The Importance of Distribution System Disinfection - Disinfection of Pipelines and Storage Facilities Field Guide - page 3

pipelines or storage facilities. Figure 1-3 illustrates the findings
from tests performed on undisturbed soil and water near pipe
installations (Kirmeyer et al. 2001).
Soil containing pathogens and other microbes is the most
common source of microbiological contamination associated with
water main installation and repair. Wet soil often contains more
of these contaminants than dry soil. Microbiological contamina-
tion of pipelines comes from:
• Accumulation of soil, sediment, and other foreign mate-

rial on the interior of new pipes, and appurtenance sur-
faces during storage and installation.

￿ Accumulation of soil on the interior of existing exposed

pipes.

100

90

80

70

60

50

40

30

20

10

0

Soil

Water

Figure 1-3 Percent positive (for various microbes) water and soil samples