Physical Sciences and Mathematics Commons^™

Bacterial Degradation Of Disinfection By-Products In Drinking Water, Laura Inga Fauntleroy

Chemistry & Biochemistry Theses & Dissertations

Chlorine became a major disinfectant for the removal of microbial contaminants in 1914. Current water chlorination procedures yield halogenated disinfection byproducts (DBPs), such as haloalkanes and haloacetic acids (HAAs), due to the reaction of chlorine with naturally occurring organic compounds. Various water utilities have observed decreased HAAs levels in maximum residence time locations (MRTLs), where they were expected to be higher. These MRTLs have low free chlorine residual and high heterotrophic bacteria plate counts. Xanthobacter autotrophicus, GJ-10, is a bacterium that has been shown to contain dehalogenase enzymes and, therefore, can biodegrade HAAs. A number of water-system bacteria were …

Assessment Of Surface Water Runoff And Groundwater Recharge Using Mathematical Models, Khaled Omer Mohamed Haroon

Theses

In arid and semi-arid regions, surface water resources are scarce and, in most cases, groundwater is the only natural resource of freshwater. Pumping of groundwater often exceeds natural recharge. Therefore, groundwater levels are declining and its quality is deteriorating. Sustainable management of groundwater is thus a key issue and requires implementation of appropriate technologies to augment groundwater resources. Artificial recharge augments the natural movement of surface water into the underground formations using some means of construction whereby surface water from streams or lakes is made to infiltrate into the ground.

The UAE is known by its arid conditions and limited …

Evaluating The Effectiveness Of Simulation-Based Instruction About Water Resources In Las Vegas, Stephanie Fincher

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study compared the effectiveness of simulation-based instruction to traditional teacher-directed instruction about water resource management in Las Vegas. Subjects, undergraduate students recruited from Psychology and Environmental Studies departments, participated in one of two treatments. All participants were given a pretest prior to instruction, a post-test immediately following instruction, and a retention-test 4 weeks after instruction. Evaluation instruments provided overall scores, gauged student learning in topic areas and different question difficulty-levels as well as attitudes toward the environment and water management. The treatments differed only in how students interacted with the system after receiving background information on Las Vegas valley’s …

Watershed Management To Control Pollution In The Ayuquila River, Jalisco, Mexico, Luis Manuel Martinez Rivera

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Ayuquila River watershed is important to western Mexico because of its biodiversity, physiography, fisheries resources, and water production. However, human activities are continuingly affecting natural resources within the basin. Soil erosion, as result of land use change, agriculture in steep land, extensive grazing activities and forest fires; and water diversion and pollution of the Ayuquila River are two relevant issues that have affected the natural resources of this watershed.

This river system plays an important role in wildlife conservation, containing 29 fish species, of which 12 are found inside the BRSM. The River also contains nine species of crustacean, …

Modeling A Field Application Of In Situ Bioremediation Of Perchlorate-Contaminated Groundwater Using Horizontal Flow Treatment Wells (Hftws), Peter G. Chosa

Theses and Dissertations

Perchlorate contaminated groundwater is rapidly becoming a significant environmental remediation issue for the Department of Defense. In this study, an existing numerical model that simulates the operation of a Horizontal Flow Treatment Well (HFTW) system to effect the in situ biodegradation of perchlorate through the addition of an electron donor is modified to include a submodel that describes bioclogging. Bioclogging restricts flow out of the HFTW due to the accumulation of biomass directly adjacent to the well. The modified model is then applied to an existing perchlorate contaminated site that will be used for an evaluation of the HFTW technology. …

Application Of Horizontal Flow Treatment Wells For In Situ Treatment Of Mtbe-Contaminated Groundwater, Preston F. Rufe

Theses and Dissertations

This study utilized a three-dimensional numerical model to evaluate the potential application of HFTWs to manage MTBE-contaminated groundwater. HFTWs consist of two dual-screened treatment wells. One well operates in an upflow mode, with MTBE-contaminated water extracted from an aquifer through a screen in the deep portion of an aquifer and injected into the aquifer through a shallow well screen, while the adjacent well operates in a downflow mode, extracting water from the shallow zone of the aquifer and injecting it into the deep zone. As the MTBE-contaminated water flows through the wells, an electron acceptor and/or another electron donor is …

Laboratory Investigation Of Transport And Treatment Of Chromium In Groundwater At Liwa District, Abu Dhabi, Wali-Ur-Rahman Din Badshah

Theses

Groundwater quality is a critical aspect affecting utilization of this source for certain purposes. In the UAE, utilization of groundwater for domestic purposes is well practiced. While the quality of groundwater at some locations does not permit direct utilization of this source, groundwater, in many cases, is mixed with desalinated water at certain proportion before being disinfected and then distributed to customers.

Groundwater of Liwa aquifer contains high level of Cr(VI) which is believed to originate from natural sources. However, little has been done to investigate the fate of this contaminant. Spreading of chromium to nearby aquifers may render the …

Consequences Of Reservoir Drainage On Downstream Water Chemistry, Suspended Sediment, And Nutrients, Southwest Missouri, Mark W. Bowen

MSU Graduate Theses

Construction and subsequent draining of reservoirs can have dramatic affects on the release of nutrients and sediments to waterways. This study describes how the temporary draining of a small reservoir for dam repair influences downstream water quality. The Valley Mill Reservoir has a surface area of 6.1 hectares and volume of 150,000 m3 when filled. Water chemistry monitoring and water sampling were performed at six sites during baseflow and ten sites during runoff events for one year. Water samples were analyzed for total nitrogen (TN), total phosphorous (TP), and total suspended sediment (TSS) concentrations. Results indicate that draining of Valley …