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- All Subjects: Environmental engineering
- Genre: Masters Thesis
- Member of: ASU Electronic Theses and Dissertations
Description
Carbon capture and sequestration (CCS) is one of the important mitigation options for climate change. Numerous technologies to capture carbon dioxide (CO2) are in development but currently, capture using amines is the predominant technology. When the flue gas reacts with amines (Monoethanaloamine) the CO2 is absorbed into the solution and forms an intermediate product which then releases CO2 at higher temperature. The high temperature necessary to strip CO2 is provided by steam extracted from the powerplant thus reducing the net output of the powerplant by 25% to 35%. The reduction in electricity output for the same input of coal increases the emissions factor of Nitrogen Oxides, Mercury, Particulate matter, Ammonia, Volatile organic compounds for the same unit of electricity produced. The thesis questions if this tradeoff between CO2 and other emissions is beneficial or not. Three different methodologies, Life Cycle Assessment, Valuation models and cost benefit analysis are used to identify if there is a net benefit to the society on implementation of CCS to a Pulverized coal powerplant. These methodologies include the benefits due to reduction of CO2 and the disbenefits due to the increase of other emissions. The life cycle assessment using ecoindicator'99 methodology shows the CCS is not beneficial under Hierarchical and Egalitarian perspective. The valuation model shows that the inclusion of the other emissions reduces the benefit associated with CCS. For a lower CO2 price the valuation model shows that CCS is detrimental to the environment. The cost benefit analysis shows that a CO2 price of at least $80/tCO2 is required for the cost benefit ratio to be 1. The methodology integrates Montecarlo simulation to characterize the uncertainties associated with the valuation models.
ContributorsSekar, Ashok (Author) / Williams, Eric (Thesis advisor) / Chester, Mikhail (Thesis advisor) / Allenby, Braden (Committee member) / Arizona State University (Publisher)
Created2012
Description
In rural and urban areas of Nigeria, dependence on groundwater is increasing since the population is growing and high quality, treated municipal water is scarce. Municipal drinking water is often compromised because of old and leaking distribution pipes. About 58% of the water consumed in Lagos State, Nigeria, comes from residential wells. However, a majority of residential wells are shallow wells that are constructed relatively close to septic tanks or pit latrines and are therefore subject to contamination. In certain parts of Africa, there is high potential of severe epidemic if water quality is not improved. With increasing reliance on groundwater, a need exists to monitor the quality of groundwater. This thesis develops a plan for a monitoring program for residential wells in Lagos State, Nigeria. The program focuses on ways by which owners can maintain reasonably good water quality, and on the role of government in implementing water quality requirements. In addition, this thesis describes a survey conducted in various areas of Lagos State to assess community awareness of the importance of groundwater quality and its impact on individuals and the community at large. The survey shows that 30% to 40% of the households have located their wells and septic tanks in the same general area. Various templates have been created to help the staff of a future monitoring program team to effectively gather information during site characterization. A "Questions and Answers" leaflet has been developed to educate citizens about the need for monitoring residential wells.
ContributorsTalabi, Omogbemiga Adepitan (Author) / Edwards, David (Thesis advisor) / Hild, Nicholas (Committee member) / Olson, Larry (Committee member) / Arizona State University (Publisher)
Created2010
Description
Educators and therapists must unify and formulate new strategies to address the academic and social needs of a newly emerging at risk demographic, "the forgotten middle." Currently, a paradigm shift within educative music therapy, human development study, and educational psychology, suggests that curriculums need to integrate alternative methods into their framework, change the definition of at-risk, and recognize math aptitude and social competency as predictors of a student's ability to gain upward mobility and self-sufficiency. Musical interaction, although considered a secondary measure within educational forums, is a viable means to address the socio-emotional and academic needs of students. In order to substantiate the need for educators to integrate educative music therapy and social competency programs into standard curriculums, the researcher conducted a study using 23 students from a beginning high school guitar class and 4 students from a high school after-school program. These students participated in a ten-week study involving educative music therapy, social competency, and math aptitude. Participants completed the math fluency and math calculations sections of the Wechsler's Individual Achievement Test version 3, along with a questionnaire examining the participants' beliefs about the influence of music on math aptitude and social competency. Although the pre- and post-test results show no statistically significant difference between educative music therapy and math aptitude, the results from the questionnaires administered suggest that students perceive that social competency and musical interaction augment academic and social performance.
ContributorsHeiskell, James D (Author) / Crowe, Barbara J. (Thesis advisor) / Rio, Robin (Committee member) / McBeath, Michael (Committee member) / Arizona State University (Publisher)
Created2010
Description
This study investigates the effect of the virgin granular activated carbon (GAC) on the properties of synthesized iron (hydr)oxide nanoparticles impregnated GAC (Fe-GAC) media and its ability to remove arsenate and organic trichloroethylene (TCE) from water. Fe-GAC media were synthesized from bituminous and lignite-based virgin GAC via three variations of a permanganate/Fe(II) synthesis method. Data obtained from an array of characterization techniques indicated that differences in pore size distribution and surface chemistry of the virgin GAC favor different reaction paths for the iron (hydr)oxide nanoparticles formation. Batch equilibrium isotherm testing (120 µg-As/L; 6 mg-TCE/L, 10 mM NaHCO3 at pH = 7.2 ± 0.1 and pH = 8.2 ± 0.1) showed arsenic removal capability was increased as a result of iron (nanoparticles) impregnation, while TCE removal properties were decreased in Fe-GAC media. This tradeoff was displayed by both lignite and bituminous Fe-GAC but was most pronounced in lignite-based Fe-GAC having the highest Fe content (13.4% Fe) which showed the most favorable Freundlich adsorption and intensity parameters for arsenic of Ka = 72.6 (µg-As/g-FeGAC)(L/µg-As)1
, 1
= 0.6; and least favorable adsorption for TCE of Ka = 0.8 (mg-TCE/g-FeGAC)(L/mg-TCE)1
, 1
= 4.47. It was concluded that iron content was the main factor contributing to enhanced arsenic removal and that this was affected by base GAC properties such as pore size distribution and surface functional groups. However high Fe content can result in pore blockage; reduction in available adsorption sites for organic co-contaminants; and have a significant effect on the Fe-GACs overall adsorption capacity.
, 1
= 0.6; and least favorable adsorption for TCE of Ka = 0.8 (mg-TCE/g-FeGAC)(L/mg-TCE)1
, 1
= 4.47. It was concluded that iron content was the main factor contributing to enhanced arsenic removal and that this was affected by base GAC properties such as pore size distribution and surface functional groups. However high Fe content can result in pore blockage; reduction in available adsorption sites for organic co-contaminants; and have a significant effect on the Fe-GACs overall adsorption capacity.
ContributorsCooper, Anne Marie (Author) / Hristovski, Kiril D (Thesis advisor) / Olson, Larry W (Committee member) / Edwards, David A. (Committee member) / Arizona State University (Publisher)
Created2010
Description
Individual and group accountability is an important part of productive group work. However, classroom evaluation of teamwork often relies on top-down assessment of group product by the teacher. Other methods include averaging group grades, group discussions, evaluative essays and random selection and application of one member's grade to the entire team. In contrast, the Teamwork Skills Inventory (TSI) developed by Strom and Strom provides assessment of individual conduct and contributions as observed by peers. The instrument also affords students with the opportunity to judge their own performance. Team members are responsible for their own behavior and skill development but are not held accountable for the actions taken by others. The TSI provides criteria for productive teamwork skills and behaviors. Students know in advance the criteria by which they and their teammates will judge each other's behavior skills. In turn, students have the opportunity to practice self-evaluation as they apply the same criteria to assess their own conduct. Self-evaluation compared with peer-evaluation provides support for confidence in behavioral strengths and can guide goal setting in areas where skills are weak and need adjustment. The TSI gives teachers an insider's view of group dynamics: the obstacles and benefits groups may encounter. Since team members have the vantage point of close interaction with peers they are more likely to know how individuals affect the thinking of others in a group. This frees teachers from the difficult task of judging group dynamics. TSI results can guide teachers in developing lessons that address the needs of individuals and groups. Data derived from the TSI can help schools provide for the needs of subgroups, such as special education and gifted classes. It can also help schools detect in-service needs for faculty and provide schools with a method of community accountability for use with cooperative learning methods and social skill achievement.
ContributorsBrown, Denise (Author) / Strom, Robert D. (Thesis advisor) / Stamm, Jill (Committee member) / Strom, Paris S. (Committee member) / Arizona State University (Publisher)
Created2010
Description
The waterways in the United States are polluted by agricultural, mining, and industrial activities. Recovery of valuable materials, such as energy and nutrients, from these waste streams can improve the economic and environmental sustainability of wastewater treatment. A number of state-of-the-art anaerobic bioreactors have promise for intensified anaerobic biological treatment and energy recovery, but they have drawbacks. The drawbacks should be overcome with a novel anaerobic biological wastewater treatment process: the anaerobic biofilm membrane bioreactor (AnBfMBR). This research works aims to advance key components of the AnBfMBR. The AnBfMBR is a hybrid suspended growth and biofilm reactor. The two main components of an AnBfMBR are plastic biofilm carriers and membranes. The plastic biofilm carriers provide the surface onto which the biofilms grow. Membranes provide liquid-solid separation, retention of suspended biomass, and a solids-free effluent. Introducing sufficient surface area promotes the biofilm accumulation of slow-growing methanogens that convert volatile fatty acids into methane gas. Biofilms growing on these surfaces will have a mixed culture that primarily consists of methanogens and inert particulate solids, but also includes some acetogens. Biomass that detaches from biofilms become a component of the suspended growth. A bench-scale AnBfMBR was designed by the AnBfMBR project team and constructed by SafBon Water Technology (SWT). The primary objective of this thesis project was to evaluate the ability of plastic biofilm carriers to minimize ceramic-membrane fouling in the AnBfMBR setting. A systematic analysis of mixing for the bench-scale AnBfMBR was also conducted with the plastic biofilm carriers. Experiments were conducted following a ‘run to failure’ method, in which the ceramic membranes provide filtration, and the time it takes to reach a ‘failure transmembrane pressure (TMP)’ was recorded. The experiments revealed two distinct trends. First, the time to failure TMP decreased as mixed liquor suspended solids concentration (MLSS) concentration increased. Second, increasing the carrier fill extend the time to failure, particularly for higher MLSS concentrations. Taken together, the experiments identified an optimized “sweet spot” for the AnBfMBR: an operating flux of 0.25-m/d, a failure TMP of 0.3-atm pressure, MLSS of 5,000 – 7,500 mg/L, and 40% carrier fill.
ContributorsRoman, Brian Aaron (Author) / Rittmann, Bruce (Thesis advisor) / Boltz, Joshua (Committee member) / Perreault, Francois (Committee member) / Fox, Peter (Committee member) / Arizona State University (Publisher)
Created2021
Description
Over 7 million students in the US choosing virtual education as they pursue their degree (U.S. Department of Education, 2021). With almost 10,000 business degrees offered online (GetEducated, 2021) digital classes now have to deliver meaningful learning experiences to prepare leaders for inherently relational challenges. This study examines how well online undergraduate students learned and connected in a 7.5-week leadership development course that used a peer coaching model. In this course design, two peer coaches met each week to process and provide feedback on the coursework. Experiential Learning Theory (ELT) suggests that learning is an individual transformation that occurs as learners move through four dialectically opposed learning modes: concrete experience, reflective observation, abstract conceptualization, and active experimentation (Kolb & Kolb, 2017). Learners make meaning of their experience (like conversations or coursework) by thinking about them and developing a mental model that influences their actions which changes the way they view new experiences. In this study, I illustrate how peer coaching supports this transformative process and can help learners expand their thinking not just academically, but personally and professionally too. Moreover, peer coaches emphasize diversity by acknowledging and leveraging markedly different mental models to enhance students’ depth of learning and relating.
I used a convergent mixed-methods design in which qualitative and quantitative data were collected in parallel, analyzed separately and then merged. The reason for collecting both quantitative and qualitative data is to develop a better understanding of the effects of learning preference and affect because each type of data will provide different pieces of evidence regarding those effects. The quantitative data was collected using Qualtrics from self-report surveys using primarily Likert scales to measure learning outcomes, learning preferences, and affect as a part of class exercises. The qualitative data was collected from students’ open-ended reflection assignments about the benefits of differences in their peer coaches. The multiple regressions did not show that learning preference contrasts significantly predicted learning outcomes nor relationships. In contrast, positive affect did predict learning outcomes. The thematic analysis offered clues as to how positive affect improves both learning outcomes and the quality of the peer coaching relationship.
ContributorsReed, Rachel M (Author) / Trinh, Mai P (Thesis advisor) / Foulger, Teresa (Committee member) / Scholar, Brent (Committee member) / Arizona State University (Publisher)
Created2021
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
The thermal conductivity of cadmium sulfide (CdS) colloidal nanocrystals (NCs) and magic-sized clusters (MSCs) have been investigated in this work. It is well documented in the literature that the thermal conductivity of colloidal nanocrystal assemblies decreases as diameter decreases. However, the extrapolation of this size dependence does not apply to magic-sized clusters. Magic-sized clusters have an anomalously high thermal conductivity relative to the extrapolated size-dependence trend line for the colloidal nanocrystals. This anomalously high thermal conductivity could probably result from the monodispersity of magic-sized clusters. To support this conjecture, a method of deliberately eliminating the monodispersity of MSCs by mixing them with colloidal nanocrystals was performed. Experiment results showed that mixtures of nanocrystals and MSCs have a lower thermal conductivity that falls approximately on the extrapolated trendline for colloidal nanocrystal thermal conductivity as a function of size.
ContributorsSun, Ming-Hsien (Author) / Wang, Robert (Thesis advisor) / Rykaczewski, Konrad (Committee member) / Wang, Liping (Committee member) / Arizona State University (Publisher)
Created2022
Description
The distribution and transport of mercury in the human body are poorly constrained. For instance, the long-term persistence and intra-individual distribution of mercury in bones from dental amalgams or environmental exposure have not been studied. A robust method validated for accuracy and precision specifically for mercury in human bones would facilitate studies of mercury in anthropological, forensic, and medical studies. I present a highly precise, accurate mercury concentration analytical method targeted to human bone samples. This method uses commercially commonly available and reliable instruments that are not limited to elemental Hg analysis. This method requires significantly lower sample amounts than existing methods because it has a much lower limit of detection compared to the best mercury analyzers on the market and other analytical methods. With the low limit of detection achieved, this mercury concentration protocol is an excellent fit for studies with a limited amount of samples for destructive analysis. I then use this method to analyze the mercury concentration distribution in modern skeletal collections provided by three U.S. anthropological research facilities. Mercury concentration and distribution were analyzed from 35 donors’ skeletons with 18 different skeletal elements (bones) per donor to evaluate both the intra-individual and inter-individual variation in mercury concentration. Considered factors include geological differences in decomposition sites and the presence of dental amalgam filling. Geological differences in decomposition sites did not statistically affect the mercury concentration in the donor’s skeleton. The presence of dental amalgam significantly affected the inter-individual and intra-individual mercury concentration variation in donors’ skeletal samples. Individuals who had dental amalgam had significantly higher mercury concentration in their skeleton compared to individuals who did not have dental amalgam (p-value <0.01). Mercury concentration in the mandible, occipital bone, patella, and proximal phalanx (foot) was significantly affected by the presence of dental amalgam.
ContributorsRen, Yi (Author) / Gordon, Gwyneth GG (Thesis advisor) / Anbar, Ariel AD (Thesis advisor) / Shock, Everett ES (Committee member) / Knudson, Kelly KJ (Committee member) / Arizona State University (Publisher)
Created2022