Engineering Commons^™

A One-Dimensional Analysis Of A Microbial Fuel Cell For Efficient Acetate Removal And Power Density Output, David Rouhani

UNLV Theses, Dissertations, Professional Papers, and Capstones

Microbial fuel cells (MFCs) are electrochemical devices that utilize microorganisms to convert organic matter into electrical energy. MFCs have been discussed to have potential application for sustainable wastewater treatment due to their ability to generate electricity while simultaneously treating contaminated water. To optimize MFC performance, numerical models can be used to understand the complex electrochemical and biological processes occurring in the system. In this study, a numerical model was developed to simulate the performance of MFCs under varying operating conditions and to investigate the performance of a MFC for treating wastewater fuel. More specifically, the MFC was modeled to oxidize …

Investigating Haloacetonitrile (Han) Formation Potential From Nitrogenous Antibiotics And Agrochemicals, Kazi Shafayet Haider

UNLV Theses, Dissertations, Professional Papers, and Capstones

Disinfection can promote safe drinking water. Chlorine and chloramines are the two most used disinfectants. While these disinfectants are effective in inactivating disease-causing pathogens, they also produce hazardous byproducts when they react with organic compounds (precursors). Nitrogenous disinfection byproducts (N-DBPs) are more toxic than their counterparts. The increased use of nitrogen-based agrochemicals and antibitics has led to their detection in different water sources. The presence of secondary amine and aniline in these compounds can act as a source of reactive nitrogen to form N-DBPs. In addition, the increased concentration of bromide in water systems due to anthropogenic activities can enhance …

Nexuscapes: A Landscape Approach For A Transdisciplinary Water-Energy-Food Nexus Decision-Making Process, Fortino Acosta

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study develops a reliable transdisciplinary framework for complex ecological and social systems by characterizing, mapping, typifying, assessing, and testing enhanced water-energy-food nexus scenarios under critical time constraints, specialized skills, or sensitive data accessibility. Detached management of limited essential resources like fresh water, reliable energy from renewable sources, and nutritious food can jeopardize regional economies and governance. Using a novel landscape approach, this study recommends a decision-making the framework focused on the circular economy that induces collaboration among diverse sectors and brings strategic coordination, specificity, and magnitude to the proposed solutions. The study elaborates on a decision-making tool that integrates …

Application Of Lanthanides In Wastewater Treatment And Water Reuse, George William Kajjumba

UNLV Theses, Dissertations, Professional Papers, and Capstones

Much of the world’s population feed on grains (wheat, rice, and corn). Corn is as sensitive as it is productive. This thirsty, fast-growing plant goes into thermal shock in drought. In 2014, California lost over $2.2 billion in crop production due to drought. The Horn of Africa (in 2011) and Sahel (in 2012) faced humanitarian disasters due to food and water scarcity. The higher frequency of climate change and the erratic nature of rain, combined with underlying economic and social vulnerabilities, has meant that food and water scarcity is here to stay. To improve food and water scarcity, water reclamation …

Quaternary Ammonium Compounds As Precursors To Disinfection Byproducts, Padmanabhan Krishnaswamy

UNLV Theses, Dissertations, Professional Papers, and Capstones

Disinfection of drinking water is crucial for providing a safe potable water supply. Some of the most common disinfectants employed are chlorine, chloramines and ozone. While these disinfectants successfully inactivate pathogenic microorganisms, they simultaneously react with inorganic or organic precursors to form toxic byproducts, most commonly referred to as disinfection byproducts (DBPs). While there is a wide variety of organic matter and disinfection byproducts known, in this study we have looked into the potential of certain quaternary ammonium compounds (QACs) to act as precursors to form DBPs, namely trihalomethanes (THMs), haloacetonitriles (HANs) and nitrosamines.

The ubiquitous nature of QACs in …

Investigation Of Bench-Scale Packed Bioreactor For Perchlorate Reduction In The Presence Of Co-Contaminants And High Salinity, Julia Ribeiro Rabello

UNLV Theses, Dissertations, Professional Papers, and Capstones

Perchlorate (ClO4-), commonly found as a salt, is naturally occurring in nature and is found in natural nitrate deposits (such as the Chilean nitrate). Perchlorate anion is considered an inhibitor of iodine by the thyroid gland, reducing the production of thyroid hormones. The latest action by the USEPA was to not determine a national drinking water standard for perchlorate. However, the states still have their own regulations on perchlorate concentration in drinking water. Contaminated sites with high concentrations of perchlorate (ppm levels) are associated with historic perchlorate manufacture and use, while those with low concentrations (ppb levels) are found in …

High Salinity, High Concentration Perchlorate Reduction In The Presence Of Hexavalent Chromium, Nitrate, And Chlorate, Nicole Martin

UNLV Theses, Dissertations, Professional Papers, and Capstones

Perchlorate is a chemically stable anion which was used as an oxidizer in rocket propellant and explosives throughout the 1950’s and 1960’s. While natural sources of perchlorate exist, perchlorate in the environment is primarily a result of contamination from anthropogenic processes. Perchlorate contamination has now been identified in at least 45 states and is hazard to human health due to perchlorate’s ability to interfere with uptake of iodine in the thyroid gland. One of the most common and cost effective treatment methods for perchlorate remediation is biological reduction—utilizing bacteria to enzymatically reduce perchlorate into chloride and oxygen.

The purpose of …

Acoustic Sonolysis Of Antibiotics In Water, Natalie Pinon

UNLV Theses, Dissertations, Professional Papers, and Capstones

Antibiotic resistance is a prominent issue in the world today. It is said by the Centers for Disease Control and Prevention that it is one of the major public health challenges we face today. Predominantly, antibiotic resistance is growing because conventional wastewater treatment processes are not able to completely break down antibiotics. As bacteria are exposed to such antibiotics, which don’t kill them due to selective pressure, they become immune and develop resistance which is a huge health concern. To prevent this from occurring, antibiotics need to be removed from hospital wastewater. Sonication is a promising technology that can be …

Abiotic, Biotic, And Bio-Enhanced Reduction Of Hexavalent Chromium, Chloroform And Co-Contaminants Using Nano-Scale Zero Valent Iron In Highly Contaminated Groundwater, Eduardo Robleto Martinez

UNLV Theses, Dissertations, Professional Papers, and Capstones

Investigations of groundwater in a former industrial perchlorate manufacturing site have shown high contamination with perchlorate, chlorate, nitrate, hexavalent chromium (Cr (VI)), and chloroform (CF) with levels greater than 3,000, 30,000, 300, 100, and 4 mg/L, respectively. Remediation efforts using biological reduction to desired contaminant levels at this site has been challenging due to high contaminant concentrations, and high total dissolved solids (TDS). Furthermore, removal of Cr(VI) and CF in the presence of nitrate, chlorate, and perchlorate has not been examined at the contaminated site. Nano-scale Zero-Valent-Iron (NZVI) has been effective at reducing groundwater contamination both with and without bacterial …

Design Of Efficient Carbon-Based Adsorbents For The Removal Of Organic And Inorganic Water Contaminants, Sayedeh Soroosh Mortazavian Dehkordi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Granular activated carbon (AC) and biochar (BC) are two carbon-based adsorbents commonly used for water and wastewater treatment. However, these adsorbents have drawbacks that suppress their aqueous contaminants removal efficiency. Their major disadvantages are that AC has low selectivity and reusability potential, and BC has a hydrophobic nature.

The scope of this dissertation is to enhance the performance of commonly-used carbon-based adsorbents for the removal of organic and inorganic water contaminants and to understand the interactive mechanism of contaminants’ ions/molecules with adsorbents. Hexavalent chromium (Cr(VI)) and trichloroethylene (TCE) are two types of inorganic and organic water contaminants, respectively, which are …

Evaluation Of Titanosilicate Materials For The Sorption Of Cesium And Strontium From High Level Wastes, Matheus Tolentino Lauar

UNLV Theses, Dissertations, Professional Papers, and Capstones

Treatment of high-level waste (HLW) stored in the U.S. Department of Energy (U.S. DOE) sites of Hanford and Savannah River involves the separation of radioactive cesium (137Cs) and strontium (90Sr). Challenges in treating the liquid HLW includes high alkalinity or acidity, and high salt content, many orders of magnitude above Cs and Sr concentrations. Ion exchange is the preferred process for removing these compounds, due to the availability of selective media and large volume-processing capacity by column operations. The crystalline silicotitanate (Na2Ti2O3SiO4·2H2O), i.e. CST, which structure is analog to the mineral sitinakite, is considered the reference material for this application. …

Utility Of Bench Scale Sand Tank Experiments At Assessing Permeable Reactive Barrier Design, Brandon Meier

UNLV Theses, Dissertations, Professional Papers, and Capstones

The objective of this work was to evaluate the utility of bench scale sand tank experiments at assessing permeable reactive barrier (PRB) design. Our criteria for meeting this goal was that differences between PRB designs could be identified solely by measuring concentration in outflow from the sand tank models. For our PRB designs (funnel-and-gate, staggered wells, and parallel bars), numerical simulations clearly showed that PRB design had a quantifiable effect on outflow concentration, provided that the solute reacted with the PRB materials. Conversely, use of a conservative (non-reactive) solute did not allow us to discern between PRB design alternatives. Employing …

Treatment Of Perchlorate And Multiple Oxyanions: Chemical And Biological Investigations, Mark Elkouz

UNLV Theses, Dissertations, Professional Papers, and Capstones

Groundwater contamination with oxyanions is an issue that must be addressed for environmental, ecological and societal reasons. Chemical and biological treatment methods of reduction are already known and practiced, but the simultaneous presence of multiple oxyanions can add complicating effects to treatment sequence and efficacy. This research was concerned with the investigation of the chemical reductive treatment of Cr(VI) using both calcium polysulfide (CaSx) and ferrous sulfate (FeSO4), and the biological reductive treatment of chlorate, Cr(VI), nitrate and perchlorate using multiple organic substrates. The chemical treatment phase consisted of initial jar tests, using CaSx and FeSO4, followed by a laboratory …

Carbon Management And Volatile Fatty Acid Production In Primary Clarifiers At A Wastewater Treatment Plant, Brittany Nicole Radke

UNLV Theses, Dissertations, Professional Papers, and Capstones

An increasing number of treatment plants are required to remove nutrients from domestic wastewater to lessen the impact of nutrient loading to water bodies. Enhanced Biological Phosphorus Removal (EBPR) is one of the processes commonly used to remove phosphorus from domestic wastewater. The presence of an adequate quantity of volatile fatty acids (VFA) in the wastewater influent to EBPR is important for process efficiency and stability. The objective of this research was to investigate the production of VFAs through fermentation of sludge in primary clarifiers as it related to improving nutrient removal, primarily targeting phosphorus.

The research tested, in full-scale, …

Application Of Data-Driven And Process-Based Modeling Approaches For Water Quality Simulation In Lakes And Freshwater Reservoirs, Ali Saber Sichani

UNLV Theses, Dissertations, Professional Papers, and Capstones

Lakes and freshwater reservoirs often serve as the primary drinking and irrigation water sources for surrounding communities. They provide recreational and tourism opportunities, thereby promoting the prosperity of neighboring communities. Reliable estimates of water quality in lakes and reservoirs can improve management practices to protect water resources.

Seasonal water temperature and solar shortwave radiation variations, and their subsequent interactions with water column aquatic life, combined with seasonal variations of mixing intensity throughout the water column, result in variations of water quality constituents with depth during the annual cycle. The complexity of these variations entails the use of advanced water quality …

Investigation Of Efficiency Loss Of Distributed Solar Power Due To Soiling And Efficiency Recovery By Rainfall, Amanda Mayumi Tanaka

UNLV Theses, Dissertations, Professional Papers, and Capstones

As the concern with global warming increases causing the need for CO2 reduction, renewable energy is of great interest as it has lower carbon footprint when compared to conventional sources (natural gas, coal, oil and nuclear). Solar energy has been drawing worldwide attention since it can transform sunlight directly into electricity with the use of photovoltaic (PV) cells. However, this technology has some drawbacks that need to be addressed including dust deposition on solar panels, also known as soiling. Soiling can decrease PV panel’s efficiency thereby resulting in less energy production. The soiling rates are very site specific and depend …

Chromium(Vi) And Oxyanion Remediation Of Vadose Zone Soils With Zero Valent Iron (Zvi) And Biological Reduction, Nicolas Kim Wong

UNLV Theses, Dissertations, Professional Papers, and Capstones

In areas with high industrial development, soil and groundwater are often heavily contaminated with hexavalent chromium [ Cr(VI) ], which commonly occurs as the oxyanions chromate ( CrO42- ) and dichromate ( Cr2O72- ). By itself, Cr(VI) is a common contaminant in various industrial wastes, but other oxyanions such as nitrate [ NO3- ], chlorate [ ClO3- ], and perchlorate [ ClO4- ] can appear with Cr(VI) as co-contaminants based on the type of industrial waste. Cr(VI) and ClO3- occur as co-contaminants in areas where sodium chlorate is manufactured as a bleaching agent for the pulp and paper industry (ERCO …

Estimation Of Stage-Area-Storage Relationships In Reservoirs And Stage-Discharge Relationships In Rivers Using Remotely Sensed Data, Sailuj Shakya

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis estimates the relationships between the water surface levels and quantities of water in reservoirs and rivers using remotely sensed data without any field measurements. However, the accuracies of the estimates were validated using the field measurements from ground stations. The relationships between the water surface levels and quantities are fundamental for monitoring water quantities for the operation of hydraulic structures, as well as analyzing variability and changes in hydrology. Accessibility and transparency are big issues in establishing a monitoring system that can provide field validation of efforts to model global climate systems. Remote sensing has a capability of …

Comparison Of Zero Valent Iron (Zvi) And Zvi+Sludge For The Removal Of High Levels Of Hexavalent Chromium And Chlorate From Waters, Kenneth R. Greenhalgh

UNLV Theses, Dissertations, Professional Papers, and Capstones

Remediation of contaminated groundwater is becoming increasingly more

important as much of the U.S. population relies on groundwater for their drinking water.

Contaminates such as Chromium, common pollutant at industrial waste sites, and

Hexavalent chromium which is toxic to humans, animals, and plants are major

concerns. Chlorate, another contaminate of concern, has been widely detected in

ground and surface water in the United States and even locally in Henderson Nevada at

the Nevada Environmental Response Trust (NERT) sites. To assist in mitigating this

issue, this research focuses on the removal of high levels of hexavalent chromium (ppm

range) (Cr(VI)) and …

The Impact Of Waters Of Low Quality On Soiling Removal From Photovoltaic Panels, Alisson Luiz Boeing

UNLV Theses, Dissertations, Professional Papers, and Capstones

Soiling, bird droppings, or the accumulation of dust on the surface of photovoltaic cells, can significantly reduce the solar energy absorption and produce power losses. In solar plants where soiling is a problem, solar facilities use demineralized or distilled water for washing the panels to avoid mineral scale deposits that might interfere with solar irradiance absorption. However, in arid and dusty environments, water is normally scarce. For cleaning solar panels, the use of low quality water in lieu of the industry-standard demineralized water could conserve fresh water. The objectives of this research were as follows: evaluate the impacts of low …

Static And Dynamic Quantitative Microbial Risk Assessment Of Potable Reuse Paradigms, Erfaneh Amoueyan

UNLV Theses, Dissertations, Professional Papers, and Capstones

In recent years, potable reuse applications have become more common due to population growth and increased water demand, especially in communities with limited or variable water resources. However, there are concerns about potential exposure to pathogens and chemical compounds in treated wastewater. Therefore, advanced wastewater treatment processes are of paramount importance in any potable reuse system. The overall aim of this study was to develop and implement static and dynamic QMRAs to compare public health risk in various potable reuse scenarios. Cryptosporidium, norovirus, adenovirus, and Salmonella were chosen as the target pathogens. The research evaluated the performance of full advanced …

N-Nitrosodimethylamine Formation And Mitigation In Potable Reuse Treatment Trains Employing Ozone Nd Biofiltration, Fernanda Bacaro

UNLV Theses, Dissertations, Professional Papers, and Capstones

Potable reuse has been growing as a strategy to augment water supplies, especially in highly populated and water-scarce regions. Ozone and chloramines have emerged as important disinfectants and oxidants in potable reuse applications, but reactions with wastewater-derived constituents can lead to the formation of potentially carcinogenic disinfection byproducts (DBPs). One DBP that has received considerable attention is the nitrogenous DBP N-nitrosodimethylamine (NDMA). NDMA is a potential human carcinogen and mutagen at trace concentrations — even at the sub-ng/L level. Several studies have reported successful attenuation of NDMA in biofiltration systems at wastewater treatment plants, but the associated mechanisms and design …

Evaluating The Feasibility And Sustainability Of Direct Potable Reuse In Las Vegas, Nv, Cory Dow

UNLV Theses, Dissertations, Professional Papers, and Capstones

Community water sources are becoming more and more strained due to several factors including severe drought, population growth, urbanization, and climate change. This has spurred several water agencies to evaluate alternative water supply options to extend their resources. One potential alternative is potable reuse. Potable reuse comes in two forms: indirect potable reuse (IPR) and direct potable reuse (DPR). IPR is the advanced treatment of wastewater effluent before discharging into an environmental buffer that is a drinking water supply such as a lake, river, or groundwater aquifer before extraction and use. DPR is the advanced treatment of wastewater effluent that …

The Future Of Construction As It Applies To The Colonization Of The Moon And Mars, Julian Prestia

UNLV Theses, Dissertations, Professional Papers, and Capstones

The goals of this research are:

1. To compile a comprehensive list of all the viable known solutions (and early stage potential solutions) to the issues related to constructing permanent, sustainable, and safe structures for human colonies on our moon and Mars,

2. Determine the most effective potential solutions, and

3. Further develop these ideas as to assist in further space endeavors.

This proposed paper will assist space experts in determining the best next steps in the development of deep-space travel and colonization technologies. Preliminary research has identified several key problems associated with establishing space colonies. They are as follows: …

Understanding The Long-Term Changes In Hydrologic Processes On A Watershed Scale Due To Climate Variability And Change, Chao Chen

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the past century, the population explosion and economic development have resulted in global warming, which has raised a series of concerns, such as sea-level rise, food security, and water resources management. The water flow patterns and features experience both short-term and long-term changes in responses to the changes in the hydrologic processes and meteorologic conditions. On a watershed scale, it is crucial to understand, quantify, and attribute the influences of climate change on the local water resources system. Such understanding can be of great help to undertake local water management tasks, such as flood control, reservoir operation, ecosystem services, …

Evaluating The Chemical And Biological Stability Of Finished Waters Blended For Direct Potable Reuse In A Simulated Distribution System, Assumption Grimaldi

UNLV Theses, Dissertations, Professional Papers, and Capstones

This work evaluated the impacts of blending several different high grade recycled waters with conventional source waters for direct potable reuse (DPR) applications. Bench-scale laboratory tests were conducted for recycled water-source water blends from four participating facilities that have either considered adopting DPR or have already implemented DPR as a feasible approach to overcome water scarcity. The chemical and biological stability of the finished waters was investigated after pipe rig incubation to simulate the quality of blended waters that had aged in a potable water distribution system. The effects of blend ratio, reclaimed water treatment, and source water quality were …

Impacts Of Ozone Dose And Empty Bed Contact Time On Bulk Organic Removal And Disinfection Byproduct Mitigation In Ozone-Biofiltration Systems, Mayara Aquino

UNLV Theses, Dissertations, Professional Papers, and Capstones

In areas where water shortages have compromised water supplies, potable reuse is a promising solution. However, additional research is needed to identify and/or optimize cost-effective treatment technologies to demonstrate compliance with potable reuse regulations. Treatment trains employing reverse osmosis (RO) and advanced oxidation, a combination known as ‘full advanced treatment’ (FAT), are required by the California Division of Drinking Water (CDDW) for surface water augmentation and direct injection of recycled water into local aquifers. A maximum concentration of 0.5 mg/L of wastewater-derived total organic carbon (TOC) is also required by CDDW in all groundwater recharge applications. This appears to be …

Evaluation Of Electron Donors For Perchlorate And Nitrate Biodegradation In Contaminated Groundwater Applications, Mayra Alejandra Sarria Cortes

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the United States, perchlorate contamination has been widely reported, including in Las Vegas, Nevada, where perchlorate has been detected at concentrations of 34.7 mg/kg in vadose zone soil and 0.18-3.7 g/L in groundwater. Once this groundwater reaches the Las Vegas Wash, there is potential for widespread contamination of drinking water sources throughout the Southwest, including in Nevada, Arizona, and California. This issue is becoming increasingly important because even at low perchlorate concentrations, sensitive populations such as infants and pregnant women can be potentially impacted due to perchlorate’s ability to hinder iodine uptake into the thyroid glands, which leads to …

Occurrence And Proliferation Of Antibiotics And Antibiotic Resistance In Wastewater Treatment Plants, Majid Neyestani

UNLV Theses, Dissertations, Professional Papers, and Capstones

Solids retention time (SRT) is one of the most important factors in designing and operating activated sludge systems for biological wastewater treatment. Longer SRTs have been shown to alter the structure and function of microbial communities, thereby leading to improved treatment efficacy with respect to bulk and trace organics, nutrient removal, and membrane fouling. However, research has also shown that longer SRTs lead to increased prevalence of antibiotic resistant bacteria, perhaps due to increased exposure to antibiotics present in influent wastewater. The purpose of this study was to characterize changes in microbial community structure in a laboratory-scale activated sludge system …

Removal Of High And Low Levels Of Ammonium From Industrial Wastewaters, Gregory Bock

UNLV Theses, Dissertations, Professional Papers, and Capstones

Over 2×10^11 kilograms of ammonia are produced globally per year by the Haber-Bosch process which combines molecular hydrogen and nitrogen to synthesize ammonia. Most is used for fertilizer and agriculture while the remaining is used for other purposes including industrial processes and explosives. Explosives used in the mining industry are commonly ammonium nitrate (����4����3)-based. Excess ammonia and nitrate which can be dissolve into mine runoff water during blasting. Ammonia in mine and mineral wastewater can range from 20-110 mg/L. Ammonia is also present in several types of industrial wastewater such as caustic soda solutions used in the oil re-refining industry …