Engineering Commons^™

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 …