Matching Items (7)
Description
Microbial fuel cells (MFCs) promote the sustainable conversion of organic matter in black water to electrical current, enabling the production of hydrogen peroxide (H2O2) while making waste water treatment energy neutral or positive. H2O2 is useful in remote locations such as U.S. military forward operating bases (FOBs) for on-site tertiary water treatment or as a medical disinfectant, among many other uses. Various carbon-based catalysts and binders for use at the cathode of a an MFC for H2O2 production are explored using linear sweep voltammetry (LSV) and rotating ring-disk electrode (RRDE) techniques. The oxygen reduction reaction (ORR) at the cathode has slow kinetics at conditions present in the MFC, making it important to find a catalyst type and loading which promote a 2e- (rather than 4e-) reaction to maximize H2O2 formation. Using LSV methods, I compared the cathodic overpotentials associated with graphite and Vulcan carbon catalysts as well as Nafion and AS-4 binders. Vulcan carbon catalyst with Nafion binder produced the lowest overpotentials of any binder/catalyst combinations. Additionally, I determined that pH control may be required at the cathode due to large potential losses caused by hydroxide (OH-) concentration gradients. Furthermore, RRDE tests indicate that Vulcan carbon catalyst with a Nafion binder has a higher H2O2 production efficiency at lower catalyst loadings, but the trade-off is a greater potential loss due to higher activation energy. Therefore, an intermediate catalyst loading of 0.5 mg/cm2 Vulcan carbon with Nafion binder is recommended for the final MFC design. The chosen catalyst, binder, and loading will maximize H2O2 production, optimize MFC performance, and minimize the need for additional energy input into the system.
ContributorsStadie, Mikaela Johanna (Author) / Torres, Cesar (Thesis director) / Popat, Sudeep (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2015-05
Description
In 2016, in the United States alone, the cosmetics industry made an estimated 62.46 billion dollars in revenue (Revenue of the Cosmetic Industry in the U.S. 2002-2016 | Forecast). With a consistent increase in sales in the last several years, the industry has reached continued success even during times of hardship, such as the Great Recession of 2008. The use of Corporate Social Responsibility (CSR), external campaigns, and thoughtful packaging and ingredients resonates with targeted consumers. This has served as an effective strategy to maintain growth in the industry. Cosmetic companies promote their brand image using these sustainability tactics, but there seems to be a lack of transparency in this unregulated industry. The purpose of this thesis is to determine if the cosmetics industry is a good steward of the sustainability movement. Important terms and concepts relating to the industry will be discussed, then an analysis of sustainability focused cosmetic brands will be provided, which highlights the extent to which these brands engage in activities that promote sustainability. This is followed by an application of findings to a company that could benefit from using such practices. Overall, the analysis of the different brands proved to be shocking and disappointing. This is due to the sheer amount that scored very poorly based on the sustainability criteria developed. The cosmetics industry is too inconsistent and too unregulated to truly act as a good steward for sustainability. Though some companies in the industry succeed, these accomplishments are not consistent across all cosmetic companies. Hence, the cosmetics industry as a good steward for sustainability can only be as strong as its weakest link.
ContributorsMamus, Sydney Wasescha (Author) / Ostrom, Amy (Thesis director) / Kristofferson, Kirk (Committee member) / Department of Marketing (Contributor) / W.P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Microbial fuel cells (MFCs) facilitate the conversion of organic matter to electrical current to make the total energy in black water treatment neutral or positive and produce hydrogen peroxide to assist the reuse of gray water. This research focuses on wastewater treatment at the U.S. military forward operating bases (FOBs). FOBs experience significant challenges with their wastewater treatment due to their isolation and dangers in transporting waste water and fresh water to and from the bases. Even though it is theoretically favorable to produce power in a MFC while treating black water, producing H2O2 is more useful and practical because it is a powerful cleaning agent that can reduce odor, disinfect, and aid in the treatment of gray water. Various acid forms of buffers were tested in the anode and cathode chamber to determine if the pH would lower in the cathode chamber while maintaining H2O2 efficiency, as well as to determine ion diffusion from the anode to the cathode via the membrane. For the catholyte experiments, phosphate and bicarbonate were tested as buffers while sodium chloride was the control. These experiments determined that the two buffers did not lower the pH. It was seen that the phosphate buffer reduced the H2O2 efficiency significantly while still staying at a high pH, while the bicarbonate buffer had the same efficiency as the NaCl control. For the anolyte experiments, it was shown that there was no diffusion of the buffers or MFC media across the membrane that would cause a decrease in the H2O2 production efficiency.
ContributorsThompson, Julia (Author) / Torres, Cesar (Thesis director) / Popat, Sudeep (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
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
The United States Department of Agriculture provides requirements for a farm operation to become certified organic, but how do these regulations influence nutrient
management on organic farms? There is insufficient evidence to show if the current
regulations on nutrient sourcing and application are feasible and effective. An online
survey was administered to owners and operators of organic farms. Survey respondents
were offered a free soil test as an incentive to participate and to compare their practices
and soil quality. Assessing the current nutrient management under organic regulations
provides information to help assess the sustainability of their nutrient management
practices. Early data suggest that organic farmers may most often be overapplying and
creating legacy sources with this key resource.
ContributorsBonham, Emma Eileen (Author) / Muenich, Rebecca (Thesis advisor) / Zanin, Alaina (Committee member) / Williams, Clinton (Committee member) / Arizona State University (Publisher)
Created2022
Description
This report chronicles the journey of Julia Chiavaroli, Mira Camunez, Katherine Schiller, and Siddharth Somani through the Founder's Lab program, leading to the creation of INEZ, an organic, all-natural beauty brand specializing in hair care products. Motivated by a shared dedication to health and wellness, the founders embarked on a collaborative path, eventually converging on the concept of crafting a natural hair care solution. Rooted in comprehensive ingredient research and product development, INEZ emphasizes purity and nature, reflected in its earthy aesthetic and western influence. The branding strategy encompasses a distinct color palette, whimsical font, and the slogan "Rustic Roots." Targeting both women and men, the marketing strategy prioritizes online presence, especially on Instagram, complemented by plans for local event engagement. Pricing strategy is informed by market demand and unit economics considerations, with products priced at $19.99. Customer discovery efforts, including surveys, have shaped product development and pricing decisions, aligning INEZ with customer preferences for sustainability and organic ingredients. Through meticulous planning and execution, the founders have established INEZ as a promising venture at the intersection of health, beauty, and sustainability.
ContributorsChiavaroli, Julia (Author) / Camunez, Mira (Co-author) / Schiller, Katie (Thesis director) / Byrne, Jared (Committee member) / McElfish, Alex (Committee member) / Barrett, The Honors College (Contributor) / Dean, W.P. Carey School of Business (Contributor) / Department of Management and Entrepreneurship (Contributor) / School of International Letters and Cultures (Contributor)
Created2024-05
Description
In arid environments such as Arizona, agricultural producers are burdened by constraints placed on them by inhospitable weather and limited access to water and fertile soil when attempting to grow produce. Farms in the arid Southwest often have to build greenhouses to overcome such constraints; however, such greenhouses may be relatively space, water, and pesticide intensive and often have demanding maintenance needs and overhead costs. In addition, many current agricultural practices exhaust land resources disparagingly, leading to irreversible environmental degradation. In an effort to improve agricultural production for those limited by weather and resource constraints while simultaneously increasing sustainability in land, resource and pesticide use, we have created Valleyponics, a hydroponic growth services company centered around creating a minimal farming footprint. The company uses a consultative services approach, leveraging NASA Veggie Growth System Technology to provide solutions to large businesses by automating their agricultural production processes and minimizing resource use year-round. Valleyponics aims to cultivate consultative partnerships which will allow our clients, their communities, and the environment to flourish.
ContributorsRamirez, Noe (Author) / Craft, Joshua (Co-author) / Valesano, Megan (Co-author) / Walsh, Samuel (Co-author) / Byrne, Jared (Thesis director) / Lee, Christopher (Committee member) / Balven, Rachel (Committee member) / Barrett, The Honors College (Contributor) / Dean, W.P. Carey School of Business (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2022-05