Matching Items (63)
Analysis of photocatalysis for precursor removal and formation inhibition of disinfection byproducts
Description
Disinfection byproducts are the result of reactions between natural organic matter (NOM) and a disinfectant. The formation and speciation of DBP formation is largely dependent on the disinfectant used and the natural organic matter (NOM) concentration and composition. This study examined the use of photocatalysis with titanium dioxide for the oxidation and removal of DBP precursors (NOM) and the inhibition of DBP formation. Water sources were collected from various points in the treatment process, treated with photocatalysis, and chlorinated to analyze the implications on total trihalomethane (TTHM) and the five haloacetic acids (HAA5) formations. The three sub-objectives for this study included: the comparison of enhanced and standard coagulation to photocatalysis for the removal of DBP precursors; the analysis of photocatalysis and characterization of organic matter using size exclusion chromatography and fluorescence spectroscopy and excitation-emission matrices; and the analysis of photocatalysis before GAC filtration. There were consistencies in the trends for each objective including reduced DBP precursors, measured as dissolved organic carbon DOC concentration and UV absorbance at 254 nm. Both of these parameters decreased with increased photocatalytic treatment and could be due in part to the adsorption to as well as the oxidation of NOM on the TiO2 surface. This resulted in lower THM and HAA concentrations at Medium and High photocatalytic treatment levels. However, at No UV exposure and Low photocatalytic treatment levels where oxidation reactions were inherently incomplete, there was an increase in THM and HAA formation potential, in most cases being significantly greater than those found in the raw water or Control samples. The size exclusion chromatography (SEC) results suggest that photocatalysis preferentially degrades the higher molecular mass fraction of NOM releasing lower molecular mass (LMM) compounds that have not been completely oxidized. The molecular weight distributions could explain the THM and HAA formation potentials that decreased at the No UV exposure samples but increased at Low photocatalytic treatment levels. The use of photocatalysis before GAC adsorption appears to increase bed life of the contactors; however, higher photocatalytic treatment levels have been shown to completely mineralize NOM and would therefore not require additional GAC adsorption after photocatalysis.
ContributorsDaugherty, Erin (Author) / Abbaszadegan, Morteza (Thesis advisor) / Fox, Peter (Committee member) / Mayer, Brooke (Committee member) / Arizona State University (Publisher)
Created2011
Description
This thesis research focuses on phylogenetic and functional studies of microbial communities in deep-sea water, an untapped reservoir of high metabolic and genetic diversity of microorganisms. The presence of photosynthetic cyanobacteria and diatoms is an interesting and unexpected discovery during a 16S ribosomal rRNA-based community structure analyses for microbial communities in the deep-sea water of the Pacific Ocean. Both RT-PCR and qRT-PCR approaches were employed to detect expression of the genes involved in photosynthesis of photoautotrophic organisms. Positive results were obtained and further proved the functional activity of these detected photosynthetic microbes in the deep-sea. Metagenomic and metatranscriptomic data was obtained, integrated, and analyzed from deep-sea microbial communities, including both prokaryotes and eukaryotes, from four different deep-sea sites ranging from the mesopelagic to the pelagic ocean. The RNA/DNA ratio was employed as an index to show the strength of metabolic activity of deep-sea microbes. These taxonomic and functional analyses of deep-sea microbial communities revealed a `defensive' life style of microbial communities living in the deep-sea water. Pseudoalteromonas sp.WG07 was subjected to transcriptomic analysis by application of RNA-Seq technology through the transcriptomic annotation using the genomes of closely related surface-water strain Pseudoalteromonas haloplanktis TAC125 and sediment strain Pseudoalteromonas sp. SM9913. The transcriptome survey and related functional analysis of WG07 revealed unique features different from TAC125 and SM9913 and provided clues as to how it adapted to its environmental niche. Also, a comparative transcriptomic analysis of WG07 revealed transcriptome changes between its exponential and stationary growing phases.
ContributorsWu, Jieying (Author) / Meldrum, Deirdre R. (Thesis advisor) / Zhang, Weiwen (Committee member) / Abbaszadegan, Morteza (Committee member) / Neuer, Susanne (Committee member) / Arizona State University (Publisher)
Created2013
Description
Bacteroides have been suggested as alternative indicators of fecal pollution since they are highly abundant in feces and are thought to have limited potential to grow in environment. However, recent literature suggests that Bacteroides can potentially survive within water distribution systems. The first objective of this study was therefore to investigate the validity of Bacteroides as a fecal indicator for drinking water through laboratory experiments and field studies. Experiments were performed using a laboratory scale PVC model water distribution system that was spiked with 109 Bacteroides. Samples were collected over the following four and analyzed by culture and molecular-based techniques. Second, field studies were performed by collecting water meters from two large chlorinated water distribution systems in central Arizona. Upon removal for repair by city personnel, meters were collected and biofilms samples were gathered within two hours. The biofilms were then analyzed using culture and molecular-based assays. The results from these studies support the hypothesis that Bacteroides DNA may be found in water distribution systems despite the difficulty of cultivating these bacterial cells. These experiments present the importance of considering biofilm interactions with fecal indicator bacteria when performing molecular assays on environmental samples, as biofilms may provide protection from high oxygen concentrations and grazing protozoa in bulk water that limit the persistence Bacteroides in the environment. Although the significance of biofilm interactions with surface or recreational waters may be small, they are likely important when considering drinking water delivered through distribution systems. The second objective of this study was to investigate alternative detection methodologies for the fecal indicator Bacteroides. In particular, this study focused on using a simplified protocol of Nucleic Acid Sequence Based Amplification (NASBA) and Thermophilic Helicase-Dependent Amplification (tHDA) to amplify the highly conserved 16s rRNA gene in the genomic DNA of fecal indicator Bacteroides. The results of this study show that the simplified NASBA procedure was not able to amplify the target, while continuous problems with tHDA exposed the methods lack of reliability. These results suggest higher reliability in the isothermal amplification methods needs to be achieved before application to environmental samples.
ContributorsDunkin, Nate (Author) / Abbaszadegan, Morteza (Thesis advisor) / Alum, Absar (Committee member) / Fox, Peter (Committee member) / Arizona State University (Publisher)
Created2012
Description
Water quality in surface water is frequently degraded by fecal contamination from human and animal sources, imposing negative implications for recreational water use and public safety. For this reason it is critical to identify the source of fecal contamination in bodies of water in order to take proper corrective actions for controlling fecal pollution. Bacteroides genetic markers have been widely used to differentiate human from other sources of fecal bacteria in water. The results of this study indicate that many assays currently used to detect human-specific Bacteroides produce false positive results in the presence of freshwater fish. To further characterize Bacteroides from fish and human, the fecal samples were cultured, speciated, and identified. As a result, forty six new Bacteroides 16S rRNA gene sequences have been deposited to the NCBI database. These sequences, along with selected animal fecal sample Bacteroides, were aligned against human B. volgatus, B. fragilis, and B. dorei to identify multi-segmented variable regions within the 16S rRNA gene sequence. The collected sequences were truncated and used to construct a cladogram, showing a clear separation between human B. dorei and Bacteroides from other sources. A proposed strategy for source tracking was field tested by collecting water samples from central AZ source water and three different recreational ponds. PCR using HF134 and HF183 primer sets were performed and sequences for positive reactions were then aligned against human Bacteroides to identify the source of contamination. For the samples testing positive using the HF183 primer set (8/13), fecal contamination was determined to be from human sources. To confirm the results, PCR products were sequenced and aligned against the four variable regions and incorporated within the truncated cladogram. As expected, the sequences from water samples with human fecal contamination grouped within the human clade. As an outcome of this study, a tool box strategy for Bacteroides source identification relying on PCR amplification, variable region analysis, human-specific Bacteroides PCR assays, and subsequent truncated cladogram grouping analysis has been developed. The proposed strategy offers a new method for microbial source tracking and provides step-wise methodology essential for identifying sources of fecal pollution.
ContributorsKabiri-Badr, Leila (Author) / Abbaszadegan, Morteza (Thesis advisor) / Bingham, Scott (Committee member) / Rock, Channah (Committee member) / Fox, Peter (Committee member) / Mclain, Jean (Committee member) / Arizona State University (Publisher)
Created2012
Description
Nanotechnology is a scientific field that has recently expanded due to its applications in pharmaceutical and personal care products, industry and agriculture. As result of this unprecedented growth, nanoparticles (NPs) have become a significant environmental contaminant, with potential to impact various forms of life in environment. Metal nanoparticles (mNPs) exhibit unique properties such as increased chemical reactivity due to high specific surface area to volume ratios. Bacteria play a major role in many natural and engineered biogeochemical reactions in wastewater treatment plants and other environmental compartments. I have evaluated the laboratory isolates of E. coli, Bacillus, Alcaligenes, Pseudomonas; wastewater isolates of E. coli and Bacillus; and pathogenic isolate of E. coli for their response to 50 & 100 nm sized Cu nanoparticles (CuNPs). Bactericidal tests, scanning electron microscopy (SEM) analyses, and probable toxicity pathways assays were performed. The results indicate that under continuous mixing conditions, CuNPs are effective in inactivation of the selected bacterial isolates. In general, exposure to CuNPs resulted in 4 to >6 log reduction in bacterial population within 2 hours. Based on the GR, LDH and MTT assays, bacterial cells showed different toxicity elicitation pathways after exposure to CuNPs. Therefore, it can be concluded that the laboratory isolates are good candidates for predicting the behavior of environmental isolates exposed to CuNPs. Also, high inactivation values recorded in this study suggest that the presence of CuNPs in different environmental compartments may have an impact on pollutants attenuation and wastewater biological treatment processes. These results point towards the need for an in depth investigation of the impact of NPs on the biological processes; and long-term effect of high load of NPs on the stability of aquatic and terrestrial ecologies.
ContributorsAlboloushi, Ali (Author) / Abbaszadegan, Morteza (Thesis advisor) / Alum, Absar (Committee member) / Fox, Peter (Committee member) / Olson, Larry (Committee member) / Arizona State University (Publisher)
Created2012
Description
The rising need for water reuse in the Southwest United States has increased awareness of the quality of wastewater. This need is caused by an increased population having basic water needs; inefficient water use, such as overwatering lawns and leaking pipes; and recent drought conditions all over the southwestern US. Reclaimed water is a possible solution. It's used for a variety of non-potable, or non-drinkable, reasons. These uses include: cooling power plants, concrete mixing, artificial lakes, and irrigation for public parks and golf courts. Cooling power plants utilizes roughly 41% of the total water consumed by the United States, which makes it the highest user of water in the US. The attention is turned to optimizing mechanical processes and reducing the amount of water consumed. Wet-recirculating systems reuse cooling water in a second cycle rather than discharging it immediately. Cooling towers are commonly used to expose water to ambient air. As the water evaporates, more water is withdrawn while the rest continues to circulate. These systems have much lower water withdrawals than once-through systems, but have higher water consumption. The cooling towers in wet-recirculating plants and other warm machinery have two major limitations: evaporation of pumped water and scale formation in the components. Cooling towers circulate water, and only draw as it evaporates, which conserves water. The scale formation in the components is due to the hardness of the water. Scale occurs when hard water evaporates and forms solid calcium carbonate. This formation can lead to reduced flow or even clogging in pipes, fouling of components or pipes, and reduced cooling efficiency. Another concern from the public over the use of reclaimed water is the possibility of there being fecal contamination. This fear stems from the stigma associated with drinking water that essentially came from the toilet. An emerging technology, in order to address these three issues, is the use of an electromagnetic device. The wires have a current flowing through which induces a magnetic field perpendicular to the direction of the flow, while the electrical field is proportional to the flow velocity. In other words, the magnetic and electrical fields will create an effect that will concentrate cations at the center of the pipe and anions at the wall of the pipe or the other way depending on the direction of the flow. Reversing the field will then cause the cations and anions to move toward one another and increase the collision frequency and energy. The purpose of these experiments is to test the effects of the electromagnetic device on the aforementioned topics. There are three tests that were performed, a surface tension test, a hardness test, and a microbial test. The surface tension test focused on the angle of a water droplet until it burst. The angle would theoretically decrease as the bond between water molecules increased due to the device. The results of this test shows a lower angle for the treated water but a higher angle for the untreated one. This means the device had an effect on the surface tension of the water. Hard water is caused by calcium and magnesium ions in the water. These ions are dissolved in the water as it travels past soil and rocks. The purpose of this test is to measure the free calcium ion amount in the water. If the free calcium number lowers, then it can be assumed it collided with the carbonate and formed calcium carbonate. This calcium carbonate causes a reduction in hardness in the water. The result of the test showed no correlation between ion concentrations in the treated/untreated system. The e. coli test focused on testing the effects of an electromagnetic device on inhibiting fecal contamination in water/wastewater at a treatment facility. In order to detect fecal contamination, we test for bacteria known as fecal coliforms, more specifically e. coli. The test involved spiking the system with bacteria and testing its concentrations after time had passed.The e. coli results showed no trend in the inactivation of the bacteria. In conclusion, the device had varying results, but multiple steps can be taken in the future in order to continue research.
ContributorsHernandez, Andres Victor (Author) / Fox, Peter (Thesis director) / Abbaszadegan, Morteza (Committee member) / Civil, Environmental and Sustainable Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2014-12
Description
The objective of this research was to predict the persistence of potential future contaminants in indirect potable reuse systems. In order to accurately estimate the fates of future contaminants in indirect potable reuse systems, results describing persistence from EPI Suite were modified to include sorption and oxidation. The target future contaminants studied were the approximately 2000 pharmaceuticals currently undergoing testing by United States Food and Drug Administration (US FDA). Specific organic substances such as analgesics, antibiotics, and pesticides were used to verify the predicted half-lives by comparing with reported values in the literature. During sub-surface transport, an important component of indirect potable reuse systems, the effects of sorption and oxidation are important mechanisms. These mechanisms are not considered by the quantitative structure activity relationship (QSAR) model predictions for half-lives from EPI Suite. Modifying the predictions from EPI Suite to include the effects of sorption and oxidation greatly improved the accuracy of predictions in the sub-surface environment. During validation, the error was reduced by over 50% when the predictions were modified to include sorption and oxidation. Molecular weight (MW) is an important criteria for estimating the persistence of chemicals in the sub-surface environment. EPI Suite predicts that high MW compounds are persistent since the QSAR model assumes steric hindrances will prevent transformations. Therefore, results from EPI Suite can be very misleading for high MW compounds. Persistence was affected by the total number of halogen atoms in chemicals more than the sum of N-heterocyclic aromatics in chemicals. Most contaminants (over 90%) were non-persistent in the sub-surface environment suggesting that the target future drugs do not pose a significant risk to potable reuse systems. Another important finding is that the percentage of compounds produced from the biotechnology industry is increasing rapidly and should dominate the future production of pharmaceuticals. In turn, pharmaceuticals should become less persistent in the future. An evaluation of indirect potable reuse systems that use reverse osmosis (RO) for potential rejection of the target contaminants was performed by statistical analysis. Most target compounds (over 95%) can be removed by RO based on size rejection and other removal mechanisms.
ContributorsLim, Seung (Author) / Fox, Peter (Thesis advisor) / Abbaszadegan, Morteza (Committee member) / Halden, Rolf (Committee member) / Arizona State University (Publisher)
Created2011
Description
The deterioration of drinking-water quality within distribution systems is a serious cause for concern. Extensive water-quality deterioration often results in violations against regulatory standards and has been linked to water-borne disease outbreaks. The causes for the deterioration of drinking water quality inside distribution systems are not yet fully understood. Mathematical models are often used to analyze how different biological, chemical, and physical phenomena interact and cause water quality deterioration inside distribution systems. In this dissertation research I developed a mathematical model, the Expanded Comprehensive Disinfection and Water Quality (CDWQ-E) model, to track water quality changes in chloraminated water. I then applied CDWQ-E to forecast water quality deterioration trends and the ability of Naegleria fowleri (N.fowleri), a protozoan pathogen, to thrive within drinking-water distribution systems. When used to assess the efficacy of substrate limitation versus disinfection in controlling bacterial growth, CDWQ-E demonstrated that bacterial growth is more effectively controlled by lowering substrate loading into distribution systems than by adding residual disinfectants. High substrate concentrations supported extensive bacterial growth even in the presence of high levels of chloramine. Model results also showed that chloramine decay and oxidation of organic matter increase the pool of available ammonia, and thus have potential to advance nitrification within distribution systems. Without exception, trends predicted by CDWQ-E matched trends observed from experimental studies. When CDWQ-E was used to evaluate the ability N. fowleri to survive in finished drinking water, the model predicted that N. fowleri can survive for extended periods of time in distribution systems. Model results also showed that N. fowleri growth depends on the availability of high bacterial densities in the 105 CFU/mL range. Since HPC levels this high are rarely reported in bulk water, it is clear that in distribution systems biofilms are the prime reservoirs N. fowleri because of their high bacterial densities. Controlled laboratory experiments also showed that drinking water can be a source of N. fowleri, and the main reservoir appeared to be biofilms dominated by bacteria. When introduced to pipe-loops N. fowleri successfully attached to biofilms and survived for 5 months.
ContributorsBiyela, Precious Thabisile (Author) / Rittmann, Bruce E. (Thesis advisor) / Abbaszadegan, Morteza (Committee member) / Butler, Caitlyn (Committee member) / Arizona State University (Publisher)
Created2010
Description
The impact of physical/chemical properties of gray water on microbial inactivation in gray water using chlorine was investigated through creating artificial gray water in lab, varying specific components, and then measuring microbial inactivation. Gray water was made through taking autoclaved nanopure water, and increasing the concentration of surfacants, the turbidity, the concentration of organic content, and spiking E. coli grown in tryptic soy broth (TSB); chlorine was introduced using Clorox Disinfecting Bleach2. Bacteria was detected using tryptic soy agar (TSA), and E. coli was specifically detected using the selective media, brilliance. The log inactivation of bacteria detected using TSA was shown to be inversely related to the turbidity of the solution. Complete inactivation of E. coli concentrations between 104-105 CFU/100 ml in gray water with turbidities between 10-100 NTU, 0.1-0.5 mg/L of humic acid, and 0.1 ml of Dawn Ultra, was shown to occur, as detected by brilliance, at chlorine concentrations of 1-2 mg/L within 30 seconds. These result in concentration time (CT) values between 0.5-1 mg/L·min. Under the same gray water conditions, and an E. coli concentration of 104 CFU/100 ml and a chlorine concentration of 0.01 mg/L, complete inactivation was shown to occur in all trials within two minutes. These result in CT values ranging from 0.005 to 0.02. The turbidity and humic acid concentration were shown to be inversely related to the log inactivation and directly related to the CT value. This study shows that chlorination is a valid method of treatment of gray water for certain irrigation reuses.
ContributorsGreenberg, Samuel Gabe (Author) / Abbaszadegan, Morteza (Thesis director) / Schoepf, Jared (Committee member) / Alum, Absar (Committee member) / Chemical Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Cerebral lateralization describes the asymmetries between the two halves of the brain which results in side-specialized processing of certain functions. This phenomenon provides a selective advantage by promoting enhanced cognitive abilities. However, due to the plastic nature of lateralization, an individual’s lateralization is highly subject to change by many external factors, such as pollution, throughout its life. Additionally, lateralized regions are dependent on different contexts, so lateralized elements do not all experience the same effects. A common pollutant found worldwide is bisphenol-A (BPA), a critical component of many plastics. BPA is a known endocrine disruptor that can agonize and antagonize the functions of sex steroids. Other studies have demonstrated the importance of sex steroids in regulating the development of cerebral lateralization; BPA may similarly affect lateralization. A popular research animal for studying toxicology is the zebrafish. Its advantages include a fully sequenced genome, many human orthologs, and more importantly, expresses lateralized behaviors that are indicative of the strength of its cerebral lateralization. This experiment analyzed the effects of BPA exposure on visual lateralization of zebrafish. Given the role that sex steroids play in moderating lateralization, it was hypothesized that exposing zebrafish to BPA would diminish the strength of lateralization in the brain which would translate into reduced behavioral lateralization. To test this, one group was exposed to 0.01 mg/L BPA for one week and compared against a control group in their eye preference when approaching a visual cue. Two settings, a foraging context and a social context, were utilized to examine the scope of impairment in lateralization. The control group in both settings displayed similar strengths in behavioral lateralization with a left eye preference. However, the lateralized response faded completely with BPA treatment. This experiment demonstrates that BPA induces loss of lateralization and possesses similar impacts on mechanisms controlling investigatory behavior in these two contexts. Wild populations may encounter higher concentrations of BPA, and although there is greater variability in these exposures, this experiment proves that exposure even beyond critical periods of development can impair lateralization. Additional research will have to be conducted to identify the effects of BPA on other lateralized behaviors and sensory modalities to pinpoint the exact mechanisms through which BPA influences lateralization.
ContributorsHuang, Alexander (Author) / Martins, Emilia (Thesis director) / Suriyampola, Piyumika (Committee member) / Conroy-Ben, Otakuye (Committee member) / School of Life Sciences (Contributor) / School of Molecular Sciences (Contributor) / Dean, W.P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05