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5.6
Storage of Membrane Cassettes
The objective for proper storage of the membrane cassettes is to ensure the membranes
remain wet and prevent microbial growth during the time the membrane cassettes are not
being used.
Compression on cassettes stored in the holder should be reduced during storage. Reduce the
torque or hydraulic pressure by 25%. Check that there is no external leaking from around the
cassettes.
5.6.1
Recommended Storage Agents for Omega Membranes
Recommended storage agents for Omega membranes is 0.05 to 0.1 N NaOH.
Cassettes may be stored for periods up to 1 year or longer. However, it is
recommended that at 6 months storage, the pH of the storage solution be tested to
determine if it is sufficiently caustic. Cassettes may be flushed with fresh storage
solution at this time.
Table 14
Recommended Storage Temperatures for Used Cassettes
Temperature
4 – 15 °C
optimal
25 °C
maximum
Caution: Do not freeze.
If cassettes will be stored in water, skip Sections 5.6.2 and 5.6.3 go to Section 5.6.4.
5.6.2
Adding Storage Agent to System
Figure 32
System Setup for Flushing Storage Agent through System
Volume of Storage Agent Required: 5 to 10 L/m
2
(0.5 to 1 L/ft
2
)
Procedure
1. Drain the system and add storage agent to the feed tank.
2. Open the retentate and permeate valves.
3. Start the pump and increase speed until the flow comes through both the
retentate and permeate lines. Allow a volume equivalent to about 2 hold-up
volumes to pass out of the retentate to waste.
Retentate
Permeate
Feed
Tank
Waste
Waste
Feed
Pump
Pp
Rp
Fp
