Environmental Engineering Commons^™

Enhanced Bioretention Modeling At The Catchment-Scale: An Integrated Drainmod-Urban And Swmm Approach, Ghada Diab

Doctoral Dissertations

Bioretention systems are increasingly being adopted in stormwater management as an effective measure to promote infiltration and restore more natural hydrology in urbanized watersheds. Given the significant financial investment in these practices, reliable bioretention models are necessary to predict the effectiveness of these practices prior to installation. One such model, DRAINMOD-Urban (DM-Urban), was recently developed to produce hydrographs with a high temporal resolution at the site-scale, showing substantial promise during initial testing. However, the dataset used for initial testing was limited, consisting of one bioretention area with minimal occasions of overflow. Additionally, DM-Urban is an input-heavy model and there is …

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 …

Enhancing Management Of Built And Natural Water And Sanitation Systems With Data Science, Nelson Da Luz

Doctoral Dissertations

In the age of the data revolution, the civil engineer can enhance the management of infrastructure systems using new techniques focused on data. This dissertation present three studies in which data science approaches are used to enhance management of water and sanitation systems in both the built and natural environments. Chapters 1 and 2 focus on improving methods for data collection relating to water quality monitoring. In Chapter 1, the efficacy of different water quality sampling program designs is evaluated as the programs relate to meeting monitoring goals. Considerations include how timing, location, and distribution system operations can affect monitoring …

Environmental Design And Optimization Of Modular Hydropower Plants, Colin Sasthav

Doctoral Dissertations

This research aimed to understand the pathways to cost-effective and sustainable low-head hydropower. Designing viable hydropower projects requires optimization across many economic, environmental, and social outcomes. However, existing run-of-river hydropower design models often focus on economic performance and customizing technologies for high-head diversion schemes. Standard modular hydropower is a new design approach that uses standardized rather than custom-designed technologies to achieve economies of scale. Oak Ridge National Laboratory established a conceptual outline for module classes based on functions, such as generation modules and fish passage modules, but further research was needed to identify how modules should be selected and operated …

Analysis And Fate Of 2,6-Dichloro-1,4-Benzoquinone In Real And Model Drinking Waters, Aarthi Mohan

Doctoral Dissertations

For many years chlorination has served as a barrier to protect human health from waterborne disease outbreaks. Chlorine is viewed as a near-universal oxidant and disinfectant, that provides a stable residual preventing microbial re-growth all the way through the consumer’s tap. Upon reaction with natural organic matter (NOM) however, it forms disinfection by-products (DBPs) many of which are potent human carcinogens and therefore have been of research interest since the 1970’s (Froese et al., 1999; Krasner et al., 2006, 1989; Richardson, 2003; Rook, 1976, 1974; Singer, 1994). The trihalomethanes (THMs) and haloacetic acids (HAAs) are the most prevalent (Krasner et …

Valorization Of Secondary Agriculture Residues, Narendra Kumar

Doctoral Dissertations

Secondary agriculture residues have the potential to be major contributors as resources for energy and sustainably sourced materials production. Separating secondary agricultural residues, which have already been transported to processing centers, into individual biomass components could convert these wastes into bioproducts. Many types of pretreatments to achieve this separation involve chemicals that are hazardous for the environment. Several deep eutectic solvents (DES) that are biocompatible have been investigated for their ability to deconstruct rice hulls and sugarcane bagasse. Mass yield, enzymatic hydrolysis of the pretreated biomass, fiber analysis, and Fourier transform infrared spectroscopy have confirmed that the DES formic acid:choline …

Investigating The Role Of Iron In The Photogranulation Phenomenon, Abeera Ayaz Ansari

Doctoral Dissertations

Oxygenic photogranules (OPGs) are dense spherical microbial aggregates that are used for self-aerating wastewater treatment. Filamentous cyanobacteria are key granulating species, providing structural backbone and integrity in OPGs. Currently, the mechanisms for selecting filamentous cyanobacteria and their ability to form spherical OPGs are not well understood. Literature shows that iron (Fe) availability plays a significant role in the cyanobacterial growth and colony formation. Moreover, Fe availability is known to be dependent upon light, which is an essential growth substrate for the phototrophs. This research has investigated the role of Fe in the photogranulation phenomenon and the impact of light intensity …

Scaling Up The Oxygenic Photogranule (Opg) Wastewater Treatment Process, Joseph G. Gitau

Doctoral Dissertations

Photogranular biomass has yet to be utilized at large scale for wastewater treatment despite their potential to lower energy demand due to self-aerating capacity in addition to better process control compared to conventional technologies. An evaluation of critical driving factors affecting scaling up has yet to be undertaken. The current generation of oxygenic photogranules under hydrostatic conditions (a deviation from orthodox conditions creating other granules) limit seeding of larger reactors in time and scale. In addition, evaluating the photosynthetic productivity of granules which exist as closely commingled consortia with tightly coupled production and consumption processes, has yet to be undertaken. …

Evaluating Policy And Climate Impacts On Water Resources Systems Using Coupled Human-Natural Models, Hassaan Furqan Khan

Doctoral Dissertations

Extensive human intervention in the terrestrial hydrosphere means that virtually every river basin globally reflects the interaction between human and natural hydrologic processes. Thus, sustainable watershed management needs to not only account for the diverse ways humans benefit from the environment but also incorporate the impact of human actions on the natural system. Informed policy making to address our water challenges requires a comprehensive understanding of these feedbacks and how they might be affected by future changes in climate. This work develops coupled human-natural models for improved surface water and groundwater management in water-scarce regions under future changes in climate. …

Evaluation Of The Erodibility Of Soft Clays And The Influence Of Biopolymers, Pamela Judge

Doctoral Dissertations

Erosion of silts and clays is less well understood than erosion of sands. Further, current and anticipated climate change impacts along coastlines compel consideration of new approaches to coastal protection measures; seawalls and breakwaters designs now include natural and nature-based measures. The first research topic consists of the Adaptive Gradients Framework which was a theoretically-informed facilitation tool. The framework was intended to aid a collaborative and interdisciplinary decision-making process to encourage inclusion of natural and nature-based measures in coastal protection planning and design. This research is the culmination of a series of workshops and fieldtrips executed by the Sustainable Adaptive …

Microbial Dynamics And Design Considerations For Decentralized Microbial Fuel Cell Applications, Cynthia Castro

Doctoral Dissertations

The purpose of this dissertation was to assess the practicality of using microbial fuel cells (MFCs) as alternative sanitation systems for wastewater treatment and energy recovery, focusing on identifying key design considerations for treating high strength wastewater and managing alternative metabolic pathways. We evaluated the energetic outputs of a lab-based pilot MFC designed to treat complex organics present in both synthetic feces and municipal wastewater. The pilot MFC produced two energetic products, methane and electricity, when treating two types of complex wastewaters. The energetic products associated with anode respiration and methanogenesis were simultaneously observed and yielded a combined energy ouput …

Sustainable Infrastructure Development: A Holistic System Based Decision Making Framework Integrating Vulnerability Indicators And Stakeholders Objectives, Mohamed Saeid Eid

Doctoral Dissertations

Infrastructure systems enable the host communities to expand, develop, and prosper in adequate socioeconomic conditions and healthy environment. Thus, the strategies for sustainable infrastructure development should aim to increase the individual utility of the local stakeholders, while reducing the vulnerability of the built environment to perturbations. Nevertheless, the available frameworks consider the development of the infrastructure systems as isolated projects and do not simultaneously address the needs of the stakeholders or the vulnerability of the built environment. The goal of this research is to provide decision makers and the research community with a novel infrastructure development framework that holistically balances …

Proactive Assessment Of Climate Change And Contaminant Spill Impacts On Source Water Quality, Lillian C. Jeznach

Doctoral Dissertations

Managing the water quality of surface drinking water sources has become an increasingly difficult task for water suppliers due to increased watershed urbanization and climate change. Changes in source water quality may affect public perceptions, treatment effectiveness, and ultimately costs to treat water to drinking standards. Although there are increased threats to current and future drinking water quality, current approaches to managing these threats are typically reactionary. Prior detailed modeling efforts of hypothetical events that may impair raw water quality allow for an understanding of constituent fate and transport, including potential maximum concentrations and travel times to the drinking water …

Impacts Of Climate Change On The Evolution Of The Electrical Grid, Melissa Ree Allen

Doctoral Dissertations

Maintaining interdependent infrastructures exposed to a changing climate requires understanding 1) the local impact on power assets; 2) how the infrastructure will evolve as the demand for infrastructure changes location and volume and; 3) what vulnerabilities are introduced by these changing infrastructure topologies. This dissertation attempts to develop a methodology that will a) downscale the climate direct effect on the infrastructure; b) allow population to redistribute in response to increasing extreme events that will increase under climate impacts; and c) project new distributions of electricity demand in the mid-21^st century.

The research was structured in three parts. The first …

Stability, Erosion, And Morphology Considerations For Sustainable Slope Design, Isaac Andres Jeldes Halty

Doctoral Dissertations

The construction of more natural and sustainable earth slopes requires the consideration of erosion and runoff characteristics as an integral part of the design. These effects not only result in high costs for removal of sediment, but also a profound damage to the ecosystem. In this dissertation, innovative techniques are developed such that more natural appearing slopes can be designed to minimize sediment delivery, while meeting mechanical equilibrium requirements. This was accomplished by: a) examining the fundamental failure modes of slopes built with minimum compaction (FRA) to enhance quick establishment of forest, b) investigating the geomechanical and erosion stability of …

Hydrologic Reconstructions Using Dendroclimatology, Climate Signals, And Pacific Ocean Sea Surface Temperature Variability, Sallyrose Anderson

Doctoral Dissertations

The Colorado River provides water to over 25 million people. Given the importance of this water supply, it is critical to understand the hydrologic variables in the Colorado River Basin. In this dissertation, I reconstructed hydrologic conditions (soil moisture, snowpack) in the Upper Colorado River Basin (UCRB) and examined different factors that influence water supply in the region (climate oscillations, oceanic-atmospheric variability).

Firstly, I reconstructed soil moisture in the UCRB. Principal components analysis (PCA) and k-Nearest Neighbor (k-NN) techniques were used to regionalize the gridded data. Correlated tree-ring chronologies (TRCs) were used as predictor variables in stepwise linear regression (SLR) …

Hydrology, Soil Erosion And Climate Interactions On Low Compaction Steep-Sloped Reclaimed Sites In The Southern Appalachian Coal Fields, Tennessee, Siavash Hoomehr

Doctoral Dissertations

The use of loose spoil on steep slopes for surface coal mining reclamation sites has been promoted by the US Department of Interior, Office of Surface Mining for the establishment of native forest. Although low-compaction spoils improve tree survival and growth, the erodibility and hydrology of steep slopes may change due to this practice. The purpose of this study was to quantify the erodibility (K factor), and the Curve Number (CN) value for low compaction, steep-sloped (> 20%) reclaimed mine lands in the Appalachian region, USA. This study also investigated the performance of the SEDCAD model in estimating erosion and …

Oceanic-Atmospheric And Hydrologic Variability In Long Lead-Time Forecasting, Abdoul Aziz Oubeidillah

Doctoral Dissertations

Water managers throughout the world are challenged with managing scarce resources and therefore rely heavily on forecasts to allocate and meet various water demands. The need for improved streamflow and snowpack forecast models is of the utmost importance. In this research, the use of oceanic and atmospheric variables as predictors was investigated to improve the long lead-time (three to nine months) forecast of streamflow and snowpack. Singular Value Decomposition (SVD) analysis was used to identify a region of Pacific and Atlantic Ocean SSTs and a region of 500 mbar geopotential height (Z500mb) that were teleconnected with streamflow and snowpack. The …

An Empirical Investigation On The Impacts Of Ground-Level Ozone Concentrations On National Ambient Air Quality Standards: The Case Of Lake Charles, Louisiana, Benedict Nweke Nwokolo

Doctoral Dissertations

This study presents information upon which the state of Louisiana can base its ozone State Implementation Plans (SIPs) designed to achieve planned emissions reduction that are required by the Clean Air Act (CAAA) of 1990. The research investigation included an assessment survey on a number of Transportation Control Measures (TCMs) and their degree of acceptability by the residents of Lake Charles area of Louisiana, the research target area. The TCMS were first ranked on the basis of people's perception of each TCM and four TCMs were later analyzed for cost-effectiveness using computer mathematical models. The Traffic Flow Improvements TCM was …