Disinfection of Pipelines - Disinfection of Pipelines and Storage Facilities Field Guide - page 40

Fill Line

Static Mixer

CL 2 Tank

6-in. Rubber
Hose

Fire Hydrant

Discharge
Hose

Pump Discharge

Sample Tap

2½-in. MFHA

6-in. B/O

1¼-in. Corp

Isolation Valve #1
Conduit

Discharge to
Environment

Conduit

Butterfly Valve #1 Butterfly Valve #2

Courtesy Nicole Peschel
Figure 3-13

Pipeline chlorination by continuous-feed method

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. Place (optional) calcium hypochlorite granules or tablets
in the pipe sections as described in the Tablet Method.
This practice provides a strong chlorine concentration
during the initial filling of the pipeline and disinfects
annular spaces at pipe joints.
4. Supply a constant flow rate from a temporary, backflow-
protected source or other approved supply source. Deter-
mine the flow using a pitot gauge in the discharge (or
other type of meter), measuring the time to fill a precali-
brated container, or use the trajectory discharge method
(shown in Figure 3-3).
5. Inject the concentrated chlorine solution no more than
10 ft (3 m) from the beginning of the new main. The dosage