Nano membrane - damaged header element

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Nano membrane - damaged header element

Hello Membrane experts,

I inspected my nano membrane elements and found many  element with crack/damage of header element (please see the attached photos).

I would like to ask whether i can continue to use it or not? And what is it  possibly caused?

I am hoping to hear from all you. Thanks for help!

Regards,

Hieu

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6 Answers

  1. It looks that you are dosing excess FeCl3 in your pre-treatment. Please share your process flow diagram with process details for analysing the probable cause and suggesting suitable solutions. 

    It is not possible to use the defective membranes and it has to be discarded.

    1 Comment

  2. Hi,

    The same element shall be use by applying tape over it, as a temporary measure. 

    I had used this technique on SWRO membranes as a temporary measure and it worked. 

    Regards,

    R.Rajaraman

    2 Comments

    2. I would not recommend using these membranes any longer. We do not have knowledge of the use of these membranes and / or the purpose of them. (Drinking Water purification, Electroplating etc...) Taping the membranes as you suggest, will just create further damage and possibly more damage to other components, NOT advisable!

      1 Comment reply

      1. Thank for your advices. These membrane elements belong to Polishing stage of leachate treatment plant. What is the further damage if i keep using them? Does the effluent get worse? Thanks!

  3. Hello Hieu

    I would have to say it looks like you have a high differential pressure condition with your system.

    Have you reviewed your normalization data?

    Review your incoming feed pressure, system feed pressure (after pump) and your permeate pressure.

    Please reply your findings.

  4. I would not be able to jump to a conclusion on the underlying reason for such failure as its not so simple. Few more questions would help pinpoint to the problem.

    1. What is the configuration of the RO system? such as 3-2-1/6M 4/2/1/4M?

    2. Which end of the membrane shows damage - feed or conc?

    3. Is the separation appear to break where the feed/exit ATD is glued to the membrane?

    4. What kind of fouling you see (iron, scale, etc.)

    5. Do you see any telescoping, which would be visible on face of spiralwound..

    1 Comment

    1. Hello DILEEP,

      Thank you for your asking!

      please take my answers at below:

      1-This is NF skid not RO, Nano membrane type is DK8040F30 (Desal SUEZ), it configs 3 loops, 4 vessels/loop and 6 elements/vessel.

      2-Most damage comes from feed side;

      3-Yes;

      4-i saw a sticky layer around the membrane casing;

      5-No.

      i am looking forward to hearing from you soon.

      Regards, 

      Hieu

  5. Looks like significant fouling ( iron?) on the membrane have caused high differential pressure and subsequent telescoping.  Chances are high that you need a new set of RO elements. 

    1 Comment

    1. The membrane used to suffer from uf collapse (upstream), and  a lot of bio-sludge got stuck NF membrane chanel. It happended last Mar. 2018. The contractor cleaned it by  water hose from permeate port. Then they reloaded and put it back into operation till i inspected last week.

      Thanks for for answer!

      Hieu

      3 Comment replies

      1. Thank you for all your replies. How bad it is if i keep using it. And how long does it last? 

        The contractor cleaned the element with fresh water @3bar. I also warned them on the damages when reversing flow from permeate port.

      3. These membranes should have been chemically cleaned/treated. When you have fowling as you have, you can not clean the membranes by just flowing water from the permeate port, which is probably the cause of the damage.
        There are ways to clean the membranes by reversing the flow through the permeate ports but not advisable if you do not know how to do it. Reversing the flow in these types of membranes (RO or Nano) is tricky.
        Do you know at what pressure the contractor used to clean the membranes?

  6. Hello. This is definitely caused by high pressure condition. I have encountered such defects in RO membranes in the past. Can I have your email address? I am interested to know more about this issue.

    2 Comments