Influence of pipe materials and VBNC cells on culturable bacteria in a chlorinated drinking water model system

• Published in: Journal of microbiology and biotechnology Vol. 17; no. 9; pp. 1558 - 1562
• Main Authors: LEE, Dong-Geun, SEONG JOO PARK, KIM, Sang-Jong
• Format: Journal Article
• Language: English
• Published: Seoul Korean Society for Applied Microbiology 01.09.2007
• Subjects: Bacteria - drug effects; Bacteria - growth & development; Bacteria - isolation & purification; Bacteriological Techniques; Biofilms - drug effects; Biofilms - growth & development; Biological and medical sciences; Biotechnology; Chlorine - pharmacology; Colony Count, Microbial; Disinfectants - pharmacology; Disinfection; Fundamental and applied biological sciences. Psychology; Materials Testing; Water Microbiology; Water Pollutants - toxicity; Water Purification - methods; Water Supply - standards; Chlorine compounds; Drinking water; pipe material; Viable but nonculturable (VBNC); Biofilm; direct viable count (DVC); Bacteria; Models; Pipe; Viability
• ISSN: 1017-7825

To elucidate the influence of pipe materials on the VBNC (viable but nonculturable) state and bacterial numbers in drinking water, biofilm and effluent from stainless steel, galvanized iron, and polyvinyl chloride pipe wafers were analyzed. Although no HPC (heterotrophic plate count) was detected in the chlorinated influent of the model system, a DVC (direct viable count) still existed in the range between 3- and 4-log cells/ml. Significantly high numbers of HPC and DVC were found both in biofilm and in the effluent of the model system. The pipe material, exposure time, and the season were all relevant to the concentrations of VBNC and HPC bacteria detected. These findings indicate the importance of determining the number of VBNC cells and the type of pipe materials to estimate the HPC concentration in water distribution systems and thus the need of determining a DVC in evaluating disinfection efficiency.