Engineering Commons^™

Water Quality Models For Stormwater Runoff In Two Lincoln, Nebraska Urban Watersheds, Jake Fisher

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Water quality monitoring was conducted in two urban watersheds (Colonial Hills and Taylor Park) located in southeast Lincoln, NE over a three year period spanning from October 2008 through September 2011. In-line probes continuously measured for turbidity, conductivity, dissolved oxygen, and water temperature while other water quality constituents were analyzed for discrete water samples collected using grab and automatic sampling techniques. The water quality data was used to calculate event mean concentrations (EMCs) for sixteen storm events sampled over the duration of the project period. Three types of stormwater quality multiple linear regression models were developed for the estimation of …

Sensitivity Analysis On Mapping Evapotranspiration At High Resolution Using Internal Calibration (Metric), Venkata Naga Ravi Kumar Choragudi

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Mapping EvapoTranspiration at high Resolution using Internal Calibration (METRIC) is most widely used to quantify evapotranspiration (ET) spatially and temporally. It is essential to inspect the model’s response to errors in various parameters used in the model. Landsat 5 images from May 30 2009, July 1 2009 and a Landsat 7 image from September 27 2009 are used in this study. Fourteen different fields composed of Corn, Soybeans, Alfalfa are randomly chosen for each crop type.

Two kinds of errors are addressed in this study. One, with the errors that are transferred and potentially compensated by calibration (Global error) and …

Application Of Shredded-Tire Biofilter And Membrane Bioreactor For Greywater Reclamation, Meng Hu

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Water scarcity is a pressing global issue. Greywater (GW) reclamation is a viable option to reduce freshwater demand. The objectives of this work were to: a) evaluate the feasibility of the combination of shredded tire biofilter (STB) technology and membrane bioreactor (MBR) technology in GW reclamation; b) study the effects of various parameters on STB performance; and c) understand the fouling mechanisms to lower the energy consumption in MBRs. Bench-scale STBs and MBRs (flat-sheet membranes) were constructed to address the first two objectives, while an independent membrane (hollow-fiber membranes) fouling experiment was designed for the third objective.

It was found …

Applied And Mechanistic Studies Of Microbial 17beta-Estradiol Degradation, Zhongtian Li

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The presence of natural estrogens, a class of endocrine disrupting compounds, in water has caused increasing concerns over their adverse impacts on the health of aquatic eco-systems and human beings. In this study, adsorption characteristics of two natural estrogens, 17β-estradiol (E2) and estrone (E1), on granular activated carbon (GAC) were investigated in isotherm tests and in a GAC column. The GAC column was then converted to a biologically active carbon (BAC) column and the removal efficiency of E2 and its primary biodegradation intermediate E1 were monitored. During BAC operation, the impacts of various reactor operation parameters, such as the carbon …

Using Laser Scanning Cytometry To Investigate The Transport Of Nano-Scale Particles In Porous Media, Ryan May

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The increased production of nanomaterials in recent years has been unprecedented. Given their potential toxicity, understanding the mechanisms controlling the transport of nanoparticles in the subsurface is important. In this study, a technique was developed for using a Laser Scanning Cytometer (LSC) to visualize and quantify the stable attachment of nano-scale particles. Experiments using three different size particles, 510 nm, 210 nm and 57 nm, in conjunction with a flow cell system containing saturated glass beads under varied injection duration, solution chemistry, Darcy velocity and solids content were performed. A technique for using the LSC data to develop spatial distributions …

Economic Input-Output Life Cycle Assessment Of Water Reuse Strategies In Residential Buildings And Communities, Derek J. Gardels

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The objective of this study was to determine the environmental sustainability and economic feasibility of five water reuse designs using economic input-output life cycle assessments and benefit/cost analyses. These five water reuse designs were evaluated for four regions of the United States including the Northwest (Seattle), Southwest (Scottsdale), Midwest (Omaha), and Southeast (Tampa). The water reuse designs include a greywater reuse system with no treatment for sub-surface landscape irrigation for a single-family residential house (Model 1), an indoor greywater reuse system with treatment for toilet flushing and laundry washing for a single-family residential house (Model 2), a hybrid untreated greywater …