamic computer model is based on a modified ASM1 (Henze et al., 2000) model. It was determined early in the project that influent soluble COD, which is normally represented by a single state variable in ASM1, had to be subdivided into two state variables (SBs and SBf, or slow and fast fractions) to simulate the performance of A-stage systems. Also, the addition of state variables differentiating colloidal COD from suspended COD was necessary due to short hydraulic residence times in A-stage systems which do not allow for complete enmeshment and bioflocculation of these particles as occurs in conventional activated sludge systems (which have longer solid retention times and hydraulic retention times). It was necessary to add several processes (both stoichiometry and kinetic equations) to the original ASM1 model including heterotrophic growth on both soluble substrate fractions and bioflocculation of colloidal solids. How to properly quantify heterotrophic growth on SBs and SBf resulted in two separate approaches with respect to process kinetic equations. In one approach the SBf was metabolized preferentially over SBs which was only utilized when SBf was not available. This is referred to as the Diauxic Model. In the other approach SBf and SBs were metabolized simultaneously, and this is referred to as the Dual Substrate Model. The Dual Substrate Model calibrated slightly better than the Diauxic Model for one of the two available pilot studies data sets (the other set was used for model verification). The Dual Substrate A-stage model was used to describe the effects of varying specific operating parameters including solids retention time (SRT), dissolved oxygen (DO), influent COD and temperature on the effluent COD:N ratio. The effluent COD:N ratio target was based on its suitability for a downstream nitrite shunt (i.e. nitritation/denitritation) process. In the downstream process the goal is to eliminate nitrite oxidizing bacteria (NOB) from the reactor while selecting for ammonia oxidizing bacteria (AOB). The results showed that a low SRT ((<)0.25 d) can produce high effluent substrates (SB and CB), and elevated COD:N ratios consistent with NOB out-selection downstream, the HRAS model was able to predict the measured higher fraction of CB in the A-stage effluent at lower SRTs and DO concentrations, and to achieve the benefits of operating an A-stage process, while maintaining an effluent COD:N ratio suitable for a downstream nitritation/denitritation process, an A-stage SRT in the range of 0.1 to 0.25 d should be maintained.This research also included an analysis of A-stage pilot data using stoichiometry to determine the bio-products formed from soluble substrate removed in an A-stage reactor. The results were used to further refine the process components and stoichiometric parameters to be used in the A-stage dynamic computer model, which includes process mechanisms for flocculation and enmeshment of particulate and colloidal substrate, hydrolysis, production of extracellular polymeric substances (EPS) and storage of soluble biodegradable substrate. Analysis of pilot data and simulations with the dynamic computer model implied (indirectly) that storage products were probably significant in A-stage COD removal.
Show less - Date Issued
- 2015
- Identifier
- CFE0005677, ucf:50161
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005677
- Title
- Development of a chemical kinetic model for the combustion of a synthesis gas from a fluidized-bed sewage sludge gasifier in a thermal oxidizer.
- Creator
-
Martinez, Luis, Cooper, David, Randall, Andrew, Vasu Sumathi, Subith, University of Central Florida
- Abstract / Description
-
The need for sustainability has been on the rise. Municipalities are finding ways of reducing waste, but also finding ways to reduce energy costs. Waste-to-energy is a sustainable method that may reduce bio-solids volume while also producing energy. In this research study bio-solids enters a bubbling bed gasifier and within the gasifier a synthesis gas is produced. This synthesis gas exits through the top of the gasifier and enters a thermal oxidizer for combustion. The thermal oxidizer has...
Show moreThe need for sustainability has been on the rise. Municipalities are finding ways of reducing waste, but also finding ways to reduce energy costs. Waste-to-energy is a sustainable method that may reduce bio-solids volume while also producing energy. In this research study bio-solids enters a bubbling bed gasifier and within the gasifier a synthesis gas is produced. This synthesis gas exits through the top of the gasifier and enters a thermal oxidizer for combustion. The thermal oxidizer has an innovative method of oxidizing the synthesis gas. The thermal oxidizer has two air injection sites and the possibility for aqueous ammonia injection for further NOx reduction. Most thermal oxidizers already include an oxidizer such as air in the fuel before it enters the thermal oxidizer; thus making this research and operation different from many other thermal oxidizers and waste-to-energy plants.The reduction in waste means less volume loads to a landfill. This process significantly reduces the amount of bio-solids to a landfill. The energy produced from the synthesis is beneficial for any municipality, as it may be used to run the waste-to-energy facility. The purpose of this study is to determine methods in which operators may configure future plants to reduce NOx emissions. NOx mixed with volatile organic compounds (VOC) and sunlight, produce ozone (O3) a deadly gas at high concentrations.This study developed a model to determine the best methods to reduce NOx emissions. Results indicate that a fuel-rich then fuel-lean injection scheme results in lower NOx emissions. This is because at fuel-rich conditions not all of the ammonia in the first air ring is converted to NOx, but rather a partial of the ammonia is converted to NOx and N2 and then the second air ring operates at fuel-lean which further oxidizes the remaining ammonia which converts to NOx, but also a fraction to N2. If NOx standards reach more stringency then aqueous ammonia injection is a recommended method for NOx reduction; this method is also known as selective non-catalytic reduction (SNCR).The findings in this study will allow operators to make better judgment in the way that they operate a two air injection scheme thermal oxidizer. The goal of the operator and the organization is to meet air quality standards and this study aims at finding ways to reduce emissions, specifically NOx.
Show less - Date Issued
- 2014
- Identifier
- CFE0005528, ucf:50301
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005528
- 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
- In-Plant and Distribution System Corrosion Control for Reverse Osmosis, Nanofiltration, and Anion Exchange Process Blends.
- Creator
-
Jeffery, Samantha, Duranceau, Steven, Randall, Andrew, Wang, Dingbao, University of Central Florida
- Abstract / Description
-
The integration of advanced technologies into existing water treatment facilities (WTFs) can improve and enhance water quality; however, these same modifications or improvements may adversely affect finished water provided to the consumer by public water systems (PWSs) that embrace these advanced technologies. Process modification or improvements may unintentionally impact compliance with the provisions of the United States Environmental Protection Agency's (USEPA's) Safe Drinking Water Act ...
Show moreThe integration of advanced technologies into existing water treatment facilities (WTFs) can improve and enhance water quality; however, these same modifications or improvements may adversely affect finished water provided to the consumer by public water systems (PWSs) that embrace these advanced technologies. Process modification or improvements may unintentionally impact compliance with the provisions of the United States Environmental Protection Agency's (USEPA's) Safe Drinking Water Act (SDWA). This is especially true with respect to corrosion control, since minor changes in water quality can affect metal release. Changes in metal release can have a direct impact on a water purveyor's compliance with the SDWA's Lead and Copper Rule (LCR). In 2010, the Town of Jupiter (Town) decommissioned its ageing lime softening (LS) plant and integrated a nanofiltration (NF) plant into their WTF. The removal of the LS process subsequently decreased the pH in the existing reverse osmosis (RO) clearwell, leaving only RO permeate and anion exchange (AX) effluent to blend. The Town believed that the RO-AX blend was corrosive in nature and that blending with NF permeate would alleviate their concern. Consequently, a portion of the NF permeate stream was to be split between the existing RO-AX clearwell and a newly constructed NF primary clearwell. The Town requested that the University of Central Florida (UCF) conduct research evaluating how to mitigate negative impacts that may result from changing water quality, should the Town place its AX into ready-reserve. The research presented in this document was focused on the evaluation of corrosion control alternatives for the Town, and was segmented into two major components: 1.The first component of the research studied internal corrosion within the existing RO clearwell and appurtenances of the Town's WTF, should the Town place the AX process on standby. Research related to WTF in-plant corrosion control focused on blending NF and RO permeate, forming a new intermediate blend, and pH-adjusting the resulting mixture to reduce corrosion in the RO clearwell. 2.The second component was implemented with respect to the Town's potable water distribution system. The distribution system corrosion control research evaluated various phosphate-based corrosion inhibitors to determine their effectiveness in reducing mild steel, lead and copper release in order to maintain the Town's continual compliance with the LCR.The primary objective of the in-plant corrosion control research was to determine the appropriate ratio of RO to NF permeate and the pH necessary to reduce corrosion in the RO clearwell. In this research, the Langelier saturation index (LSI) was the corrosion index used to evaluate the stability of RO:NF blends. Results indicated that a pH-adjusted blend consisting of 70% RO and 30% NF permeate at 8.8-8.9 pH units would produce an LSI of +0.1, theoretically protecting the RO clearwell from corrosion.The primary objective of the distribution system corrosion control component of the research was to identify a corrosion control inhibitor that would further reduce lead and copper metal release observed in the Town's distribution system to below their respective action limits (ALs) as defined in the LCR. Six alternative inhibitors composed of various orthophosphate and polyphosphate (ortho:poly) ratios were evaluated sequentially using a corrosion control test apparatus. The apparatus was designed to house mild steel, lead and copper coupons used for weight loss analysis, as well as mild steel, lead solder and copper electrodes used for linear polarization analysis. One side of the apparatus, referred to as the (")control condition,(") was fed potable water that did not contain the corrosion inhibitor, while the other side of the corrosion apparatus, termed the (")test condition,(") was fed potable water that had been dosed with a corrosion inhibitor. Corrosion rate measurements were taken twice per weekday, and water quality was measured twice per week. Inhibitor evaluations were conducted over a span of 55 to 56 days, varying with each inhibitor. Coupons and electrodes were pre-corroded to simulate existing distribution system conditions. Water flow to the apparatus was controlled with an on/off timer to represent variations in the system and homes. Inhibitor comparisons were made based on their effectiveness at reducing lead and copper release after chemical addition. Based on the results obtained from the assessment of corrosion inhibitors for distribution system corrosion control, it appears that Inhibitors 1 and 3 were more successful in reducing lead corrosion rates, and each of these inhibitors reduced copper corrosion rates. Also, it is recommended that consideration be given to use of a redundant single-loop duplicate test apparatus in lieu of a double rack corrosion control test apparatus in experiments where pre-corrosion phases are implemented. This recommendation is offered because statistically, the control versus test double loop may not provide relevance in data analysis. The use of the Wilcoxon signed ranks test comparing the initial pre-corroding phase to the inhibitor effectiveness phase has proven to be a more useful analytical method for corrosion studies.
Show less - Date Issued
- 2013
- Identifier
- CFE0005008, ucf:50001
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005008
- Title
- Development of Treatment Train Techniques for the Evaluation of Low Impact Development in Urban Regions.
- Creator
-
Hardin, Mike, Wanielista, Martin, Cooper, David, Randall, Andrew, University of Central Florida
- Abstract / Description
-
Stormwater runoff from urban areas is a major source of pollution to surface water bodies. The discharge of nutrients such as nitrogen and phosphorus is particularly damaging as it results in harmful algal blooms which can limit the beneficial use of a water body. Stormwater best management practices (BMPs) have been developed over the years to help address this issue. While BMPs have been investigated for years, their use has been somewhat limited due to the fact that much of the data...
Show moreStormwater runoff from urban areas is a major source of pollution to surface water bodies. The discharge of nutrients such as nitrogen and phosphorus is particularly damaging as it results in harmful algal blooms which can limit the beneficial use of a water body. Stormwater best management practices (BMPs) have been developed over the years to help address this issue. While BMPs have been investigated for years, their use has been somewhat limited due to the fact that much of the data collected is for specific applications, in specific regions, and it is unknown how these systems will perform in other regions and for other applications. Additionally, the research was spread across the literature and performance data was not easily accessible or organized in a convenient way. Recently, local governments and the USEPA have begun to collect this data in BMP manuals to help designers implement this technology. That being said, many times a single BMP is insufficient to meet water quality and flood control needs in urban areas. A treatment train approach is required in these regions. In this dissertation, the development of methodologies to evaluate the performance of two BMPs, namely green roofs and pervious pavements is presented. Additionally, based on an extensive review of the literature, a model was developed to assist in the evaluation of site stormwater plans using a treatment train approach for the removal of nutrients due to the use of BMPs. This model is called the Best Management Practices Treatment for Removal on an Annual basis Involving Nutrients in Stormwater (BMPTRAINS) model.The first part of this research examined a previously developed method for designing green roofs for hydrologic efficiency. The model had not been tested for different designs and assumed that evapotranspiration was readily available for all regions. This work tested this methodology against different designs, both lab scale and full scale. Additionally, the use of the Blaney-Criddle equation was examined as a simple way to determine the ET for regions where data was not readily available. It was shown that the methods developed for determination of green roof efficiency had good agreement with collected data. Additionally, the use of the Blaney-Criddle equation for estimation of ET had good agreement with collected and measured data.The next part of this research examined a method to design pervious pavements. The water storage potential is essential to the successful design of these BMPs. This work examined the total and effective porosities under clean, sediment clogged, and rejuvenated conditions. Additionally, a new type of porosity was defined called operating porosity. This new porosity was defined as the average of the clean effective porosity and the sediment clogged effective porosity. This porosity term was created due to the fact that these systems exist in the exposed environment and subject to sediment loading due to site erosion, vehicle tracking, and spills. Due to this, using the clean effective porosity for design purposes would result in system failure for design type storm events towards the end of its service life. While rejuvenation techniques were found to be somewhat effective, it was also observed that often sediment would travel deep into the pavement system past the effective reach of vacuum sweeping. This was highly dependent on the pore structure of the pavement surface layer. Based on this examination, suggested values for operating porosity were presented which could be used to calculate the storage potential of these systems and subsequent curve number for design purposes.The final part of this work was the development of a site evaluation model using treatment train techniques. The BMPTRAINS model relied on an extensive literature review to gather data on performance of 15 different BMPs, including the two examined as part of this work. This model has 29 different land uses programmed into it and a user defined option, allowing for wide applicability. Additionally, this model allows a watershed to be split into up to four different catchments, each able to have their own distinct pre- and post-development conditions. Based on the pre- and post-development conditions specified by the user, event mean concentrations (EMCs) are assigned. These EMCs can also be overridden by the user. Each catchment can also contain up to three BMPs in series. If BMPs are to be in parallel, they must be in a separate catchment. The catchments can be configured in up to 15 different configurations, including series, parallel, and mixed. Again, this allows for wide applicability of site designs. The evaluation of cost is also available in this model, either in terms of capital cost or net present worth. The model allows for up to 25 different scenarios to be run comparing cost, presenting results in overall capital cost, overall net present worth, or cost per kg of nitrogen and phosphorus. The wide array of BMPs provided and the flexibility provided to the user makes this model a powerful tool for designers and regulators to help protect surface waters.
Show less - Date Issued
- 2014
- Identifier
- CFE0005503, ucf:50338
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005503
- Title
- The Fate of Nitrogen and Phosphorus from a SImulated Highway Cross-Section.
- Creator
-
Wasowska, Zuzanna, Chopra, Manoj, Randall, Andrew, Wang, Dingbao, University of Central Florida
- Abstract / Description
-
Nutrient pollution as a result of excessive fertilizer application is of major concern for Florida's water resources. Excess fertilizer can be lost either via surface runoff or by leaching through the soil mass eventually reaching water bodies and leading to eutrophication. The focus of this study is to analyze the effect of low rainfall intensities and overland flow from an adjacent roadway surface on the loss of nutrients from two different fertilizers. This study focuses on the fate of the...
Show moreNutrient pollution as a result of excessive fertilizer application is of major concern for Florida's water resources. Excess fertilizer can be lost either via surface runoff or by leaching through the soil mass eventually reaching water bodies and leading to eutrophication. The focus of this study is to analyze the effect of low rainfall intensities and overland flow from an adjacent roadway surface on the loss of nutrients from two different fertilizers. This study focuses on the fate of the nitrogen and phosphorus present in fertilizers utilized by the Florida Department of Transportation for the stabilization of highway embankments. This research was performed on a field-scale test bed and rainfall simulator located at the Stormwater Management Academy at the University of Central Florida.The loss of nutrients was measured from two soil and sod combinations typically found in Florida and used for highway stabilization (-)Pensacola Bahia on AASHTO A-2-4 soil and Argentine Bahia on AASHTO A-3 soil. Two different fertilizers were analyzed, an all-purpose, quick-release 10-10-10 (N-P-K) fertilizer previously used by FDOT, and the new slow-release 16-0-8 (N-P-K) fertilizer, both applied at a rate of 0.5 lb/1000 ft2 consistent with FDOT's practice. Each combination was analyzed under two rainfall intensities: 0.1 in/hr and 0.25 in/hr at a slope consistent with typical highway cross-sections found in Florida. Nutrient losses were measured by collection of runoff and/or baseflow that escaped the test bed. Additionally, from the soil samples collected throughout the testing period, the mass of the nutrients was compared to the mass balances values based on literature from a previous study on fertilizers performed at the Stormwater Management Academy.The experimental findings of this study showed that there was a reduction in total nitrogen and total phosphorus on both A-2-4 soil and A-3 soil at the 0.25 in/hr intensity as a result of switching to the slow-release 16-0-8 (N-P-K) fertilizer. Results from the 0.1 in/hr rainfall intensity, which were available only for the A-2-4 soil, showed that at this intensity there was no apparent benefit to the switch in fertilizers. Furthermore, it was found that less total nitrogen and total phosphorus was lost from A-3 soil than A-2-4 soil at 0.25 in/hr when using 10-10-10 (N-P-K). At 0.1 in/hr, there was no apparent difference in total nitrogen lost. However, less total phosphorus was lost at this intensity. The results of this study showed that there is an environmental benefit to applying slow-release fertilizers. This was more significant for the 0.25 in/hr intensity than the 0.1 in/hr intensity at which no apparent benefit was found. In addition, it was found that runoff was a greater source of nutrient loss than baseflow, although baseflow losses were substantial. Furthermore, it was found that total nitrogen tends to be lost via both pathways of runoff and baseflow while phosphorus has a lower tendency to leach through the soil but readily runs off the soil surface. It was also observed that because fresh sod tends to be heavily fertilized, applications of fertilizer could be reduced or avoided entirely after sod placement and applied as needed.
Show less - Date Issued
- 2014
- Identifier
- CFE0005440, ucf:50401
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005440
- 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
- Application and Optimization of Membrane Processes Treating Brackish and Surficial Groundwater for Potable Water Production.
- Creator
-
Tharamapalan, Jayapregasham, Duranceau, Steven, Cooper, Charles, Randall, Andrew, Clausen, Christian, University of Central Florida
- Abstract / Description
-
The research presented in this dissertation provides the results of a comprehensive assessment of the water treatment requirements for the City of Sarasota. The City's drinking water supply originates from two sources: (1) brackish groundwater from the Downtown well field, and (2) Floridan surficial groundwater from the City's Verna well field. At the time the study was initiated, the City treated the brackish water supply using a reverse osmosis process that relied on sulfuric acid for pH...
Show moreThe research presented in this dissertation provides the results of a comprehensive assessment of the water treatment requirements for the City of Sarasota. The City's drinking water supply originates from two sources: (1) brackish groundwater from the Downtown well field, and (2) Floridan surficial groundwater from the City's Verna well field. At the time the study was initiated, the City treated the brackish water supply using a reverse osmosis process that relied on sulfuric acid for pH adjustment as a pretreatment method. The Verna supply was aerated at the well field before transfer to the City's water treatment facility, either for softening using an ion exchange process, or for final blending before supply.For the first phase of the study to evaluate whether the City can operate its brackish groundwater RO process without acid pretreatment, a three-step approach was undertaken that involved: (1) pilot testing the plan to reduce the dependence on acid, (2) implementing the plan on the full-scale system with conservative pH increments, and (3) continuous screening for scale formation potential by means of a (")canary(") monitoring device. Implementation of the study was successful and the annual savings in operating expenditure to the City is projected to be about $120,000.From the acid elimination study, using the relationship between electrical conductivity in water and total dissolved solids in water samples tested, a dynamic approach to evaluate the performance of the reverse osmosis plant was developed. This trending approach uses the mass transfer coefficient principles of the Homogeneous Solution Diffusion Model. Empirical models were also developed to predict mass transfer coefficients for solutes in terms of total dissolved solids and sodium. In the second phase of the study, the use of nanofiltration technology to treat aerated Verna well field water was investigated. The goal was to replace the City's existing ion exchange process for the removal of hardness and total dissolved solids. Different pretreatment options were evaluated for the nanofiltration pilot to remove colloidal sulfur formed during pre-aeration of the groundwater. Sandfilters and ultrafiltration technology were evaluated as pretreatment. The sandfilter was inadequate as a pre-screen to the nanofiltration pilot. The ultrafiltration pilot (with and without a sandfilter as a pre-screen) proved to be an adequate pretreatment to remove particulates and colloids, especially the sulfur colloids in the surficial groundwater source. The nanofiltration pilot, was shown to be an efficient softening process for the Verna well field water, but it was impacted by biofoulants like algae. The algae growth was downstream of the ultrafiltration process, and so chlorination was used in the feed stream of the ultrafiltration process with dechlorination in the nanofiltration feed stream using excess bisulfite to achieve stable operations. Non-phosphonate based scale inhibitors were also used to reduce the availability of nutrients for biofilm growth on the nanofiltration membranes.The combined ultrafiltration-nanofiltration option for treatment of the highly fouling Verna water samples is feasible with chlorination (to control biofouling) and subsequent dechlorination. Alternatively, the study has shown that the City can also more economically and more reliably use ultrafiltration technology to filter all water from its Verna well field and use its current ion exchange process for removal of excess hardness in the water that it supplies.
Show less - Date Issued
- 2012
- Identifier
- CFE0004609, ucf:49926
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004609