Matching Items (111)
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- All Subjects: Environmental engineering
- Genre: Masters Thesis
- Creators: Arizona State University
- Member of: ASU Electronic Theses and Dissertations
Description
Hydrophobic ionizable organic compounds (HIOCs) like per- and polyfluoroalkyl substances (PFAS), certain pharmaceuticals, and surfactants have been detected in groundwater, wastewater, and drinking water. Anion exchange resin treatment is an effective process for removal of anionic contaminants from water. Spent anion exchange resins are conventionally regenerated with high alcohol by volume (ABV) methanol in solution with brine. While effective for regeneration of resins saturated with inorganic anions such as sulfate, nitrate, and perchlorate, HIOCs prove more resistant to regeneration. This research investigated the efficacy of using novel cosolvent solutions with brine to regenerate resins saturated with organic carboxylate and sulfonate anions to understand the effects cosolvent properties have on regenerative ability. Experiments were conducted on six PFAS compounds to evaluate trends in regeneration for three alcohols. For all PFAS species, equivalent ABV and brine solutions showed greatest regeneration with 1-propanol over ethanol and methanol. Experiments with the pharmaceutical sodium diclofenac were conducted showing similar regeneration of 75% methanol and 25% 1-propanol for equivalent salt concentrations and higher regeneration with 1-propanol than ethanol and methanol for equivalent ABV. A series of experiments with surfactant dodecylbenzene sulfonate determined that the key parameters to determine regeneration of the resin for an alcohol cosolvent solution were cosolvent volume fraction, molar mass, Kow value, solution ionic strength, and dielectric constant. Individual assessments on the cost-effectiveness, flammability, and sustainability of cosolvent solutions point to possible future experiments and opportunities for recycled distillery waste streams as regenerative solutions for anion exchange resin.
ContributorsGraham, Cole David (Author) / Boyer, Treavor H (Thesis advisor) / Conroy-Ben, Otakuye (Committee member) / Garcia Segura, Sergio (Committee member) / Arizona State University (Publisher)
Created2022
Description
Plastics, when released into the environment, undergo surface weathering due to mechanical abrasion and ultraviolet (UV) exposure that leads to the formation of microplastics. Weathering also introduces oxygen functional groups on the surface, which will affect surface interactions compared to pristine plastics. In this study, the adsorption of selected model contaminants of high environmental relevance was evaluated at different level of abiotic and biotic transformation to understand how microplastics aging influences contaminant adsorption on high density polyethylene (HDPE) and polypropylene (PPE). Microplastics were aged through an accelerated weathering process using UV exposure with or without hydrogen peroxide. The effect of UV aging on the microplastics’ morphology and surface chemistry was characterized by Fourier Transform Infrared Spectroscopy, X-Ray Photoelectron Spectroscopy, streaming Zeta potential, Brunauer–Emmett–Teller Krypton adsorption analyses and Computed X-Ray Tomography. Sorption of organic contaminants was found to be higher on aged microplastics compared to pristine ones for all contaminants investigated. This increase in sorption affinity was found to be associated with a change in the surface chemistry and not in an increase in specific surface area after aging. Biological surface weathering (i.e., biofilm formation) was carried out at a lab-scale setting using model biofilm-forming bacteria followed by adsorption affinity measurement of biofilm-laden microplastics with the model organic contaminants. The amount of microbial biomass accumulated on the surface was also evaluated to correlate the changes in sorption affinity with the change in microplastic biofilm formation. The results of this study emphasize the need to understand how contaminant-microplastics interactions will evolve as microplastics are altered by biotic and abiotic factors in the environment.
ContributorsBhagat, Kartik (Author) / Perreault, Francois (Thesis advisor) / Westerhoff, Paul (Committee member) / Oswald, Jay (Committee member) / Arizona State University (Publisher)
Created2022
Description
Corrosion is known to have severe infrastructure integrity implications in a broad range of industries including water and wastewater treatment and reclamation. In the U.S. alone, the total losses due to corrosion in drinking water and wastewater systems can account for economic losses as high as $80 billion dollars a year. Microbially induced corrosion is a complex phenomenon which involve various phases; 1) formation of biofilms on submerged surfaces, 2) creation of micro-environmental niches associated with biofilm growth, 3) altered availability nutrients, 4) changes in the pH and oxygen concentrations. Biofilms can harbor opportunistic or pathogenic bacteria for a long time increasing the risk of pathogen exposure for the end users. The focus of this thesis research was to study the kinetics of microbially induced corrosion of various materials in water and reclaimed water systems. The specific objective was to assess the biofilms formation potential on stainless steel 304, stainless steel 316, galvanized steel, copper, cPVC, glass, carbon steel, and cast iron in water and reclaimed water systems. Experiments were conducted using bioreactor containers, each bioreactor housed four sampling boxes with eight partitions, dedicated to each material type coupon. One bioreactor was stationed at ASU, and one at Vistancia Aquifer Storage and Recovery (ASR) well; while three bioreactors were stationed at Butler facility, at pre-disinfection, post-UV and post-chlorination. From each location, one submerged sampling box was retrieved after 1, 3, 6 and 12 months. Time series of biofilm samples recovered from various types of coupons from different locations were analyzed using physical and culture-based techniques for quantification of biofilms and detection of heterotrophic plate count (HPC) bacteria, Legionella, Mycobacterium, and sulfate reducing bacteria (SRB).
After one-year, galvanized steel had the highest concentration of HPC at 4.27 logs while copper had the lowest concentration of 3.08 logs of HPC. Bacterial growth data collected from the SRB tests was compiled to develop a numerical matrix using growth potential, biofilm formation potential and metal reduction potential of SRB isolates. This risk assessment matrix can be a useful tool for the water industry to evaluate the potential risk of MIC in their systems.
ContributorsNeal, Amber (Author) / Abbaszadegan, Morteza (Thesis advisor) / Fox, Peter (Committee member) / Alum, Absar (Committee member) / Arizona State University (Publisher)
Created2022
Description
Hexavalant chromium (Cr(VI)) poses an emerging concern in drinking water treatment with stricter regulations on the horizon. Photocatalytic reduction of Cr(VI) was investigated as an engineering scale option to remove hexavalent chromium from drinking or industrial waters via a UV/titanium dioxide (TiO2) process. Using an integrated UV lamp/ceramic membrane system to recirculate TiO2, both hexavalent and total chromium levels were reduced through photocatalytic processes without additional chemicals. Cr(VI) removal increased as a function of higher energy input and TiO2 dosage, achieving above 90% removal for a 1g/L dose of TiO2. Surface analysis of effluent TiO2 confirmed the presence of chromium species.
ContributorsStancl, Heather O'Neal (Author) / Westerhoff, Paul K (Thesis advisor) / Chan, Candace (Committee member) / Hristovski, Kiril (Committee member) / Arizona State University (Publisher)
Created2013
Description
Bioremediation of trichloroethene (TCE) using Dehalococcoides mccartyi-containing microbial cultures is a recognized and successful remediation technology. Our work with an upflow anaerobic sludge blanket (UASB) reactor has shown that high-performance, fast-rate dechlorination of TCE can be achieved by promoting bioflocculation of Dehalococcoides mccartyi-containing cultures. The bioreactor achieved high maximum conversion rates of 1.63 ± 0.012 mmol Cl- Lculture-1 h-1 at an HRT of 3.6 hours and >97% dechlorination of TCE to ethene while continuously fed 2 mM TCE. The UASB generated bioflocs from a microbially heterogeneous dechlorinating culture and produced Dehalococcoides mccartyi densities of 1.73x10-13 cells Lculture-1 indicating that bioflocculation of Dehalococcoides mccartyi-containing cultures can lead to high density inocula and high-performance, fast-rate bioaugmentation culture for in situ treatment. The successful operation of our pilot scale bioreactor led to the assessment of the technology as an onsite ex-situ treatment system. The bioreactor was then fed TCE-contaminated groundwater from the Motorola Inc. 52nd Street Plant Superfund site in Phoenix, AZ augmented with the lactate and methanol. The bioreactor maintained >99% dechlorination of TCE to ethene during continuous operation at an HRT of 3.2 hours. Microbial community analysis under both experimental conditions reveals shifts in the community structure although maintaining high rate dechlorination. High density dechlorinating cultures containing bioflocs can provide new ways to 1) produce dense bioaugmentation cultures, 2) perform ex-situ bioremediation of TCE, and 3) increase our understanding of Dehalococcoides mccartyi critical microbial interactions that can be exploited at contaminated sites in order to improve long-term bioremediation schemes.
ContributorsFajardo-Williams, Devyn (Author) / Krajmalnik-Brown, Rosa (Thesis advisor) / Torres, César I (Committee member) / Popat, Sudeep C (Committee member) / Arizona State University (Publisher)
Created2015
Description
Since its first report in 1976, many outbreaks linked to Legionella have been reported in the world. These outbreaks are a public health concern because of legionellosis, which is found in two forms, Pontiac fever and Legionnaires disease. Legionnaires disease is a type of pneumonia responsible for the majority of the illness in the reported outbreaks of legionellosis. This study consists of an extensive literature review and experimental work on the aerosolization and UV inactivation of E.coli and Legionella under laboratory conditions. The literature review summarizes Legionella general information, occurrence, environmental conditions for its survival, transmission to human, collection and detection methodologies and Legionella disinfection in air and during water treatment processes.
E. coli was used as an surrogate for Legionella in experimentation due to their similar bacterial properties such as size, gram-negative rod-shaped, un-encapsulated and non-spore-forming bacterial cells. The accessibility and non-pathogenicity of E. coli also served as factors for the substitution.
Three methods of bacterial aerosolization were examined, these included an electric spray gun, an air spray gun and a hand-held spray bottle. A set of experiments were performed to examine E. coli aerosolization and transport in the aerosolization chamber (an air tight box) placed in a Biological Safety Cabinet. Spiked sample was sprayed through the opening from one side of the aerosolization chamber using the selected aerosolization methods. The air sampler was placed at the other side to collect 100 L air sample from the aerosolization chamber. A Tryptic Soy Agar plate was placed inside the air sampler to collect and subsequently culture E. coli cells from air. Results showed that the air spray gun has the best capability of aerosolizing bacteria cells under all the conditions examined in this study compared to the other two spray methods. In this study, we provide a practical and efficient method of bacterial aerosolization technique for microbial dispersion in air. The suggested method can be used in future research for microbial dispersion and transmission studies.
A set of experiments were performed to examine UV inactivation of E. coli and Legionella cells in air. Spiked samples were sprayed through the opening from one side of the aerosolization chamber using the air spray gun. A UV-C germicidal lamp inside the Biological Safety Cabinet was turned on after each spray. The air samples were collected as previously described. The application of UV-C for the inactivation of bacterial cells resulted in removing aerosolized E. coli and Legionella cells in air. A 1 log reduction was achieved with 5 seconds UV exposure time while 10 seconds UV exposure resulted in a 2 log bacterial reduction for both bacteria. This study shows the applicability of UV inactivation of pathogenic bacterial cells in air by short UV exposure time. This method may be applicable for the inactivation of Legionella in air ducts by installing germicidal UV lamps for protecting susceptible populations in certain indoor settings such as nursing homes or other community rooms.
E. coli was used as an surrogate for Legionella in experimentation due to their similar bacterial properties such as size, gram-negative rod-shaped, un-encapsulated and non-spore-forming bacterial cells. The accessibility and non-pathogenicity of E. coli also served as factors for the substitution.
Three methods of bacterial aerosolization were examined, these included an electric spray gun, an air spray gun and a hand-held spray bottle. A set of experiments were performed to examine E. coli aerosolization and transport in the aerosolization chamber (an air tight box) placed in a Biological Safety Cabinet. Spiked sample was sprayed through the opening from one side of the aerosolization chamber using the selected aerosolization methods. The air sampler was placed at the other side to collect 100 L air sample from the aerosolization chamber. A Tryptic Soy Agar plate was placed inside the air sampler to collect and subsequently culture E. coli cells from air. Results showed that the air spray gun has the best capability of aerosolizing bacteria cells under all the conditions examined in this study compared to the other two spray methods. In this study, we provide a practical and efficient method of bacterial aerosolization technique for microbial dispersion in air. The suggested method can be used in future research for microbial dispersion and transmission studies.
A set of experiments were performed to examine UV inactivation of E. coli and Legionella cells in air. Spiked samples were sprayed through the opening from one side of the aerosolization chamber using the air spray gun. A UV-C germicidal lamp inside the Biological Safety Cabinet was turned on after each spray. The air samples were collected as previously described. The application of UV-C for the inactivation of bacterial cells resulted in removing aerosolized E. coli and Legionella cells in air. A 1 log reduction was achieved with 5 seconds UV exposure time while 10 seconds UV exposure resulted in a 2 log bacterial reduction for both bacteria. This study shows the applicability of UV inactivation of pathogenic bacterial cells in air by short UV exposure time. This method may be applicable for the inactivation of Legionella in air ducts by installing germicidal UV lamps for protecting susceptible populations in certain indoor settings such as nursing homes or other community rooms.
ContributorsYao, Wei (Author) / Abbaszadegan, Morteza (Thesis advisor) / Fox, Peter (Committee member) / Alum, Absar (Committee member) / Arizona State University (Publisher)
Created2015
Description
This study reports on the treatment of ammunition wastewater containing RDX (1,3,5-Trinitro-1,3,5-triazinane), HMX (1,3,5,7-Tetranitro-1,3,5,7-tetrazoctane), and the oxyanion co-contaminants nitrate (NO3-) and perchlorate (ClO4-) in a membrane biofilm reactor (MBfR), a Palladium (Pd)-coated MBfR (Pd-MBfR), and an abiotic Pd-coated film reactor (Pd-film reactor). A consortium of nitrate- and perchlorate-reducing bacteria, continuously fed with synesthetic ammunition wastewater featuring 4 mM nitrate and 0.1-2 mM perchlorate, formed robust biofilms on the membrane surfaces in the MBfR and Pd-MBfR. PdNPs with diameter 4-5-nm auto-assembled and stabilized on the surfaces of membrane and biofilm in MPfR and Pd-MBfR. Nitrate and perchlorate were rapidly reduced by the biofilms in the MBfR and Pd-MBfR, but they were not catalytically reduced through PdNPs alone in the MPfR. In contrast, RDX or HMX was recalcitrant to enzymatic degradation in MBfR, but was rapidly reduced through Pd-catalytic denitration in the MPfR and Pd-MBfR to form ‒N‒NHOH or ‒N‒H. Based on the experimental results, the synergistic coupling of Pd-based catalysis and microbial activity in the Pd-MBfR should be a viable new technology for treating ammunition wastewater.
ContributorsZheng, Chenwei (Author) / Rittmann, Bruce (Thesis advisor) / Delgado, Anca (Committee member) / Lai, Yen-Jung (Committee member) / Arizona State University (Publisher)
Created2019
Description
Zero-Valent Metals (ZVM) are highly reactive materials and have been proved to be effective in contaminant reduction in soils and groundwater remediation. In fact, zero-Valent Iron (ZVI) has proven to be very effective in removing, particularly chlorinated organics, heavy metals, and odorous sulfides. Addition of ZVI has also been proved in enhancing the methane gas generation in anaerobic digestion of activated sludge. However, no studies have been conducted regarding the effect of ZVM stimulation to Municipal Solid Waste (MSW) degradation. Therefore, a collaborative study was developed to manipulate microbial activity in the landfill bioreactors to favor methane production by adding ZVMs. This study focuses on evaluating the effects of added ZVM on the leachate generated from replicated lab scale landfill bioreactors. The specific objective was to investigate the effects of ZVMs addition on the organic and inorganic pollutants in leachate. The hypothesis here evaluated was that adding ZVM including ZVI and Zero Valent Manganese (ZVMn) will enhance the removal rates of the organic pollutants present in the leachate, likely by a putative higher rate of microbial metabolism. Test with six (4.23 gallons) bioreactors assembled with MSW collected from the Salt River Landfill and Southwest Regional Landfill showed that under 5 grams /liter of ZVI and 0.625 grams/liter of ZVMn additions, no significant difference was observed in the pH and temperature data of the leachate generated from these reactors. The conductivity data suggested the steady rise across all reactors over the period of time. The removal efficiency of sCOD was highest (27.112 mg/lit/day) for the reactors added with ZVMn at the end of 150 days for bottom layer, however the removal rate was highest (16.955 mg/lit/day) for ZVI after the end of 150 days of the middle layer. Similar trends in the results was observed in TC analysis. HPLC study indicated the dominance of the concentration of heptanoate and isovalerate were leachate generated from the bottom layer across all reactors. Heptanoate continued to dominate in the ZVMn added leachate even after middle layer injection. IC analysis concluded the chloride was dominant in the leachate generated from all the reactors and there was a steady increase in the chloride content over the period of time. Along with chloride, fluoride, bromide, nitrate, nitrite, phosphate and sulfate were also detected in considerable concentrations. In the summary, the addition of the zero valent metals has proved to be efficient in removal of the organics present in the leachate.
ContributorsPandit, Gandhar Abhay (Author) / Cadillo – Quiroz, Hinsby (Thesis advisor) / Olson, Larry (Thesis advisor) / Boyer, Treavor (Committee member) / Arizona State University (Publisher)
Created2019
Description
Humans are exposed up to thousands of per- and polyfluoroalkyl substances (PFAS) in the environment, but most of the research and action has been directed towards only two PFAS compounds. These two compounds are part of a subcategory of PFAS called perfluoroalkyl acids (PFAAs). It has been a challenge for the environmental community to mitigate risks caused by PFAAs due to their high persistence and lack of effective measures to remove them from the environment, especially in heavily impacted areas like fire-training sites. The goal of this work was to further answer some questions regarding the removal of PFAAs in the environment by looking at anion exchange resin characteristics and presence of a competing compound, natural organic matter (NOM), in the adsorption of environmentally relevant PFAS compounds including the two often monitored 8-carbon chain PFAAs. Two different resins were tested with two forms of counterions, in both groundwater and NOM impacted groundwater. Resin polymer matrix was the most important property in the adsorption of PFAAs, the two resins used A520E and A860 had similar properties except for their matrices polystyrene (PS) and polyacrylic (PA), respectively. The PS base is most effective at PFAAs adsorption, while the PA is most effective at NOM adsorption. The change in the counterion did not negatively affect the adsorption of PFAAs and is, therefore, a viable alternative for future studies that include regeneration and destruction of PFAAs. The presence of NOM also did not significantly affect the adsorption of PFAAs in the PS resin A520E, although for some PFAAs compounds it did affect adsorption for the PA resin. Ultimately, PS macroporous resins with a strong Type I or Type II base work best in PFAAs removal.
Contributorsdel Moral, Lerys Laura (Author) / Boyer, Treavor (Thesis advisor) / Abbaszadegan, Morteza (Committee member) / Hamilton, Kerry (Committee member) / Arizona State University (Publisher)
Created2019
Description
Mobile sources emit a number of different gases including nitrogen oxides (NOx) and volatile organic compounds (VOCs) as well as particulate matter (PM10, PM2.5). As a result, mobile sources are major contributors to urban air pollution and can be the dominant source of some local air pollution problems. In general, mobile sources are divided into two categories: on-road mobile sources and non-road mobile sources. In Maricopa County, the Maricopa County Air Quality Department prepares inventories of all local sources [11], [12]. These inventories report that for Maricopa County, on-road mobile sources emit about 23% of total PM2.5 annually, 58% of the total NOx, and 8% of the total VOCs. To understand how future changes how vehicles might impact local air quality, this work focuses on comparing current inventories of PM2.5, black carbon (BC), NOx, and VOCs to what may be expected emissions in future years based on different scenarios of penetration of hybrid gas-electric vehicles (HEV) and electric vehicles (EV) as well as continued reduction in emissions from conventional internal combustion (IC) vehicles. A range of scenarios has been developed as part of this thesis based on literature reports [6], [8], air quality improvement plan documentation [5], projected vehicle sales and registration [3], [4], as well as using EPA’s Motor Vehicle Emission Simulator (MOVES) [9]. Thus, these created scenarios can be used to evaluate what factors will make the most significant difference in improving local air quality through reduced emissions of PM2.5, BC, NOx and VOCs in the future. Specifically, the impact of a greater fraction of cleaner alternative vehicles such as hybrid-electric and electric vehicles will be compared to the impact of continual reductions in emissions from traditional internal combustion vehicles to reducing urban air pollution emissions in Maricopa County.
ContributorsAlboaijan, Fahad A M S (Author) / Fraser, Matthew (Thesis advisor) / Andino, Jean (Committee member) / Lackner, Klaus (Committee member) / Arizona State University (Publisher)
Created2020