HEALTH AND SANITATION
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a proposed UV installation. Power protection, power
conditioning equipment or an uninterruptible power
supply may be necessary in some cases.
Alarm and reactor shutdown conditions should be
clearly identified.
A lamp breakage response plan should be
developed that defines emergency response actions
that will be taken if a lamp breaks. Low velocity
traps or other piping configurations to collect
broken lamp components should be considered.
The potential for hydraulic transients should be
evaluated because they may cause the quartz
sleeves that house UV lamps to fail.
MAINTENANCE NEEDS
UV reactors, like other legionella treatment options,
require routine maintenance to ensure that the UV
dose remains adequate for inactivation of pathogens.
Some of the basic maintenance items include
cleaning the quartz sleeves housing the lamps and
periodically replacing the lamps, as their output
decreases with time. Most UV lamps installed in
smaller reactors will typically be rated for 8 000–
12 000 hours of operation (one year of continuous
operation equals 8 736 hours).
To better understand the lamp output over time,
premise plumbing operators may want to consult with
the UV equipment manufacturer (USEPA, 2006c). In
addition, some reactor components can be affected
by disinfectants, including chlorine, added prior to
the reactor, requiring additional maintenance. For a
detailed list of recommended maintenance activities for
a UV reactor, please see EPA’s Ultraviolet Disinfection
Guidance Manual for the Final Long Term 2 Enhanced
Surface Water Treatment Rule. PA
Water treated using
only UV disinfection
may, in some cases,
be susceptible to
contamination at
downstream points.
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