Disinfection Procedure:
UV disinfection is a physical disinfection process and does not add any potentially
harmful chemicals to the water. As UV does not provide a disinfection residual, it
is imperative that the entire distribution system located after the UV be chemically
disinfected to ensure that the water is free from any bacteriological contaminants.
The disinfection process must be performed immediately after the UV unit is installed
and repeated thereafter whenever the UV is shut down for service, without power, or
inoperative for any reason. The procedure for sanitizing the plumbing system is
readily accomplished as follows:
1. Shut off the upstream water supply that feeds water into the reactor chamber and
depressurize water system. Remove the pre-filter cartridge and fill the sump with
1-2 cups of household (5.25%) bleach (chlorine) – Do NOT use hydrogen
peroxide.
Note: Make sure the carbon filter is removed from the sump while
performing this function as the carbon filter will remove the bleach from the
system thus preventing the disinfection process.
At all times during this process,
make sure the UV unit (and lamp) is turned on and operational!
2. Repressurize water system, open each faucet and allow cold water to run until you
smell chlorine, shut the faucet off and then repeat the process for each faucet,
including hot water. You must ensure that all taps, including outside faucets,
dishwashers, shower heads, washing machines, connections to refrigerators,
toilets, etc., pass chlorinated water.
3. Once all the locations have passed the chlorine disinfection solution, you will
need to leave the solution sit for a period of 20–30 minutes. Reinstall the pre-filter
cartridge into the filter and then flush the chlorine solution from the system until
no chlorine smell is detectable. Make sure that each fixture that was disinfected in step
two is completely flushed of the chlorine solution as the consumption of this water is
not advised due to the extremely high concentrations of chlorine. It is important to
remember that in the event that a UV is briefly shut down for routine cleaning or
during power interruptions where water could have passed through the system, the
aforementioned procedure must also be followed.
Note A: The addition of chlorine (bleach) to a hot water tank that has in the past
been fed with untreated raw water with high levels of other contaminants (iron,
manganese, hydrogen sulphide, organics, etc.) will result in oxidation of these
contaminants and may require repeated flushing of the hot water tank. This
contingency must be dealt with independently under the start-up procedure for
any other conditioners that may form a part of the pre-treatment for the UV unit.
Note B: The above procedure (Steps 1 to 3) will result in a massive chlorine
residual far in excess of the 0.5 to 1.0 mg/L typically present in municipally
chlorinated water and of a magnitude consistent with the minimum 50 mg/L
chlorine solution recommended for the disinfection of distribution systems known
to be contaminated. Do not consume water until complete system has been
flushed.
pLEAsE NOTE:
As the SCM series systems include a 254nm UV intensity monitor, it should
be noted that the introduction of the bleach solution required for disinfection
WILL
trigger
a temporary low UV condition. This is due to the fact that the bleach physically “clouds”
the raw water. Once the bleach runs through the system, the alarm condition will return to
normal. During this sanitization process, the audible alarm condition on the Cobalt “Plus”
controller can be temporarily deferred by pressing the “RESET” switch for 5 seconds. By
doing this, the audible alarm will be silenced and the solenoid relay will close (AC power
will be provided to the normally closed (NC) solenoid, allowing water to pass through the
system). The system will display on the controller LED. This condition will remain for
12 hours unless the system is manually reset as outlined on page 10 of this manual.
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