Engineering Commons^™

The Effect Of Malathion On The Activity And Performance Of Activated Sludge, Erik G. Rauglas

Theses and Dissertations

Decontamination activities following a chemical weapons incident may generate significant quantities of contaminated wash water that may enter the wastewater collection system either intentionally or accidentally. This raises concerns about the effect of chemical warfare agents (CWAs) on the operation of a biological wastewater treatment plant. The goal of the study was to evaluate the effect of malathion on the activity and performance of activated sludge. Malathion is an organophosphate (OP) and is considered an environmental surrogate for VX. This study employed respirometry, short term batch tests, and long term exposure experiments to investigate the effects of different concentrations of …

Quantifying Stormwater Runoff Contaminant Mitigation By Bioretention Cells, Patrick J. Walsh

Department of Biological Systems Engineering: Dissertations, Theses, and Student Research

This research study has three objectives, quantify the presence and concentration of selected contaminants in urban stormwater runoff from several urban locations within Lincoln, Nebraska, quantify the effectiveness of two, 10-year old bioretention cells, for reducing concentrations of contaminants in effluent and quantify the effectiveness of six rain gardens.

The primary research sites were two bioretention cells using automated samplers collecting grab samples of stormwater runoff influent and effluent for at least six precipitation events during a two-year period. Additional research sites included samplers for two rainfall, six rain garden, two commercial rooftop, two commercial parking lot, and six residential …

Flow, Spray Pattern, And Droplet Spectra Characteristics Of An Electronically Actuated Variable-Orifice Nozzle, Joe D. Luck, Santosh Pitla, M. P. Sama, S. A. Shearer

Department of Biological Systems Engineering: Papers and Publications

The purpose of this study was to develop and evaluate the flow rate, spray pattern, and droplet spectra characteristics of an actively controlled variable-orifice nozzle at constant carrier pressures. A commercially available variable- orifice nozzle (VariTarget) was modified to allow for direct electromechanical control of the metering stem. The modified system was tested at five carrier pressures ranging from 138 to 414 kPa and five metering stem (and thus orifice) positions. The metering stem position range was chosen because it provided a linear response in flow rate at each carrier pressure. Flow rate testing indicated a turndown ratio of 2.4:1 …