Matching Items (5)
Filtering by
- All Subjects: Bioreactor Landfills
- All Subjects: Operations Research
- Member of: Theses and Dissertations
- Member of: Barrett, The Honors College Thesis/Creative Project Collection
Description
United States Environmental Protection Agency (USEPA) had identified and recommended air quality monitoring to take place at 63 schools throughout the country. Unfortunately, tribal schools were not considered during the time USEPA conducted the analysis. The importance of identifying any air toxic pollutants affecting school children needs to be analyzed. Conducting an air monitoring toxic analysis on the Navajo Nation at Church Rock Elementary School, Church Rock, New Mexico (CRNM) was carried out. The current school location posed a concern, in regards to the surrounding stationary, mobile, and natural emissions emitted all types of toxic pollutants. USEPA sponsors various air monitoring program, which Tribal Air Monitoring Support (TAMS) program undertook, and offered tribal programs, organizations or agencies to utilized air monitoring equipment's. The air monitoring setup was conducted with the contract Eastern Research Group, Inc. (ERG) laboratory, where collection of 24-hour ambient air samples for 60 days on a 6-day sampling interval were performed. The analysis for volatile organic compounds (VOCs)were collected from canister samples using USEPA Compendium Method TO-15, polycyclic aromatic hydrocarbons (PAHs) from polyurethane foam (PUF) and XAD-2 resin samples using USEPA Compendium Method TO-13A. Carbonyl compounds were collected by sorbent cartridge samples using USEPA Compendium Method TO-11A, and trace of metals from filters were sampled using USEPA Compendium Method IO-3.5 and FEM EQL-0512-202. A total of 53 VOC concentrations were greater than 1 μg/m3, where dichlorodifluoromethane, trichlorofluoromethane, chloromethane, dichloromethane, propylene, toluene, acrolein and acetylene were detected. A total of 23 carbonyl compound concentrations were greater than 1 μg/m3, where acetone and formaldehyde were measured. Naphthalene average with the highest average for PAHs, where phenanthrene and retene were the second and third highest averages. As for the metals the highest averages resulted from manganese, chromium and lead. Overall, the air toxic pollutants resulted from CRNM surrounding monitoring site were detected. Identifying the potential emitter source or sources cannot be assessed.
ContributorsBilley, Karmen (Author) / Olson, Larry (Thesis advisor) / Peterson, Danny (Committee member) / Brown, Albert (Committee member) / Arizona State University (Publisher)
Created2015
Description
Currently conventional Subtitle D landfills are the primary means of disposing of our waste in the United States. While this method of waste disposal aims at protecting the environment, it does so through the use of liners and caps that effectively freeze the breakdown of waste. Because this method can keep landfills active, and thus a potential groundwater threat for over a hundred years, I take an in depth look at the ability of bioreactor landfills to quickly stabilize waste. In the thesis I detail the current state of bioreactor landfill technologies, assessing the pros and cons of anaerobic and aerobic bioreactor technologies. Finally, with an industrial perspective, I conclude that moving on to bioreactor landfills as an alternative isn't as simple as it may first appear, and that it is a contextually specific solution that must be further refined before replacing current landfills.
ContributorsWhitten, George Avery (Author) / Kavazanjian, Edward (Thesis director) / Allenby, Braden (Committee member) / Houston, Sandra (Committee member) / Civil, Environmental and Sustainable Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2013-05
Description
Efforts to enhance the quality of life and promote better health have led to improved water quality standards. Adequate daily fluid intake, primarily from tap water, is crucial for human health. By improving drinking water quality, negative health effects associated with consuming inadequate water can be mitigated. Although the United States Environmental Protection Agency (EPA) sets and enforces federal water quality limits at water treatment plants, water quality reaching end users degrades during the water delivery process, emphasizing the need for proactive control systems in buildings to ensure safe drinking water.Future commercial and institutional buildings are anticipated to feature real-time water quality sensors, automated flushing and filtration systems, temperature control devices, and chemical boosters. Integrating these technologies with a reliable water quality control system that optimizes the use of chemical additives, filtration, flushing, and temperature adjustments ensures users consistently have access to water of adequate quality. Additionally, existing buildings can be retrofitted with these technologies at a reasonable cost, guaranteeing user safety.
In the absence of smart buildings with the required technology, Chapter 2 describes developing an EPANET-MSX (a multi-species extension of EPA’s water simulation tool) model for a typical 5-story building. Chapter 3 involves creating accurate nonlinear approximation models of EPANET-MSX’s complex fluid dynamics and chemical reactions and developing an open-loop water quality control system that can regulate the water quality based on the approximated state of water quality. To address potential sudden changes in water quality, improve predictions, and reduce the gap between approximated and true state of water quality, a feedback control loop is developed in Chapter 4.
Lastly, this dissertation includes the development of a reinforcement learning (RL) based water quality control system for cases where the approximation models prove inadequate and cause instability during implementation with a real building water network. The RL-based control system can be implemented in various buildings without the need to develop new hydraulic models and can handle the stochastic nature of water demand, ensuring the proactive control system’s effectiveness in maintaining water quality within safe limits for consumption.
ContributorsGhasemzadeh, Kiarash (Author) / Mirchandani, Pitu (Thesis advisor) / Boyer, Treavor (Committee member) / Ju, Feng (Committee member) / Pedrielli, Giulia (Committee member) / Arizona State University (Publisher)
Created2023
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
Drinking water quality violations are widespread in the United States and elsewhere in the world. More than half of Americans are not confident in the safety of their tap water, especially after the 2014 Flint, Michigan water crisis. Other than accidental contamination events, stagnation is a major cause of water quality degradation. Thus, there is a pressing need to build a real-time control system that can make control decisions quickly and proactively so that the quality of water can be maintained at all times. However, towards this end, modeling the dynamics of water distribution systems are very challenging due to the complex fluid dynamics and chemical reactions in the system. This challenge needs to be addressed before moving on to modeling the optimal control problem. The research in this dissertation leverages statistical machine learning approaches in approximating the complex water system dynamics and then develops different optimization models for proactive and real-time water quality control. This research focuses on two effective ways to maintain water quality, flushing of taps and injection of chlorine or other disinfectants; both of these actions decrease the equivalent “water age”, a useful proxy for water quality related to bacteria growth. This research first develops linear predictive models for water quality and subsequently linear programming optimization models for proactive water age control via flushing. The second part of the research considers both flushing and disinfectant injections in the control problem and develops mixed integer quadratically constrained optimization models for controlling water age. Different control strategies for disinfectant injections are also evaluated: binary on-off injections and continuous injections. In the third part of the research, water demand is assumed to be uncertain and stochastic. The developed approach to control the system relates to learning the optimal real-time flushing decisions by combing reinforced temporal-difference learning approaches with linear value function approximation for solving approximately the underlying Markov decision processes. Computational results on widely used simulation models demonstrates the developed control systems were indeed effective for water quality control with known demands as well as when demands are uncertain and stochastic.
ContributorsLi, Xiushuang (Author) / Mirchandani, Pitu (Thesis advisor) / Boyer, Treavor (Committee member) / Ju, Feng (Committee member) / Pedrielli, Giulia (Committee member) / Arizona State University (Publisher)
Created2021