In a society where equality is sought as the norm, occupational gender representation is still skewed in some disciplines. One field where gender equality in representation has not yet been achieved is engineering, whether in college or at the professional level. This imbalance is not only a potentially vicious cycle...
Industrial waste heat composed of saturated liquid water can be redirected to charge a thermochemical energy storage (TCES) system. This energy can be stored long-term in the inherently energy-dense chemical bonds and used for space heating. Initial reactor scale cycling experiments were conducted in tandem with TCES material improvements. Hydration...
This work focuses primarily the development of methods for imaging microbial biofilms in opaque porous media using x-ray computed microtomography (CT). Two methods for evaluating biofilms in porous media are presented. The first focuses on the addition of silver-coated, hollow glass microspheres to a biofilm-containing micro-model. The silver-coated microspheres affix...
The integration of low-pressure membrane filtration and aerobic granular sludge (AGS) reactor leads to a novel environmental biotechnological process with strong potential to overcome membrane fouling and demonstrate excellent wastewater treatment performance. However, membrane fouling mechanisms in the AGS based membrane bioreactor (MBR) are lack of systematic elaboration. In the...
Trichloroethene (TCE) is a common groundwater contaminant. Bioremediation, or the enhancement of natural microbial processes for the transformation of toxic compounds in soil and groundwater, is an effective solution to this widespread problem. The organisms that transform TCE in the subsurface are sensitive to environmental conditions, especially to the presence...
Gender has been the subject of study in engineering education and science social research for decades. However, little attention has been given to transgender and gender nonconforming (TGNC) experiences or perspectives. The role of cisgender or gender conforming status has not been investigated nor considered in prevailing frameworks of gender...
The ability of Mycobacterium sp. ELW1, a novel microbe capable of alkene oxidation, to co-metabolize phenanthrene (PHE) was studied. ELW1 was able to completely co-metabolize PHE, at different concentrations below its water solubility limit, in an aqueous environment. The alkene monooxygenases in ELW1, used to initiate oxidation of PHE, were...
Carbon tetrachloride (CT) and chloroform (CF) were transformed in batch reactor experiments conducted with anaerobic dechlorinating cultures and supernatant (ADC+S) harvested from continuous flow reactors. The Evanite (EV-5L) and Victoria/Stanford (VS-5L) cultures capable of respiring trichloroethene (TCE), 1,2-cis-dichloroethene (cDCE), and vinyl chloride (VC) to ethene (ETH) were grown in continuous...
Stream chemistry studies conducted in the forested Watershed 1 of the HJ Andrews Experimental Forest show a contribution of CO2 from the hyporheic zone. Hyporheic CO₂ concentrations, measured as pCO₂, have a seasonal trend as well as a responsiveness to storm events. Concentrations are highest at the end of the...
Best Management Practices (BMP) are widely used as a method for stormwater volume control in urban areas to prevent an overload of water on receiving water bodies and treatment facilities. BMPs ability to treat stormwater has gone under critical review in the last few decades, and their performance varies both...
Engineered nanomaterials (ENMs) are small anthropogenic colloids with at least one length dimension <100 nanometers. Due to the nature of their use, ENMs are being increasingly released to the environment. Yet the environmental risks posed by ENMs are unknown due to a variety challenges, including limitations with detecting and quantifying...
The production of titanium dioxide (TiO2) nanoparticles has increased significantly in the past decades, which has generated concern due to their known toxicity in the environment. As a result of the production, use and disposal of productions containing TiO2, TiO2 nanoparticles are often received by wastewater treatment facilities. The adsorption...
This project determined how the presence of environmental biofilms on sand, granular activated carbon and biochar affected the sorption capacity and desorption quantity of copper, zinc, nutrients and organic carbon from stormwater. These contaminants have harmful and toxic environmental impacts on aquatic life, can lead to eutrophication of surface waters,...
Due to the effective antimicrobial properties of silver nanoparticles they represent a significant proportion of all consumer-‐related nanomaterials. The introduction of silver nanoparticles from these products into domestic and industrial wastewater streams poses potential complications for biological treatment systems. A critical component of biological treatment that is extremely sensitive to...
Methanotrophic bacteria are promising means of producing value-added products as they have the ability to transform methane under atmospheric temperature and pressure. Efforts to develop methanotrophs to produce value-added products are hoped to incentivize a decrease in methane flaring operations. The data collected during this study was used to inform...
Geologic CO₂ sequestration is a climate change mitigation strategy that involves the injection of supercritical CO₂ into deep underground rock formations. This thesis focuses on capillary trapping in which capillary forces immobilize CO₂ bubbles at the pore scale. During injection of supercritical CO₂, brine is displaced in what is known...
We do not fully understand reasons behind extinction of populations and species. Consequently, our ability to anticipate extinction (which can be considered a permanent type of an ecological threshold) has remained elusive. In particular, it is not clear how the attributes of episodic disturbance regimes can elicit extinction. In this...
Over the last two decades, urban stormwater management has grown to include green infrastructure, such as bioswales. These systems were primarily designed to mitigate hydraulic peaking during rainstorms but were also found to remove particulate and dissolved contaminants. However, little is known about the fate of these particulate contaminants after...
Several types of channel morphology measurement parameters used to
characterize fish habitat of small streams are refined, developed and evaluated in terms
of their accuracy, precision, and sensitivity to disturbance. Data for 74 stream reaches
in Oregon and Alaska are used in analysis. Over half the reaches are from a...
Natural stream systems contain a variety of flow geometries which contain flow separation, turbulent shear layers, and recirculation zones. This work focuses on streams with dead zones. Characterized by slower flow and recirculation, dead zones are naturally occurring cutouts in stream banks. These dead zones play an important role in...