Off-season storage of my membrane

[Woodsrover]

Done for the year and I have a XLE-4040 membrane in my RO that I want to store properly until next year. I remember seeing someone here that I should take it out and store it in a 4" pvc pipe with some sort of solution, but I can't seem to find that thread. Any help would be appreciated.

Thanks!

[Russell Lampron]

My RO is in a heated room so I leave my membrane in my machine. I just leave it full of permeate. The permeate soaks up the minerals in the membrane and I don't have to flush out any toxic chemicals before I can concentrate again. Last season my membrane was pretty much plugged up at the end of the season and I was hoping to be able to make enough permeate to flush out the new membrane that I bought. To my surprise it cleaned up and I'm still using it now more than half a season later. You can store yours the same way in a PVC tube. Just fill the tube with permeate and store it where it won't freeze.

[jmayerl]

The industry approved way to store a membrane after properly cleaning it would be in a separate vessel filled with sodium metabisulfite.

[Woodsrover]

So I ran 250 gallons of sap through my RO on Saturday. When I was done I pulled the pre-filter and ran 60 gallons of permeate through the machine and stuck it in the basement. (This is a brand new membrane that only had these 250 gallons of sap through it.) Last night, two days later, I pulled the membrane out to store it in a 4" piece of PVC pipe filled with water and preservative. It was stinky. Not sure what's happening with it but one thing for sure is that a 60 gallon wash isn't enough. Next year I'm considering pulling the membrane after every weekend of running and figuring out a way to clean it better. I'm a bit disappointed in what seems to be a whole lot of maintenance to running an RO. Wondering what you guys are doing between use. Any help is appreciated.

[Urban Sugarmaker]

So I ran 250 gallons of sap through my RO on Saturday. When I was done I pulled the pre-filter and ran 60 gallons of permeate through the machine and stuck it in the basement. (This is a brand new membrane that only had these 250 gallons of sap through it.) Last night, two days later, I pulled the membrane out to store it in a 4" piece of PVC pipe filled with water and preservative. It was stinky. Not sure what's happening with it but one thing for sure is that a 60 gallon wash isn't enough. Next year I'm considering pulling the membrane after every weekend of running and figuring out a way to clean it better. I'm a bit disappointed in what seems to be a whole lot of maintenance to running an RO. Wondering what you guys are doing between use. Any help is appreciated.

60 gallons is probably the minimum. The smell is bacteria growing and releasing gasses that have an unpleasant odor. It doesn't matter that it is a new membrane with only 250 gallons of sap. I would have done a soap wash before storing the membrane. At least a warm water wash followed by a soap wash. Then mix a 1% SMBS solution and store the membrane in it for the off-season. I use a 4" PVC pipe with caps for storage. After 6 months, replace the solution.

The SMBS will keep any remaining bacteria at bay. Last year I soap washed and rinsed, then left town for a week and when I got back, it stunk and had blisters on the tape wrap. Again, that was from gasses released by the bacteria. I re-washed and then stored it in teh SMBS solution, and no more issues. The SMBS has smell to it as well but it is more like a chemical smell, not a foul smell.

During the season I soap wash after every third use or if performance is dropping. After each use I do a thorough rinse of at least 75 gallons. Be sure to use a different filter for wash which can be reused multiple times. The filter you use when concentrating will harbor a tremendous amount of bacteria. You said you pulled yours so that's good, but still use a filter. The purpose of the "soap" is to break down organic fouling which will contribute to odor and decreasing performance. Did you use detergent?

You say you are disappointed with maintenance. I had 190 taps this on the same evaporator and my longest boil was 6 hours with close to 300 gallons of sap that became about 60 gallons of concentrate. I'll take that any day with my full time job in the mix. Can't imagine a 25-30 hour boil. You have 200 taps, so I think even with the RO maintenance, you are WAY ahead on time and firewood.

[Russell Lampron]

First you didn't say if you did a soap wash or not.

Second when you are done concentrating you need to flush the sugar out of the machine. Run the machine on concentrate and run permeate through it to flush out the sugar. Keep flushing until the concentrate reads 0% sugar. This takes about 5 minutes on my RO.

Third change the pre filter, fill your wash tank and do a wash cycle according to the manufacturers recommendation. You will need to heat the wash water if your RO doesn't do it for you. You should run at least 3 wash cycles at the end of the season to properly clean the membrane(s) for storage.

Forth drain the wash tank and rinse the machine with permeate. Sixty gallons isn't enough! You need to store and use twice as much permeate as what your RO is rated for.

Fifth run membrane preservative through your RO if you want to. I skip this step so that I don't have to flush the preservative out before I can concentrate again.

Sixth remove and store your membrane(s) in a pvc tube filled with permeate or a storage solution. I have the luxury of leaving the membrane in my RO because I heat my RO room in the freezing months.

[VT_K9]

We have a CDL 250 RO. Everytime after using the RO we rinse with 100 gallons of permeate. We run a wash cycle with soap. We rinse with 100-150 (whatever is left in the tank) galls of permeate. At the end of the past seasons we had CDL test the membranes. They came back great. We are going to store the membranes this year in the storage solution after a more thorough cleaning/rinse cycle. I have stored by membranes in permeate only after a wash for a short time and had the odor you are talking about. I ran about 100 gallons of permeate (or house water) for the first rinse of the year (my house water is from a well not a city system).

I would recommend a longer rinse and wash cycle, but I am sure it won't effect the eventual bacteria growth. The maintenance will help the expensive membranes work properly longer.

Mike