VI.
RO CLEANING & SANITIZATION PROCEDURES
Page - 33
In normal operation, a Reverse Osmosis membrane can become fouled by
mineral scale, biological matte, colloids and insoluble organic constituents.
Deposits build up on the membrane surface during operation until they cause
loss in water output, loss of rejection or both.
Membranes should be cleaned whenever normalized water output rate drops by
10 %, the permeate quality drops noticeably or differential pressure increases
by 15 % from the initial conditions established and recorded within the first 24
to 48 hours of initial start-up.
NOTES
The feed water temperature will effect the permeate rate of a Reverse
Osmosis unit under constant pressure. As the temperature decreases, the
permeate rate will decline. This is normal and does not indicate fouling.
Changes in feed water characteristics can also effect the rate of production
and quality of membrane permeate. Changes in pretreatment equipment
performance should be considered prior to establishing that the
membranes have fouled.
3)
Cleaning Chemicals
A relatively wide variety of chemicals are available to clean Reverse Osmosis
membranes. In general, the compounds available are formulated to address
specific membrane foulants.
This section discusses two such cleaning chemicals which are available
through U.S. Filter. Used as recommended, these products can be applied to
thin film composite membranes on a regular cleaning schedule without
compromising membrane integrity.
Additional cleaning chemicals are also available through U.S. Filter. If there is
reason to believe the compounds discussed here will not work for the expected
foulants in your system, or if additional information is required, please contact
the U.S. Filter Technical Service Department at 800-875-7873 (ext. 5000).
Disclaimer
Every Reverse Osmosis system application is unique in the characteristics of
its feed stream. Additionally, those characteristics may not remain constant
over the operational life of the unit. For this reason, U.S. Filter neither states
nor implies any warranty of the ability of the compounds or procedures
presented in this manual to partially or completely recover any membrane to its
pre-fouled performance. Furthermore, U.S. Filter accepts no liability for
personal or material loss resulting from the use of the chemicals recommended.
This disclaimer extends to the compounds and procedures which might be
recommended by U.S. Filter or its representatives for the purpose of Reverse
Osmosis membrane cleaning in the future.
Chemicals Used to Clean Inorganic Fouling
