Matching Items (6)
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- All Subjects: Water resources management
- All Subjects: Carbon Sequestration
- Genre: Academic theses
- Creators: Allenby, Braden
Description
Urban water systems face sustainability challenges ranging from water quality, leaks, over-use, energy consumption, and long-term supply concerns. Resiliency challenges include the capacity to respond to drought, managing pipe deterioration, responding to natural disasters, and preventing terrorism. One strategy to enhance sustainability and resiliency is the development and adoption of smart water grids. A smart water grid incorporates networked monitoring and control devices into its structure, which provides diverse, real-time information about the system, as well as enhanced control. Data provide input for modeling and analysis, which informs control decisions, allowing for improvement in sustainability and resiliency. While smart water grids hold much potential, there are also potential tradeoffs and adoption challenges. More publicly available cost-benefit analyses are needed, as well as system-level research and application, rather than the current focus on individual technologies. This thesis seeks to fill one of these gaps by analyzing the cost and environmental benefits of smart irrigation controllers. Smart irrigation controllers can save water by adapting watering schedules to climate and soil conditions. The potential benefit of smart irrigation controllers is particularly high in southwestern U.S. states, where the arid climate makes water scarcer and increases watering needs of landscapes. To inform the technology development process, a design for environment (DfE) method was developed, which overlays economic and environmental performance parameters under different operating conditions. This method is applied to characterize design goals for controller price and water savings that smart irrigation controllers must meet to yield life cycle carbon dioxide reductions and economic savings in southwestern U.S. states, accounting for regional variability in electricity and water prices and carbon overhead. Results from applying the model to smart irrigation controllers in the Southwest suggest that some areas are significantly easier to design for.
ContributorsMutchek, Michele (Author) / Allenby, Braden (Thesis advisor) / Williams, Eric (Committee member) / Westerhoff, Paul (Committee member) / Arizona State University (Publisher)
Created2012
Description
Increasing concentrations of carbon dioxide in the atmosphere will inevitably lead to long-term changes in climate that can have serious consequences. Controlling anthropogenic emission of carbon dioxide into the atmosphere, however, represents a significant technological challenge. Various chemical approaches have been suggested, perhaps the most promising of these is based on electrochemical trapping of carbon dioxide using pyridine and derivatives. Optimization of this process requires a detailed understanding of the mechanisms of the reactions of reduced pyridines with carbon dioxide, which are not currently well known. This thesis describes a detailed mechanistic study of the nucleophilic and Bronsted basic properties of the radical anion of bipyridine as a model pyridine derivative, formed by one-electron reduction, with particular emphasis on the reactions with carbon dioxide. A time-resolved spectroscopic method was used to characterize the key intermediates and determine the kinetics of the reactions of the radical anion and its protonated radical form. Using a pulsed nanosecond laser, the bipyridine radical anion could be generated in-situ in less than 100 ns, which allows fast reactions to be monitored in real time. The bipyridine radical anion was found to be a very powerful one-electron donor, Bronsted base and nucleophile. It reacts by addition to the C=O bonds of ketones with a bimolecular rate constant around 1* 107 M-1 s-1. These are among the fastest nucleophilic additions that have been reported in literature. Temperature dependence studies demonstrate very low activation energies and large Arrhenius pre-exponential parameters, consistent with very high reactivity. The kinetics of E2 elimination, where the radical anion acts as a base, and SN2 substitution, where the radical anion acts as a nucleophile, are also characterized by large bimolecular rate constants in the range ca. 106 - 107 M-1 s-1. The pKa of the bipyridine radical anion was measured using a kinetic method and analysis of the data using a Marcus theory model for proton transfer. The bipyridine radical anion is found to have a pKa of 40±5 in DMSO. The reorganization energy for the proton transfer reaction was found to be 70±5 kJ/mol. The bipyridine radical anion was found to react very rapidly with carbon dioxide, with a bimolecular rate constant of 1* 108 M-1 s-1 and a small activation energy, whereas the protonated radical reacted with carbon dioxide with a rate constant that was too small to measure. The kinetic and thermodynamic data obtained in this work can be used to understand the mechanisms of the reactions of pyridines with carbon dioxide under reducing conditions.
ContributorsRanjan, Rajeev (Author) / Gould, Ian R (Thesis advisor) / Buttry, Daniel A (Thesis advisor) / Yarger, Jeff (Committee member) / Seo, Dong-Kyun (Committee member) / Arizona State University (Publisher)
Created2015
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
Cities are, at once, a habitat for humans, a center of economic production, a direct consumer of natural resources in the local environment, and an indirect consumer of natural resources at regional, national, and global scales. These processes do not take place in isolation: rather they are nested within complex coupled natural-human (CNH) systems that have nearby and distant teleconnections. Infrastructure systems—roads, electrical grids, pipelines, damns, and aqueducts, to name a few—have been built to convey and store these resources from their point of origin to their point of consumption. Traditional hard infrastructure systems are complemented by soft infrastructure, such as governance, legal, economic, and social systems, which rely upon the conveyance of information and currency rather than a physical commodity, creating teleconnections that link multiple CNH systems. The underlying structure of these systems allows for the creation of novel network methodologies to study the interdependencies, feedbacks, and timescales between direct and indirect resource consumers and producers; to identify potential vulnerabilities within the system; and to model the configuration of ideal system states. Direct and indirect water consumption provides an ideal indicator for such study because water risk is highly location-based in terms of geography, climate, economics, and cultural norms and is manifest at multiple geographic scales. Taken together, the CNH formed by economic trade and indirect water exchange networks create hydro-economic networks. Given the importance of hydro-economic networks for human well-being and economic production, this dissertation answers the overarching research question: What information do we gain from analyzing virtual water trade at the systems level rather than the component city level? Three studies are presented with case studies pertaining to the State of Arizona. The first derives a robust methodology to disaggregate indirect water flows to subcounty geographies. The second creates city-level metrics of hydro-economic vulnerability and functional diversity. The third analyzes the physical, legal, and economic allocation of a shared river basin to identify vulnerable nodes in river basin hydro-economic networks. This dissertation contributes to the literature through the creation of novel metrics to measure hydro-economic network properties and to generate insight into potential US hydro-economic shocks.
ContributorsRushforth, Richard Ray (Author) / Ruddell, Benajmin L (Thesis advisor) / Allenby, Braden (Committee member) / Chester, Mikhail (Committee member) / Seager, Thomas (Committee member) / Arizona State University (Publisher)
Created2016
Description
This thesis examines the composition, flow rate, and recyclability of two abundant materials generated in modern society: municipal sewage sludge (SS) generated during conventional wastewater treatment, and single-use plastic packaging (specifically, plastic bottles) manufactured and dispersed by fast-moving consumer goods companies (FMCG). The study found the presence of 5 precious metals in both American and Chinese sewage sludges. 13 rare elements were found in American sewage sludge while 14 were found in Chinese sewage sludge. Modeling results indicated 251 to 282 million metric tons (MMT) of SS from 2022 to 2050, estimated to contain some 6.8 ± 0.5 MMT of valuable elements in the USA, the reclamation of which is valued at $24B ± $1.6B USD. China is predicted to produce between 819 - 910 MMT of SS between 2022 and 2050 containing an estimated 14.9 ± 1.7 MMT of valuable elements worth a cumulative amount of $94B ± 20B (Chapter 2 and 3). The 4th chapter modeled how much plastic waste Coca-Cola, PespiCo and Nestlé produced and globally dispersed in 21 years: namely an estimated 126 MMT ± 8.7 MMT of plastic. Some 15.6 MMT ± 1.3 MMT (12%) is projected to have become aquatic pollution costing estimated at $286B USD. Some 58 ± 5 MMT or 46% of the total mass were estimated to result in terrestrial plastic pollution, with only minor amounts of 9.9 ± 0.7 MMT, deemed actually recycled. Absent of change, the three companies are predicted to generate an additional 330 ± 15 MMT of plastic by 2050, thereby creating estimated externalities of $8 ± 0.4 trillion USD. The analysis suggests that a small subset of FMCG companies are well positioned to change the current trajectory of global plastic pollution and ocean plastic littering. Chapter 5 examined the barriers to Circular Economy. In an increasingly uncertain post pandemic world, it is becoming progressively important to conserve local resources and extract value from materials that are currently interpreted a “waste” rather than a current or potential future resource.
ContributorsBiyani, Nivedita (Author) / Halden, Rolf U. (Thesis advisor) / Allenby, Braden (Committee member) / Jalbert, Kirk (Committee member) / Arizona State University (Publisher)
Created2022
Description
Crises at Teton Dam in 1976, Roosevelt Dam in 1980, Tempe Town Lake Dam in 2010, Oroville Dam in 2017, and the Edenville and Sanford Dams in 2020 prove the substantial and continuing threats to communities posed by major dams. Sociotechnical systems of dams encompass both social or governance characteristics as well as the technical or architectural characteristics. To reduce or overcome chances of failure, experts traditionally focus on making the architectural characteristics of dams safe from potential modes of failure. However, governance characteristics such as laws, building codes, and emergency actions plans also affect the ability of systems of dams that include downstream communities to sustainably adapt to crises. Increasingly, emerging threats such as climate change, earthquakes, terrorism, cyberattacks, or wildfires worsen known modes of failure such as overtopping.Considering these emerging threats, my research assesses whether the architectural and governance characteristics of the aging population of systems of dams in the United States can sustainably adapt to challenges posed by emerging threats. First, by analyzing architectural characteristics of dams, my research provides a useful definition of infrastructures of dams. Next, to assess the governance characteristics of dams, I review institutional documents to heuristically outline seven sociotechnical imaginaries and assess whether an eighth based on resilience is appearing. Further, by analyzing interview transcripts and professional conference presentations, and by conducting case studies, my research reveals ways that experts and stakeholders assess the safety and resilience of systems of dams.
The combined findings of these studies suggest that experts and stakeholders are not sufficiently informed about or focused upon important aspects of the resilience of dams. Therefore, they may not be able to sustainably adapt to crises caused or worsened by emerging threats such as climate change, earthquakes, terrorism, cyberattacks, or wildfires. I offer explanations of why this is so and formulate recommendations.
ContributorsDwyer, Kevin Thomas (Author) / Fisher, Erik (Thesis advisor) / Maynard, Andrew (Committee member) / Allenby, Braden (Committee member) / Arizona State University (Publisher)
Created2022