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Resource Recovery Through Halophyte Production In Marine Aquaponics: An Evaluation Of The Nutrient Cycling And The Environmental Sustainability Of Aquaponics, Suzanne Boxman

USF Tampa Graduate Theses and Dissertations

Aquaculture, the farming of aquatic animals and plants, is an important component of global food production, which supplies a nutritious protein source for millions of people. Interest in improving the sustainability of aquaculture has led to the development of aquaponics in which fish production is combined with plant production to create zero-discharge systems. A need for more fundamental science and engineering research on marine aquaculture and growing interest in production of halophytes motivated this novel research on marine aquaponics. One objective was to evaluate the growth and nutrient removal capacity of halophytes in marine aquaponics. Bench-scale studies were conducted to …

Ammonium Removal From High Strength Wastewater Using A Hybrid Ion Exchange Biological Process, Veronica Ester Aponte-Morales

USF Tampa Graduate Theses and Dissertations

Anaerobic digestion (AD) has been shown to be an effective technique for energy recovery and stabilization of livestock wastes, municipal sludges and industrial wastewaters. However, further treatment is required to remove nitrogen from AD effluents to avoid detriments to surface and ground waters. The high free ammonia (FA) concentrations present in AD effluents can inhibit nitrification processes in conventional biological nitrogen removal (BNR) systems. The overall goal of this research was to develop a process for removal of nitrogen from AD swine waste (ADSW) effluent. The proposed solution was to incorporate particulate chabazite, which has a high cation exchange capacity, …

Pathogen Removal In Natural Wastewater Treatment And Resource Recovery Systems: Solutions For Small Cities In An Urbanizing World, Matthew Eric Verbyla

USF Tampa Graduate Theses and Dissertations

Sanitation, renewable energy, and food security are among the most pressing global development needs of the century, especially for small cities with rapid population growth. Currently, 53% of the world’s population either lacks access to improved sanitation or discharges fecal waste to the environment without treatment. Furthermore, 80% of food consumed in developing regions is produced by 500 million small farms, and while many of them are still rain-fed, irrigated agriculture is increasing. The post-2015 Sustainable Development Goals, recently adopted by the United Nations, include targets to address the water-energy-food nexus. Wastewater reuse in agriculture can be an important solution …

Corrosion Of Steel In Submerged Concrete Structures, Michael Thomas Walsh

USF Tampa Graduate Theses and Dissertations

This investigation determined that severe corrosion of steel can occur in the submerged portions of reinforced concrete structures in marine environments. Field studies of decommissioned pilings from actual bridges revealed multiple instances of strong corrosion localization, showing appreciable local loss of steel cross-section. Quantitative understanding of the phenomenon and its causes was developed and articulated in the form of a predictive model. The predictive model output was consistent with both the corrosion rate estimates and the extent of corrosion localization observed in the field observations. The most likely explanation for the observed phenomena that emerged from the understanding and modeling …

Effect Of Mineral And Chemical Admixtures On Durability Of Cementitious Systems, Victor Tran

USF Tampa Graduate Theses and Dissertations

Mineral and chemical admixtures are used today in almost all concrete mixtures to improve concrete fresh and hardened properties, and to enhance concrete durability. In this study, four mineral and four chemical admixtures were investigated: namely, metakaolin (MK), silica fume (SF), Class F fly ash (FA), blast-furnace slag (BFS), two high-range water reducers (SP), water reducer/retarder (WRD), and air-entrainer (AEA). The objective of this study is to assess the effects of commonly used mineral and chemical admixtures on the durability of the cementitious system. Two durability issues were addressed in this study: the potential of the cementitious system to generate …

Evaluating Corrosion Resistance Of Reinforcing Steel In A Novel Green Concrete, Andrea Carolina Ramirez

USF Tampa Graduate Theses and Dissertations

Reinforced concrete structures are expected to have a long service life with minimal maintenance. Corrosion of reinforcing steel is a major factor in reducing concrete structure lifespan, as corrosion products occupy a larger volume than that of the consumed steel and generate tensile stresses that crack the concrete cover. Procedures to control corrosion in traditional concrete, which is made with Portland-cement (PC), have been well established. However, in recent years novel concrete materials based on alternatives to normally cured PC have been developed in response to global needs to reduce greenhouse gases emissions. In particular, a promising new cement has …

Evaluation Of Low-Cost Low Impact Development Practices In Southwest Florida For The Control Of Urban Runoff, Laura Kathren Rankin

USF Tampa Graduate Theses and Dissertations

Stormwater management is required due to development and alteration of the natural environment. It is heavily regulated in Florida and at the national level. Over the last two decades, Low Impact Development (LID) has been promoted as a sustainable and environmentally friendly method of controlling urban runoff. Case studies, provided in Chapter 2, show that LIDs can restore watershed hydrology by balancing the water budget. The difference in runoff between pre-development and post-development appears to increase with soil perviousness. However, the potential for mitigating the impacts of urbanization through runoff reduction is also greater for pervious, sandy soils that dominate …

Feasibility Of Cathodic Protection In Grouted Post Tensioned Tendons - Exploratory Model Calculations, Jacob Dharma Bumgardner

USF Tampa Graduate Theses and Dissertations

Recent corrosion related failures of grouted post tensioned tendons, even after the introduction of improved grouts, have led to renewed interest in supplemental or backup means of corrosion control for these systems. A finite element model is presented to explore feasibility of impressed current cathodic protection of strand in grouted tendons. The model examines polarization evolution as function of service time and includes consideration of anode placement and size, grout porosity, pore water alkalinity, electrochemical species diffusivity and applied voltage on the polarization efficacy and durability of such a system. The exploratory model projections suggested that, within the context of …

Consumer Perception And Anticipated Adoption Of Autonomous Vehicle Technology: Results From Multi-Population Surveys, Nikhil Menon

USF Tampa Graduate Theses and Dissertations

Emerging automotive and transportation technologies, such as autonomous vehicles (AVs) have created revolutionary possibilities in the way we might travel in the future. Major car manufacturers and technology giants have demonstrated significant progress in advancing and testing AV technologies in real-life traffic conditions.

Results from multi-population surveys indicate that despite enjoying moderate familiarity with AVs, more than 40% of the respondents were likely to use them when they become available. Simply looking at the demographic differences without paying any regard to the perceptions might suggest that the demographic differences are the primary causal factors behind the differences observed in the …

Binding Of Nitrite In Concrete, Cement Mortar And Paste, Saad Alshehri

USF Tampa Graduate Theses and Dissertations

Calcium nitrite as a corrosion inhibitor is mainly used to protect steel reinforcement in concrete by reducing its corrosion rate. Hence the effectiveness of calcium nitrite depends on its availability as a free nitrite in the pore solution. The present research work aims to determine the concrete mixture component mostly responsible for nitrite binding in concrete. Firstly, the experimental program included testing of nitrite binding in cement paste. Secondly, the effect of adding the fine aggregate (mortar mix) on nitrite binding was assessed. Finally, the mix with coarse aggregate (concrete mix) was evaluated. In-situ leaching method was used to obtain …

Kelvin Probe Electrode For Field Detection Of Corrosion Of Steel In Concrete, Leonidas Philip Emmenegger

USF Tampa Graduate Theses and Dissertations

While the Kelvin Probe (KP) has been used in a variety of surface scanning applications, the use of the KP in reinforced concrete structures to detect corrosion has been pioneered by previous work performed at the University of South Florida. However, in that work, the scale and construction of the probes was not suited to use in the field. This is primarily attributable to the small operating disk-to-concrete gap which would make the probe unable to accommodate road conditions, such as irregularities in the grading of the road, and local pitting of the surface. Therefore, it was important to investigate …

Prediction Of The Optimum Binder Content Of Open-Graded Friction Course Mixtures Using Digital Image Processing, Yolibeth Mejias De Pernia

USF Tampa Graduate Theses and Dissertations

Florida Department of Transportation (FDOT) has been using Open Graded Friction Course (OGFC) mixture to improve skid resistance of asphalt pavements under wet weather. The OGFC mixture design strongly depends on the Optimum Binder Content (OBC) which represents if the mixture has sufficient bonding between the aggregate and asphalt binder. At present, the FDOT designs OGFC mixtures using a pie plate visual draindown method (FM 5-588). In this method, the OBC is determined based on visual inspection of the asphalt binder draindown (ABD) configuration of three OGFC samples placed on pie plates with pre-determined trial asphalt binder contents (AC). The …

High-Solids Anaerobic Digestion Of The Organic Fraction Of Municipal Solid Waste State Of The Art, Outlook In Florida, And Enhancing Methane Yields From Lignocellulosic Wastes, Gregory Richard Hinds

USF Tampa Graduate Theses and Dissertations

Anaerobic digestion (AD) is a biotechnology that employs natural microbial metabolism under oxygen-free conditions to stabilize organic waste. AD has been shown to be the most environmentally sustainable technology for treating the organic fraction of municipal solid waste (OFMSW), as it allows for the recovery of energy and nutrients from the waste. AD of OFMSW also saves landfill space and reduces leachate generation and fugitive methane emissions from landfills. High-solids AD (HS-AD) technologies (those designed to process feedstocks with >15% total solids content) have been shown to yield additional benefits when compared with liquid AD (L-AD) for treating OFMSW, including …

Evaluation Of First Order Error Induced By Conservative-Tracer Temperature Approximation For Mixing In Karstic Flow, Philippe Machetel, David A. Yuen

Sinkhole Conference 2015

Fluid dynamics in karst systems is complex due to the heterogeneity of hydraulic networks that combine the Porous Fractured Matrix (PFM) and the interconnected drains (CS). These complex dynamic systems often need to be treated as “black boxes” in which only input and output properties are known. In this work, we propose to assess the first-order error induced by considering the temperature as a conservative tracer for flows mixing in karst (fluvio-karst). The fluvio-karstic system is treated as an open thermodynamic system (OTS), which exchanges water and heat with its surrounding. We propose to use a cylindrical PFM drained by …

Numerical Simulation Of Karst Soil Cave Evolution, Long Jia, Yan Meng, Zhende Guan, Lipeng Liu

Sinkhole Conference 2015

This study is focused on numerical simulation of the formation and development of karst soil caves related to cover-collapse sinkholes. The so-called ‘karst soil cave’ refers to the caves formed in the soil layers above bedrock of sinkhole regions. Because the soil caves are formed and developed under groundwater seepage, studying groundwater level changes can help understand soil cave development and collapse. Based on the improved Terzaghi loosening pressure theory and using excess pore water pressure, two kinds of critical groundwater level decline are discussed. The first, denoted as ∆H0, is the critical groundwater level decline related to soil cave …

Building Codes To Minimize Cover Collapses In Sinkhole-Prone Areas, George Veni, Connie Campbell Brashear, Andrew Glasbrenner

Sinkhole Conference 2015

Cover- collapse sinkholes are forming with increasing frequency under buildings. Analyses of sinkhole distribution in Beacon Woods, Florida, preliminarily indicate their occurrence is an order of magnitude greater in urban versus undeveloped areas, suggesting the structures themselves are enhancing the collapse process. The most likely causes are induced recharge via at least one of two sources. First, runoff and drainage from roads, structures, and impoundments that is not adequately dispersed will promote sinkhole development. Second, leaking water, sewer, and septic systems beneath or adjacent to a structure will also promote collapse. The process of cover-collapse from induced recharge is well …

Hazard Of Sinkhole Flooding To A Cave Hominin Site And Its Control Countermeasures In A Tower Karst Area, South China, Fang Guo, Guanghui Jiang, Kwong Fai Andrew Lo, Qingjia Tang, Yongli Guo, Shaohua Liu

Sinkhole Conference 2015

Zengpiyan Cave, one of the most important cave hominin sites of the Neolithic in the South of China, was listed on the national register of cultural preservation sites in 2001. Large quantities of precious material in the Zengpiyan site were unearthed since the beginning of the trial excavation in 1973. These materials include hominin skeletal remains, fire pits, human burials, stone implements, tools fashioned from mollusk shells and animal or plant fossils. According to the historical record, ancient people lived in caves in the karst plain of Guilin. They moved out of the caves approximately 7000 years ago. These cave …

A Method Of Mapping Sinkhole Susceptibility Using A Geographic Information System: A Case Study For Interstates In The Karst Counties Of Virginia, Alexandra L. Todd, Lindsay Ivey-Burden

Sinkhole Conference 2015

Karst terrain is landscape underlain by limestone that has been chemically dissolved by acidic groundwater, producing subsurface voids that pose risks for sinkholes if the overlaying soils can no longer support their own weight and collapse. The western counties of Virginia are heavy in karst due to their natural, geographic boundary of the western Ridge Province and the eastern Blue Ridge Mountain Range. As a result, the Commonwealth of Virginia Hazard Mitigation Plan recommends that the Virginia Department of Transportation (VDOT) develop a method to determine the roadways and regions most susceptible to experiencing sinkholes, in an effort to reduce …

Evaluation Of Cavity Distribution Using Point-Pattern Analysis, Raghav Ramanathan, Yongli Gao, M. Melih Demirkan, Bulent Hatipoglu, Mazen Adib, Michael Rosenmeier, Juan Gutierrez, Hesham El Ganainy

Sinkhole Conference 2015

Presence of solution cavities of different sizes poses major engineering problems in some areas of Abu Dhabi City Municipality (ADM) underlain by soluble rocks such as gypsum, calcarenite, or mudstone. This is especially critical if they are located at a relatively shallow level and are likely to cause settlement or sudden soil collapse. The Gachsaran Formation, which is composed of interlayered mudstone and gypsum, underlies all of the ADM and is known to be vulnerable to cavity formation in the area. The mudstone and gypsum beds within the upper part of the Gachsaran Formation are prone to dissolution. Numerous sinkholes …

Development Of Cavity Probability Map For Abu Dhabi Municipality, Yongli Gao, Raghav Ramanathan, Bulent Hatigoplu, M. Melih Demirkan, Mazen Adib, Juan Gutierrez, Hesham El Ganainy, Daniel Barton

Sinkhole Conference 2015

Cavity collapse and settlement due to the presence of shallow solution cavities cause significant geotechnical and other engineering problems in certain areas within the Abu Dhabi City Municipality (ADM). A cavity probability map helps to identify regions that are more susceptible to the formation of cavities by identifying and analyzing influential factors contributing to its formation. Information relating to cavities was cataloged and reviewed based on available data from the Geotechnical Information Management System (GIMS), which is a consolidated geotechnical database developed by the ADM. Geological and geotechnical subsurface conditions are obtained from previous site investigation campaigns performed in the …

Study On Monitoring And Early Warning Of Karst Collapse Based On Botdr Technique, Zhende Guan

Sinkhole Conference 2015

Brilliouin Optical Time Domain Reflectometer (BOTDR) is a newly developed measurement and monitoring technique, which utilizes Brilliouin spectroscopy and Optical Time Domain Reflectometer (Jiang et al., 2006; Zhang et al., 2009; Xu et al.,2011) to measure strain generated in optical fibers as distributed in the longitudinal direction. This paper introduces the principle and characters of BOTDR technique firstly, and makes an example of karst collapse monitoring at section K14 of highway from Guilin to Yangshuo. And we talk about how to use this technique in underlying karst collapse monitoring in karst highway, discuss environmental factors, like temperature and vehicle dynamic …

Down The Rabbit Hole: Identifying Physical Controls On Sinkhole Formation In The Uk, Tamsin Green

Sinkhole Conference 2015

Heavy precipitation in the UK in February 2014 induced ground subsidence and consequently a rapid increase in the frequency of sinkhole occurrences. These new sinkhole collapses emphasise the need to further analyse the causes of the increased occurrence by investigating the relative importance of various surficial factors. Malham and the Mendips are two areas of particular interest, since both are underlain by limestone bedrock and are susceptible to subsidence. This is due to limestone being primarily permeable in joints, and so it dissolves to form an extensive network of karstic caves. It was therefore useful to compare two sites of …

Successful Foundation Preparations In Karst Bedrock Of The Masonry Section Of Wolf Creek Dam, David M. Robison

Sinkhole Conference 2015

Extensive foundation preparations during construction of the Wolf Creek Dam concrete masonry section precluded the need for additional rehabilitation to mitigate seepage through karstic limestone bedrock. Wolf Creek Dam on the Cumberland River in southern Kentucky has become well known for karst related seepage issues underneath the embankment section, and yet has had little to no seepage issues associated with the concrete masonry portion of the dam. Post-construction efforts to control seepage underneath the embankment began in 1967 and 1968. Emergency grouting commenced and continued through 1970. Between 1975 and 1979 a more permanent solution of a concrete diaphragm cut-off …

Pre-Construction Rock Treatment And Soil Modification Program Using Low Mobility Grout To Mitigate Future Sinkhole Development In A 2,787.1 Square Meter (30,000 Sf) Maintenance Facility, Steven W. Shifflett

Sinkhole Conference 2015

The US Army required construction of a 2,787.1 square meters (30,000 sf) maintenance facility supported on shallow foundations at the Fort Campbell Military Installation. During the subsurface investigation a seven foot air-filled void was encountered in the bedrock within the building footprint. Electrical Resistivity Imaging (ERI) was conducted in an attempt to determine the lateral extent of the encountered void and to establish the general prevalence of karst features at the site. Due to uncertainty in the subsurface conditions, a rock treatment and soil modification program was developed which consisted of a series of targeted exploratory grout holes advanced in …

Monitoring The Threat Of Sinkhole Formation Under A Portion Of Us 18 In Cerro Gordo County, Iowa Using Tdr Measurements, Kevin O'Connor, Matthew Trainum

Sinkhole Conference 2015

Sinkhole formation is a common occurrence in northeast Iowa, and U.S. 18 in Cerro Gordo County was constructed over an area where sinkhole formation had only been locally known. It had not been recorded or identified in the Iowa DNR database at the time. Since 2004, sinkholes have developed along the right of way. Geophysical surveys contributed very little in the identifying the cause. However a Soil Survey (drilling program) identified numerous voids within carbonate bedrock. The soil borings indicated that shale overlying the carbonate rock has been removed/eroded, and resulted in the development of a karst subsurface through the …

Sinkhole Physical Models To Simulate And Investigate Sinkhole Collapses, Mohamed Alrowaimi, Hae-Bum Yun, Manoj Chopra

Sinkhole Conference 2015

Florida is one of the most susceptible states for sinkhole collapses due to its karst geology. In Florida, sinkholes are mainly classified as cover subsidence sinkholes that result in a gradual collapse with possible surface signs, and cover collapse sinkholes, which collapse in a sudden and often catastrophic manner. The future development of a reliable sinkhole prediction system will have the potential to minimize the risk to life, and reduce delays in construction due to the need for post-collapse remediation. In this study, different versions of small-scale sinkhole physical models experimentally used to monitor the water levels in a network …

Spatiotemporal Response Of Cvoc Contamination And Remedial Actions In Eogenetic Karst Aquifers, Ingrid Y. Padilla, Vilda L. Rivera, Celys Irizarry

Sinkhole Conference 2015

The northern karst region of Puerto Rico has a long and extensive history of toxic spills, chemical waste, and industrial solvent release into the subsurface. High potential for exposure in the region has prompted aggressive remediation measures, which have extended for over 40 years. Of particular concern is contamination with chlorinated volatile organic compounds (CVOCs) because of their ubiquitous presence and potential health impacts. This work evaluates historical groundwater quality data to assess the spatiotemporal distribution of CVOC contamination in the karst aquifer system of northern Puerto Rico, and its response to remedial action in two superfund sites contaminated with …

Seeps And Springs At A Platteville “Observatory” On The River Bluffs, Bj Bonin, Greg Brick, Julia R. Steenberg

Sinkhole Conference 2015

Residential building construction along the Mississippi River bluffs in the 1970s created a unique enclosed outcrop of the Late Ordovician Platteville Formation at Lilydale, Minnesota. This outcrop was examined in early 2013 after a newly-formed spring flooded an elevator shaft the previous year, drawing attention to the foundation conditions. The Lexington Riverside property is a six story condominium complex constructed within the top of the bluff. A two-level underground parking garage was built into the bluff. Bedrock was mechanically excavated to accommodate the construction of the building, creating an unweathered rock surface. The space between the structure and the excavated …

Karst Spring Cutoffs, Cave Tiers, And Sinking Stream Basins Correlated To Fluvial Base Level Decline In South-Central Indiana, Garre A. Conner

Sinkhole Conference 2015

The Mitchell Aquifer averages 80m in thickness and underdrains a karst region in the Crawford Upland and Mitchell Plateau region in south-central Indiana (110,000 km2). The Springville Escarpment is a transitional boundary between the upland and plateau. Cave stream linking between cave tiers in the aquifer and correlation of cave tier inception horizons to a base level decline surface is interpreted for the Kirby Watershed, encompassing the prekarst headland of Indian Creek (42km2). The watershed was severed from lower Indian Creek at Eller Col by limestone cavern drainage on the ridge between White River and East Fork. Correlation of recharge …

Tracer Studies Conducted Nearly Two Decades Apart Elucidate Groundwater Movement Through A Karst Aquifer In The Frederick Valley Of Maryland, Keith A. White, Michael K. Cobb, Thomas Aley, Ethan Weikel

Sinkhole Conference 2015

A pair of groundwater tracer studies at a single karst test site were completed 18 years apart. The results of these studies have provided evidence of both relatively rapid advective transport via conduits and an extreme capacity for dye storage and retardation. The tracer results, coupled with other subsurface investigation data, are used to develop a conceptual model for groundwater movement through this karst aquifer in the Frederick Valley of Maryland, as well as identify implications for remediation. Three fluorescent tracer dyes used in the initial study were detected in several background monitoring locations established for the second study conducted …