Waterborne disease outbreaks and increased cases of
gastrointestinal illness have raised questions about the
adequacy of distribution system barriers. The expansive
nature of the distribution system makes it vulnerable to contamination.
In particular, pressure transients such as surges or water
hammer offer opportunities for intrusion of contaminants from
the external environment.
This study set out to determine the occurrence of indicator
microorganisms and pathogens in the vicinity of potable water
pipelines and assess the potential for intrusion created by transient
distribution system pressure changes. Soil and water samples
were collected immediately exterior to drinking water
pipelines at eight locations in six states. Samples were tested for
the occurrence of total and fecal coliforms, Clostridium perfringens,
Bacillus subtilis, coliphage, and enteric viruses. Indicator
microorganisms and enteric viruses were detected in more than
half of the samples examined.
Utilities need to be aware of the potential for water quality
degradation to occur during pressure transients. Study results
emphasize the need to maintain an effective disinfectant residual
in all parts of the distribution system and to reduce leakage
to minimize the potential for microbial intrusion into potable
water supplies. In addition, research should focus on gaining
insight into the role of pressure transients on drinking water
quality, including development of techniques to evaluate system
vulnerability to negative pressure and use of microbial or other
indicators to predict pathogen intrusion into the distribution
system. Includes 24 references, tables, figures.
| Edition : | Vol. 95 - No. 5 |
| File Size : | 1
file
, 310 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 13 |
| Published : | 05/01/2003 |
