Environmental Engineering Commons^™

Functionalized Nanoparticles As Removable Coatings For Reverse Osmosis Membranes, Megan Smith

All Theses

Reverse osmosis (RO) desalination is increasingly used to produce potable water throughout the world. Despite their promising abilities, membrane filtration processes are limited by fouling. Fouling is a broad term for organics, inorganics, colloids and organisms that interact physically, chemically, or biologically with the membrane surface, resulting in reduced flux and shortened membrane lifespan. There is potential to create a snakeskin-like barrier between the membrane and foulants by electrostatically binding a coating material to the membrane that can be released by pH manipulation, removing foulants in the process. The feasibility of using functionalized nanoparticles as removable adsorptive coatings on RO …

Laboratory Characterization And Theoretical Analysis Of Contaminant Mass Transfer, Xiaoling Liu

All Dissertations

Chlorinated volatile organic compounds (CVOCs) in fractured, low permeability material can be a long-term source of groundwater contaminants and they are among the most difficult remediation challenges. Thermal methods are a possible remediation option, where heat is used to boil water and the volatile compounds are stripped out by partitioning into the resulting water vapor. Theoretical analysis indicates that only a small fraction of pore water removal may lead to a significant geometric reduction in the dissolved concentration [(Udell(, 1998]. Previous modeling studies [(Falta and Murdoch(, 2011; (Pruess(, 1983] suggest that a lower permeability limit exists for effective mass transfer …

Impact Of Secondary Treatment Types And Sludge Handling Processes On Estrogen Concentration In Wastewater Sludge, Erica J. Marti

UNLV Theses, Dissertations, Professional Papers, and Capstones

Endocrine-disrupting compounds (EDCs), such as estrogen, are known to be present in the aquatic environment at concentrations that negatively affect fish and other wildlife. Wastewater treatment plants (WWTPs) are major contributors of EDCs into the environment. EDCs are released via effluent discharge and land application of biosolids. Estrogen removal in WWTPs has been studied in the aqueous phase; however, few researchers have determined estrogen concentration in sludge. This study focuses on estrogen concentration in wastewater sludge as a result of secondary treatment types and sludge handling processes. Grab samples were collected before and after multiple treatment steps at two WWTPs …

Hydrologic Evaluation Of Established Rain Gardens In Lincoln, Nebraska, Andrew R. Anderson, Thomas G. Franti, David P. Shelton

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Increased urbanization has resulted in water quality and flooding problems for many receiving waters in the United States. Rain gardens are one type of best management practice commonly used in low impact development (LID). Many studies have evaluated large engineered bioretention cells in research settings. There is little information on the effectiveness of homeowner-maintained rain gardens that rely on deep percolation as the method for water exfiltration. Repeatable controlled experiments are very rare in hydrologic studies due to the inherent variability of weather data. The objective of this study was to evaluate the hydrologic properties of twelve established rain gardens …

Recovery Of Sensitive Watersheds In The Northeastern United States From Chronic Acidification: The Role Of Soil Chemistry, Chris E. Johnson

Civil and Environmental Engineering - All Scholarship

No abstract provided.

Developing Archetypes For Domestic Dwellings:An Irish Case Study, Albert Famuyibo, Aidan Duffy, Paul Strachan

Articles

Stock modelling, based on representative archetypes, is a promising tool for exploring areas for resource and emission reductions in the residential sector. The use of archetypes developed using detailed statistical analysis (multi-linear regression analysis, clustering and descriptive statistics) rather than traditional qualitative techniques allows a more accurate representation of the overall building stock variability in terms of geometric form, constructional materials and operation. This paper presents a methodology for the development of archetypes based on information from literature and a sample of detailed energy-related housing data. The methodology involves a literature review of studies to identify the most important variables …

Preservation Of Methanogenic Cultures To Enhance Anaerobic Digestion, Ujwal H. Bhattad

Dissertations (1934 -)

The use of anaerobic biotechnology is increasing as a sustainable process to treat various organic wastes. Methanogens convert organic COD into CH4 and play the key role to drive thermodynamically unfavorable biochemical fermentation reactions and keep the digestion process steady and efficient. Progressive understanding of anaerobic microbiology with digester functionality may help to develop efficient, customized methanogenic cultures to enhance anaerobic bioprocesses. Preservation of methanogenic cultures via drying would be a cost-effective option for research and practical applications. However, preservation of methanogenic cultures is challenging due to methanogen sensitivity to O2 toxicity and drying, and very limited work is reported …

Relating Methanogen Community Structure And Function In Anaerobic Digesters, Benjamin T.W. Bocher

Dissertations (1934 -)

A deeper understanding of how microbial community structure relates to process function would help improve anaerobic digester design. This dissertation describes both qualitative and quantitative relationships between anaerobic digester function and microbial community structure. Community structure was characterized using banding pattern intensities from denaturing gradient gel electrophoresis (DGGE) for the mcrA gene of methanogenic Archaea. The first project compared a single-stage continuously mixed stirred tank reactor (CSTR) and staging with an acidogenic CSTR followed by a methanogenic CSTR. After seeding with the same biomass, these unique process configurations exhibited different function and qualitatively different methanogen communities. Compared to a single-stage …

Using Life Cycle Assessment Methods To Guide Architectural Decision-Making For Sustainable Prefabricated Modular Buildings, Jeremy Faludi, Michael Lepech, George Loisos

Dartmouth Scholarship

Within this work, life cycle assessment modeling is used to determine top design priorities and quantitatively inform sustainable design decision-making for a prefabricated modular building. A case-study life-cycle assessment was performed for a 5,000 ft² prefabricated commercial building constructed in San Francisco, California, and scenario analysis was run examining the life cycle environmental impacts of various energy and material design substitutions, and a structural design change. Results show that even for a highly energy-efficient modular building, the top design priority is still minimizing operational energy impacts, since this strongly dominates the building life cycle's environmental impacts. However, as an …

Estimating Annual Precipitation For The Colorado River Basin Using Oceanic-Atmospheric Oscillations, Ajay Kalra, Sajjad Ahmad

Civil and Environmental Engineering and Construction Faculty Research

Estimating long-lead time precipitation under the stress of increased climatic variability is a challenging task in the field of hydrology. A modified Support Vector Machine (SVM) based framework is proposed to estimate annual precipitation using oceanic-atmospheric oscillations. Oceanic-atmospheric oscillations, consisting of Pacific Decadal Oscillation (PDO), North Atlantic Oscillation (NAO), Atlantic Multidecadal Oscillation (AMO), and El Niño–Southern Oscillation (ENSO) for a period of 1900–2008, are used to generate annual precipitation estimates with a 1 year lead time. The SVM model is applied to 17 climate divisions encompassing the Colorado River Basin in the western United States. The overall results revealed that …

Flexible Urban Drainage Systems In New Land-Use Areas, Jochen Eckart

USF Tampa Graduate Theses and Dissertations

Urban drainage systems are influenced by several future drivers that affect the performance as well as the costs of the systems. The uncertainties associated with future drivers and their impact creates difficulties in designing urban drainage systems sustainably. A review of the different future drivers for urban drainage systems illustrates that no sufficient future predictions for the long operational life spans of the systems are possible. This dissertation contends that to deal with future uncertainties, flexibility in urban drainage systems is necessary.

At present, profound insights about defining, measuring, and generating flexible urban drainage systems do not exist. This research …

Rainfall Organization And Geomorphologic Controls On The Flood Response Of Mild-Slope Basins In The South Atlantic Region Of Us, Yiwen Mei

Master's Theses

This study uses data from the Tar-River Basin in North Carolina to explore how space-time rainfall variability influences the hydrologic response from observational and modeling perspectives. For understanding the basin scale effect, the Tar-River Basin is divided into four cascade sub-basins ranging from 1106 km² up to 5654 km². The study evaluates the catchments’ response to rainfall for a large number of storm events by computing the event runoff coefficient based on streamflow observations and through simulations from a semi-distributed hydrological model. Comparison of observed to simulated hydrographs from the hydrological model shows that distributed rainfall forcing …

Concentration Effects And Ion Properties Controlling The Fractionation Of Halides During Aerosol Formation, Marcelo I. Guzman, Richa R. Athalye, Jose M. Rodriguez

Chemistry Faculty Publications

During the aerosolization process at the sea surface, halides are incorporated into aerosol droplets, where they may play an important role in tropospheric ozone chemistry. Although this process may significantly contribute to the formation of reactive gas phase molecular halogens, little is known about the environmental factors that control how halides selectively accumulate at the air-water interface. In this study, the production of sea spray aerosol is simulated using electrospray ionization (ESI) of 100 nM equimolar solutions of NaCl, NaBr, NaI, NaNO(2), NaNO(3), NaClO(4), and NaIO(4). The microdroplets generated are analyzed by mass spectrometry to study the comparative enrichment of …

Implementation, Design, And Cost Analysis Of A Concrete Washout System, Omar Adina

BioResource and Agricultural Engineering

With the increase of environmental pollution in today’s world, many strategies and regulations are being enforced. These enforcements come from the state and federal governments, but public awareness is often overlooked. Stormwater regulations here in California have dramatically changed over the last decade, as the topic is investigated more often.

This senior project encompassed the design prototype and cost analysis of a permanent concrete washout station for the BioResource and Agricultural Engineering Department at California Polytechnic State University, San Luis Obispo. The design parameters given were to construct a steel bin for the excess concrete to be dumped into during …

Using Ground Penetrating Radar Signal Reflection To Model A Highly Transmissive Bedrock Aquifer, Daniel J. Brockmeyer Mr.

Master's Theses

The use of numerical modeling software to characterize groundwater contaminant fate and transport requires an understanding of the distribution of hydraulic properties of the aquifer. As the complexity of this distribution increases, a more sophisticated understanding is required. Modeling contaminant transport in bedrock aquifers requires that the spatial distributions of highly conductive geologic features are characterized along with the hydraulic transmissivities of those features (Shapiro, 2003). The goal of this research is to refine the numerical model of a highly transmissive crystalline aquifer by characterizing the spatial variability of the hydraulic transmissivity using the attenuation of the ground penetrating radar …

College Of Engineering Senior Design Competition Spring 2018, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Part of every UNLV engineering student’s academic experience, the senior design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. A capstone to the student’s educational career, the senior design project encourages the student to use everything learned in the engineering program to create a practical, real world solution to an engineering challenge. The senior design competition helps focus the senior students in increasing the quality and potential for commercial application for their design projects. Judges from local industry evaluate the projects on …

Surface Mass Transfer In Large Eddy Simulation (Les) Of Langmuir Turbulence, Cigdem Akan

USF Tampa Graduate Theses and Dissertations

Over the past century the study of gas exchange rates between the atmosphere and the ocean has received increased attention because of concern about the fate of greenhouse gases such as CO₂ released into the atmosphere. Of interest is the oceanic uptake of CO₂ in shallow water coastal regions as biological productivity in these regions is on average about three times larger than in the open ocean. It is well-known that in the absence of breaking surface waves, the water side turbulence controls gas transfer of sparingly soluble gases such as CO₂ from the air to the …

Evaluation Of An Enrichment Culture That Reductively Dechlorinates Γ-Hexachlorocyclohexane, Christina Anderson

All Theses

In a previous study using microcosms from a site contaminated with γ- hexachlorocyclohexane (γ-HCH), rapid anaerobic biodegradation of γ-HCH to benzene and chlorobenzene was observed. Enrichment cultures were developed and subsequently transferred to an anaerobic sulfate-free HEPES buffered medium without loss of γ-HCH dechlorination, thus suggesting γ-HCH undergoes anaerobic biodegradation via chlororespiration. The overall objective of this thesis was to further characterize the enrichment culture.
To do so, one specific objective was to determine the effect of vancomycin on γ-HCH in an enrichment culture grown in a sulfate-free HEPES buffered medium using hydrogen as the electron donor. This objective would …

Synergy Of Alum And Chlorine Dioxide For Curbing Disinfection Byproduct Formation Potential At Central Arkansas Water, Corey W. Granderson

Graduate Theses and Dissertations

Central Arkansas Water (CAW), the water utility for Little Rock, AR, draws their source water from Lake Maumelle and Lake Winona. To curb disinfection byproduct (DBP) formation, CAW has begun retrofitting their two plants to use chlorine dioxide as an alternative primary disinfectant followed by free chlorine secondary disinfection in the distribution system. In this study, fluorescence parallel factor (PARAFAC) analysis was combined with free chlorine simulated distribution system (SDS) tests and DBP formation potential (DBPFP) tests to study the benefit of chlorine dioxide primary disinfection (CDPD) with alum coagulation. Of the DBPs screened, trichloromethane (TCM) was formed in highest …

Application Of Microbial Fuel Cells In A Forested Wetland, Jianing Dai

All Theses

ABSTRACT
Electricity can be generated from forest residues, especially the organic matter from litter fall, in freshwater forested wetland environments with a microbial fuel cell (MFC) system. Electricity generation efficiency was examined for cypress, tupelo, and pine litter extracts, using dual-chamber reactors. The maximum power density generated with cypress extracts was on the level of 320 mW/m2, higher than tupelo (230 mW/m2), and pine (210 mW/m2). The efficacy of cypress extracts was also higher than tupelo and
pine, demonstrating that organic matter from cypress litter is a preferred substrate for electricity generation with MFCs. Meanwhile, low aromaticity of the substrate …