Engineering Commons^™

The Tidal Prism, Viable Eelgrass Habitat, And The Effects Of Sea Level Rise In Morro Bay, Kaden A. Caliendo

Master's Theses

The tidal prism, or the volume of water exchanged from the sea to an estuary from mean low to mean high tide, influences system hydrodynamics and ecological functioning. Since 1884, the tidal prism in Morro Bay, California has been estimated to be decreasing over time due to sedimentation from upstream practices. What is the current tidal prism in Morro Bay and how will that change with sea level rise? How will eelgrass respond to rising sea levels?

For this study, inexpensive tidal gauges were deployed at four locations in Morro Bay from March to August 2023 to measure spatially varying …

Biodegradation Of Methyl Tert-Butyl Ether And Tert-Butyl Alcohol Using Bioaugmentation With Biowish® Aqua, Elizabeth Villanueva

Master's Theses

Aqua, a commercial product manufactured by BiOWiSH® Technologies, was utilized in this research to study its effectiveness to biodegrade methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA). Microcosms containing varying concentrations of MTBE and TBA as well as a growth media and mineral salt solution were examined. Analytical instrumentation used in this study included the use of a gas chromatograph-mass spectrometer (GC/MS) to determine concentrations of MTBE and TBA and a spectrophotometer to extrapolate approximate active biomass concentrations in each experiment. Four different environmental conditions were tested for both MTBE and TBA. The environmental conditions tested for each contaminant included: …

Fabrication Of Thin-Film Composite, Reverse-Osmosis Membranes With Polyethylenimine Modifications For Enhancing Membrane Fouling Resistance, Stephanie N. Hamilton

Master's Theses

Increasing water reuse opportunities for communities has become increasingly important as access to clean water is becoming more scarce. Reverse Osmosis (RO) is an advanced treatment technology used in water recycling wastewater for potable reuse applications. RO is a promising technology; however, the membranes have limitations including their high energy demand and their susceptibility to membrane fouling. The main objective of this study was to develop a reproducible method for the fabrication of RO membranes with enhanced flux and reduced susceptibility to fouling. Literature contains numerous publications on fabrication of thin film composite (TFC) RO membranes with high performance. However, …

Effects Of Experimental Scale On The Adsorption Of Two Pharmaceutical Drugs Detected In Municipal Wastewater Effluent, Michael Moore

Master's Theses

Pharmaceutical drugs are being produced and consumed in increasing quantities every year and are poorly treated by conventional wastewater treatment processes, leading to increasing detection of such compounds in surface water, groundwater, and municipal drinking water. Soil aquifer treatment (SAT) is a promising method for treating these emerging compounds through combined adsorption and degradation of target compounds in soil. This thesis examines the consistency of results from typical studies like adsorption isotherms and soil columns utilized in analysis of SAT performance, across varying experimental scales. The adsorption behavior of two pharmaceuticals was investigated as a function of experimental scale and …

Potential Impact Of Contour Bunds On Diclofenac Removal For Stormwater Control In Rangeland Applications, Braden Alan Whitehead

Master's Theses

Diclofenac (DCF) and other emerging contaminants have been found in environments worldwide. These contaminants may enter the environment due to the application of treated wastewater, biosolids and direct excrement related to veterinary application. Leakage from the soils toward the groundwater is largely controlled by sorption and microbial degradation. Most studies on the environmental fate of DCF have focused on degradation during wastewater treatment processes. However, little is known about their behavior in soil. In this study, the combined effect of adsorption and degradation of diclofenac has been investigated in four (4) 24 ft³ agricultural soil-filled beds designed to mimic …

Comparison Of Two Advanced Oxidation Processes For Their Production Of Hydroxyl Radicals And Evaluation Of A Uv/Ozone Aop At Varying Uv Fluence For Treating Diclofenac, Alexandra Cass

Master's Theses

This study explores the efficacy of two advanced oxidation processes for generation of hydroxyl radicals to promote degradation of emerging contaminants. Drought and water shortage have become pressing issues caused by our world’s changing climate. Water reclamation and reuse are increasingly important options for relieving this water stress. Water reuse runs the risk of reintroducing recalcitrant compounds that can accumulate in our bodies and environment. Advanced treatment methods that degrade these compounds are vital to protect our health and the health of the environment while providing necessary water resources. Advanced oxidation processes (AOPs) have shown great promise for removing recalcitrant …

Analysis And Optimization Of A Colorimetric Nanosensor For Rapid Detection Of Escherichia Coli In Water, Sarah M. Stabler

Master's Theses

Safe drinking water is essential for life, yet at least two billion people around the world consume water contaminated with pathogens among other pollutants. Standard methods like polymerase chain reaction (PCR) and membrane filtration have been developed to detect enteric pathogens in water. However, these methods are limited in their accessibility due to long wait times to obtain results, and the requirements of skilled expertise, electricity, and laboratory equipment. This research has focused on addressing some of these limitations by analyzing the mechanisms of work and optimizing an indirect colorimetric nanosensor developed in previous research. The colorimetric nanosensor investigated herein …

Modeling The Groundwater Basin In The Northern Cities Management Area, Allyson Swain

Master's Theses

A model was developed to simulate the groundwater of 8,300 acres of the Northern Cities Management Area (NCMA), which encompasses the northern portion of the Arroyo Grande Watershed and a small subset of the Santa Maria Valley Groundwater Basin. This watershed and groundwater basin is located on the coast and contains Oceano and the Cities of Arroyo Grande, Grover Beach, Pismo Beach. Groundwater in the NCMA is used heavily for agricultural irrigation in the southern portion and municipal applications in the northern portion. Up to 18 of these municipal wells and over 50 irrigation wells are drawing groundwater at any …

Adaptive Laboratory Evolution Of Scenedesmus Obliquus For Increased Carbohydrate Content And Biomass Productivity, Nahel Ali

Master's Theses

The economics of microalgal bioproduct commercialization would benefit from increased accumulation of energy storage compounds, such as carbohydrates and lipids, and increased biomass productivity. This thesis explores two adaptive laboratory evolution strategies for improving Scenedesmus obliquus: single UV-mutagenesis and low light cultivation at a high dilution rate to produce cultigens with greater carbohydrate content and iterative UV-mutagenesis and selection under outdoor conditions in a raceway pond at a high dilution rate to increase biomass productivity.

Two cultigens were generated with the goal of increased carbohydrate content: K5 and K7. Both were mutagenized for 5 seconds and cultivated in 50-mL …

Dairy Manure Flushwater Treatment By Algae Raceway Ponds And Aerated Biofilm Reactors, Darin Son

Master's Theses

Nitrogen removal technologies can help dairy industries meet their nutrient management needs. This thesis investigated two separate treatment technologies for total ammonia nitrogen (TAN) removal: algae raceway ponds and aerated biofilm reactors. Six 1000- liter algae raceway ponds and four 1000-liter tote tanks, each equipped with 10 sheets of nonwoven geotextile (i.e., thermally bonded or needle-punched) biofilm substrate, were used to treat the effluent from a flush dairy in central coastal California (TAN = 251 mg/L, cBOD5 = 204 mg/L). For the algae raceway ponds (TAN loading rate = 7 - 35 g/m³-day among 7-, 10- and 14-day hydraulic residence …

Development Of Zeolitic Imidazolate Frameworks For Enhancing Post-Combustion Co2 Capture, Dustin Lee

Master's Theses

Post-combustion CO₂ capture is a promising approach for complementing other strategies to mitigate climate change. Liquid absorption is currently used to capture CO₂ from post-combustion flue gases. However, the high energy cost required to regenerate the liquid absorbents is a major drawback for this process. As a result, solid sorbents have been investigated extensively in recent years as alternative media to capture CO₂ from flue gases. For example, metal organic frameworks (MOFs) are nanoporous materials that have high surface areas, large pore volumes, and flexible designs. A large number of MOFs, however, suffer from 1) low CO …

Surface Modifications Of Reverse Osmosis Membranes For Removal Of Bromide And Reduction Of Fouling, Joseph Seo

Master's Theses

Reverse osmosis (RO) is widely used for water reuse and desalination. Although RO membranes are known for their high salt rejection and practical permeate flux, their performance can be impaired by fouling, and their removal of some disinfection byproducts and their precursors (e.g., bromide, N-Nitrosodimethylamine [NDMA]) does not meet drinking water standards. RO membrane modifications have been widely studied to overcome these limitations. In this research, RO membranes were grafted with cationic polymers to induce a positive charge on the RO membrane surface. This modification aimed at enhancing the rejection of negatively charged bromide ions by removing them from solution …

Optimization And Longevity Of Functionalized Multi-Walled Carbon Nanotube-Enabled Membranes For Water Treatment, Madeleine Michael Isabella White

Master's Theses

Water scarcity is a growing concern at the global scale. Large scale water reuse is growing both in necessity and popularity. Before water reuse can be performed efficiently on a large scale or be used for potable supply, even indirectly, contaminants of emerging concern (CECs) will need to be treated at the full scale. Advanced oxidation processes (AOPs) are a form of advanced water treatment capable of treating a wide range of CECs. This study contributes to the growing field of AOPs and more specifically AOPs using ozone combined with functionalized multi-walled carbon nanotubes (MWCNTs). Ozonation of MWCNTs has been …

Investigation Of New Forward Osmosis Draw Agents And Prioritization Of Recent Developments Of Draw Agents Using Multi-Criteria Decision Analysis, Jodie Wei Yu

Master's Theses

Forward osmosis (FO) is an emerging technology for water treatment due to their ability to draw freshwater using an osmotic pressure gradient across a semi-permeable membrane. However, the lack of draw agents that could both produce reasonable flux and be separated from the draw solution at a low cost stand in the way of widespread implementation. This study had two objectives: evaluate the performance of three materials — peptone, carboxymethyl cellulose (CMC), and magnetite nanoparticles (Fe₃O₄ NPs) — as potential draw agents, and to use multi-criteria decision matrices to systematically prioritize known draw agents from literature for …

Quantitative And Qualitative Error Re-Analysis Of Tidal Datasets, Ernesto Andrew Ledezma

Master's Theses

Tidal data forms the basis for understanding and quantifying sea-level rise and tidal statistics. While quality assurance methods based upon spectral and harmonic analysis have been applied to individual tidal records, these methods have not been used to assess global tidal datasets. In this thesis, four west coast tidal records were examined using harmonic analysis methods to investigate uncertainty on a monthly averaged basis. Uncertainty was identified using a method that quantifies time lag as a linear regression of height difference between a predicted and measured tidal height and the predicted rate of change of tidal height. Errors identified through …

Modeling Artificial Groundwater Recharge In The Santa Rosa Creek Watershed, Alexander J. Murray

Master's Theses

The Santa Rosa Creek Watershed is an approximately 48 mi2 large watershed located on the central coast of California. This watershed drains to the Pacific Ocean through Santa Rosa Creek as it passes through agricultural land and the town of Cambria. Historically the groundwater within the Santa Rosa Creek Watershed has been used for irrigation, municipal and domestic uses, and the creek is critical habitat steelhead trout. During dry years, there is less water for all uses. When low groundwater levels occur, water can be drawn out of the creek and into the soil, drying out steelhead habitat. Seven agricultural …

Analysis And Optimization Of Colorimetric Nanosensors For Rapid Detection Of Microbes In Water, Ruby A. Lang

Master's Theses

Access to safe water is a basic human right recognized by the United Nations General Assembly in 2010 (WHO, 2020). However, a least 2.2 billion people globally still are without safely managed water services meaning they use a drinking water source that can be contaminated with faeces (WHO, 2020). With such a pressing global health issue, it is clear that improvement to water systems is important and required in the Agenda 2030 Sustainable Development Goals (SDGs). However, to improve water systems and prove they are safe water sources, water quality testing must occur. A solution to this issue is the …

Methods To Increase Algae Biomass Productivity In Raceway Pond Monocultures, Ryan S. Anderson

Master's Theses

The economics of algae biofuels and bioproducts would be improved by increased biomass productivity. Two studies on this potential are described in this thesis – one on a locally isolated filamentous yellow-green alga and the other on a planktonic strain genetically improved via selective enrichment.

Polycultures have been viewed as productive, stable, and, in some cases, harvestable by natural bioflocculation. Local native strains might have higher productivity than culture collection strains because they are already adapted to local outdoor conditions. In this study, the filamentous yellow-green alga Tribonema minus was isolated from a local volunteer polyculture. Its productivity as a …

Model Block Press Design, Ben Todd Van Hamersveld, Chester Wong, Alexander Wing-Jon Giannousis

Mechanical Engineering

This project’s goal is to redesign the Center for Vocational Building Technology (CVBT) BP9 earth block press, which makes 1/3 scale compressed earth blocks to build demonstration model homes in Thailand. The full-scale block press, the BP6, provides a sustainable and affordable technique for constructing habitable homes in Thailand. The BP9 serves as a tool to inform the public of the advantages of human-powered earth block presses through demonstration. The BP9 press design has multiple problems: it is too expensive to manufacture, there is too much friction when used, it has several weak points due to users unintentionally applying excessive …

A Comparison Of The Army Corps Of Engineers Hydrologic Modeling System And Autodesk Storm And Sanitary Analysis For Hydraulic And Hydrologic Analysis And Design, Foster Josef Heifetz Campbell

Master's Theses

Hydrological and hydraulic effects of urban development is one of the key issues of study for improved water management. The addition of impervious surfaces to once pervious land and re-routing open channels and flow paths can cause flooding or declining water levels within a watershed. Many studies of these issues have found that there can be multiple factors causing hydrological and hydraulic impacts, and it can be hard to analyze and develop effective solutions without appropriate drainage software packages. However, there are multiple software packages available for use, and determining the correct one to use for a specific challenge can …

A Study On The Simultaneous Nitrification And Denitrification Process Of A Membrane Aerated Bioreactor Augmented By Biowish Aqua, Gavrielle Orman

Master's Theses

Nitrogen pollution is a growing problem that is detrimental to the environment and the economy. Traditional treatment of nitrogen is a multi-stage process, expensive, operationally intensive, and requires large land areas. This research studied the effects of BiOWiSH® Aqua (Aqua), a biological enhancement product, on the simultaneous nitrification and denitrification process in a membrane aerated bioreactor (MABR) to determine if it is a feasible application for wastewater treatment. The MABR used during experimentation was a small-scale batch reactor with a continuous flow of air through a silicone membrane.

The effect of carbon source and concentration on nitrogen removal rates and …

Integrated Aeration For Enhanced Nitrogen Conversion And Removal And The Effect Of Sampling Frequency On Productivity Estimates In Algae-Based Wastewater Treatment Systems, Lauren Parker

Master's Theses

Raceway ponds can be used to cultivate microalgae for purposes such as wastewater treatment and feedstock for animal feeds and biofuels. Besides nitrogen assimilation in biomass, nitrification can be a wastewater treatment mechanism but one that is hindered by the low nighttime dissolved oxygen concentrations (DO) common in wastewater treatment raceways. The large diel difference in pond conditions and changing influent wastewater quality also raises the question of the optimal frequency and timing of grab sample collection, to obtain representative water quality data. Three sets of triplicate pilot raceways (1,000-L, 0.30-m deep, fed primary clarifier effluent) were operated at an …

Degradation Of Emerging Contaminants By Advanced Oxidation Using Multi-Walled Carbon Nanotubes And Continuous Ozone Injection, Emily N. Miller

Master's Theses

With a growing population and continuous accumulation of pollutants, water resources worldwide are quickly being depleted. Drastic improvements need to be made in both water conservation and treatment. Advanced oxidation processes (AOPs) have been developed to go above and beyond the capabilities of traditional wastewater treatment facilities to eliminate emerging contaminants from our water systems. AOPs increase the generation of hydroxyl radicals (•OH) in oxidation reactions, which are less selective and more reactive than other oxidants, such as ozone, so they are more effective at degrading persistent compounds. This study explored an AOP that utilizes ozonated multi-walled carbon nanotubes (MWCNTs) …

Case Study: Using Geofoam On A School Project In Encinitas, Ca, Matthew D. Gaebe

Construction Management

This paper is a case study that identifies why Geofoam was used as in-fill material for a construction project located at a high school in Encinitas, CA. The Geofoam was installed under a stairway that connects to a structural retaining wall. The concrete formwork was connected directly to the foam and the stairs were poured in place onsite. The foam acted as the on-grade material, so the concrete stairs did not have to be self-supporting. The purpose of this study is to understand the benefits of using Geofoam, as the in-fill material, as opposed to other traditional materials. An analysis …

Carbonate Chemistry Characterization In A Low-Inflow Estuary With Recent Seagrass Loss, Jolie Higgins

Master's Theses

Estuaries are dynamic environments that are strongly affected by natural variability, as well as direct and indirect anthropogenic impacts. A better understanding of the drivers of carbon fluxes and biogeochemical variability in estuarine systems is needed, particularly with the increasing threat of ocean acidification. Morro Bay in Central California is a small nationally protected estuary, with seasonally low freshwater inputs. Since 2007, the bay has experienced a significant loss of native seagrass, Zostera marina, which is an important component of the marine ecosystem. Because seagrass photosynthesis decreases carbon dioxide and increases oxygen in the water column, the loss of seagrass …

Effect Of Bio-Augmentation Product Biowish® Septic Rescue On The Wastewater Treatment Performance Of Residential Septic Tanks, Kimberly Michelle Lamar Merilles

Master's Theses

Residential septic systems provide reliable wastewater treatment for over 26 million homes and facilities in the United States, and many more worldwide. When properly maintained, these systems are reliable, low-cost, and long-term treatments for residential wastewater. When neglected, septic systems can fail and lead to health concerns and ecological harm to soil and groundwater contamination through the improperly treated wastewater effluent.

This study tested the effect of the bio-augmentation product BiOWiSH® Septic Rescue of BiOWiSH® Technologies International, Inc. (hereafter referred to as BiOWiSH) on the biological treatment of residential septic tanks. BiOWiSH is meant to act as a bio-augmentation product …

Indoor Air Monitoring Of Ethanol And Benzene In A Pilot Winery Using Active Sampling, Andrew I. Kaneda

Master's Theses

Acute indoor concentrations of benzene and ethanol were evaluated in the California Polytechnic State University San Luis Obispo’s pilot winery workroom. Air samples were collected during four different wine-making activities: fermentation, fermentation with Brix content testing, post-alcoholic fermentation pressing, and storage/finishing. Average workroom benzene concentrations ranged from 0.05 to 0.12 mg/m³. Ethanol concentrations in the winery workroom varied with the activity, ranging from 0.9 to 12 mg/m³. Pressing and fermentation with Brix content testing both led to higher indoor ethanol concentrations than fermentation without Brix content testing and storage/finishing.

Tracer gas decay air exchange tests were …

Wastewater Treatment And Nitrogen Removal In Bench-Scale Photobioreactors Operated With Solids Recycling, Erik Hoffnagle

Master's Theses

This thesis examines the effect of solids recycling on nitrification, organic carbon removal, and algal-bacterial productivity in bench-scale photobioreactors (PBRs) simulating winter pond conditions in San Luis Obispo, California and a 6-acre raceway system in Delhi, California. Two sets of duplicate photobioreactors operated with or without solids recycling were fed primary clarifier effluent (1^oEff) for the first experiment, and facultative pond effluent (FAC) for the second experiment.

In both experiments mean productivity was lower in solids recycled PBRs (3.67 and 2.3 g/m²-day), than in controls without solids recycling (4.15 and 3.9 g/m²-day). When fed …

Increasing Algal Productivity And Treatment Potential In Raceways Fed Clarified Municipal Wastewater, Christopher D. Pittner

Master's Theses

Two sets of triplicate pilot algal raceway ponds (1000-L, 0.30-m deep, paddle wheel mixed) were operated for 14 months at a California wastewater treatment plant to treat wastewater and generate algal-bacterial biomass as biofuel feedstock. Two experiments were run to determine the effect on biomass productivity of (1) hydraulic residence time (HRT: 2, 3, 4, or 4.5 days) and (2) feeding schedule (18 small pulses during 8 AM-4 PM [diurnal] versus 20 large pulses during 4 AM-12 AM [diel]). The target productivity was at least 20 g volatile suspended solids per m2 of pond per day. Additional output variables were …

Design And Analysis Of A Parabolic Trough Solar Concentrator, George N. Skouras

Master's Theses

A prototype solar desalination system (SODESAL) with a parabolic-trough solar concentrator (PTSC) and evacuated tube was designed and analyzed to determine the solar thermal capabilities for small-scale distillation and energy generation. A proof-of-concept study verified that distillation is possible with the system as designed, however a rupture occurred in the copper heat-pipe heat exchanger due to overheating. The internal temperatures of an aluminum heat transfer fin were measured inside an evacuated tube typically used in solar water heater systems to understand the lateral heat distribution and identify possible causes of the rupture. Solar radiation was measured for both the summer …