Pipeline Chlorination Simplified - Disinfection of Pipelines and Storage Facilities Field Guide - page 109

7. Final flushing
8. Bacteriological testing
9. Connection to distribution system
10. Documentation
Simplified Pipeline Chlorination Methods
The method selected by most utility system operators to dis-
infect pipelines generally depends on the size of the pipes. There
are three possible methods commonly used for this purpose:
• Tablet (granules)
￿ Continuous feed
￿Slug
Many system operators have abandoned the tablet (granules)
method in favor of the other two. A common explanation of this
preference is that the granules are often washed to one end of the
pipeline during the filling procedure. This often occurs despite
using great care to fill the pipeline slowly. When this happens
only part of the pipe is exposed to the correct disinfection dosage.
Another problem occurs when using tablets because they do not
always completely dissolve or they do not dissolve uniformly as
the pipe is filled. This results in a similar condition. Tablets and
granules are, however, commonly used to disinfect hydrants,
valve branches, and other appurtenances.
When employing any of the chlorination methods there are
several measurements that are always needed. Some of these are
defined by the pipeline measurements and some are the result of
the chlorination method selected. The values for the measure-
ments listed in the following chlorination checklist should be
obtained.
Using the following procedures provides the values for each of
these necessary measurements. Some of the measurements are
calculated using the tables and calculator formulas, while some
are given as elements of the description of the job.