VI.
RO CLEANING & SANITIZATION PROCEDURES
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to be redirected to alternate destinations. This function is frequently used to
send this water to a sanitizing system return line. This becomes especially
useful when it is desirable to sanitize the RO system without sending chemicals
to the unit’s drain connection.
3)
Sanitization Procedures
CAUTION
The use of any cleaning or sanitizing solution is a complex process and if done
incorrectly, could destroy the membranes. Refer to the specific operation and
maintenance manual, the manufacturer’s literature, or consult the factory prior
to performing any cleaning or sanitization operation.
NOTE
Any type of deposit on the membrane should be removed by cleaning,
prior to sanitization. Removal of these deposits, which harbor
microorganisms, will maximize the degree of sanitization. After cleaning
and prior to sanitization, the unit should be placed in the
Rinse
mode to
flush the system with RO product water.
a)
Concentrate Sanitization
Much of the bacterial growth experienced within a Reverse Osmosis unit
should generally be limited to the “concentrate” side of the RO membranes. If
high counts within the RO unit appear to be limited to feed and concentrate
piping, a “Concentrate Sanitization” may be suitable for bacterial reduction.
This type of sanitization follows the same steps as a typical RO cleaning with
the sanitization chemicals premixed to the proper concentration in the RO
cleaning tank, instead of the RO cleaning chemicals. Note that some RO
cleaning procedures may also reduce bacterial counts to some degree.
Complete RO Sanitization
In order to completely sanitize an RO unit, including the permeate components
and piping, the sanitizing chemicals may be injected into the RO feed during
operation or mixed to the proper concentration in an RO feed tank and fed
through the unit during operation. In either case, the permeate produced should
either be diverted to drain during the sanitizing, or recycled and diverted to
drain when sanitization has been completed. Injecting the sanitant can be
accomplished through an existing chemical feed port, or sample valve
upstream of the RO feed pump. When injection of the sanitizing chemical is
chosen, make sure that a pump suitable to maintain the sanitant manufacturer’s
recommended sanitizing concentration is utilized.
CAUTION
Be aware that while running the RO with a sanitization chemical injected, the
RO reject stream and any product diverted to drain will contain some quantity
