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.
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!
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!
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..
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.
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.
Pierre Dreher You are absolutely right, but please emphsis that the problem of membrane collapse is due to sudden high-pressure supply (start-up) on the clogged membranes and was ignored.
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?
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.