Civil and Environmental Engineering Commons^™

Mechanisms Of Advanced And Energy Efficient Wastewater Treatment Technologies, Derek Belka

Civil Engineering ETDs

This dissertation combines meta-omics, microbial ecology, and hydrodynamic analysis to explore mechanisms of enhanced biological phosphorus removal (EBPR) and aerobic granular sludge (AGS) in municipal wastewater treatment. Metagenomic and functional gene profiling of a laboratory sequencing batch reactor fed with amino acids and proteins, and with a low abundance of known polyphosphate-accumulating organisms (PAOs), revealed abundant Herpetosiphonaceae and Dermatophilaceae families possessed key PAO metabolic traits, including phosphate scavenging, anaerobic carbon pathways, and ppk2 gene variants aligned with established PAOs. These findings suggest amino acid-driven EBPR can occur via previously unrecognized taxa, challenging current engineering assumptions and highlighting the need for …

Effect Of Geothermal Conditions On Silica Flour Modified Wellbore Cement, Travis Benjamin Broadhurst

Civil Engineering ETDs

Considerable work has been conducted on modified wellbore cements, but a knowledge gap exists in the effects of downhole conditions on cement, especially tensile strength. In this study, a pressure vessel simulates representative downhole conditions (200⁰C, 1.5 MPa) with a reference solution for geothermal brine and naturally occurring geothermal gases. Samples are removed after 28-days for unconfined compressive strength testing, Brazilian tensile strength testing, elastic moduli measurement, and chemical analyses by X-ray diffraction and electron microprobe. Aqueous chemical analysis suggests multiple active reactions between the geothermal fluid and cement that are exacerbated by higher temperatures, but do not …

Wildfire Impacts On Fluvial Hydrology From Watershed To National Scales, Paige G. Tunby

Civil Engineering ETDs

Wildfires alter the water quantity and quality in downstream river networks. Fires promote biodiversity, maintain habitat, and provide many ecosystem services in a fire-adapted landscape. However, changes in the natural fire regimes can alter ecosystem function and threaten the water security of impacted downstream communities. The magnitude, timing, and persistence of these impacts are difficult to predict due to the lack of high-resolution datasets with adequate coverage to evaluate spatiotemporal trends after a fire. This dissertation moves us beyond the status quo to evaluate post-fire fluvial responses across scales, from the event-scale impacts after the Hermit’s Peak-Calf Canyon wildfire in …

Post-Fire Flood Modeling In Ruidoso, New Mexico: Improving Burn Scar Runoff Predictions, Pramesh Bhaila

Civil Engineering ETDs

Recent large wildfires in New Mexico have demonstrated severe hydrological driven by vegetation loss and the development of hydrophobic soil surfaces. This thesis evaluates the performance of three infiltration models—Curve Number (CN), Linear Constant (LC), and Green–Ampt (GA)— for the watershed impacted by the 2024 South Fork and Salt Fires near Ruidoso, New Mexico. All three models performed comparably during post‑fire simulations, with strong performance in 2024 and notable degradation in 2025, particularly for the CN. Post-fire analyses indicate substantial reductions in infiltration capacity, with CN increasing by 18–24%, LC initial deficit decreasing by 65–77%, effective hydraulic conductivity reduced by …

Assessing Uranyl-Specific Dnazymes And Dna-Aptamers For Uranium Binding In Environmentally Relevant Waters, Ashley R. Apodaca-Sparks

Civil Engineering ETDs

The legacy of uranium mining affects many communities in the western United States, resulting in elevated levels of uranium in surface water. The ability to quickly and accurately detect uranium on site in affected communities can lead to real-time water quality analysis that informs risk assessment and remediation efforts. The objective of this work is to advance the application of biosensing technologies for the measurement of uranium in waters affected by mining legacy. The third chapter of this thesis compares ANDalyze by AlpHa Instruments, a commercially available uranium biosensor, and inductively coupled plasma mass spectrometry (an EPA-verified method for uranium …

Investigating Workforce Development Gaps In Tribal Transportation Agencies, Benson Long Jr

Civil Engineering ETDs

Tribal transportation programs face challenges in recruiting and retaining qualified staff, prompting reliance on external consultants for key responsibilities. This study explores how workforce constraints and organizational structures influence tribal outsourcing decisions. Survey data from 57 tribes informed a logistic regression model examining how geographic isolation, population size, training access, and the presence of a transportation department affect preferences for internal work, actual task completion, and instances where tribes intended to perform tasks in-house but outsourced instead. Findings indicate that outsourcing is driven by limited internal capacity, including staffing shortages, lack of certified personnel, and training opportunities. Geography also plays …

Workforce Resilience In Public Transportation Agencies, Kristal D. Metro

Civil Engineering ETDs

A strong, resilient public workforce is necessary to keep the United States’ infrastructure system running smoothly. Across the public sector, hiring is lagging behind increasing retirement rates, leaving public agencies facing the loss of institutional knowledge at unprecedented levels. Combined with above-average retirement rates, low unemployment rates, and below-average salaries, workforce shortages are expected to become critical, putting the resilience of the public transportation workforce, and by extension, the United States public infrastructure and services at risk. The purpose of this research is to determine the best practices for recruiting and retaining employees at public transportation agencies, thereby positively influencing …

Design And Evaluation Of The Influence Of Mutual Induction On Microbial Electrolysis Cell Performance And Biogas Production, Ashley L. Blackwell

Civil Engineering ETDs

Microbial electrolysis cells (MECs) present a pathway for energy recovery in wastewater treatment by converting organic substrates into methane or hydrogen. Traditional MEC designs typically rely on physical electrode contacts and expensive materials, which restrict their scalability. This study introduces the first induction-based MEC that uses mutual inductance between an external copper wrap and an internal coil to generate a fluctuating electrical potential, removing the need for expensive electrodes. The induction-stimulated reactor showed faster total organic carbon removal and a higher CH4/CO2 ratio compared to a conventional anaerobic digester, indicating improved carbon-to-methane conversion, although total gas yield remained similar. Microbial …

Improving Infiltration Model Performance In Arid And Urban Regions, Samuel Stephen Coulter

Civil Engineering ETDs

Flooding in arid regions is infrequent but damaging and limited historical data makes flood modeling an important tool for flood infrastructure design. This study improves flood modeling guidance by using plot-scale tests to determine the impact of slope, compaction, gravel mulch and landscape fabric on infiltration and runoff rates in sandy soil types. This data will be used as guidance for the linear and constant model. The performance of this model was compared with the curve number model for a hypothetical 100-year design storm. Results showed that gravel mulch increased infiltration rates by 66% and reduced erosion on steep and …

Finite Element Investigation Of Blast Load Responses In Nuclear Power Plant Containment Structures, Janak Raj Awasthi

Civil Engineering ETDs

Some significant incidents like the Chernobyl disaster (1986), the Fukushima Daiichi hydrogen explosion (2011), and some frequent military and terror threats to the nuclear Power plant structures have led to studying the capacity of power plant structures to withstand blast loadings. From this research, even one-third of the loss of the coolant is enough to damage the power plant structure. Crack starts from the wall and propagates toward the top of the dome and the foundation. The external blast shows high damage symptoms near the foundation area. Most of the steel members, including the rebars, Liner, and Tendons, showed high …

Eyes On The Road: Disentagling Cyclist Mental Workload At Intersections, James Joseph Rawson

Civil Engineering ETDs

In North America, cyclists often share infrastructure with motor vehicles and encounter frequent conflicts with them at intersections. While past research assumes cyclists' experiences mirror those of drivers, most studies focus on roadway segments rather than intersections. This study addresses that gap by, for the first time we are aware of, examining cyclist perceptions at intersections using head and gaze movement data. Leveraging naturalistic data conducted in Albuquerque New Mexico, and statistical techniques, including t-test and repeated measures ANOVA, our findings suggest that – similar to drivers - cyclists do experience greater mental workload when performing turning movements than when …

Performance-Based Full Depth Reclamation Design, Moatasem H. Algburi

Civil Engineering ETDs

The Full-Depth Reclamation (FDR) technique is a cold-mix asphalt (CMA) technology employed in New Mexico to rehabilitate existing pavements. It results in minor disruption to traffic, environmental advantages, and decreased construction period and costs. However, insufficient data on the material properties of FDR mixtures and their characterization limits the use of the mechanical-empirical (M-E) design method of FDR materials. The MEPDG develops performance models using the structural response of pavement layers to predict pavement structure systems based on material properties, climate models, and loading conditions. This study has developed MEPDG models to predict the long-term performance of FDR materials and …

Analyzing The Key Characteristics And Benefits Of Ccpr (Cold Central Plant Recycling) In Road Rehabilitation And Sustainability, Bassam Abou Yassine

Civil Engineering ETDs

Cold mix asphalt (CMA) technologies are being used in the United States and have environmental benefits. However, these technologies are not fully developed. We do not yet know their resilient and dynamic modulus, which are important for designing pavement thickness. They have not being used widely because we do not know also their performance. This study looks at three Cold Central Plant Recycling (CCPR) materials to help fill this gap. We conducted several lab tests, including the Hamburg Wheel Tracking Test (HWTT), Semi-Circular Bending Test (SCB), and Texas Overlay Test (TOT). We also tested the mechanical properties of the CCPR …

How Wildfires Threaten Water Resources: A Case Study Following The Largest Wildfire Recorded In New Mexico, Eric A. Joseph

Civil Engineering ETDs

Wildfire disturbance propagation along fluvial networks remains poorly understood. We use incident, atmospheric, and water-quality data from the largest wildfire in New Mexico’s history to quantify how this gigafire affected surface runoff processes and mobilized wildfire disturbances into fluvial networks after burning 1382 km². Surface runoff post-fire increased compared to pre-fire conditions, and precipitation events that are frequently observed in the affected watershed (<2-year recurrence) and fell during the post-fire first rainy season resulted in uncorrelated, less frequently observed runoff events (10-year recurrence). Wavelet coherence analysis highlighted that water quality disturbances propagated variably along the network, even at sites located >160 km downstream of the burn perimeter. Our findings emphasize the need to incorporate spatially resolved longitudinal sampling designs into wildfire water quality research and highlight the spatiotemporal co-dependency among atmospheric, terrestrial, aquatic processes …

Longitudinal Pedestrian Safety Trends By Vehicle Type And Model: A 2015-2022 Study Of Texas, Olivia Tafoya

Civil Engineering ETDs

We observed pickup trucks, SUVs, and passenger cars and their two most popular vehicle models across Texas from 2015 through 2022. For each vehicle type and model, we obtained all reported pedestrian crashes, counts of registered vehicles, and vehicle design characteristics. Results suggest that older vehicles are more likely to seriously injure or kill a pedestrian than newer ones. They also indicate that SUVs were more deadly, after controlling for exposure using the number of registered vehicles, than other vehicle types. Of the models studied, the full-size SUVs proved to be particularly dangerous for pedestrians, being 2.08 times more likely …

Analysis Of Water Usage And Greenhouse Gas Emissions As Transition Fuel From Coal To Natural Gas In San Juan County, New Mexico, Tahereh Kookhaei

Civil Engineering ETDs

Abstract

Coal is a major contributor to various environmental issues, making the transition to alternative energy sources essential for reducing environmental impacts and combating climate change. San Juan County in New Mexico has historically depended on coal-fired power plants for producing electricity. However, due to environmental and economic pressures, there is a move to reassess energy strategies. This study explores the transition from coal to natural gas (NG) in San Juan County, with a focus on assessing changes in water usage and emissions (CO₂, NO_x, and SO₂) at the Four Corners (coal-fired) and Afton …

Understanding Longitudinal Top-Down Cracking To Enhance Asphalt Mix Design, Md Mehedi Hasan

Civil Engineering ETDs

This study focuses on developing a deformation rate-dependent bilinear constitutive equation for cohesive zone modeling of asphalt concrete's fracture process zone to accurately predict the longitudinal top-down crack initiation and propagation. A mathematical model has been developed for the AC materials' deformation rate-dependent cohesive zone fracture characteristics and incorporated into the ABAQUS software as a customized user element subroutine (UEL). The developed model has been validated by comparing the simulation results with the laboratory test results, which show good agreement with the results. In addition, an enhanced asphalt mix design approach, referred to as SP5, has been developed to mitigate …

Evaluation Of Machine Learning Algorithms And Statistical Analysis For Predicting Crash Severity And Determining Contributing Factors: A Comparative Study, Arian Golrokh Amin

Civil Engineering ETDs

Improving road traffic safety relies on the ability to accurately predict traffic crashes and understand the factors contributing to severe injuries. This study employs a dual approach, utilizing both statistical analysis and machine-learning methodologies. Initially, statistical analyses such as chi-squared tests and Cramer's V values are applied to a decade's worth of police report data from Albuquerque, New Mexico, to identify primary causal factors behind crashes. Subsequently, machine-learning models are developed and rigorously compared to predict the severity of traffic crash injuries. The selection of the most effective algorithm is based on comprehensive metrics including accuracy, precision, recall, and F1 …

Thermal Oxidative Degradation Of Polystyrene Plastics Used For Food Packaging During Incomplete Waste Incineration, Maycee Hurd

Civil Engineering ETDs

We identified the physical and chemical degradation of polystyrene (PS) plastic used for food packaging after thermal oxidative weathering. Open waste incineration is a widely used waste management practice in isolated and underserved communities. However, the generation of partially incinerated plastics and microplastics (MPs) from this practice is overlooked. Near surface XPS C 1s high resolution analyses show an increase in the intensity of peaks greater than 285 eV corresponding to C/O bonds after burning of PS. Bulk analyses using ATR-FTIR show that thermal oxidation decreased the alkene (3040-3000 cm-1) and alkane (3000-2850 cm-1) C-H stretch signals suggesting PS chain …

Effect Of Air Filtration On Water Quality During Atmospheric Water Harvest In The Southwest United States, A.J. Barney

Civil Engineering ETDs

Access to sustainable drinking water is a concern across the globe. Atmospheric water harvest (AWH) offers a potential supplemental drinking water source. However, the sources and processes affecting AWH water quality are not well understood and must be thoroughly studied to consistently utilize AWH for drinking water. The objective of this research is to assess how removing particulate matter (PM) 2.5 and PM10 in the air used to produce AWH with air-filters affects the water quality of AWH. AWH samples were collected simultaneously with three identical dehumidifiers, utilizing three different air-filter configurations (no-filter, MERV8, and MERV12) in Albuquerque, NM from …

3d Printing Of Local New Mexican Soil Material: Improving Durability Properties By Assessing Traditional Methods Towards Alternative Sustainable Construction, Daiquiri Devon Zozaya

Civil Engineering ETDs

3D printing (3DP), or additive manufacturing, represents a dynamic and swiftly advancing manufacturing method in which diverse materials are deposited layer by layer through computer-controlled processes, creating intricate geometries. This technology has demonstrated success in various construction applications, including the construction of bridges, bus stop stations, and even residential homes. Nonetheless, the predominant application of 3DP in construction relies heavily on cement due to its robustness, convenience, and ease of use. Regrettably, the cement sector is a substantial source of greenhouse gas emissions, responsible for approximately 8% of worldwide CO₂ emissions. Investigating all facets of carbon emissions reduction is …

Building A Trusted Relationship Among Project Participants In Construction Projects On Tribal Land, Dominica J. Bennett

Civil Engineering ETDs

There are 574 federally recognized tribes in the United States, and these tribal communities differ by culture, language, history, and self-governance. Performing a tribal construction project is different than a non-tribal project due to tribal sovereignty, tribes are both legally and regulatory independent. The United States has recognized its trust with Indigenous tribes through treaties, statutes, and historical relations, however treaties and statutes have been broken over time. This paper aims to qualitatively and quantitatively identify relationships and trust built between contractors, designers, and owners on construction projects while identifying challenges. The methodology involves survey distribution to rank the level …

A Stable Isotope Study To Investigate Water Movement In The Los Lagos Region Of Southern Chile, Kritan Subedi

Civil Engineering ETDs

The Los Lagos region in southern Chile, located in northwest Patagonia, features rain-fed agricultural lands, glacial lakes, forests, farmlands, and volcanic soils. This study investigates water movement within a micro-basin using stable isotope analysis and hydrological modeling over eight weeks. It aims to develop a conceptual model of water movement by elucidating interactions between precipitation, soil water, and streamflow. Findings highlight the critical role of deeper soil layers in sustaining streamflow during dry spells and indicate that soil acts as a buffer, maintaining hydrological continuity despite variable precipitation. Improved understanding of these dynamics can inform watershed management and water resource …

Engineered Cementitious Composites: The Good, The Bad, And The Possibilities, Michele M. Anderson, Michele M. Anderson

Civil Engineering ETDs

Construction materials require testing in the laboratory and field to be accepted as viable tools. Engineered cementitious composites (ECC) are a new material in the class of ultra-high-performance concrete studied and tested in the lab but not in the field. This research aimed to answer questions about ECC's ability to be a viable and cost-efficient construction material. The cost of ECC continues to be a factor in the acceptance of the material. Cost savings in construction and labor have not been identified until now, and it is good. Field condition testing of ECC in a desert climate known for extreme …

Longitudinal Spatial Trends In U.S. Pedestrian And Bicyclist Fatalities, Ossiris Rodriguez, Nicholas N. Ferenchak

Civil Engineering ETDs

Between 2009 and 2022 in the United States (U.S.), pedestrian fatalities increased 82.3% and bicyclist fatalities increased 70.8%. Several studies have researched crash characteristics such as the people and roadways involved in these crashes. But where are these fatalities occurring within our regions and what spatial characteristics of these locations could be influencing this trend? We analyzed pedestrian and bicyclist fatality data from the last two decades using NHTSA’s Fatality Analysis Reporting System (FARS) in relation to built-environment and socio-economic characteristics (such as street network density, transit access, poverty, and educational attainment) obtained from the U.S. Census and the U.S. …

Insight Into The Application Of Engineered Phenol Polymer Nanocomposites For Geothermal Well Applications To Modify Fracture Permeability, Fatemeh Hamidi

Civil Engineering ETDs

In enhanced geothermal systems, the efficient transfer of heat from the formation to the fluid circulating through the fracture network can be compromised when thermal short-circuiting occurs due to preferential flow through highly conductive fractures. This study introduces a pioneering approach using newly developed phenol polymer nanocomposites as an engineering solution to address the challenges associated with preferential flow in geothermal wells, which can lead to thermal short-circuiting. Multiple phenol polymer nanocomposites were formulated, incorporating aluminum oxide, COOH-functionalized graphitized multi-walled carbon nanotubes (MWCNTs), and graphene nanoparticles, each with a 0.5 wt.% polymer dosage. This research successfully modified the crosslinking process …

Optimizing Flash Flood Prediction In Arid And Semi-Arid Regions: A Comparative Evaluation Of Infiltration Models And Parameter Estimation Guidance Across Spatial Scales, Sara Rassa

Civil Engineering ETDs

This study improves flash flood prediction by analyzing the vital role of infiltration models in hydrologic modeling, especially for areas with scarce data. It offers new parameter estimation guidance for three infiltration models—initial-constant (IC), linear-constant (LC), and Green-Ampt (GA)—based on plot-scale rainfall simulations. The research emphasizes the impact of soil texture, moisture, and crust on model parameters. A comparative analysis of four models (curve-number, IC, GA, and LC) using data from Arizona's Walnut Gulch Experimental Watershed under different calibration scenarios shows the GA model's superiority in certain conditions, though it faces issues of equifinality in unconstrained calibrations. Meanwhile, the simpler …

Evaluation Of Error Sources In Dynamic Multiple-Input Multiple-Output (Mimo) Tests, Odey Yousef

Civil Engineering ETDs

Dynamic testing of systems is used to characterize the relationship between inputs and outputs using frequency response functions (FRFs). Multiple input and multiple output (MIMO) techniques are crucial for realistic representation. In MIMO tests, environmental conditions are replicated by inverting the FRF matrix for input estimation. Steps include system identification, FRF inversion, input estimation, and input application. Each of these steps are nontrivial and require careful attention. Error sources manifest as error between desired and experimental outputs. Significant efforts to minimize this error exist, yet literature lacks a formal understanding of their origins. This research focuses on 3 of these …

Multi-Physics-Based Modeling Of Cracks In Asphalt Concrete, Md Amanul Hasan

Civil Engineering ETDs

Cracking is the most prevalent distress in an asphalt concrete (AC) pavement, and it leads to structural deterioration and premature failure, thereby costing taxpayers a lot of dollars. Accurately assessing AC's cracking performance is necessary for pavement longevity, yet current methods often fall short. For instance, relying solely on binder creep tests to determine low-temperature grade inadequately predicts the AC pavement's low-temperature cracking problem. Understanding AC's loading rate- and temperature-dependent fracture behavior is crucial for gaining insight into the crack propagation in AC. In the first part of this study, a new physics-based analytical methodology is developed utilizing the bending …

Physical And Stochiometric Controls On Nutrient Uptake And Ecosystem Respiration In Contrasting Sites, Jancoba K. Dorley

Civil Engineering ETDs

Meteorological, hydrological, and biogeochemical processes naturally control stream ecosystems. These processes define the frequency and distribution of precipitation and the supply and demand of solutes and particles to support aquatic food chains through space and time. Studies have also found that stream ecosystems are also controlled by anthropogenic activities, which occur on a much shorter timescale. These anthropogenic activities affect stream ecosystems' structure and function from local to planetary changes to the environment. It is essential for scientists and engineers to understand the relationships between naturally occurring processes and those created by human activities for a better interpretation of stream …