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Retention of a Model Pathogen in a Porous Media Biofilm: Author: Bauman, Wesley James; Date: 2007-05-15; Program: Environmental Engineering; Abstract: The inadvertent or deliberate introduction of bacterial pathogens into drinking water systems can lead to serious public health consequences. As a result, rapid sampling opportunities within distribution systems are needed that can provide information on the source, species and fate of introduced pathogens. In this study, a porous media biofilm reactor was used to investigate the ability of an established mixed-species drinking water biofilm to immobilize cyan-labeled Escherichia coli 0157:H7 as a model pathogen. Test reactors were colonized with biofilm for two or three weeks at 0.5 mg/l C, r...; Download File | View full details

A Quantitative Description at Multiple Scales of Observation of Accumulation and Displacement Patterns in Single and Dual-Species Biofilms: Author: Klayman, Benjamin Joseph; Date: 2007-08-15; Program: Engineering; Abstract: This research represents a novel approach for describing biofilm accumulation at multiple scales of observation in both single and dual-species biofilms. Pseudomonas aeruginosa PAO1 and Escherichia coli O157:H7 were grown as single and dual-species biofilms in 1 mm glass capillary flow cells and monitored over time using confocal microscopy. Colonization and biofilm development patterns were associated with the fluid flow regime as evaluated using the finite volume analysis program CFX (ANSYS Europe, Ltd). The shear stress was shown to vary along the surface from a minimum near the edges to a ...; Download File | View full details

Hydraulic model calibration for the Girdwood, Alaska water distribution system: Author: Trasky, Trevor Ryan; Date: 2008-05-15; Program: Environmental Engineering; Abstract: The possible EPA promulgation of regulations requiring flushing programs for water distribution systems to regulate water age is encouraging many utilities to develop a better understanding of their systems. This usually involves the development of a hydraulic model. For the hydraulic model to be of use it must be calibrated using collected field data. Few established guidelines exist for utilities to perform such data collection and calibration. There are many different types of data that can be collected using many different methods. There are also various model calibration methods that can ...; Download File | View full details

Keys to unlocking the biofilm phenotype of a virulent environmental isolate of Salmonella: Author: Clark, Stewart James; Date: 2008-08-15; Program: Microbiology; Abstract: The aim of this research was to elucidate the phenotypic adaptation of an environmental isolate of Salmonella enterica grown in a single species biofilm using transcriptomic analysis. This environmental isolate was obtained from an outbreak in Gideon, MO, and was classified as Salmonella enterica serotype Missouri. Gene expression profiles obtained from this environmental isolate were compared with profiles of the ATCC type strain Salmonella enterica serotype Typhimurium LT2 grown under the same conditions. It was shown that there were distinct transcriptional differences in both of the strain...; Download File | View full details

Nitrification in premise plumbing systems: Author: Rahman, Mohammad Shahedur; Date: 2008-08-15; Program: Environmental Engineering; Abstract: Monochloramine is increasingly used instead of free chlorine as a secondary disinfectant. Ammonia is introduced into water for monochloramine formation or by decay. Nitrification can have deleterious effects on water quality that may lead to regulatory violations. In this project water quality and influence of pipe material on the onset of nitrification and consequences of nitrification in premise plumbing were investigated. Also potential control strategies for nitrification were evaluated. Initially two types of copper coupons (new and old, i.e., pre-exposed to 0.1N NaOH solution) were used ...; Download File | View full details