Engineering Commons^™

A Network Of Low-Cost Multi-Pollutant Air Quality Sensors For Evaluating Fine-Scale Exposure Disparity In Twin Cities, Mn, P M Varuni Abhayaratne

Masters Theses

"Poor air quality is detrimental to health and is a leading environmental risk factor for early death globally. The massive scale of urbanization and population growth has led urban air quality to become a global concern as the release of air pollutants into the atmosphere continues to increase. Air quality has traditionally been monitored using reference-grade monitoring stations that are expensive and sparsely distributed. Low-cost sensors can complement existing regulatory networks to provide more spatial detail, capturing fine-scale variations. This study investigates spatiotemporal pollutant patterns, exposure disparities and environmental justice using data collected from a two-year (2019-2021) deployment of a …

Rapid-Throughput Analysis Of 1,4-Dioxane In Plants By Centrifugal Sampling And Phytoforensic Analysis For Site Delineation And Assessing Enhanced Rhizodegradation, Anthony Eberechukwu Oha

Masters Theses

"Owing to its broad use and environmental persistence, 1,4-dioxane (dioxane) poses a notable threat to public health and is recalcitrant to traditional remedial systems. Dioxane moves readily in an aqueous environment and is an emerging contaminant in drinking water, surface water, groundwater, and wastewater. The extent of dioxane in the biosphere is also difficult to delineate, particularly in the subsurface. Phytoremediation has demonstrated the potential for dioxane groundwater remediation. Recent findings indicate that plant-microbial symbiosis may be more advantageous for limiting potential transport and transfer into plant tissues and the atmosphere. Bioaugmentation of the rhizosphere paired with soil amendments has …

Wind Flow Characteristics Of Multi-Vortex Tornadoes And Their Wind Effects On Residential Houses, Yi Zhao

Doctoral Dissertations

"Tornadoes strike the USA very frequently, with an average of 1200 reports per year, and the average annual tornado-induced property loss has reached $10B. The devastation from recent tornadoes have prompted a renewed interest in better understanding tornado dynamics, their interactions with the built environment, and the performance of civil structures during tornadoes. In the past, the wind effects caused by single-vortex tornadoes have been widely studied, while the multi-vortex tornadoes were rarely considered. In fact, many previous deadly, costly tornadoes involved multiple vortices. Therefore, it is important to understand the wind flow characteristics of multi-vortex tornadoes in order to …

Assessing Phenotypic Response Of Plants Irrigated With Municipal Solid Waste Landfill Leachate Using Computer Visualization, Rahel Pommerenke

Masters Theses

"Most solid waste collected in the US is disposed of in sanitary landfills, which have a lingering legacy of unintended negative impacts on the environment. Landfill design and operation are expensive, prone to multiple failure modes, and often do not address human and ecological risks presented by contaminants of emerging concern. A notable and common failure mechanism is leachate production. Moisture in the waste mixes with infiltrating water to form wastewater that must be collected and treated prior to discharge. Recycling leachate at landfills by recirculating it onto vegetated landfill covers relies on the evapotranspiration potential of plants to reduce …

Ecological Restoration Of Lead/Zinc/Copper Mine Tailings: Phytomanagement And Amendment Strategies To Enhance Substrate Functionality And Biomass Production, Mariam K. Al-Lami

Doctoral Dissertations

“The extreme physiochemical characteristics of mine tailings inhibit microbial processes and natural plant growth. Consequently, vast and numerous tailings sites remain barren for decades and highly susceptible to wind and water erosion. Phytostabilization is a cost-effective and ecologically productive remediation approach; however, tailings revegetation is generally challenging and must often be assisted with appropriate soil amendments. Amendments applied individually in greenhouse studies discussed herein revealed notable improvement in bioenergy crops growth only with biosolids treatments. Recalcitrant carbon amendments (biochar and humus) showed notable impact only on tailings physichochemical and hydraulic properties. Nevertheless, biosolids may not support sustained vegetation due to …

Early Wildfire Detection By Air Quality Sensors On Unmanned Aerial Vehicles: Optimization And Feasibility, Doaa Rjoub

Masters Theses

“Millions of acres of forests are destroyed by wildfires every year, causing ecological, environmental, and economical losses. The recent wildfires in Australia and the Western U.S. smothered multiple states with more than fifty million acres charred by the blazes. The warmer and drier climate makes scientists expect increases in the severity and frequency of wildfires and the associated risks in the future. These inescapable crises highlight the urgent need for early detection and prevention of wildfires. This work proposed an energy management framework that integrated unmanned aerial vehicle (UAV) with air quality sensors for early wildfire detection and forest monitoring. …

Exposure Assessment Of Emerging Contaminants: Rapid Screening And Modeling Of Plant Uptake, Majid Bagheri

Doctoral Dissertations

"With the advent of new chemicals and their increasing uses in every aspect of our life, considerable number of emerging contaminants are introduced to environment yearly. Emerging contaminants in forms of pharmaceuticals, detergents, biosolids, and reclaimed wastewater can cross plant roots and translocate to various parts of the plants. Long-term human exposure to emerging contaminants through food consumption is assumed to be a pathway of interest. Thus, uptake and translocation of emerging contaminants in plants are important for the assessment of health risks associated with human exposure to emerging contaminants. To have a better understanding over fate of emerging contaminants …

Development Of Amine-Functionalized Mesoporous Alumina For Radioiodine Removal From Water, Mansour Mohammed Alsalbokh

Masters Theses

“Radioactive materials have spread due to careless disposal and nuclear disasters. Some radionuclides can exist in an aqueous media, like radioactive iodine. As a result, in this work amine-functionalized mesoporous alumina was developed to adsorb radioactive iodine from the liquid phase. Bismuth was incorporated, using a wet impregnation method, to test it as a possible silver replacement. Amine grafting was used to functionalize the surface of the mesoporous alumina. All materials prepared in this work were characterized by N₂ physisorption, FTIR and TGA to determine the textural properties, surface functionality, and amine loading. The synthesized materials were tested for …

Soil-Water-Energy Nexus Of Green Roofs, Katherine Ann Bartels

Masters Theses

"As the urban landscape continues to sprawl into previously undeveloped land to accommodate population growth, the need to design cities that effectively manage urban stormwater is imperative for a sustainable future. Green roofs use rain-harvesting techniques to reduce urban stormwater discharge while simultaneously providing traditional roof services as well as several ecosystem services. However, green roof media design varies greatly among commercial applications, and little guidance is available to engineers when selecting the media for prospective green roofs. Efforts to maximize stormwater retention and enhance urban heat island mitigation capabilities of green roofs while concurrently reducing nutrient loading were examined …

Investigation Of Urea Decomposition And Deposit Formation In Diesel Exhaust After-Treatment System, Anand Alembath

Doctoral Dissertations

“Urea-selective catalytic reduction (SCR) system has proved to be an effective solution to reduce NO_x emissions in commercial vehicle (CV) diesel engines. A significant challenge in urea injection is to comprehend its decomposition chemistry that leads to formation of undesired deposits in the exhaust system unit. Due to complex interaction of multi-phase fluid flow and transport processes, significant uncertainty is associated with the identification of interacting factors that control the deposit initiation and its growth. To meet the future ultra-low NO_x emissions and to deliver ammonia without deposit formation, there is an imminent need to develop the urea-SCR …

Physical And Biological Factors Affecting Oxygen Transfer In The Activated Sludge Wastewater Treatment Process, Kenneth A. Campbell

Doctoral Dissertations

“The activated sludge (AS) process is widely utilized for wastewater treatment due to its versatility and general resiliency, but is energy intensive, requiring aeration and mixing energy inputs to maintain the biochemical reaction and optimize treatment performance. This study is focused on determining different factors that influence oxygen transfer and consequently its energy demand.

AS morphology, as described by the d₁₀, d₂₀, d₃₂, specific filament length (SFL), 30 min settleability (SV₃₀), etc., does influence the OTE. Filamentous organisms increase the hydrodynamic radius of suspended particles, which dilates mixed liquor apparent viscosity (µ …

The Combined Toxic Effect Of Nanoparticles And Lead In The Presence Of Algae (Raphidocelis), Xuesong Liu

Doctoral Dissertations

"The elevated toxicity of toxic metals in the presence of nanoparticles (NPs) has raised significant concerns on the NP environmental safety. This research focuses on the impact of environmental conditions, specifically algae, on this type of toxicity. An indicator aquatic organism, Ceriodaphnia dubia (C. dubia), was used to examine the combined toxicity and toxicity mitigation from algae by monitoring its 24-h mortality. Four papers are included in this research, which focus on four aspects of the combined toxicity and the corresponding algae (Raphidocelis) impact. The first paper examines the algae impact on the combined toxicity of …

Evaluation Of Naturally Occurring And Anthropogenic Contamination In Missouri Streams, Christina Jane Sehrt

Masters Theses

"The goal of this study is to observe the values and variability of water quality parameters and benthic macroinvertebrates in watersheds with very little anthropogenic impact and to compare these values with those acquired in watersheds with more anthropogenic impact. The following five HUC 12-digit watersheds had very little anthropogenic impact and were considered "pristine": Rogers Creek, Mill Creek, Middle West Fork-Black River, Bee Fork, and Ottery Creek. Five largely urban sub-basins were also considered; these basins are: Grand Glaize Creek, Glaize Creek, Sugar Creek, Hominy Creek, and Grindstone Creek. For each watershed, both water quality parameters and benthic macroinvertebrates …

Designing Bifunctional Materials For In-Situ Capture And Conversion Of Volatile Organic Compounds, Anirudh Krishnamurthy

Doctoral Dissertations

”Volatile organic compounds (VOCs) are a class of organic liquid compounds with low vapor pressures, which enables them to vaporize at ambient conditions. VOCs are largely toxic, carcinogenic, and mutagenic, and have profound adverse effects on human health and the ecological environment. Many VOCs cause ruinous health effects even at very low concentrations (ppm) and therefore control of these organic compounds is essential for ensuring good air quality. A large portion of VOCs cause catastrophic health effects such as cancer or liver damage even at very low concentrations (ppm), and the control of these compounds is vital in ensuring good …

Cellulose And Sulfate Degradation In A Biochemical Reactor During Treatment Of Mine Drainage, Sweta Ojha

Masters Theses

"Seventy-two biochemical reactors were set up, and operated using a mixture of chip-bark, horse manure, and gravel as the biochemical treatment substrate. The simulated mine water containing sulfate (1000 mg/l) was pumped into each reactor at a flow rate of 0.5 ml/minute (approximate), giving an empty bed contact time of 8 days. The main idea is that the microorganisms present in horse manure would convert the cellulose in chip-bark into volatile fatty acids. The produced volatile fatty acid would enhance the metabolism of sulfate-reducing bacteria (SRB) initially present in horse manure, which would degrade (and eventually remove) the sulfate from …

Bioaccessibility Of Lead From Contaminated Soil Using Phosphate Treatment -- Physiologically Based Extraction Test And In Vitro Gastrointestinal Method Test, Austin Charles Doss

Masters Theses

"Phosphate treatments are used to immobilize lead in soil by forming pyromorphite. Soil from Bonne Terre, Mo was collected to study whether such treatment decreases the bioaccessibility of lead. The soil was treated using 0.5 soil wt% of phosphate. Treatments were: none, phosphoric acid, triple super phosphate, and organic bone meal. Each sample was studied after one, four, sixteen, and twenty weeks; during this time span, water was added approximating the average rainfall rate. Percolated water was collected to test the leached phosphate concentrations. Phosphate was below the detection limit in that leachate. Remediated soil samples were used in Physiologically …

Numerical Modeling Of Capillary-Driven Flow In Open Microchannels: An Implication Of Optimized Wicking Fabric Design, Mehrad Gholizadeh Ansari

Masters Theses

"The use of microfluidics to transfer fluids without applying any exterior energy source is a promising technology in different fields of science and engineering due to their compactness, simplicity and cost-effective design. In geotechnical engineering, to increase the soil's strength, hydrophilic wicking fibers as type of microfluidics have been employed to transport and drain water out of soil spontaneously by taking advantage of natural capillary force without using any pumps or other auxiliary devices. The objective of this study is to understand the scientific mechanisms of the capability for wicking fiber to drain both gravity and capillary water out of …

Atomic Layer Deposition Prepared Nanostructured Materials For Various Catalytic Reactions, Xiaofeng Wang

Doctoral Dissertations

"Atomic layer deposition (ALD) has been widely used for thin film coating and metal nanoparticles (NPs) preparation. In this report, the applications of ALD prepared nanostructured materials in catalysis were examined.

Highly dispersed Pt monometallic catalysts with different substrates and multi-walled carbon nanotubes (MWCNTs) supported Pt-Co bimetallic catalysts were synthesized by ALD for selective hydrogenation of α, β-unsaturated aldehydes to unsaturated alcohols (UA). Pt/MWCNTs showed the highest selectivity of UA in selective hydrogenation of citral, as compared to Pt/SiO₂, Pt/ALD-Al₂O₃, and Pt/γ-Al₂O₃. After adding Co, the highest selectivity was achieved …

Cloth-Air Partitioning Of Oxybenzone, Jonathan T. Hill

Masters Theses

"Clothing has been proven to be a significant accumulator of chemicals from the air. Semi-volatile organic compounds (SVOCs) have a high affinity towards textiles, and measuring the equilibrium partition coefficient between cloth and air (K_cloth-air) for SVOCs is crucial in predicting human exposure to these compounds. This study aims to quantify K_cloth-air for oxybenzone to contribute to a larger human exposure experiment carried out at the Technical University of Denmark (DTU). K_cloth-air for oxybenzone was calculated using data collected from the exposure chamber at DTU and from performing extractions of oxybenzone in fabric samples from the …

Towards A Better Understanding Of Indoor Exposure To Air Pollutants: Window Opening Occurrence In U.S. Residences, Gauri Dilip Date

Masters Theses

"Opening a window dramatically alters how we are exposed to air pollutants. Online questionnaire surveys were deployed to assess window-opening occurrence of the occupants of US homes. This information will be used to better quantify population exposure to pollutants of indoor and outdoor origin. Frequency distributions of demographics were generated which showed percentages of respondents who participated in the surveys from categories including gender, race, household income and occupancy. In April 2016, 49.3% of the people surveyed opened their windows for at least 1 hour in a day. This increased to 52.5% in September 2016 and reduced considerably to 24.4% …

Advanced Buffer Materials For Indoor Air Co₂ Control In Commercial Buildings, Pavithra Ethi Rajan

Masters Theses

"The following describes a novel passive approach to control the indoor CO₂ levels in enclosed spaces, primarily focusing on commercial buildings. Amine impregnated silica sorbents were identified as suitable candidates and synthesized; the amine loading ratio was varied to create a range of materials. These samples along with other commercial zeolite candidates have been tested over a range of CO₂ concentrations to determine the CO₂ adsorption capacity in laboratory systems and under simulated room conditions. The research work also focuses on the CO₂ desorption capacity of the candidate adsorbents. The desorption is allowed to occur gradually …

The Use Of Ceramic Water Filters Under Pressure In An In-Line Water Pumping System, Travis Dean Gardner

Masters Theses

"Ceramic pot filters (CPFs) have proven an effective point of use (POU) filter due to their relative low cost, ease to manufacture, and effectiveness at treating contaminated water. These filters are used by individual homes, and sometimes multiple filters are needed for each home in order to produce enough water for the family's household. If these filters could be used in-line with a pumping system or elevated storage tank, water could be filtered and used on demand for a community in an economically feasible way. However, CPFs are too fragile to use under pressure due to the weak points where …

Vegetation Based Assessment And Monitoring Tools For Landfill Leachate Treatment And Fugitive Plumes, Rahul Sukharia

Masters Theses

"Solid waste and leachate generation from solid waste landfills has a legacy of detrimental and toxic impacts on the environment. Disposal practices are expensive, failure prone and have not been able to keep up with the pace of disposal of toxic compounds. In general, a landfill acts as a "bathtub" with infiltration of water through the landfill cover into the landfill, reacting with the waste and transferring toxic components into the leachate. Irrigating the evapotranspiration (ET) covers with leachate collected from the landfill has been developed and applied. Such methods can keep the leached pollutants in a loop, which reduces …

Bioaccessibility Of Lead From Lead-Contaminated Soil Upon Phosphate Amendment Using A Physiologically-Based Extraction Test, Samantha Jo Dicenso

Masters Theses

"Lead is known to cause health problems in humans, especially children, and an effective in‐situ remediation option has been sought for years. Adding phosphoric acid (PA) to contaminated soil causes a reaction that binds the lead to phosphate to produce pyromorphite (Pb₅(PO₄)₃Cl), a form of lead believed to be non‐bioavailable; however, field trials have given varied results (Bosso et al 2008; Munksgaard and Lottermoser 2011; Tang et al. 2009). One explanation for these results might be the impact of the agent used to raise pH after phosphoric acid addition. In order to examine this explanation soil was collected from the …

Contributing Factors To Child Stunting In Guatemala: A Systems Analysis Focused On Enteric Disease Transmission And Mycotoxin Exposure, Lee Emerson Voth-Gaeddert

Doctoral Dissertations

"Child stunting -- low height-for-age -- is a United Nation's indicator for chronic malnutrition that has been linked to both acute and chronic health problems. Data from Guatemala suggests for children under five years of age, 49% are classified as stunted. This dissertation tests the following hypotheses, among children in Guatemala 1) environmental enteric dysfunction (EED) is correlated with height-for-age, 2) aflatoxin B (AFB) exposure is correlated with height-for-age, and 3) AFB exposure is correlated with EED. A network analysis was conducted on data from the US Agency for International Development (USAID) collected in 2012 to identify trends in a …

Phytoforensics: Applications In Vapor Intrusion Assessment, Jordan Lee Wilson

Doctoral Dissertations

"Vapor intrusion (VI) occurs when contaminants in the vapor phase migrate in the shallow subsurface and enter buildings through cracks, seams, and gaps and has been recognized as a serious human-health threat as occupants are exposed to potentially harmful concentrations over long periods of time. The VI pathway has recently (2017) been identified as a primary exposure pathway and implemented into the Hazard Ranking System for inclusion on the Nation Priorities List. However, assessing VI and human exposure is not simple and current methods are time-, cost-, and labor-intensive; intrusive; and temporally and spatially variability. Trees are ideal candidates for …

Phytoforensics Tools: The Degradation And Detection Of Chlorinated Solvents In Integrated Systems, Tommy J. Goodwin Jr.

Masters Theses

"Due to decades of mismanaged pollutants entering groundwater, subsurface pollution of various compounds has become a widespread challenge. Chlorinated solvents are the most common groundwater contaminants that persist in aquifers, and remediation of these wide-spread plumes is difficult. Bioremediation, permeable reactive barriers, and phytoremediation are remedial technologies that have been developed and applied to chlorinated solvents in groundwater systems. This study integrates these technologies in different combinations to demonstrate the remediation potential of this approach. Zerovalent iron (ZVI) and bioaugmentation with a Dehalococcoides sp. (DHC) culture were applied separately and in combination for degradation of perchloroethene (PCE). Salix pentandra were …

Imaging Reinforced Concrete: A Comparative Study Of Ground Penetration Radar And Rebarscope, Abhishek Kodi

Masters Theses

"Geophysical techniques have been playing a very vital role in subsurface imaging in the recent past. Technology has been making it both reliable and convenient to utilize non-destructive geophysics techniques like Ground Penetration Radar, Induction current based Rebarscope, Seismic methods, ERT, etc. The applications range from shallow subsurface investigation of Bridge decks to old tunnels, mapping of rabars in a pre-existing construction and analyzing the concrete strength.

The thesis constitutes of a comparative study and analysis of a Ground Penetration Radar system and a Rebarscope. Individual parameters obtained directly from the study and obtained indirectly from the study shall be …

Particle Mediated Enhanced Mass Transfer Of Diethylhexyl Phthalate: A Pilot Scale System Design, Melissa Buechlein

Masters Theses

"Phthalates are a class of SVOCs that are widely used as plasticizers and recently epidemiological and toxicological research has found a link between phthalate exposure and increased occurrences of adverse health effects. SVOCs can potentially partition into household dust and airborne particles. Models and micro chamber studies have identified that airborne particles effectively increase SVOC deposition to or emissions from surfaces; SVOCs partition to aerosols in the bulk air, the aerosols then migrate to the surfaces due to eddy and Brownian motion, and then the SVOCs is released inside the SVOC concentration boundary layer adjacent to the surface. Concentration boundary …

Silicone Hollow Fiber Membrane Bioreactors For Mixed Aerobic And Anaerobic Treatment Of Gas Phase Toluene And Trichloroethylene, Alexander Lee Korff

Masters Theses

"Volatile Organic Compounds (VOCs) are common in effluent waste streams from many sectors of industry and low-cost emission control technologies have the potential to mitigate long-term impacts on the environment. Federal Regulations, such as the Clean Air Act and National Emission Standards for Hazardous Air Pollutants (NESHAPS), as well as state regulations are imposing stricter requirements on point-source emissions, with an emphasis on toxic VOCs. Trichloroethylene (TCE) and tetrachloroethylene (PCE), which are toxic VOCs, have been used since the 1920's for a variety of industrial applications like: degreasing, paint and printing operations, as extraction solvents, and for cleaning and drying …