Scholarly Work - Center for Biofilm Engineering
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/9335
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Item Color measurement as a means of quantifying surface biofouling(1998-11) Pitts, Betsey; Hamilton, Martin A.; McFeters, Gordon A.; Stewart, Philip S.; Willse, Alan Ray; Zelver, NickLaboratory reactors fitted with removable ceramic porcelain growth surfaces were inoculated with a consortium of biofilm forming environmental isolates. A Minolta colorimeter CR-200 (Minolta Camera Co., Ltd, Ramsey, NJ) was used in conjunction with a specially designed adapter to evaluate the reflective color of the porcelain disks as biofilm accumulated on them. Areal viable cell counts were monitored over a period of eleven days in two separate experiments and direct color measurements of the untreated, microbially fouled test surfaces were collected. This colorimetric assay was both non-destructive and immediate. A strong linear relationship between log cell density and log color change was observed. The Pearson product moment correlation coefficient for all 45 observations combined was r=0.95. Separate regression lines for each experiment were not significantly different (P=0.19). When adjusted for time, the (partial) correlation coefficient between log cell density and log color change was r=0.87, which suggests that the relationship between the two measures can not be explained by their mutual dependence on time. Reflective color measurement provided a rapid, non-destructive and quantitative measure of biofilm accumulation.Item Bacterial characterization of toilet bowl biofilms(1998-08) Pitts, Betsey; Stewart, Philip S.; McFeters, Gordon A.; Hamilton, Martin A.; Willse, Alan Ray; Zelver, NickMethods have been developed and applied for sampling, characterizing and quantifying naturally occurring toilet bowl biofilms. Ceramic porcelain disks mounted in neoprene rubber strips were sealed in place in toilet bowls in three residences in Bozeman, Montana. In each bowl, duplicate strips were placed above, at and below the water level. In 7 consecutive weeks, duplicate disks from each zone in each bowl were removed. Surface biofouling was measured by viable cell areal density. Specific fouling rates were calculated and variability among toilet bowls and water levels was assessed. Specific fouling rates ranged from 0.0 to 0.46d‐1. Average areal cell densities at the end of 7 weeks ranged from 103 to 107cfu cm‐2. The extent of fouling was highest below the water line. Neutralization of the chlorine residual (typically 0.9 mg l‐1) in one toilet did not increase the extent of fouling compared to the controls. Biofilm areal viable cell densities and bowl water viable counts were positively correlated (r = 0.78). The visual threshold for detection of toilet bowl biofilm by the naked eye was approximately 105 cfu cm‐2. In a heavily fouled toilet bowl, the biofilm was up to 20 μm thick. Microorganisms were isolated from the biofilm and identified. Of the 32 organisms that were further characterized, 10 were identified as Pseudomonas, Sphingomonas or Chryseomonas species.Item Development of a standardized antibiofilm test(2001) Zelver, NickItem Measuring antimicrobial effects on biofilm bacteria: From laboratory to field(1999) Zelver, Nick; Hamilton, Martin A.; Pitts, Betsey; Goeres, Darla M.; Walker, Diane K.; Sturman, Paul J.; Heersink, JoannaItem On-line side-stream monitoring of biofouling(1993) Roe, Frank L.; Wentland, Eric Jon; Zelver, Nick; Warwood, B. K.; Waters, Ralf; Characklis, William G.Item Microbial Films and Energy Losses(1984) Characklis, William G.; Zelver, Nick; Turakhia, Mukesh HarilalFouling microbial film formation can cause significant energy losses as reflected by increased fluid frictional resistance and heat tranfer resistance. Methods to predict and monitor rate of microbial film formation and its effect on energy losses in different environments is essential for efficient design and operation of engineering systems. This paper will discuss measurement methods and their incorporation in predictive models.Item Potential for Monitoring Fouling in the Food Industry(1985) Zelver, Nick; Roe, Frank L.; Characklis, William G.Item Tube Material, Fluid Velocity, Surface Temperature and Fouling: A Field Study(1984) Zelver, Nick; Characklis, William G.; Robinson, J. R.; Roe, Frank L.; Dicic, Z.; Chapple, K. R.; Ribaudo, A.Item Influence of biofouling and biofouling control techniques on corrosion of copper-nickel tubes(1983) Characklis, William G.; Zelver, Nick; Nelson, Christopher H.; Lewis, R. O.; Dobb, David E.; Pagenkopf, G. K.Item Analysis and Monitoring of Heat Transfer Tube Fouling(1982-10) Zelver, Nick; Flandreau, J. R.; Spataro, W. H.; Chapple, K. R.; Characklis, William G.; Roe, Frank L.
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