Full Description

Waterborne disease outbreaks and increased cases ofgastrointestinal illness have raised questions about theadequacy of distribution system barriers. The expansivenature of the distribution system makes it vulnerable to contamination.In particular, pressure transients such as surges or waterhammer offer opportunities for intrusion of contaminants fromthe external environment.This study set out to determine the occurrence of indicatormicroorganisms and pathogens in the vicinity of potable waterpipelines and assess the potential for intrusion created by transientdistribution system pressure changes. Soil and water sampleswere collected immediately exterior to drinking waterpipelines at eight locations in six states. Samples were tested forthe occurrence of total and fecal coliforms, Clostridium perfringens,Bacillus subtilis, coliphage, and enteric viruses. Indicatormicroorganisms and enteric viruses were detected in more thanhalf of the samples examined.Utilities need to be aware of the potential for water qualitydegradation to occur during pressure transients. Study resultsemphasize the need to maintain an effective disinfectant residualin all parts of the distribution system and to reduce leakageto minimize the potential for microbial intrusion into potablewater supplies. In addition, research should focus on gaininginsight into the role of pressure transients on drinking waterquality, including development of techniques to evaluate systemvulnerability to negative pressure and use of microbial or otherindicators to predict pathogen intrusion into the distributionsystem. Includes 24 references, tables, figures.

Product Details

Edition: Vol. 95 - No. 5 Published: 05/01/2003 Number of Pages: 13 File Size: 1 file , 310 KB