We own a 2000 ltr/h water treatment plant and it was working fine till two days ago. We were getting < 100 mg/l TDS with 2500 TDS of raw water and ~4000 mg/l TDS of wastage water.
Now all of sudden the RO membrane (DoW made BW30-400) is giving high output TDS of ~200 mg/ltr while the raw water is still having same TDS. Output wastage water TDS is now around 3000; it was around 4000 previously.
What could be the reason for this sudden increase in TDS? I don't think membrane can stop working all of sudden.
I tried cleaning the membrane and it gave 130 TDS for 2 minutes and started increasing after that to 200 again. Please suggest what to do?
Based on your short information I see two reasons for the higher TDS in the permeate of your RO unit - the life time cycle of the RO membrane is running out or one of the sealing element is leaky.
What about the Permeat flow? If permeat (produced clean water) flow has been increased, there is a broken probably membrane connector, or even broken membrane. If it is so, you will notify a continous TDS raising during time.
Bien entendu qu'il s'agit de la membrane qui maintenant est colmatée
C'est la problématique majeure de ce genre de dispositif: Dès sa mise en service elle perd de sa performance épuratoire pour finir par colmater ou laisser passer en masse toute la pollution retenue
Hello, of course, that it is the membrane that now is closed it is the major issue of this sort of device: from its commissioning it loses its purification performance eventually plug or pass all the accepted pollution mass
Do you follow Cleaning / Flushing CIP of RO Membranes as per DOW recommendations on timely intervals
Did you check your Inlet TDS, if this is same or changed?
Do you have a Pre-Filtratioin System before hand also which is functioning well?
Did you check ORP Meter is funcitioning well if you are using NaOCl as disinfectant in pre-filtration?
Does your SMBS Dosing Pump functioning well?
Does Cartridge Filter cleaned properly or needs replacement?
The most important, if you recently cleaned/opened the Vessel, then inserting membranes into the vessel is a careful job, each membrane module to be properly "Interlocked" and "Rubber O Ring" must be in place properly, otherwise, this could be the main reason for your issue.
Increase in Permeate TDS and Decrease in Reject TDS is a clear indication any of your Membranes has worn out/damaged/clogged thus not being able to perform properly the system as a whole.
Kindly do the above checks first, then take out membranes. I am sure your problem will be solved.