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EFFECTS OF REDUCED RAS AND VOLUME ON ANAEROBIC ZONE PERFORMANCE FOR A SEPTIC WASTEWATER BIOLOGICAL PHOSPHOROUS REMOVAL SYSTEM
Title
EFFECTS OF REDUCED RAS AND VOLUME ON ANAEROBIC ZONE PERFORMANCE FOR A SEPTIC WASTEWATER BIOLOGICAL PHOSPHOROUS REMOVAL SYSTEM.
Creator
Magro, Daniel, Randall, Andrew, University of Central Florida
Abstract / Description
Enhanced Biological Phosphorous Removal (EBPR) performance was found to be adequate with reduced Return Activated Sludge (RAS) flows (50% of available RAS) to the anaerobic tank and smaller than typical anaerobic zone volume (1.08 hours hydraulic retention time or HRT). Three identical parallel biological nutrient removal (BNR) pilot plants were fed with strong, highly fermented (160 mg/L VFAs), domestic/industrial wastewater from a full scale wastewater treatment facility (WWTF). The pilot...
Show moreEnhanced Biological Phosphorous Removal (EBPR) performance was found to be adequate with reduced Return Activated Sludge (RAS) flows (50% of available RAS) to the anaerobic tank and smaller than typical anaerobic zone volume (1.08 hours hydraulic retention time or HRT). Three identical parallel biological nutrient removal (BNR) pilot plants were fed with strong, highly fermented (160 mg/L VFAs), domestic/industrial wastewater from a full scale wastewater treatment facility (WWTF). The pilot plants were operated at 100%, 50%, 40% and 25% RAS (percent of available RAS) flows to the anaerobic tank with the remaining RAS to the anoxic tank. In addition, varying anaerobic HRT (1.08 and 1.5 hours), and increased hydraulic loading (35% increase) was examined. The study was divided in four Phases, and the effect of these process variations on EBPR were studied by having one different variable between two identical systems. The most significant conclusions were that only bringing part of the RAS to the anaerobic zone did not decrease EBPR performance, instead changing the location of P release and uptake. Bringing less RAS to the anaerobic and more to the anoxic tank decreased anaerobic P release and increased anoxic P release (or decreased anoxic P uptake). Equally important is that with VFA rich influent wastewater, excessive anaerobic volume was shown to hurt overall P removal even when it resulted in increased anaerobic P release. Computer modeling with BioWin and UCTPHO was found to predict similar results to the pilot test results. Modeling was done with reduced RAS flows to the anaerobic zone (100%, 50%, and 25% RAS), increased anaerobic volume, and increased hydraulic loading. The most significant conclusions were that both models predicted EBPR did not deteriorate with less RAS to the anaerobic zone, in fact, improvements in EBPR were observed. Additional scenarios were also consistent with pilot test data in that increased anaerobic volume did not improve EBPR and increased hydraulic loading did not adversely affect EBPR.
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Date Issued
2005
Identifier
CFE0000329, ucf:46285
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0000329
A study of organo-phosphorous simulants thermal destruction using shock tube/laser diagnostics techniques and chemical kinetics modeling
Title
A study of organo-phosphorous simulants thermal destruction using shock tube/laser diagnostics techniques and chemical kinetics modeling.
Creator
Neupane, Sneha, Vasu Sumathi, Subith, Kassab, Alain, Chow, Louis, Peale, Robert, University of Central Florida
Abstract / Description
High-fidelity chemical kinetic models are critical in predictive modeling during design and optimization of next generation energy systems. Shock tube provides an ideal tool to investigate high-temperature chemical kinetics. Non-intrusive laser absorption diagnostics provide in-situ measurements of quantitative, time-resolved species concentration data in this complex chemically reacting system. In this work, shock tube and laser absorption spectroscopy were utilized to measure species...
Show moreHigh-fidelity chemical kinetic models are critical in predictive modeling during design and optimization of next generation energy systems. Shock tube provides an ideal tool to investigate high-temperature chemical kinetics. Non-intrusive laser absorption diagnostics provide in-situ measurements of quantitative, time-resolved species concentration data in this complex chemically reacting system. In this work, shock tube and laser absorption spectroscopy were utilized to measure species concentration time-histories during pyrolysis and oxidation of organo-phosphorous compounds (OPCs). The experiments data obtained were used as benchmark to develop an improved kinetic model of OPCs combustion. Interest in combustion chemistry of OPCs is associated to their use as fire suppressants and as chemical weapons. Pyrolysis and oxidation of OPCs were carried out behind reflected shock wave and laser absorption spectroscopy utilizing quantum cascade laser at mid-IR wavelength region was used to measure time resolved intermediate CO concentration produced during the process. Utilizing the experiments data, an improved chemical kinetic model for combustion of an OPC (-) Triethyl Phosphate (TEP) was developed. Various steps taken to develop the improved model include: calculation of thermochemical properties; updating hydrocarbon kinetics; calculation of reaction rates and addition of alternative TEP decomposition pathways. The prediction of TEP combustion, in terms intermediate CO concentration yield during its pyrolysis and oxidation, made by the improved model is in much better agreement with the experiments. Such an accurate kinetic model is critical in predicting the effectiveness of OPCs as flame retardants when used as dopants in hydrocarbon fuels; and in devising counter weapon of mass destruction strategies to destroy chemical weapons.
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Date Issued
2019
Identifier
CFE0007691, ucf:52444
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007691
Comparison of a modified and traditional rapid infiltration basin for treatment and control of nutrients in wastewater effluent
Title
Comparison of a modified and traditional rapid infiltration basin for treatment and control of nutrients in wastewater effluent.
Creator
Cormier, Jessica, Duranceau, Steven, Wang, Dingbao, Sadmani, A H M Anwar, University of Central Florida
Abstract / Description
Rapid infiltration basins (RIB) have been historically used in Florida for groundwater recharge, effluent disposal, or a combination of both. However, this technique has proven ineffective in providing nitrogen control unless the RIB is modified in some manner. In this study, a traditional RIB was compared to a modified RIB constructed with manufactured biosorption activated media (BAM) to evaluate nitrate removal from reclaimed water. The RIBs are used for reclaimed and excess storm water...
Show moreRapid infiltration basins (RIB) have been historically used in Florida for groundwater recharge, effluent disposal, or a combination of both. However, this technique has proven ineffective in providing nitrogen control unless the RIB is modified in some manner. In this study, a traditional RIB was compared to a modified RIB constructed with manufactured biosorption activated media (BAM) to evaluate nitrate removal from reclaimed water. The RIBs are used for reclaimed and excess storm water disposal. Few, if any, studies have been published where BAM-modified RIBs have been used for this purpose. In this work, a mixture of clay, tire crumb, and sand (CTS) was selected to serve as the BAM material (Bold and Gold(TM) CTS media). Each RIB was constructed with two feet of either sand or BAM, covering more than 43,600 square feet of surface area. The BAM-modified RIB had an initial 90 pounds per cubic-foot in-place density, and the density of the control RIB approximated about 94 pounds per cubic-foot. Over an eight-month period, loadings to the BAM RIB and control RIB approximated 5.4 million gallons (MG) per acre each. Water samples, collected from lysimeters installed below the 2-foot of sand or BAM materials, were gathered monthly during 2017 (except for September and October due to the impacts of hurricane Irma); these samples were analyzed for water quality to determine nitrate removal. Soil moisture and weather data were also collected over the study period. This study demonstrated the nitrate removal effectiveness of a field-scale BAM-modified RIB as compared to a traditional field-scale sand-based RIB. Results suggest that BAM removed 30 percent more nitrates than the Control (78% and 47%, respectively) under the conditions of the study. Furthermore, BAM removed higher percentages of TN (31%) and TP (62%) than the Control (12% and 28%, respectively).
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Date Issued
2018
Identifier
CFE0007566, ucf:52583
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007566
THE EFFECTS OF PHOSPHATE AND SILICATE INHIBITORS ON SURFACE ROUGHNESS AND COPPER RELEASE IN WATER DISTRIBUTION SYSTEMS
Title
THE EFFECTS OF PHOSPHATE AND SILICATE INHIBITORS ON SURFACE ROUGHNESS AND COPPER RELEASE IN WATER DISTRIBUTION SYSTEMS.
Creator
MacNevin, David, Taylor, James, University of Central Florida
Abstract / Description
The effects of corrosion inhibitors on water quality and the distribution system were studied. This dissertation investigates the effect of inhibitors on iron surface roughness, copper surface roughness, and copper release. Corrosion inhibitors included blended poly/ortho phosphate, sodium orthophosphate, zinc orthophosphate, and sodium silicate. These inhibitors were added to a blend of surface water, groundwater, and desalinated brackish water. Surface roughness of galvanized iron, unlined...
Show moreThe effects of corrosion inhibitors on water quality and the distribution system were studied. This dissertation investigates the effect of inhibitors on iron surface roughness, copper surface roughness, and copper release. Corrosion inhibitors included blended poly/ortho phosphate, sodium orthophosphate, zinc orthophosphate, and sodium silicate. These inhibitors were added to a blend of surface water, groundwater, and desalinated brackish water. Surface roughness of galvanized iron, unlined cast iron, lined cast iron, and polyvinyl chloride was measured using pipe coupons exposed for three months. Roughness of each pipe coupon was measured with an optical surface profiler before and after exposure to inhibitors. For most materials, inhibitor did not have a significant effect on surface roughness; instead, the most significant factor determining the final surface roughness was the initial surface roughness. Coupons with low initial surface roughness tended to have an increase in surface roughness during exposure, and vice versa, implying that surface roughness tended to regress towards an average or equilibrium value. For unlined cast iron, increased alkalinity and increased temperature tended to correspond with increases in surface roughness. Unlined cast iron coupons receiving phosphate inhibitors were more likely to have a significant change in surface roughness, suggesting that phosphate inhibitors affect stability of iron pipe scales. Similar roughness data collected with new copper coupons showed that elevated orthophosphate, alkalinity, and temperature were all factors associated with increased copper surface roughness. The greatest increases in surface roughness were observed with copper coupons receiving phosphate inhibitors. Smaller increases were observed with copper coupons receiving silicate inhibitor or no inhibitor. With phosphate inhibitors, elevated temperature and alkalinity were associated with larger increases in surface roughness and blue-green copper (II) scales.. Otherwise a compact, dull red copper (I) scale was observed. These data suggest that phosphate inhibitor addition corresponds with changes in surface morphology, and surface composition, including the oxidation state of copper solids. The effects of corrosion inhibitors on copper surface chemistry and cuprosolvency were investigated. Most copper scales had X-ray photoelectron spectroscopy binding energies consistent with a mixture of Cu2O, CuO, Cu(OH)2, and other copper (II) salts. Orthophosphate and silica were detected on copper surfaces exposed to each inhibitor. All phosphate and silicate inhibitors reduced copper release relative to the no inhibitor treatments, keeping total copper below the 1.3 mg/L MCLG for all water quality blends. All three kinds of phosphate inhibitors, when added at 1 mg/L as P, corresponded with a 60% reduction in copper release relative to the no inhibitor control. On average, this percent reduction was consistent across varying water quality conditions in all four phases. Similarly when silicate inhibitor was added at 6 mg/L as SiO2, this corresponded with a 25-40% reduction in copper release relative to the no inhibitor control. Hence, on average, for the given inhibitors and doses, phosphate inhibitors provided more predictable control of copper release across changing water quality conditions. A plot of cupric ion concentration versus orthophosphate concentration showed a decrease in copper release consistent with mechanistic control by either cupric phosphate solubility or a diffusion limiting phosphate film. Thermodynamic models were developed to identify feasible controlling solids. For the no inhibitor treatment, Cu(OH)2 provided the closest prediction of copper release. With phosphate inhibitors both Cu(OH)2 and Cu(PO4)·2H2O models provided plausible predictions. Similarly, with silicate inhibitor, the Cu(OH)2 and CuSiO3·H2O models provided plausible predictions.
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Date Issued
2008
Identifier
CFE0002001, ucf:47621
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0002001