Environmental Engineering Reference
In-Depth Information
section. Bacteriological testing is then conducted before the tem-
porary service is placed into use.
Chlorination
Three methods of chlorination are described in this field
guide: tablet or granules, continuous feed, and slug. Factors to
consider when selecting one of these methods are the length
and diameter of the main, the type of joints, availability of mate-
rials, equipment required, training of the personnel, and safety
concerns.
Each method has advantages and disadvantages that need to
be considered. The calculation of the amount and the application
procedures for each method are discussed in detail later in this
chapter (summary shown in Table 3-5).
Tablets (granules)
Pipe must be clean and dry
Convenient for use in mains up to 24 in. diameter
Need adequate time to dissolve in water
Water flow may move granules to one end of a pipeline
Disinfection may not be uniform
Continuous feed
Suitable for general application
Gas chlorinator needed
Chlorine gas safety issues
Slug
Suitable for large-diameter mains
Chlorine gas feed and safety issues
May save chemicals
Reduces volume of high-chlorine water for disposal
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. Filling out the chlorination
chemical amount calculation checklist ensures that the procedure
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