Environmental Engineering Commons^™

Evaluating Direct Filtration As An Alternative To Conventional Carbon-Based Advanced Treatment For Indirect Potable Reuse, Savannah M. Flemmer

Civil & Environmental Engineering Theses & Dissertations

Hampton Roads Sanitation District (HRSD) is recharging purified wastewater into the Potomac Aquifer via the Sustainable Water Initiative for Tomorrow (SWIFT) project. Conventional SWIFT treatment applies coagulation, flocculation, sedimentation, ozonation, biofiltration, granular activated carbon (GAC) adsorption, and ultraviolet disinfection to secondary effluent to produce water that meets drinking water standards for managed aquifer recharge. HRSD is considering implementing direct filtration as an alternative to conventional treatment for two additional SWIFT facilities. Direct filtration presents an opportunity for significant cost savings by eliminating sedimentation, shortening flocculation detention time, and reducing coagulant usage. Without upstream removal of solids and organics, however, biofilters …

Stability Of Low Crested And Submerged Breakwaters: A Reanalysis And Model Development, Christopher P. Burgess

Civil & Environmental Engineering Theses & Dissertations

Low-crested and submerged structures (LCS) play an integral part in the stabilization of shorelines for recreational purposes, yet there are a plethora of empirical models and gaps in the understanding of their stability and damage progression. The objectives were: i) to evaluate the present formulae, ii) explore variable importance, iii) formulate a stability model, iv) extend the current datasets and v) explore a new model for LCS. The literature points to an increasing understanding of the initiation of damage of LCS and recent exploration of the shear stress-induced erosion (van Rijn, 2019). Assessment of two existing models (Kramer, 2006 and …

Large-Scale Variation In Wave Attenuation Of Oyster Reef Living Shorelines And The Influence Of Inundation Duration, Rebecca L. Morris, Megan K. La Peyre, Bret M. Webb, Danielle A. Marshall, Donna M. Bilkovic, Just Cebrian, Giovanna Mcclenachan, Kelly M. Kibler, Linda J. Walters, David Bushek, Eric L. Sparks, Nigel A. Temple, Joshua Moody, Kory Angstadt, Joshua Goff, Maura Boswell, Paul Sacks, Stephen E. Swearer

Civil & Environmental Engineering Faculty Publications

One of the paramount goals of oyster reef living shorelines is to achieve sustained and adaptive coastal protection, which requires meeting ecological (i.e., develop a self-sustaining oyster population) and engineering (i.e., provide coastal defense) targets. In a large-scale comparison along the Atlantic and Gulf coasts of the United States, the efficacy of various designs of oyster reef living shorelines at providing wave attenuation was evaluated accounting for the ecological limitations of oysters with regards to inundation duration. A critical threshold for intertidal oyster reef establishment is 50% inundation duration. Living shorelines that spent less than half of the time ( …

The Impacts Of Surface Gravity Waves On Buoyant Plume Dilution, Bruce William Husselbee

Civil & Environmental Engineering Theses & Dissertations

A common practice in coastal areas is to collect, treat and discharge fluids including treated wastewater, stormwater or power plant effluent to areas of lesser impact. The discharge of these fluids, conveyed through pipelines into coastal areas, continues to be an important human health and environmental concern. The fluid discharged from these pipelines is often buoyant which allows for dilution and dispersion into these ambient waters.

Initial dilution, defined as the maximum concentration of a discharged fluid at the maximum rise in height within a buoyant plume, is critical in the consideration of the environmental impacts of a discharge into …

Measuring And Modeling Bare Desert Wind Erosion From Steppe Grassland Of Northern China As Affected By Soil Moisture And Climate, Nicholas Morgan Potter

Civil & Environmental Engineering Theses & Dissertations

Soil erosion by wind has been found to be negatively related to soil water content, as evidenced by that for a given area, such a soil erosion can be much less in a wet than a dry year. However, few studies have examined the functional relationship between wind erosion and soil moisture, primarily due to lack of field measured data. The objectives of this study were to: 1) measure wind erosion in field using a portable wind tunnel devised and made by the author; 2) use the measured data to calibrate/validate a wind erosion model previously developed by the author; …

Tsunamigenic Potential Of The Baiyun Slide Complex In The South China Sea, Linlin Li, Fengyan Shi, Gangfeng Ma, Qiang Qiu

Civil & Environmental Engineering Faculty Publications

The Baiyun slide complex contains geological evidence for some of the largest landslide ever discovered in the continental slopes of the South China Sea. High-resolution seismic data suggest that a variety of landslides with varied scales have occurred repeatedly in this area. The largest landslide reconstructed from bathymetric and seismic data has an estimated spatial coverage of ~5,500 km² and a conservative volume of ~1,035 km³. Here, using geomorphological and geotechnical data, we construct a series of probable landslide scenarios and assess their tsunamigenic capacity. By treating the slides as deformable mudflows, we simulate the dynamics of …

Techno-Economic And Life Cycle Assessment Of Hydrothermal Processing Of Microalgae For Biofuels And Co-Product Generation, Andrew P. Bessette

Civil & Environmental Engineering Theses & Dissertations

Traditional processing methods of algae to biofuels require dewatering after harvesting of the algae before the lipids can be extracted. This is typically the most energy intensive and therefore the most expensive step. Old Dominion University (ODU) has successfully utilized a flash hydrolysis (a kind of hydrothermal) process where proteins are solubilized into the liquid phase of product and the remainder lipid-rich, low nitrogen product is separated into a solid phase. The solid phase (lipid-rich) is then an ideal candidate for biofuel feedstock and the liquid phase, or hydrolysate, can be used for coproducts such as a source of nutrients …

Collaborative Strategies For Sea Level Rise Adaptation In Hampton Roads, Virginia, Carol Considine, Emily Steinhilber

Engineering Technology Faculty Publications

[Introduction] The Hampton Roads region is located in southeastern Virginia where the Chesapeake Bay meets the Atlantic Ocean. The region includes seventeen municipal governments and has a large federal government presence with 26 federal agencies represented (See Figure 1). The region has a population that exceeds 1.7 million and is home to the deepest water harbor on the U.S. East Coast. Hampton Roads' economy is dependent on the local waterways and houses the world's largest naval facility, the sixth largest containerized cargo complex and supports a thriving shipbuilding and repair industry as well as a tourism industry. However, the region's …

Simulated Dynamics Of Soil Water And Pore Vapor In A Semi-Arid Sandy Ecosystem, Shohreh Pedram

Civil & Environmental Engineering Theses & Dissertations

Understanding dynamics of soil water content (SWC) and pore air relative humidity (RHpa), as influenced by wetting-drying cycles, is crucial for sustaining fragile ecosystems of desert lands across the world and needed for improving the prediction accuracy of global climate change. However, to date, such an understanding is still incomplete. The objective of this dissertation was to examine such dynamics at a typical desert site within the Horqin Sandy Land, located in Mongolian Plateau of north China. The examination was done by using a HYDRUS-1D computer simulation model and the continuous sensor-based soil water data for two calendar years. HYDRUS-1D …

Modeling Algae Powered Neighborhood Through Gis And Bim Integration, Florina Dutt, Steven Jige Quan, Erik Woodworth, Daniel Castro-Lacouture, Ben J. Stuart, Perry Pei-Ju Yang

Civil & Environmental Engineering Faculty Publications

This paper aims to propose a modeling method for algae powered neighborhoods through GIS-BIM integration. In the first part of the paper, the applicability of different types of algae systems in an urban neighborhood are studied. The various systems of algae provide different strengths and weakness that affect their performance and suitability for given urban scenarios. Through extensive literature review, the variables that affect the performance of the micro-algae in the built environment are identified, with a focus on flat-panel photo bio-reactors and tubular photobioreactors. A previous GIS model for data management, performance analysis and design of the algae systems …

A Risk Assessment Of The Impacts Of Coastal Flooding And Sea Level Rise On The Existing And New Pump Stations 113, Norfolk, Va, David A. Pezza

Civil & Environmental Engineering Theses & Dissertations

The author assessed the risk to a wastewater pump station and a planned replacement located nearby due to coastal flooding and rising sea levels. The locations for the pump stations are in the Larchmont neighborhood by the Lafayette River tidal estuaries in Norfolk, Virginia. The Lafayette River is a tributary to the Elizabeth River, which flows to the Chesapeake Bay. The low-lying areas along the river are subject to coastal surges caused by tropical and extra-tropical storms that flood the bay.

The region is considered one of the urban areas most exposed to the accelerating rate of rising sea levels. …

Feasibility Of Mainstream Nitrite Oxidizing Bacteria Out-Selection And Anammox Polishing For Enhanced Nitrogen Removal, Pusker Raj Regmi

Civil & Environmental Engineering Theses & Dissertations

Short-cut nitrogen removal avoids nitrite oxidation to nitrate by nitrite oxidizing bacteria (NOB) and allows a) reduction of formed nitrite to nitrogen gas via heterotrophic denitrification and/or b) oxidation of remaining ammonia with formed nitrite to nitrogen gas via anaerobic ammonia oxidation (anammox). The precondition for achieving shortcut nitrogen removal is suppression of NOB, which is favored by warm and high ammonia strength conditions found in internally generated ammonia-rich waste streams through anaerobic digestion of waste solids referred to as sidestreams or reject water. The discovery of anammox bacteria in the mid-1990s, which are capable of transforming NH₄+ …

Dimensionless Criteria For Selecting Tidally-Influenced Advective-Dispersive Desalination Brine Mixing Plume Characterization Models, Alireza Shahvari

Civil & Environmental Engineering Theses & Dissertations

The very nature of requirements for implementing a desalination process is highly spatial due to the need to secure both a source for the operation and sink for brine dilution. Thus, the applicable coastal location is bound to natural tidal mixing characteristics and subjected to a near- or a far-field availability for source and sink. Mixing characteristics of coastal waters are very different from one point to another due to the spatiotemporal tidal characteristic in loco in a manner that it can vary from being highly advective to completely dispersive dominant. Once a location is identified, estimation of corresponding water …

Evaluation Of Hydraulic Conductivity Of Non Aqueous Phase Liquids In Partially Saturated Soils, Chijioke Ekeleme Akamiro

Civil & Environmental Engineering Theses & Dissertations

This study seeks to investigate a problem of predicting the hydraulic conductivity of NAPLs in partially saturated soils and to relate the hydraulic conductivity to basic soil parameters that are either easy to determine or are in wide use. To evaluate hydraulic conductivity in partially saturated soils, previous researchers have focused on flow geometry, soil and chemical properties, etc. used in CHEMFLO program by Nofziger et al., (1989) and saturation equations by such authors as Van Genutchen (1980) and Brooks and Corey (1964). Among those, the soil-water characteristic curve (SWCC) is the most widely used constitutive relations for unsaturated soils …

Analysis Of Primary-Secondary Incident Events On Urban Freeways, Hongbing Zhang

Civil & Environmental Engineering Theses & Dissertations

The objective of this study is to understand the nature of primary and secondary traffic incidents, assess their impacts and explore the implications in traffic operations, safety, and planning. To achieve the objective, a queue-based secondary incident identification method was developed and applied based on detailed incident, traffic and geometric data sets from Hampton Roads, Virginia. This identification method can overcome the limitations in earlier studies and identify secondary incidents in both road directions. An innovative event categorization defines the term "primary-secondary incident event", as one characterized by a primary incident and one or more associated secondary incidents in both …

A Study Of The Correlation Of Sub-Aqueous Beach Profile Change And The Coastal Storm Impulse (Cosi) Parameter, Kevin Bryan Conner

Civil & Environmental Engineering Theses & Dissertations

The Coastal Storm Impulse (COSI) parameter is a recently developed storm-strength parameter that was first introduced at the San Diego, California International Conference of Coastal Engineering in 2006 (ICCE) and further examined in 2008 at the ICCE in Hamburg, Germany. This new parameter used the principles of conservation of horizontal momentum to combine storm characteristics such as surge, wave dynamics, currents, and duration into a relative scale used to classify and measure storm response and impacts. The resultant classification system was intended to evaluate potential coastal erosion and the associated loss of coastal infrastructure, as well as provide a storm …

Application Of The Coastal Storm Impulse (Cosi) Parameter To Predict Coastal Erosion, Robert Aaron Walker

Civil & Environmental Engineering Theses & Dissertations

A new coastal storm-strength parameter, the Coastal Storm Impulse (COSI) parameter, was introduced at the 2006 International Conference of Coastal Engineering (ICCE) in San Diego and further discussed at the ICCE 2008 in Hamburg. COSI is based on the conservation of linear, horizontal momentum to combine storm surge, wave dynamics, and currents over the storm duration. Both tropical storms (hurricanes) and extra-tropical storms (northeasters) can produce similar COSI parameters. Potential implications of such a storm classification system include the evaluation of potential coastal erosion and coastal infrastructure, as well as providing a universal storm strength indicator that is directly tied …

Spatiotemporal Estuarine Water Quality Parameterization Using Remote Sensing And In-Situ Characteristics, Kwisun Park Yu

Civil & Environmental Engineering Theses & Dissertations

This dissertation develops a new paradigm in a water quality monitoring approach to parameterize spatiotemporal estuarine water quality with sustainable reliability, less cost and less time. A key underpinning of this paradigm of the spatiotemporal estuarine water quality parameterization is various water quality parameters' interrelationship with ambient water temperature as a common factor, their time dependent characteristics, and spatiotemporal characteristics of remote sensing. It has two core models to provide input data of water quality parameterization model in a system; the transfer function models of the physical system and an analytical temperature time series model. The objective of this dissertation …

Analysis Of Ultraviolet Energy Distribution In Uv Disinfection Systems Using Monte Carlo Ray -Trace Method, Khoi Trung Nguyen

Civil & Environmental Engineering Theses & Dissertations

Determination of fluence rate in ultraviolet (UV) disinfection systems is a crucial part in evaluating disinfection efficiency of the systems. A robust Monte Carlo Ray Trace (MCRT) method has been developed to determine fluence rates in three-dimensional space of the systems. This is a statistical sampling method in which millions of random light energy bundles are simulated from the axis of each UV lamp and traced through the system until their energies reduce to a minimum threshold level. Inherent phenomena including refraction through quartz tubes, specular reflection at quartz tube surfaces, and absorption by quartz and water, along with specific …

Landfill Leachate Production And Gas Generation Numerical Model, John Edward Riester Jr.

Civil & Environmental Engineering Theses & Dissertations

Numerous processes occur in landfills which lend themselves to modeling. Many of the processes are mutually interdependent. An unsteady numerical model is developed combining the major processes. The three-dimensional moisture transport equations and boundary conditions are solved using an implicit finite difference scheme. The boundaries are determined through a two-dimensional runoff model for the landfill surface and a one-dimensional leachate liner flow model at the bottom of the landfill. The runoff model accounts for evapotranspiration, runoff, infiltration, and leachate recirculation. Richard's equation is solved for saturated and unsaturated vertical flows and Darcy's Equation is solved for lateral flow between adjacent …