Engineering Commons^™

Physical And Stochiometric Controls On Nutrient Uptake And Ecosystem Respiration In Contrasting Sites, Jancoba K. Dorley

Civil Engineering ETDs

Meteorological, hydrological, and biogeochemical processes naturally control stream ecosystems. These processes define the frequency and distribution of precipitation and the supply and demand of solutes and particles to support aquatic food chains through space and time. Studies have also found that stream ecosystems are also controlled by anthropogenic activities, which occur on a much shorter timescale. These anthropogenic activities affect stream ecosystems' structure and function from local to planetary changes to the environment. It is essential for scientists and engineers to understand the relationships between naturally occurring processes and those created by human activities for a better interpretation of stream …

Gold Thin Film Electrodes For High Sensitivity & Selectivity Electrochemical Detection Of Arsenite In Water, Tybur Q. Casuse Driovínto

Civil Engineering ETDs

This is partial fulfillment of a dissertation defense on electrochemical detection of Arsenic (As) in water using gold (Au) nanofilms as sensing electrodes. The maximum contaminant level of Arsenic in drinking water is set at 10 g L^-1 by the WHO and USEPA. Electrochemical detection by linear stripping voltammetry has comparable detection limits to more expensive laboratory-based methods but with added benefits of being portable and manufacturable. The work has developed sputtered and crystallographically oriented nanofilms for detection of trace As (III). Ultraflat Au(111) oriented thin films, Au(UTF), were compared to single crystal model electrodes to identify the impacts …

Additive Manufacturing Of Engineered Cementitious Composites With Ultra-High Tensile Ductility, Amir Bakhshi

Civil Engineering ETDs

One of the critical factors in the development of additive manufacturing in the construction industry is designing suitable materials for 3D printing applications. 3D concrete printing (3DCP) has gained significant attention due to the abundance and availability of concrete. However, concrete is a brittle material and, without proper reinforcement, cannot meet the requirements for structural purposes. Engineered Cementitious Composites (ECC), known for high ductility, and strain-hardening with low fiber contents, can potentially eliminate the need for steel reinforcement in 3D printing without any need for manual placement of reinforcement. A set of systematic tests on ECC mix designs' fresh and …

Minimizing Surface Run-Off, Improving Underground Water Recharging, And On-Site Rain Harvesting In The Kathmandu Valley, Ambika P. Adhikari, Keshav Bhattarai

Himalayan Research Papers Archive

Nepal's political institutions and administrative units were thoroughly restructured in 2015 with the promulgation of the new Constitution. Several rural areas were combined to meet the definition of urban threshold criteria to classify rural areas into urban categories. Accordingly, over 3,900 local political and administrative units were amalgamated into 753 units, of which, 293 units are classified as urban. Within these newly defined urban areas, many natural environments have been converted into impervious surfaces such as paved roads, sidewalks, and building roofs. These impervious surfaces have drastically increased the amount of surface run-offs-often termed as "urban floods"--under increasing precipitation caused …

The Effect Of Ph On Organic Carbon Uptake And Biological Phosphorus Removal By Tetrasphaera Polyphosphate Accumulating Organisms, Derek Belka

Civil Engineering ETDs

Tetrasphaera polyphosphate accumulating organisms (PAOs) have been found in greater abundance and may remove more P in full-scale enhanced biological phosphorus removal (EBPR) water resource recovery facilities (WRRF) worldwide than the more extensively studied Accumulibacter PAO. Understanding the effect that environmental conditions, such as pH, have on Tetrasphaera metabolisms is critical to understanding EBPR WRRF process upsets, achieving consistent low effluent P concentrations, and formulating optimization strategies. The objective of this study was to determine pH effects over the range from 5.5 to 8.5 on anaerobic amino acid uptake, P release, and cation release in a Tetrasphaera-enriched culture from …

An Investigation Of Phosphorus Removal By Purple Bacteria In Dairy Wastewater Lagoons, Lauren M. Gomez, Andrew J. Schuler, Jose M. Cerrto, David T. Hanson

Civil Engineering ETDs

The objective of this study was to determine whether the polyphosphate metabolism in purple photosynthetic bacteria (PPB) is similar to that of wastewater polyphosphate-accumulating organisms (PAOs) such as Accumulibacter. Dairy lagoon samples were studied in continuous and batch laboratory tests to evaluate whether cyclic light and dark conditions for PPB are similar to aerobic and anaerobic conditions for PAOs in domestic wastewater treatment systems. 16s rRNA gene amplicon sequencing indicated the presence of the purple sulfur bacterium Thiolamprovum (53.92%) in one lagoon source, and Thiodictyon (3.50%) in a second lagoon. Phosphorus contents were at least 0.7% higher than the …

Chemical Interfacial Reactions Affecting The Speciation And Solubility Of Uranium In Organic-Rich Environments, Carmen A. Velasco

Civil Engineering ETDs

The aim of this dissertation was to investigate the interfacial reactions between uranium (U) and natural organic matter NOM) affecting the solubility, adsorption, and precipitation of U in organic-rich environments. The chemical interactions between U and NOM are not well understood, which justified the following research objectives: 1) Identify the effect of pH on U speciation and the organic functional chemistry in mineralized deposits from the Jackpile Mine.; 2) Identify the precipitation of U(VI) and NOM as a function of pH (2, 4 and 7); 3) Identify changes in DOM chemistry due to the reaction of NOM and U at …

Effect Of Membrane Aging And Operating Conditions On The Rejection Of Trace Organics For Potable Reuse, Jose Pedro Hernandez

Civil Engineering ETDs

The aim of this study is to provide a better understanding of the effect that membrane degradation and operating conditions have on the removal of selected organic compounds via reverse osmosis (RO). Originally, the study included laboratory experiments in which ESPA2-LD membranes from Hydranautics were to be chemically damaged and the passage of the suite of trace organics through the membranes was to be evaluated. Unfortunately, the degradation experiments were cut short due to lab closures associated with the COVID-19 pandemic. The study then changed direction to provide insight into the role operating conditions have on the removal of trace …

Biogeochemical Processes Affecting Arsenic (As) Release And Bioavailability Near Abandoned Mine Wastes, Cherie L. Devore

Civil Engineering ETDs

The aim of this dissertation was to investigate the biogeochemical processes affecting the mobilization and bioavailability of arsenic (As) from mining-impacted sediments to surface water sources and plants. The Cheyenne River Watershed has been affected by mining legacy for several decades. The biogeochemical cycling of As on tribal land is not well understood, which justified the following research objectives: 1) Investigate the effect of competing anions on the release of As from sediments exposed to oxidizing conditions; 2) Evaluate chemical and microbiological processes affecting the release of soluble As, Fe, and Mn from contaminated sediments under laboratory controlled aerobic and …

Biointerfacial Studies Of Nitrifying Biofilms On Physically And Chemically Modified Surfaces, Philip Marley Roveto

Civil Engineering ETDs

Interactions between bacteria and surfaces during the initiation of biofilm formation are complex phenomena with significant and wide-ranging implications for nutrient cycling, ecosystem and human health, and the remediation of anthropogenic pollutants. Nitrifying biofilms are currently used for ammonia removal in wastewater treatment plant (WWTP) systems. As well-studied biofilms, they can serve as models towards understanding crucial aspects of biofilm engineering. The overall objective of this research was to better understand how variations in specific surface chemistries and topographical features affect nitrification rates and microbial populations in an effort to develop technologies for improved productivity. The experimental approach was to …

Recovery Of Gypsum & Magnesium Hydroxide From Brackish Water By Chemical Precipitation, Sugam Tandukar

Civil Engineering ETDs

Exhaust gases from coal combustion contain contaminants such as sulfur dioxide (SO₂) and nitrous oxide (NO_x), and traces of other pollutants such as arsenic (As), mercury (Hg), nitrate (NO₃), and selenium (Se). Exhaust gas scrubbers are used to limit the emissions of these constituents to air. Treating exhaust gases to remove SO₂ is referred to as flue gas desulfurization (FGD), and the most common method is the use of wet scrubbers using limestone slurries. The limestone slurry is recycled multiple times in the scrubber, and to limit the concentration of dissolved constituents, a …

Organic/Inorganic Interfacial Interactions Affecting Metal Reactivity: Water Treatment And Sensor Applications, Mohamed Nabil Shaikh

Civil Engineering ETDs

The aim of this dissertation was to investigate the interactions occurring at the organic – inorganic interface between solid media and aqueous contaminants for water treatment and sensor applications. The gaps in current literature on these interfacial organic-inorganic interactions must be bridged in order to develop advanced water treatment and monitoring technologies for improving water quality and thus, restore and protect the contaminated water resources. As a part of this dissertation, manganese oxides-based composites and electrospun polymer mats were developed and investigated for gaining mechanistic insights of organic (bisphenol A and acetaminophen) and inorganic (uranium) contaminants removal, respectively. These reactions …

Application Of Cation Exchange And Nanofiltration To Treat Flue Gas Desulfurization Wastewater, Ayush R. Shahi

Civil Engineering ETDs

Flue gas emitted from coal-fired power plants is one of the major sources of sulfur and nitrogen oxides emissions to the atmosphere in the world today. Although coal use has decreased, it is still a major contributor to such emissions. The Clean Air Act in the United States established regulations for coal-fired power plants to limit SO_x and NO_x emissions into the atmosphere. To meet regulatory requirements, power plants have been using scrubbers to limit their air emissions. Flue-gas desulfurization (FGD) is a pollution prevention method that is employed to limit sulfur dioxide emissions directly in the environment …

Is Transportation Planning Effective? A Critical Review Of Long-Range Regional Transportation Planning In The United States, Razieh Nadafianshahamabadi

Civil Engineering ETDs

The Federal-Aid Highway Act requires urban areas with a population greater than 50,000 to create Metropolitan Planning Organizations (MPOs) to ensure that funding for transportation projects and programs are based on a continuing, cooperative, and comprehensive planning process. A major responsibility of each MPO is the creation of a long-range transportation plan (LRTP) that addresses the transportation needs of a metropolitan region over the next twenty years or more. While long-range regional transportation planning goals have grown to include a wide range of concerns and technical methods for evaluating planning scenarios have advanced substantially over the past 50 years, there …

Low Loading Gold Vapor Deposited Electrode For High Sensitivity As (Iii) Detection, Tybur Casuse

Civil Engineering ETDs

The objective of this thesis is to develop a method for detection of arsenite, As (III), using a thin film of gold (Au) vapor deposited onto carbon paper as an electrode. Currently, availability of drinking water arsenic (As) concentration information for rural communities is diminished due to high cost per sample analysis and limited access to analytical laboratories which can accurately determine concentrations near the 10 maximum contaminant level (MCL) set by the World Health Organization (WHO) and the US Environmental Protection Agency (EPA). The use of a minimal amount of gold aids in decreasing the cost of an electrode. …

Nitrate Dynamics In An Arid Irrgation Network: Can Nutrient Loops Be Closed With Management Techniques?, Kelsey B. Bicknell

Civil Engineering ETDs

Nutrients are the third leading cause of impairment in aquatic ecosystems, yet they remain necessary to support our growing agriculture system. Mining (as with phosphorus) and manufacturing (as with synthetic nitrogen) fertilizers deplete non-renewable resources and consume large amounts of energy. We have opportunities to optimize food-energy-water (FEW) resources, particularly in arid regions where wastewater, rather than agriculture, is the number one contributor of nutrients. This study evaluates the capacity of three unique channels (i.e., the Drain canal, the Delivery canal, and the Rio Grande River) within the agriculture system of the Middle Rio Grande Valley to process nutrients from …

Investigation Of Acetaminophen And Caffeine Removal Using Manganese Oxides And Granular Activated Carbon In Column Experiments, Rachael E. Miera

Civil Engineering ETDs

This study was conducted to investigate the application of manganese dioxide (MnO_x(s)) and granular activated carbon (GAC) media for the removal of the acetaminophen and caffeine. Treatment of emerging micropollutants has become a concern due to their effects on environmental health. Manganese oxides can be a viable alternative for water treatment due to their abundance in the environment. Laboratory scale flow through column experiments were performed using different combinations of commercial MnO_x(s) and GAC to assess the removal of caffeine and acetaminophen, and the release of Mn due to the reductive dissolution of MnO_x(s). Results …

Dna Identification Of Polyculture, Andrew Schuler

Energize New Mexico (NSF EPSCoR Track 1 IV)

DNA sequencing of algae polyculture growing in oilfield produced water. It is dominated by the algae species Parachlorella kessleri and Cyanobacterium aponinum.

Characterizing Patterns In E. Coli Levels In Rio Grande River Water And Riverbed Sediments Near Albuquerque, Nm, James Fluke

Civil Engineering ETDs

In this work I examined how Fecal indicator Bacteria (FIB) behave in a large environmental system (Rio Grande near Albuquerque, ~60 km distance). I addressed the questions: How do FIB levels in river water and riverbed sediments of this reach change with distance along the river and throughout one year?

I conducted year-round river water and sediment sampling for concentration of E. coli bacteria, a persistent contaminant in the area. I found that over the year, E. coli loading in river water increased along the 60 km reach and E. coli in the sediments mainly increased near the Albuquerque urban …

Metal Reactivity In Laboratory Burned Wood From A Watershed Affected By Wildfires, Asifur Rahman

Civil Engineering ETDs

Massive amounts of wood ash are deposited into nearby streams as a result of runoff from storm events after increasing frequency of wildfire events that negatively affect water quality. Ash and debris from burned vegetation can alter the pH, turbidity and dissolved oxygen (DO) in water and can release heavy metals, organic matter, and nutrients. We investigated interfacial processes affecting metal mobility in wood ash burned under laboratory-controlled conditions using aqueous chemistry, microscopy and spectroscopy analyses. Wood was collected from the Valles Caldera National Preserve in New Mexico which has experienced two wildfires since 2011 that have caused devastating effects. …

Physical And Chemical Interactions Affecting U And V Transport From Mine Wastes, Sumant Avasarala

Civil Engineering ETDs

This research investigates the physical and chemical interactions that affect the transport of uranium (U) and vanadium (V) from uranium mine waste sites by integrating laboratory experiments and reactive transport modelling with various spectroscopy, microscopy, and diffraction techniques. The document consists of results from three related studies. In the first study (Chapter 3), the reactive transport of U and V was investigated by sequentially reacting mine wastes collected from Blue Gap/Tachee Claim-28 mine site, AZ with 10mM NaHCO₃ (7.9) and 10mM CH₃COOH (3.4) during continuous flow through column experiments. Under both of these conditions (pH 3.4 and …

Moving Bed Biofilm Reactors: Evaluation Of Geometry, Attachment Surface Material And Biofilm Populations On The Uptake Of Ammonia And Synthetic Organic Contaminants In Wastewater., Patrick D. Mclee

Civil Engineering ETDs

Plastic biofilm carriers are used in biological wastewater treatment to encourage the attachment and retention of microorganisms that metabolize pollutants. The following research was conducted to better understand how different characteristics of the biofilm carrier affect the treatment performance of the attached biofilms in moving bed bioreactors. Lab scale reactors were used in this study to grow nitrifying biofilms in reactors with contrasting and controlled conditions. The effect of surface geometry on nitrification performance was evaluated by testing commercially available moving bed bioreactor media that contrast in physical design, and by varying operational parameters. Additionally, mature biofilm from a similar …

Hydrogeochemical Investigation Of Recharge Pathways To Intermediate And Regional Groundwater In Cañon De Valle And Technical Area 16, Los Alamos National Laboratory, Brendan W. Brady

Civil Engineering ETDs

In aquifers consisting of fractured or porous igneous rocks, as well as conglomerate and sandstone products of volcanic formations, silicate minerals actively dissolve and precipitate (Eby, 2004; Eriksson, 1985; Drever, 1982). Dissolution of hydrated volcanic glass is also known to influence the character of groundwater to which it is exposed (White et al., 1980). Hydrochemical evolution, within saturated zones of volcanic formations, is modeled here as a means to resolve the sources feeding a perched groundwater zone. By observation of solute mass balances in groundwater, together with rock chemistry, this study characterizes the chemical weathering processes active along recharge pathways …

Rejection Of Low Molecular Weight Neutral Organics By Reverse Osmosis Membranes For Potable Reuse, Lauren N. Breitner

Civil Engineering ETDs

Factors such as increasing population, urbanization, and climate change have made the management of water resources a challenge for many municipalities. Water reuse, especially direct potable reuse (DPR) of treated wastewater, is increasingly seen as a potential source of water for communities facing water shortages. Due to improvements in analytical capabilities as well as concerns regarding toxicology of contaminants of emerging concern (CECs), the need for investigating the removal of CECs has become crucial for further DPR considerations. Reverse osmosis (RO) has been demonstrated to remove many CECs. Many studies, however, have investigated the removal of well-known CECs, often with …

Comprehensive Silica Removal With Ferric Compounds For Industrial Wastewater Reuse, Ehren D. Baca

Civil Engineering ETDs

Cooling towers, integrated circuit (IC) manufacture and reverse osmosis (RO) generate copious amounts of wastewater high in colloidal and reactive silica inhibiting on-site or synergistic reuse. Silica present in cooling water can reach solubility limits via evaporation and form impervious scale on heat transfer surfaces that decreases efficiency. When water is treated by RO operating at high rejection, silica forms difficult-to-remove scale on the membrane feed side in the form of glassy patches and communities of aggregate particles, inhibiting aspirations for zero liquid discharge. Current methods for silica scale mitigation include abundant dosing with chemical antiscalents or complex operating schemes. …

Predictions Of Ponderosa Pine Resiliency To Climate Change In The Cebolla Canyon Watershed, New Mexico, Breana N. Chavez

Water Resources Professional Project Reports

This project was designed to understand the potential impacts of climate change on soil moisture and the resiliency of ponderosa pine in the forested region of the Cebolla Canyon watershed (Cebolla), located in eastern New Mexico. Much of the watershed is administered as public domain land by the U.S. Bureau of Land Management (BLM). This project aims to help BLM managers understand how climate change is projected to impact ponderosa pine seedling establishment and mature ponderosa pine productivity in Cebolla.

Current and potential future soil moisture regimes in Cebolla were simulated on three hills using HYDRUS-1D. The soil moisture regimes …

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 10 - Play 3 - 2016/06/15), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 1/2 - Play 3 - 2016/06/12), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 1 - Play 2 - 2016/06/07), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment.

University Of New Mexico Bioalgal Energy, Photosynthesis Rates Of Poplar Plants - Measurements With Tdl Machine (Enriched Co2 - Enriched-Exposed - Tray 1/3 - Play 1 - 2016/06/08), David Hanson

Energize New Mexico (NSF EPSCoR Track 1 IV)

Collect the photosynthetic rate of poplar plants under different isotopic compositions of CO2 with the TDL machine and with the Licor equipment.