Biofilm Composition and Threshold Concentration for Growth of Legionella pneumophila on Surfaces Exposed to Flowing Warm Tap Water without Disinfectant.

in potable water installations poses a potential health risk, but quantitative information about its replication in biofilms in relation to water quality is scarce. Therefore, biofilm formation on the surfaces of glass and chlorinated polyvinyl chloride (CPVC) in contact with tap water at 34 to 39°C was investigated under controlled hydraulic conditions in a model system inoculated with biofilm-grown The biofilm on glass (average steady-state concentration, 23 ± 9 pg ATP cm) exposed to treated aerobic groundwater (0.3 mg C liter; 1 μg assimilable organic carbon [AOC] liter) did not support growth of the organism, which also disappeared from the biofilm on CPVC (49 ± 9 pg ATP cm) after initial growth.

Probability of detecting and quantifying faecal contaminations of drinking water by periodically sampling for E. coli: a simulation model study.

Drinking water supply companies monitor the presence of Escherichia coli in drinking water to verify the effectiveness of measures that prevent faecal contamination of drinking water. Data are lacking, however, on the sensitivity of the monitoring programmes, as designed under the EU Drinking Water Directive. In this study, the sensitivity of such a monitoring programme was evaluated by hydraulic model simulations of contamination events and calculations of the detection probability of the actual sampling programme of 2002.

Sampling and quantifying invertebrates from drinking water distribution mains.

Water utilities in the Netherlands aim at controlling the multiplication of (micro-) organisms by distributing biologically stable water through biologically stable materials. Disinfectant residuals are absent or very low. To be able to assess invertebrate abundance, methods for sampling and quantifying these animals from distribution mains were optimised and evaluated.