Matching Items (11)
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- All Subjects: Water
- Creators: School of Human Evolution and Social Change
- Creators: Hristovski, Kiril
- Member of: Theses and Dissertations
Description
Nitrate is the most prevalent water pollutant limiting the use of groundwater as a potable water source. The overarching goal of this dissertation was to leverage advances in nanotechnology to improve nitrate photocatalysis and transition treatment to the full-scale. The research objectives were to (1) examine commercial and synthesized photocatalysts, (2) determine the effect of water quality parameters (e.g., pH), (3) conduct responsible engineering by ensuring detection methods were in place for novel materials, and (4) develop a conceptual framework for designing nitrate-specific photocatalysts. The key issues for implementing photocatalysis for nitrate drinking water treatment were efficient nitrate removal at neutral pH and by-product selectivity toward nitrogen gases, rather than by-products that pose a human health concern (e.g., nitrite). Photocatalytic nitrate reduction was found to follow a series of proton-coupled electron transfers. The nitrate reduction rate was limited by the electron-hole recombination rate, and the addition of an electron donor (e.g., formate) was necessary to reduce the recombination rate and achieve efficient nitrate removal. Nano-sized photocatalysts with high surface areas mitigated the negative effects of competing aqueous anions. The key water quality parameter impacting by-product selectivity was pH. For pH < 4, the by-product selectivity was mostly N-gas with some NH4+, but this shifted to NO2- above pH = 4, which suggests the need for proton localization to move beyond NO2-. Co-catalysts that form a Schottky barrier, allowing for localization of electrons, were best for nitrate reduction. Silver was optimal in heterogeneous systems because of its ability to improve nitrate reduction activity and N-gas by-product selectivity, and graphene was optimal in two-electrode systems because of its ability to shuttle electrons to the working electrode. "Environmentally responsible use of nanomaterials" is to ensure that detection methods are in place for the nanomaterials tested. While methods exist for the metals and metal oxides examined, there are currently none for carbon nanotubes (CNTs) and graphene. Acknowledging that risk assessment encompasses dose-response and exposure, new analytical methods were developed for extracting and detecting CNTs and graphene in complex organic environmental (e.g., urban air) and biological matrices (e.g. rat lungs).
ContributorsDoudrick, Kyle (Author) / Westerhoff, Paul (Thesis advisor) / Halden, Rolf (Committee member) / Hristovski, Kiril (Committee member) / Arizona State University (Publisher)
Created2013
Description
Arsenic (As) and chromium (Cr) occur naturally in AZ surface and groundwaters, pose different health impacts, and exhibit different treatment efficacies. Hexavalent chromium (Cr(VI)) has newly recognized human health concerns, and State and Federal agencies are evaluating a low Cr(VI)-specific maximum contaminant level (MCL) for drinking water. Occurrence of Cr and As in municipal drinking waters and industrial cooling tower waters was quantified by grab samples and compared with sampling results obtained from a new passive sampler developed specifically for Cr(VI). Cr(VI) and As concentrations in groundwater used for cooling tower make-up water concentrations were ~3 ppb and ~4 ppb, respectively, and were concentrated significantly in blowdown water (~20 ppb and ~40 ppb). Based upon pending Cr(VI), As, and other metal regulations, these blowdown waters will need routine monitoring and treatment. Cr(VI) concentrations in a water treatment plant (WTP) raw and finished water samples varied from 0.5 and 2 ppb for grab samples collected every 4 hours for 7 consecutive days using an ISCO sampler. The development of an ion exchange (IX) based passive sampler was validated in the field at the WTP and yielded an average exposure within 1 standard deviation of ISCO sampler grab data. Sampling at both the WTP and cooling towers suggested sources of Cr(III) from treatment chemicals or wood preservatives may exist. Since both facilities use chlorine oxidants, I quantified the apparent (pH=5) second-order rate constant for aqueous chlorine (HOCl/OCl-) with Cr(III) to form Cr(VI) as 0.7 M-1s-1. Under typical conditions (2 ppb Cr(III) ; 2 mg/L Cl2) the half-life for the conversion of Cr(III) to the more toxic form Cr(VI) is 4.7 hours. The occurrence studies in AZ and CA show the Cr(VI) and As treatment of groundwaters will be required to meet stringent Cr(VI) regulations. IX technologies, both strong base anion (SBA) and weak base anion (WBA) resin types were screened (and compared) for Cr removal. The SBA IX process for As removal was optimized by utilizing a reactive iron coagulation and filtration (RCF) process to treat spent IX brine, which was then reused to for SBA resin regeneration.
ContributorsBowen, Alexandra (Author) / Paul, Westerhoff K. (Thesis advisor) / Hristovski, Kiril (Committee member) / Halden, Rolf (Committee member) / Arizona State University (Publisher)
Created2014
Description
Population growth and fresh water depletion challenge drinking water utilities. Surface water quality is impacted significantly by climate variability, human activities, and extreme events like natural disasters. Dissolved organic carbon (DOC) is an important water quality index and the precursor of disinfection by-products (DBPs) that varies with both hydrologic and anthropogenic factors. Granular activated carbon (GAC) is a best available technology for utilities to meet Stage 2 D/DBP rule compliance and to remove contaminants of emerging concern (CECs) (e.g., pharmaceutical, personal care products (PCPs), etc.). Utilities can operate GAC with more efficient and flexible strategies with the understanding of organic occurrence in source water and a model capable predicting DOC occurrence. In this dissertation, it was found that DOC loading significantly correlated with spring runoff and was intensified by dry-duration antecedent to first flush. Dynamic modeling based on reservoir management (e.g., pump-back operation) was established to simulate the DOC transport in the reservoir system. Additionally, summer water recreational activities were found to raise the level of PCPs, especially skin-applied products, in raw waters. GAC was examined in this dissertation for both carbonaceous and emerging nitrogenous DBP (N-DBP) precursors (i.e., dissolved organic nitrogen (DON)) removal. Based on the experimental findings, GAC preferentially removes UV254-absorbing material, and DOC is preferentially removed over DON which may be composed primarily of hydrophilic organic and results in the low affinity for adsorption by GAC. The presence of organic nitrogen can elevate the toxicity of DBPs by forming N-DBPs, and this could be a major drawback for facilities considering installation of a GAC adsorber owing to the poor removal efficiency of DON by GAC. A modeling approach was established for predicting DOC and DON breakthrough during GAC operation. However, installation of GAC adsorber is a burden for utilities with respect to operational and maintenance cost. It is common for utilities to regenerate saturated GAC in order to save the cost of purchasing fresh GAC. The traditional thermal regeneration technology for saturated GAC is an energy intensive process requiring high temperature of incineration. Additionally, small water treatment sites usually ship saturated GAC to specialized facilities for regeneration increasing the already significant carbon footprint of thermal regeneration. An innovative GAC regeneration technique was investigated in this dissertation for the feasibility as on-site water treatment process. Virgin GAC was first saturated by organic contaminant then regenerated in-situ by iron oxide nanocatalysts mixed with hydrogen peroxide. At least 70 % of adsorption capacity of GAC can be regenerated repeatedly for experiments using modeling compound (phenol) or natural organic matter (Suwannee River humic acid). The regeneration efficiency increases with increasing adsorbate concentration. Used-iron nanocatalysts can be recovered repeatedly without significant loss of catalytic ability. This in-situ regeneration technique provides cost and energy efficient solution for water utilities considering GAC installation. Overall, patterns were found for DOC and CEC variations in drinking water sources. Increasing concentrations of bulk (DOC and DON) and/or trace organics challenge GAC operation in utilities that have limited numbers of bed-volume treated before regeneration is required. In-situ regeneration using iron nanocatalysts and hydrogen peroxide provides utilities an alternative energy-efficient operation mode when considering installation of GAC adsorber.
ContributorsChiu, Chao-An (Author) / Westerhoff, Paul (Thesis advisor) / Rittmann, Bruce (Committee member) / Hristovski, Kiril (Committee member) / Arizona State University (Publisher)
Created2012
Description
Local municipalities in the Phoenix Metropolitan Area have voiced an interest in purchasing alternate source water with lower DBP precursors. Along the primary source is a hydroelectric dam in which water will be diverted from. This project is an assessment of optimizing the potential blends of source water to a water treatment plant in an effort to enable them to more readily meet DBP regulations. To perform this analysis existing water treatment models were used in conjunction with historic water quality sampling data to predict chemical usage necessary to meet DBP regulations. A retrospective analysis was performed for the summer months of 2007 regarding potential for the WTP to reduce cost through optimizing the source water by an average of 30% over the four-month period, accumulating to overall treatment savings of $154 per MG ($82 per AF).
ContributorsRice, Jacelyn (Author) / Westerhoff, Paul (Thesis advisor) / Fox, Peter (Committee member) / Hristovski, Kiril (Committee member) / Arizona State University (Publisher)
Created2011
Description
The study examines cross-cultural perceptions of wastewater reuse from 282 participants from four global sites representing varied levels of socio-economic and political development from the Global North and Global South: Spain, New Zealand, Fiji, and Guatemala. The data comes from the Global Ethnohydrology Survey conducted by the School of Human Evolution and Social Change during the summer of 2013. The Global Ethnohydrology Study is a transdisciplinary multi-year research initiative that examines the range of variation in local ecological knowledge of water issues, also known as "ethnohydrology." Participants were asked about their willingness, level of disgust, and concern with using treated wastewater for various daily activities. Additionally, they were asked to draw schematic representations of how wastewater should be treated to become drinkable again. Using visual content analysis, the drawings were coded for a variety of treatment levels and specific treatment processes. Conclusions about the perceived health implications from wastewater reuse that can stem from drinking treated wastewater were made. The relationship between humans and wastewater is one that has many direct social and health impacts on communities at large. In reaction to global limitations of freshwater, wastewater serves as a valuable resource to tap into. This research examines the cross-cultural public health concerns about treated wastewater in order to draw conclusions that can aid in strategic implementation of advocacy and public education about wastewater reuse.
ContributorsPatel, Sarah Shakir (Author) / Wutich, Amber (Thesis director) / Rice, Jacelyn (Committee member) / Barrett, The Honors College (Contributor) / School of Politics and Global Studies (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2015-05
Description
Children's drawings are increasingly being used to assess understanding and diagnose misconceptions about water issues and the environment. As part of Arizona State University's Global Ethnohydrology Study and Community Health and Medical Anthropology Field School, 315 pieces of artwork from 158 Guatemalan schoolchildren, ages 9-10, were collected using ethnographic field methods. The children were asked to draw two pieces of art: one showing how they saw water being used in their neighborhood today and one showing how they imagined water would be used in their neighborhood 100 years from now. Using visual content analysis, the drawings were coded for the presence of vegetation, scarcity, pollution, commercial sources, existing technology, technological innovation, domestic use, and natural sources of water. The study finds that (1) students' drawings of the future contain significantly more pollution and scarcity than those in the present, and (2) both boys and girls depict existing technology significantly more often in the drawings of today than the drawings of the future. Additionally, (1) boys are significantly more likely than girls to draw more negative depictions of water (i.e., pollution and scarcity), and (2) boys are significantly more likely than girls to depict the natural world (i.e., natural sources of water). Through examining gendered perceptions and future expectations of climate change and water issues, this study explores possible areas of intervention in environmental education in a developing country.
ContributorsMcAtee, Hannah Lee (Author) / Wutich, Amber (Thesis director) / Brewis, Alexandra (Committee member) / Barrett, The Honors College (Contributor) / School of Human Evolution and Social Change (Contributor) / School of International Letters and Cultures (Contributor)
Created2015-05
Description
The influenza virus, also known as "the flu", is an infectious disease that has constantly affected the health of humanity. There is currently no known cure for Influenza. The Center for Innovations in Medicine at the Biodesign Institute located on campus at Arizona State University has been developing synbodies as a possible Influenza therapeutic. Specifically, at CIM, we have attempted to design these initial synbodies to target the entire Influenza virus and preliminary data leads us to believe that these synbodies target Nucleoprotein (NP). Given that the synbody targets NP, the penetration of cells via synbody should also occur. Then by Western Blot analysis we evaluated for the diminution of NP level in treated cells versus untreated cells. The focus of my honors thesis is to explore how synthetic antibodies can potentially inhibit replication of the Influenza (H1N1) A/Puerto Rico/8/34 strain so that a therapeutic can be developed. A high affinity synbody for Influenza can be utilized to test for inhibition of Influenza as shown by preliminary data. The 5-5-3819 synthetic antibody's internalization in live cells was visualized with Madin-Darby Kidney Cells under a Confocal Microscope. Then by Western Blot analysis we evaluated for the diminution of NP level in treated cells versus untreated cells. Expression of NP over 8 hours time was analyzed via Western Blot Analysis, which showed NP accumulation was retarded in synbody treated cells. The data obtained from my honors thesis and preliminary data provided suggest that the synthetic antibody penetrates live cells and targets NP. The results of my thesis presents valuable information that can be utilized by other researchers so that future experiments can be performed, eventually leading to the creation of a more effective therapeutic for influenza.
ContributorsHayden, Joel James (Author) / Diehnelt, Chris (Thesis director) / Johnston, Stephen (Committee member) / Legutki, Bart (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor) / Department of Chemistry and Biochemistry (Contributor)
Created2014-05
Description
In this project we examine the geographical availability of water resources for persons experiencing homelessness in Phoenix, Arizona, U.S.A. Persons experiencing homelessness spend a significant portion of their time outdoors and as such have a higher risk of dehydration, heat-related illness, and heat stress. Our data was collected using archival data, participant- observation, focal follows with water distributors that serve homeless populations, phone and internet surveys with social service providers, and expert interviews with 14 local service providers. We analyzed this data using methods for thematic coding and geospatial analysis. We find that the sources of water and geographic availability vary across the economic sectors of the population and that they become more unconventional and more difficult to access with further isolation. We conclude that many persons who are experience homelessness have inconsistent and unreliable access to water for hydrating, maintaining hygiene, cooking and cleaning for reasons that are largely due to geographic inaccessibility.
ContributorsWarpinski, Chloe Larue (Author) / Wutich, Amber (Thesis director) / Whelan, Mary (Committee member) / School of Human Evolution and Social Change (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
The Culture, Health, and Environment Lab (CHEL) at Arizona State University uses anthropological methods and field-based studies to research how cultural knowledge may be used to help understand and respond to contemporary environmental and health issues—primarily the global challenges of water insecurity and obesity. In their efforts to research water insecurity and it implications, CHEL has been working on studying water insecurity through the Global Ethnohydrology Study (GES). The Global Ethnohydrology study examines local knowledge and perceptions of water issues, using transdisciplinary methods in a multi-year and cross-country program. In the 2015-2016 study, the GES examined water, hygiene norms, and hygiene stigma. It sought to investigate how hygiene norms are impacted by the level of water security, examining if water-poor communities have laxer laxer or more accommodating hygiene norms. This paper will explore the development of the codebook for this study, following the process in which the qualitative data from the GES 2015 was organized through a series of codes so that it may later be analyzed.
ContributorsPfeiffer, Ainsley Josephine (Author) / Wutich, Amber (Thesis director) / Schuster, Roseanne (Committee member) / School of Human Evolution and Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Advancements in both the medical field and public health have substantially minimized the detrimental impact of infectious diseases. Health education and disease prevention remains a vital tool to maintain and propagate this success. In order to determine the relationship between knowledge of disease and reported preventative behavior 180 participants amongst the ASU student population were surveyed about their knowledge and prevention behavior for 10 infectious diseases. Of the 180 participants only 138 were completed surveys and used for analysis. No correlation was found between knowledge or perceived risk and preventative measures within the total sample of 138 respondents, however there was a correlation found within Lyme disease and Giardia exposure to information and prevention. Additionally, a cultural consensus analysis was used to compare the data of 17 US-born and 17 foreign-born participants to analyze patterns of variation and agreement on disease education based on national origins. Cultural consensus analysis showed a strong model of agreement among all participants as well as within the US-born and foreign-born student groups. There was a model of agreement within the questions pertaining to transmission and symptoms. There was not however a model of agreement within treatment questions. The findings suggest that accurate knowledge on infectious diseases may be less impactful on preventative behavior than social expectations.
ContributorsVernon, Samantha (Author) / Maupin, Jonathan (Thesis director) / Jehn, Megan (Committee member) / Barrett, The Honors College (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2018-05