Disinfection of Pipelines - Disinfection of Pipelines and Storage Facilities Field Guide - page 48

Chlorination

CL 2 Tank

Dechlorinator

Pump Discharge

Hydrant
Source

Discharge

6-in.
Hose

Discharge to
Environment

Valve #1 Valve #2

Courtesy Nicole Peschel
Figure 3-15 Slug method pipeline disinfection example

the main to remove air; flushing the main; and then moving a
slug of 100 mg/L chlorinated water through the pipeline to
ensure at least a 3-hr contact time. The specific steps required for
this procedure are listed below.

Chlorination steps and precautions.
1. Flush the new main at a velocity of at least 2.5 ft/sec
(Table 3-1) unless site-specific conditions prevent this
practice. Large mains (greater than 24 in., or 600 mm)
may be broom-swept.
2. Hydrostatic testing must be completed prior to disinfection.
3. During construction, place (optional) calcium hypochlorite
granules or tablets in the pipe sections as described in
the Tablet Method using Tables 3-7a, 3-7b, 3-8a, and 3-8b
to determine the amount of granules and tablets needed.
This practice provides a strong chlorine concentration
during initial filling of the pipeline and disinfects annular
spaces at pipe joints. Do not use this procedure on
solvent-welded plastic or on screwed-joint steel pipe.