Browsing by Author "Bargmeyer, Alex Martin"

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Assessment of the ability of the bioelectric effect to eliminate mixed-species biofilms
(2005-10) Shirtliff, Mark E.; Bargmeyer, Alex Martin; Camper, Anne K.
Microbes have been able to persist in water distribution systems through the development of multicellular communities known as biofilms. This study evaluated the usefulness of the bioelectric effect for the elimination of water distribution system biofilms from annular reactors. The bioelectric effect did not have any bactericidal action either alone or when coupled with free chlorine.
Innovative biofilm control strategies
(Montana State University - Bozeman, College of Engineering, 2003) Bargmeyer, Alex Martin; Chairperson, Graduate Committee: Anne K. Camper
Minimizing biofilm in presence of iron oxides and humic substances
(2002-09) Butterfield, Phillip W.; Camper, Anne K.; Biederman, Joel A.; Bargmeyer, Alex Martin
Based upon circumstantial evidence linking elevated coliform bacteria counts in drinking water distribution systems with unlined cast iron pipe, it was hypothesized that adsorption of humic substances by iron oxide containing corrosion products (CPs) can stimulate and/or support biofilm development. Using porous media consisting of iron-oxide-coated glass beads (IOCBs) or actual iron Cps, experiments were performed to evaluate the effectiveness of different corrosion control and disinfection treatments in reducing biofilm when humic substances were the carbon source. Free chlorine was the most effective treatment in minimizing biofilm. Addition of phosphate alone did not significantly reduce biofilm using the CPs, but there was weak evidence it did using the IOCBs. The combination of free chlorine and phosphate was more effective at minimizing biofilm than free chlorine alone when CPs were the media. The presence of humic substances was a major factor when considering biofilm minimization based on results of experiments using both types of iron oxide media. The combination of humic substances and CPs led to an increase in biofilm biomass when free chlorine was not present, similar to conditions that could occur at distribution system dead-ends. Treatment to raise the pH to 9 did not reduce biofilm in experiments using both media, and actually increased biofilm in the experiment using CPs under the conditions tested.
Modified enzyme activity assay to determine biofilm biomass
(2002-06) Butterfield, Phillip W.; Bargmeyer, Alex Martin; Camper, Anne K.; Biederman, Joel A.
An assay of potential exoproteolytic enzyme activity was modified to quantitatively measure the biomass of attached biofilm. The assay utilized the nonfluorescent compound l-leucine-β-naphthylamide (LLβN) that becomes fluorescentwhen bacterial exoenzymes break the peptide bond, releasing the fluorochrome β-naphthylamine. Fluorescence development was measured by pumping the liquid phase of a biofilm sample through a fluorescence detector and recording the detector output using a personal computer. A significant linear relationship was shown to exist between the rate of fluorescence development and the biofilm's biomass as carbon, determined using total direct cell counts, measured cell volumes and an existing relationship between cell volume and cell carbon. The technique was used to measure biofilm biomass for experiments where iron oxides were the substratum. Biofilm biomass measurements made using heterotrophic plate counts (HPCs) on R2A medium were shown to correlate well to biomass measurements made using the modified enzyme assay. The technique was shown to be sufficiently sensitive to measure biomass on samples containing little biofilm biomass, such as those exposed to free chlorine. While granular and porous media were used for the experiments presented, small biofilm coupons could easily be used to measure biofilm biomass, expanding the number of possible applications for the enzyme assay technique.