Environmental Engineering Reference
In-Depth Information
According to the Centers for Disease Control and Prevention
(CDC), deficiencies in the distribution systems are significant
contributing factors leading to waterborne disease outbreaks.
Figure 1-2 illustrates the relative contribution of various disease
outbreak causes. Distribution system deficiencies account for 32
percent of the total, and these sources are second only to treat-
ment deficiencies at 48 percent. Therefore, careful attention is
needed to ensure the integrity of distribution systems, including
disinfection of pipelines and storage facilities to reduce the possi-
bility microbiological contamination.
Pathogens can enter the distribution system through open-
ings in storage facilities, and during water main installation and
repair procedures. Pathogens present in water or soil in proxim-
ity to water mains and storage facilities (contaminated by sew-
age, farmland runoff, or other polluted sources) may also enter
Miscellaneous or
Unknown Causes, 7%
Contaminated Water Source,
No Treatment, 13%
Treatment
Inadequacies, 48%
Distribution System
Deficiencies, 32%
Figure 1-2 Drinking water associated waterborne disease outbreak causes,
Community Water Survey, 1971-2002
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