Disinfection of Storage Facilities - Disinfection of Pipelines and Storage Facilities Field Guide - page 67

conducted by contractors, full documentation of all aspects of the
disinfection process should be required and test results certified.

Chlorination Methods
There are three methods for the chlorination of water storage
facilities:
1. The full storage facility chlorination method.
2. The surface application method.
3. The chlorinate and fill method.
A summary of the major features of each method is listed in
Table 5-1. Generally, the full storage facility method is used for
smaller size tanks. Both the surface application and chlorinate
and fill methods are commonly used for larger facilities.

Table 5-1 Storage facility disinfection methods summary

Chlorine
Dosage

Holding
Time

Chlorine
Residual Method Notes

Full Storage
Facility

10 mg/L 6 hr if

continuously
fed during
filling or 24 hr
if two-step
process is
used

10 mg/L

Repeat
procedure if
residual is less
than 10 mg/L,
reduce residual
prior to using

Surface
Application

200 mg/L,
add to drains
to achieve
10 mg/L
when filled

30 min 10 mg/L for

drains

Remove water
from drains
and fill with
potable water

Chlorinate and
Fill

50 mg/L in
about 5% of
the volume

6 hr, then fill
with potable
water and
hold for
another 24 hr

2 mg/L in full
facility after
holding period

Remove water
from drains
before filling