Environmental Engineering Reference
In-Depth Information
Courtesy Nicole Peschel
Figure 4-2
Sprayers for repair part disinfection
must be returned to service quickly. The repaired main is flushed
(dechlorinate if necessary) until the chlorine residual is no higher
than the distribution system feed water (distribution systems
that use chloramines require testing for free and combined
chlorine).
The repaired main should be thoroughly flushed regardless of
whether it is chlorinated or not. Flushing is the best way to
remove any foreign material that may have entered the main
during the repair. The water should be flushed until it is clear
and the chlorine residual is equivalent to the distribution system
feed water.
Ops Tip
Flushing the repaired main before returning it to service is
critical.
Tapping sleeves are used to install a tap in the main without
the need to shut down the main. When using these devices, the
exterior of the main should be cleaned in the tap location. Also,
calcium hypochlorite should be applied to the interior of the
sleeve. After the tap is made, it is impossible to disinfect the
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