Engineering Commons^™

Trihalomethane, Dihaloacetonitrile, And Total N-Nitrosamine Precursor Adsorption By Carbon Nanotubes: The Importance Of Surface Oxides And Pore Volume, Erin Needham

Graduate Theses and Dissertations

As drinking water sources become increasingly impaired, enhanced removal of natural organic matter (NOM) may be required to curb formation of disinfection byproducts (DBPs) upon chlor(am)ination. While carbon nanotubes (CNTs) can adsorb NOM, their properties for DBP precursor adsorption have not been elucidated. Nine types of CNTs were assessed for trihalomethane (THM), dihaloacetonitrile (DHAN), and total N-nitrosamine (TONO) precursor adsorption. Batch isotherm experiments were completed with lake water and, to simulate an impaired condition, effluent from a wastewater treatment plant (WWTP). Adsorption varied with CNT type and dose, with TONO precursors having the highest percent removals from WWTP effluent (up …

Understanding N-Nitrosodimethylamine Formation In Water: Chloramine Chemistry, Kinetics, And A Proposed Reaction Pathway, Huong Thu Pham

Graduate Theses and Dissertations

The formation of N-nitrosodimethylamine (NDMA) in drinking water systems is a concern because of its potential carcinogenicity and occurrence at toxicologically relevant levels. The postulated mechanism for NDMA formation involves a substitution between dichloramine and amine-based precursors to form an unsymmetrical dimethylhydrazine (UDMH), which is then oxidized by ground-state molecular oxygen to form NDMA. However, this latter reaction is spin forbidden, thus likely occurs at a slow rate. It is hypothesized that the reaction between monochloramine and hydroxylamine (a nitrification product) may form an intermediate, which is involved in the NDMA formation pathway. This intermediate may also be generated from …

The Role Of Organic Matter In The Fate And Transport Of Antibiotic Resistance, Metals, And Nutrients In The Karst Of Northwest Arkansas, Victor Lee Roland Ii

Graduate Theses and Dissertations

Organic matter (OM) in the environment acts as a nutrient, but may also act as a transport vector for harmful chemical compounds and bacteria. Acetate is a labile form of OM produced during fermentation in anaerobic lagoons used to store animal fecal-waste from concentrated animal feeding operations (CAFOs). Dry and liquid fertilizers from CAFOs pose a threat to groundwater by introducing excessive amounts of nutrients (e.g. OM, nitrate and ammonia), metals, and antibiotic compounds. In the epikarst of Northern Arkansas in the Buffalo River watershed additional input of labile dissolved organic carbon (DOC) from liquid CAFO waste-fertilizers was hypothesized to …

Nanofiltration Rejection Of Contaminants Of Emerging Concern From Municipal Water Resource Recovery Facility Secondary Effluents For Potable Reuse Applications, Steven Michael Jones

Graduate Theses and Dissertations

As reuse of municipal water resource recovery facility (WRRF) effluent becomes vital to augment diminishing fresh drinking water resources, concern exists that conventional barriers may prove deficient and the upcycling of contaminants of emerging concern (CECs) could prove harmful to human health and aquatic species if more effective and robust treatment barriers are not in place.

There are no federal Safe Drinking Water Act (SDWA) regulations in place specifically for direct potable reuse (DPR) of WRRF effluent. Out of necessity, some states are developing their own DPR reuse regulations. Currently, reverse osmosis (RO) is the default full advanced treatment (FAT) …

Assessing Trichloromethane Formation And Control In Algal-Stimulated Waters Amended With Nitrogen And Phosphorus, Clinton Mash

Graduate Theses and Dissertations

Nitrogen (N) and phosphorus (P) enrichments can stimulate algal growth in drinking water sources, which can cause increased production of disinfection byproduct (DBP) precursors. However, the effect of systematic N and P enrichments on DBP formation and control has not been adequately studied. In this work, we enriched samples from a drinking water source - sampled on April 5, May 30, and August 19, 2013 - with N and P to stimulate algal growth at N:P ratios covering almost five orders of magnitude (0.2-4,429). To simulate DBP-precursor removal processes at drinking water treatment plants (DWTPs), the samples were treated with …

Assessing The Impact Of Chlorine Residual On Trihalomethane And Haloacetonitrile Formation Under Chlorination And Chloramination Disinfection Regimes, Thien Duc Do

Graduate Theses and Dissertations

A disinfection byproduct (DBP) formation potential (FP) test can be used to indirectly measure the concentration of DBP precursors in natural waters, permitting assessment of various DBP-related treatment processes and control strategies. While these tests require a 7-day chlorine residual (CR) between 3-5 mg L^-1 as Cl², it is not well known if this recommended residual corresponds to the true DBPFP (i.e., the maximum concentrations) for trihalomethanes (THMs) and haloacetonitriles (HANs). In this study, THMs and HANs were quantified as a function of CR under three common disinfection regimes: (1) free chlorine at pH 7.0 (FC7), (2) …

Evaluation Of Broiler Litter Heat Production During Windrowing & Nitrogen Based Gas Emission Mitigation Using Biofilter, Min Lei

Graduate Theses and Dissertations

Ammonia emission from animal feeding operations (AFOs) has negative effects on environment and animals' health. Thus measuring and mitigating ammonia emission from AFOs is important for environmental protection. In chapter I, different ammonia measurements were discussed and a mitigation technology- biofilter was represented.

In-house windrowing of built-up litter has been used by broiler producers to reduce pathogen loads and rejuvenate litter for the next flock. When litter is piled up for an extended period during downtime, heat generated by the litter pile can become a substantial heat source due to the metabolism of microorganisms. In chapter II, heat production rates …

A Watershed Scale Evaluation Of Selected Second Generation Biofeedstocks On Water Quality, Gurdeep Singh

Graduate Theses and Dissertations

This study compares a novel simulation approach to the conventional Soil and Water Assessment Tool (SWAT) modeler's approach for targeting biofuel crop production on marginal lands. In conventional SWAT modeling approach, non-spatial definition of hydrological response units (HRUs) results in the simulation of biofuel crops on both marginal and non-marginal land. This study provides an alternative approach in which a marginal-land raster was integrated into the land use and land cover (LULC) raster in such a way that the land uses were divided into marginal and non-marginal components. This modified LULC was used for model setup which resulted in marginal …

Effects Of Testing Time On Anaerobic Toxicity Assessment, Omolola Atinuke Akintomide

Graduate Theses and Dissertations

Anaerobic digestion has been widely used for wastewater treatment for decades. Several Anaerobic Toxicity tests have been developed to screen wastewater for toxicity and assess the treatability of such toxicants. However, past research and reviews on Biochemical Methane Potential (BMP) test and Anaerobic Toxicity Assay (ATA) were considered in this study.

The experimental tests included ammonium-nitrogen and sodium chloride toxicity tests with varied concentration and solid retention time. These tests were designed to demonstrate the impact of ammonia- nitrogen and sodium chloride on the biological degradation process. The anaerobic test set-up includes bench-scale test reactors and respirometers used for measuring …

The Development Of A High Performance Concrete To Store Thermal Energy For Concentrating Solar Power Plants, Emerson Esmond John

Graduate Theses and Dissertations

In recent years, due to rising energy costs as well as an increased awareness of the environmental effects of greenhouse gas emissions produced through traditional forms of energy production, there is great interest in developing alternative sources of energy. One of the most viable alternative energy sources is solar energy. In particular, concentrating solar power (CSP) technologies have been identified as an option for meeting utility needs in the U.S. Southwest. These systems are required to produce electricity not only during periods of high solar radiation but also during times of reduced radiation due to cloud cover, and even extend …

New Insights Into Disinfection Byproduct Formation And Control: Assessing Dissolved Organic Matter Diffusivity And Chemical Functionality, Ashley Pifer

Graduate Theses and Dissertations

Methods were developed for application of asymmetric flow field-flow fractionation (AF4) and fluorescence parallel factor (PARAFAC) analysis to raw and treated samples from drinking water sources to improve characterizations of dissolved organic matter (DOM) and discover DOM properties correlated to disinfection byproduct (DBP) formation potential (FP). Raw water samples were collected from a reservoir, adjusted to pH 6, 7, and 8 and subjected to (1) jar tests using aluminum sulfate (alum) and (2) treatment with magnetic ion exchange (MIEX^®) resin. Both treatments were followed by DBPFP tests at pH 7. AF4 was used to size DOM in raw …

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 …

Mathematical Modeling Of Fluid Spills In Hydraulically Fractured Well Sites, Oluwafemi Michael Taiwo

Graduate Theses and Dissertations

Improved drilling technology and favorable energy prices have contributed to the rapid pace at which the exploitation of unconventional natural gas is taking place across the United States. As a natural gas well is being drilled, reserve pits are constructed to hold the drilling fluids and other materials returned from the drilling process. These reserve pits can fail, and when they do, plant and animal life of the surrounding area may be adversely affected. This project develops a screening tool for a suitable location for a reserve pit. This work will be a critical piece of the Infrastructure Placement Analysis …

Removal Of Disinfection By-Product Precursors Using Magnetic Ion Exchange (Miex(R)): The Effects Of Ph And Source Water Variability, Sarah Cousins

Graduate Theses and Dissertations

Disinfection by-products (DBPs) form as an unintended result of drinking water disinfection, from chemical reactions between disinfectants (e.g., free chlorine) and naturally occurring dissolved organic matter (DOM). At present, 11 DBPs are regulated in treated drinking waters due to potential adverse health effects, including four trihalomethanes (THMs). Despite nearly 40 years of DBP research, compliance with DBP regulations remains a challenge for many drinking water treatment plants (DWTPs), including the four DWTPs located on the Beaver Lake Reservoir in Northwest Arkansas. Due to the high net negative surface charge on DOM, anion exchange is one potentially viable method for removing …

Water Quality Trends For Section 319 Priority Watersheds In Northwest Arkansas, 1997-2010, Bryan William Bailey

Graduate Theses and Dissertations

Northwest Arkansas contains two Section 319 Priority Watersheds that the Arkansas Natural Resources Commission (ANRC) has identified as being impacted by point and nonpoint sources of pollution (i.e., phosphorus, nitrogen, and sediment), and the Arkansas Water Resources Center (AWRC) has monitored the water quality at several sites within these watersheds. Water-quality data has been collected over the last decade within the Illinois River Watershed (HUC #11110103) and the Upper White River Basin (Beaver Reservoir HUC# 11010001), each watershed containing three sampling sites. The Illinois River Watershed sites are located on the Illinois River, Osage Creek, and Ballard Creek, and the …