Membrane Preservation At Shutdowns - JOSMOSE 8040 Serie Manual De Usuario

2. Recirculation of the cleaning solution in the system:
The membrane must be cleaned at low pressure (< 2 bar) and the flow must not
exceed the set limits. Recirculation and rest periods should be inserted in order to
favor the contact of the cleaning solution with the dirt and facilitate its removal.
If the cleaning solution shows a strong color chanching and/or precipitation appears,
it should be discarded and a new one should be made, repeating the process. During
the entire cleaning phase, the return concentrated and permeate valves of the
cleaning tank must be kept open, but the permeate valve of the product water tank
must remain closed during the entire process and will only be opened once the quality
of permeate water is optimal.
When the fouling is massive, it is usually recommended to clean while recirculating at
a low flow for 10-15 hours.
In case of high temperature cleanings 35-45°C (depending on the cleaning solution
pH), a low flow rate is also recommended.
3. Ejection of cleaning/rinsing solution
After cleaning (or between cleaning steps), the membranes and the cleaning circuit
must be rinsed with water of appropriate quality for each type of membrane.
The rinsing process ends when there is evidence that the cleaning solution inside the
membranes has been completely ejected.
4. Production start-up
Once the rinsing process is complete, the system is started by ejecting the product
water for 30 minutes at the design nominal flow rate, to ensure the complete
elimination of cleaning chemicals traces in the osmotized water line.
There are products designed specifically for membrane cleaning, where in addition to
acids or bases, detergents, pH regulators and other compounds are added to help
with the removal of dirt.
All products used in the membrane cleaning must be approved by makers

10.3 MEMBRANE PRESERVATION AT SHUTDOWNS

In all cases of shutdown, before being shutdown from service, it is advisable to rinse or
flush with product or feed water, in order to minimize the risk of incrustation and/or
deposition.
In case of less than 48 hours shutdown, it may be enough to carry out an ejecting with
permeate water or start the equipment every 24 hours for 30 minutes
In case of shutdowns between 48 hours to 5 days, during periods of inactivity of the
equipment or in order to perform maintenance works, it is necessary to protect the
membranes from microbiological growths that would subsequently affect the
performance of the installation. One of the procedures consists on the introduction of a
solution of permeate water and sodium bisulfite (food grade) with a concentration of 500-
1,000 ppm.
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8040_6000TDS_std_V1.3