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Nitrification Inhibition Of Activated Sludge Due To Short-Term And Long-Term Exposure To Hydrothermal Liquefaction Aqueous Phase
No full textThe excessive use of fossil fuels, industrialization, and growing populations have increased environmental pollution, global warming, and global energy demands (Dimitriadis & Bezergianni, 2017). Due to these problems, a new alternative energy source must be used. Biomass conversion to liquid transportation fuels is a major category of renewable energy, with various waste biomasses as leading candidates (Dimitriadis & Bezergianni, 2017). Multiple thermo-chemical conversion (TCC) technologies exist to convert biomass into fuels with one of the most promising methods being hydrothermal liquefaction (HTL). The main benefit of HTL is that it does not require that the biomass be dried before processing which would be a fuel- and cost-intensive process (Grande et al., 2021; SundarRajan et al., 2021). However, HTL produces toxic solid, gaseous, and aqueous byproducts.
The hydrothermal liquefaction aqueous-phase byproduct (HTL-AP) is thought to be the factor limiting commercial viability of the HTL process, particularly because some of the constituents have inhibitory effects on nitrifying bacteria (Macêdo et al., 2023). There are existing treatment technologies for HTL-AP such as anaerobic digestion, wet air oxidation (WAO), and more. The simplest treatment method at a wastewater treatment plant (WWTP) using HTL for sludge disposal would be to return the HTL-AP to the v headworks to be treated alongside standard wastewater flow (MBE, 2019). However, the inhibitory effects may cause the WWTP to not meet ammonia regulations, if relevant.
In this project, four 3.5-L bench-scale aerated reactors were built to simulate conventional activated sludge wastewater treatment to develop methods to determine the long-term effects of HTL-AP on nitrification. Two reactors were controls fed only synthetic wastewater, and two reactors were fed synthetic wastewater with a small dilution of HTL-AP, called AP reactors.
Two different doses of hydrothermal liquefaction aqueous phase (HTL-AP) were tested on long-operated activated sludge systems. A 275x dilution factor (DF) of HTL-AP was tested for 132 days and a 2750x DF was tested for 23 days. The weekly nitrogen data (total ammonia nitrogen, nitrate, and nitrite) suggested that both doses inhibited nitrification in the bench-scale activated sludge systems. Additionally, the nitrifying bacteria did not adapt over time to be able to nitrify the wastewater with HTL-AP. During the first experiment with a 275x DF, no nitrate was detected in the AP reactors (/L NO3 - -N) and nitrite was sparsely detected. The control reactors had low concentrations of nitrate of around 3-8 mg/L NO3 - -N and high concentrations of nitrite, typically around 10-40 mg/L NO2 - -N. Therefore, the AP reactors were performing minimal nitrification, if any, while the control reactors were primarily performing partial nitrification. Before implementing the 2750x DF of HTL-AP, all reactors were emptied, cleaned, and restarted with nitrifying mixed liquor from the San Luis Obispo Water Resource Recovery Facility membrane bioreactor (SLO WRRF MBR). By the end of the 23 days of HTL-AP exposure at a 2750x DF, the treatment reactors had a sharper nitrate decline with final NO3 - -N concentrations around 1 mg/L compared to about 5-7 mg/L vi NO3 - -N in the control reactors. At this time, nitrite concentrations were not considerable in any reactor. Because nitrification was not ideal even in the control reactors, future work is advised, including stabilizing the solids retention time and changing the synthetic wastewater formula to support higher concentrations of treatment bacteria.
Some methods for the specific oxygen uptake rate (SOUR) test that are not explicitly or extensively outlined in ISO 8192 (ISO, 2007) were examined. First, a 10- minute trial duration was deemed sufficient compared to 20 minutes (R 2\u3e0.99 in either case and
Preliminary SOUR tests using the correct methods found that raw HTL-AP doses of 50x, 125x, and 250x dilution factors (DF’s) inhibited nitrification by about 80 to 105% in nitrifying sludge from the SLO WRRF MBR. Raw HTL-AP doses of 500x and 1000x DF’s did not inhibit nitrification respiration rates. From a SOUR test on this same sludge but on a different day, HTL-AP pretreated by wet air oxidation (WAO) had near-zero vii (neg. 0.9%) inhibition on nitrification respiration rates at a 250x DF compared to the 66% nitrification inhibition found in raw HTL-AP at this 250x DF on this testing date
Manufacturing Silicone In-House For The Creation Of Customized Neurovascular Blood Vessel Mimics
Get PDFThe Tissue Engineering Lab at California Polytechnic State University San Luis Obispo focuses on creating tissue-engineered Blood Vessel Mimics (BVMs) designed for the preclinical testing of neurovascular devices. These BVMs are composed of silicone models, representing anatomically accurate neurovasculatures, that are sodded with vascular cell types and then cultivated in bioreactors (which maintain physiologic conditions). These silicone models are currently sourced externally from industry partners, so the primary goal of this thesis was to develop the means and methods for the Tissue Engineering Lab to manufacture silicone models in-house.
The first aim of this thesis was to develop and explore injection molding as a possible technique for manufacturing silicone models; this included prototyping various designs of molds, developing a viable workflow for injection molding, then assessing the resulting silicone models through measurement characterization, cytotoxicity screening, and BVM set-ups. The first aim found that injection molding was a viable manufacturing technique for making silicone models. The second aim of this thesis explored an alternative manufacturing method, dip-casting, to produce silicone models. The development of dip-casting was similar to injection molding, where several prototyping stages resulted in a viable workflow for making silicone models; the resulting silicone models were then assessed via measurement characterization and a BVM set-up. The second aim found that, in addition to injection molding, dip-casting was a viable technique for making silicone models, although the overall morphology of the resulting models was less desirable than those made by injection molding. The third and final aim of this thesis compared both manufacturing techniques (i.e., injection molding and dip-casting); this aim established that injection molding was preferable for making simple (less intricate) silicone models, whereas dip-casting was preferable for producing complex (more intricate) silicone models. Although the dip-casting technique requires more development to capture complex shapes and produce models with desirable morphologies, the injection molding protocol was formalized into a prescribed workflow for the Tissue Engineering Lab to reference. Overall, this thesis developed and explored two different manufacturing techniques for making silicone models and found that both were capable of making silicone models that could be used to create tissue-engineered BVMs, with injection molded models being ready to implement as the dip-casting process continues to be refined
Providing Cadence Feedback In Real-Time To Guide Cardiovascular Workouts
No full textCardiovascular workouts offer numerous health benefits, yet beginners often find it challenging to initiate them. Existing wearable technologies, although providing valuable feedback such as heart rate zones, often disrupt the workout flow and distract users due to the need for interaction with the wearable display. In response, we propose an alternative feedback mechanism: cadence, measured in steps per minute. This feedback mechanism uses multiplicative control to produce the correct cadence for the user’s target heart rate (HR). To model the HR and cadence relationship, a first-order system was used. The prototype implementation of this system was completed in Arduino, using a force sensitive resistor (FSR) to measure the user’s cadence and a POLAR HR strap to measure the user’s HR. The cadence is updated every 10 seconds to allow the user to sync to the cadence metronome provided by earbuds. This proposed system has shown promising experimental results for both moderate-intensity and high-intensity workouts, skipping the transition zone between them. This allows the user to avoid awkward workout intensities between a fast walk and a jog
Implementation And Efficiency Of Electric Motors In Lygus Bug Vacuums For Strawberries
Get PDFFurther automation of the agricultural industry and an increase in organic fruit production are needed to address labor shortage and increased demand. The move to an autonomous bug vacuum is easier if the equipment is electric, and not powered by a tractor’s PTO (power take-off) shaft. The main objective of this project was to design a set of lygus bug vacuums to go on a robot that meets industry standards while using electric power instead of hydraulic. The frame of the vacuum was designed using the industry standard. While hydraulic systems have been a very effective power source for vacuums until now, electronic motors with VFD (variable frequency drive) control allow for a cost effective, precise control, of the lygus bug vacuums with less failures. This also allows a robot type system to be able to run the vacuums using a preexisting power source without the addition of a bulky hydraulic system
Mary Ann Starkey: Domesticity & Political Leadership In New Bern, North Carolina During The Civil War
Get PDFMary Ann Starkey was a pivotal change agent in New Bern, North Carolina during the Civil War. She was born into slavery, yet by 1863 was in a position to bring together abolitionists and recruiters from the North and refugees and freedom fighters from her community. She was president of the 400-member Colored Women’s Union Relief Association of Newbern, North Carolina which worked to heal, feed and support the first colored regiments in North Carolina in their fight for freedom. This thesis looks closely at the Civil War through the life of this one woman, by examining the archival evidence and the ways in which the narrative of her life has been crafted thus far in an attempt to further the excavation of Starkey’s life and work. It contends that the role of African American women was pivotal to the Union victory, and that Mary Ann and her organization were key to providing the sustenance and intelligence network necessary for a Union victory in New Bern. It also looks at the ways that she used domesticity to establish social standing in the late nineteenth century and the ways that the black community organized politically during this time, as well as the changing nature of marriage for African Americans and how that impacted Mary Ann and her daughter Nancy
“There Are People Who Will Not Like You Because of the Skin You Were Born in”: Content and Impact of Socialization Messages About Racism in Black Families
Get PDFGuided by Critical Race Theory (Crenshaw, 1995; Delgado & Stefancic, 2017), the current study explored how Black adults made sense of their own racial identity through family messaging about racism and what it means to be a Black person in America, as well as how participant’s experiences with racism counter the dominant narrative that the U.S. is a “post-racial” society. We conducted retrospective interviews with 19 self-identifying Black adults. In our first research question, three primary themes emerged from participants’ recollections of conversations with parents about what it means to Black in the U.S.: (1) Black people are considered “others” in society, (2) being treated unfairly is inevitable as a Black person, and (3) Black people have to be more careful than white people. Our second research question revealed four primary themes that counter the dominant narrative of U.S. post-racialism: (1) being physically or verbally attacked because of their skin color, (2) getting followed around in stores by employees or owners, (3) unjust interactions with the police, and (4) their hair being a spectacle to white folx. Findings exhibit how Black adults make sense of their racial identity through both family messaging about and real-life experiences with racism. The current study offers unique theoretical and practical implications. Theoretically, findings highlight the connection between racial socialization, critical incidents, and counter-narratives in Black families and personal development. Practically, findings highlight ways professions can increase awareness and understanding of Black folx’ experiences of racial identity development in family contexts, as well as considering the mental and physical traumas Black adults may possess from experiencing racism. Limitations and future research directions are discussed
Cheap Clothes and Costly Consequences: A Study on College Students’ Shopping Habits Surrounding Fast Fashion and The Theory of Reasoned Action and Planned Behavior
Get PDFThis study investigates the impact of perceived attitudes and behaviors with regards to fast fashion and consumerism amongst Cal Poly students. Drawing on the Theory of Reasoned Action and Planned Behavior, the research measures student’s perceived facilitation, beliefs, and the influence of subjective norms towards consumption of fast fashion. The literature review establishes the theoretical framework, highlighting the importance of the Theory of Reasoned Action and Planned Behaviors. The study’s method involves a 17 item questionnaire administered to 108 participants. Half of the participants, 53, were randomly assigned to either a persuasive message or no message at all. The group with no message is the control group. After participants completed the study, the results found that the hypothesis was incorrect because there was an insignificant difference in behaviors amongst the two groups. The study contributes to the understanding of trends in students’ behaviors and shopping motivations and the effectiveness of the TRA/TPB
Light Based Wireless Communication
Get PDFThe demand for high-speed, secure wireless communication is escalating, particularly in high-density environments like urban areas, and critical sectors such as healthcare and defense. Traditional Wi-Fi struggles with issues like signal congestion, electromagnetic interference, and security vulnerabilities, compromising connectivity quality. LiFi is much more suitable for areas like hospitals which contain equipment highly sensitive to electromagnetic interference, has a high bandwidth far away from standard radio waves which enables strong communication in highly congested areas.
We developed a small scale, low-cost LiFi system to demonstrate a proof of concept of LiFi that grants the user full access to the internet. While a small number of companies have production LiFi to buy, it’s typically very expensive, and any proof-of-concept projects we’ve seen aren’t fast enough, or don’t have the software, to enable internet access. We used two Raspberry Pi computers to accomplish this, with one acting as a gateway connected to an internet network and the other as a client, connected with LiFi to the gateway. We were able to achieve a very slow internet access of 0.06 Mbps with this circuitry by using UART with a baud rate of 115,200 to communicate a Point-To-Point through a modulating LED and phototransistor circuit. We predicted a maximum of 16Mbps communication speed, but fell short due to the low intensity of the LEDs compared to the surrounding area, as well as the relatively low speed of UART. While this speed is painfully slow for web browsing, we were able to run an internet speed test through Chromium, and the system is more suited for lower-intensity network applications, such as SSHing into the Raspberry Pi from another internet-connected device, or pinging an ip address
Manor & Meadow
Get PDFWith the prevalence of DIY content on platforms like TikTok, many projects lack detailed guidance, making them challenging for individuals to replicate. By offering pre-packaged kits tailored to various interests and skill levels, this project seeks to democratize the DIY experience and empower users to unleash their creativity in a hassle-free manner
Expanding Learn By Doing: Creating a Culture of Extracurricular Lab Work in the Graphic Communication Department
Get PDFThe existing Graphic Communication (GrC) curriculum immerses students in print production through hands-on labs, exposing them to a variety of industrial machinery.
However, outside the context of required labs, students will rarely use the department’s equipment, which is a lost learning opportunity.
This project proposes exploring opportunities for students to use machinery outside the context of required classes, in order to both foster familiarity with industry tools and generate new industry knowledge. The aim is to research and develop a plan for implementing a program that helps to encourage students to further develop skills and pursue research projects using department facilities beyond class time