Disinfection of Pipelines - Disinfection of Pipelines and Storage Facilities Field Guide - page 28

Table 3-5 Pipeline disinfection methods summary

Minimum
Chlorine
Residual

Chlorine
Dosage

Holding
Time Method Notes

Tablet or
granules

25 mg/L 24 hr, 48 hr if

temperature
<5°C

Detectable Add enough to

fill entire
pipeline
segment

Continuous feed 25 mg/L 24 hr 10 mg/L Add enough to

fill entire
pipeline
segment

Slug 100 mg/L 3 hr 50 mg/L at

any point

Fill % of
pipeline with
slug and move
the slug slowly
to give 3 hr
contact

is completed satisfactorily. This checklist is used for all of the
examples shown in this field guide.

Chlorination Chemical Amount Calculation Checklist

❑ The pipeline diameter and length.

❑ Valves, hydrants, tees, and other appurtenances.

❑ Volume of chlorination (Table 3-6) water to disinfect pipeline (this is

the volume for disposal; chlorine residual is needed to determine
dechlorination chemical amount needed).

❑ Amount of chlorine chemical needed to complete the disinfection

procedure.

Final Flushing
Heavily chlorinated water should be flushed from the main
following the required holding period (usually at least 24 hr). All
main fittings, valves, and branches must be flushed. Chlorine