Other Civil and Environmental Engineering Commons^™

Efficiency Of Bank Filtration In The Removal Of Cyanotoxins Under Different Levels Of Nutrients, Luke Walkenhorst

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

Harmful Algal Blooms (HABs) are an increasing concern not only in Nebraska, but across the world. Increasing global temperatures in conjunction with overuse of synthetic fertilizers are leading causes to the increasing frequency and concern of HABs. In the present work, the effectiveness of simulated bank filtration (BF), as an economical water treatment option, to remove cyanotoxins under different levels of nutrients (nitrates and phosphates) was investigated. Vertical flow-through columns pre-acclimated with two levels of nutrients (e.g., nitrate and phosphate—10 vs. 50 mg/L) were exposed to two different levels of cyanotoxins (10 vs. 75 μg/L). Results from the study confirmed …

Effects Of Nutrient Level And Growth Rate On Mutation And Conjugation Processes That Confer Antibiotic Resistance To E. Coli, Mohammadreza Shafieifini

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

Antibiotic resistance genes (ARGs) may enter surface water with the discharge of treated wastewater. Conjugation is a main mechanism for the horizontal gene transfer of ARGs from wastewater microbiome to the microbiome indigenous to surface water. However, little is known about how environmental factors affect the conjugation process of ARGs.

In this thesis, an extensive research related to spreading antibiotic resistance genes in the environment is reported. The project investigated how environmental parameters may affect the rate of dissemination of ARGs and in what extent the resistance level of the population is changed after mutation and conjugation event. The chemostat …

Biofiltration Of Volatile Organic Compounds Emitted At Ethanol Plants, Christopher Arthur Duerschner

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

Ethanol manufacturing is an important and growing sector in the biofuels marketplace. At ethanol plants, the control of volatile organic compound containing emissions from fermentation tanks and distillers dried grains with solubles driers is accomplished through the use of air scrubbers and regenerative thermal oxidizers. The operation of these control units imposes substantial operating costs for the ethanol plant. Biotrickling filters have the ability to replace scrubbers and regenerative thermal oxidizers resulting in significant economic and environmental benefits. Two biotrickling filters were operated in parallel under acetaldehyde loadings ranging from 4 to 136 gm^-3hr^-1. To examine …

Simulation And Prediction Of The Groundwater Level In The Surrounding Area Of The Nebraska Management System Evaluation Area Site In Central Nebraska., Cesar Augusto Gomez Peña

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

An efficient water budget is necessary to develop sustainable practices in irrigated lands and determine future trends. Despite a lack of detailed knowledge, climate change is found to profoundly influence groundwater resources through changes in groundwater recharge, groundwater elevation, and groundwater flow processes. Prediction of the groundwater level (GWL) under a changing climate is essential to improve agricultural management.

The goal of this research is to predict the GWL from 2056 to 2060 in the surrounding area of the MSEA. In order to achieve the target, the first research task is to develop a groundwater flow model and then simulate …

Passive Stormwater Samplers For Sampling Highway Runoff From Bmps: Feasibility Studies, Mitchell R. Klein

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

Pollution from highway stormwater runoff has been an increasing area of concern within the environmental field. To respond to the need for reduced contamination within runoff many Best Management Practices (BMPs) have been implemented. One difficult aspect of BMPs is monitoring their effectiveness along with determining effluent concentrations. The current methods for stormwater sampling include sending technicians or installing an auto-sampler to collect either grab or composite samples. These methods become costly, cumbersome and infeasible due to the potentially large amount of BMPs across a region and the irregularity and difficulty of predicting storms. Passive samplers have proven themselves as …

Development Of Best Management Practice Design Guidance For Roadway Applications In Nebraska, Benedict Vacha

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

Runoff from roadways carries pollutants which may be detrimental to aquatic ecosystems. The primary pollutants of concern for roadway runoff are solids and heavy metals, particularly cadmium, copper, and zinc. Roadway runoff falls under the legislation of the Clean Water Act (CWA) via the National Pollutant Discharge Elimination System (NPDES). CWA regulates discharge of nonpoint source pollutants, such as roadway runoff, by issuing permits to public entities which manage Municipal Separate Storm Sewer Systems (MS4s). Part of the Nebraska Department of Roads (NDOR) permitting requirement is to create a design guide for Best Management Practices (BMPs) tailored to remediate roadway …

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 …

Effects Of Warm-Mix Asphalt Additives On Asphalt Mixture Characteristics And Pavement Performance, Jun Zhang

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

The primary objective of this research is to evaluate the feasibility of several WMA mixtures as potential asphalt paving mixtures for Nebraska pavements. To that end, three well-known WMA additives (i.e., Sasobit, Evotherm, and Advera synthetic zeolite) were evaluated. For a more realistic evaluation of the WMA approaches, trial pavement sections of the WMA mixtures and their HMA counterparts were implemented in Antelope County, Nebraska. More than one ton of field-mixed loose mixtures were collected at the time of paving and were transported to the NDOR and UNL laboratories to conduct comprehensive laboratory evaluations and pavement performance predictions of the …