Membrane Cleaning

[danno]

Can someone go through a step by step process for cleaning membranes, including which cleaner I should be using. I just bought DOW Filmtec XLE 4040's. I just checked the DOW website, but still don't have my answers.

If I recall - I want a PH of 13 and solution temp of 110? How long do you wash and at what pressure? Same with the rinse cycle - what pressure?

I don't have recirc pumps - so my options are just using the flo pump or that pump and high pressure pump.

Thanks!

[DrTimPerkins]

Can someone go through a step by step process for cleaning membranes, including which cleaner I should be using.

Contact your maple equipment dealer or RO manufacturer and let them know the machine and membrane you're using. Using the wrong chemical and/or procedure in an RO can ruin your day in a hurry.

[danno]

RO manu is no longer making RO's - it's older unit, thus the reason for no recirc pumps. Membrane dealer was Joe at Atlantic. He referred me back to the board as he thought those on this board would know better than anybody. So, I'll rely on the collective wisdom of those here.

[sapman]

Dan, I would grab your catalog and start calling around to reputable dealers. See what the consensus is. Many dealers buy from Joe instead of the big guys.

Tim

[wiam]

What brand is the RO?

Will

[danno]

Tim - Sandy was going to fax me the instruction sheet they hand out. She thought the powder detergent, not the liquid. Was just hoping to learn from other Traders with experience cleaning these.

Will - it's an old Sap Brothers.

[tuckermtn]

danno- is your RO from Maple Harry by any chance? he is a great resource on those older sap brothers. he lives out by Tim- I think its a bit north of Jack Reef.

[danno]

Yes Eric - it's Harry's. He lives about 10 minutes from me. He did give me cleaning instructions when I bought it, and that's how I cleaned it last year. But that was on 20 year old Osmonic membranes, using bleach as the wash solution.

[Homestead Maple]

The membrane that I have in my Lapierre RO is a Dow Mark 1 and the cleaning chemical is sodium hydroxide solid (powdered, not liquid). The cleaning solution you mix with hot water (100 degrees) to get a ph of 11. The solution temperature should never reach 120 degrees. Circulate this solution through the membrane with the high pressure off for 1 1/2 hours for a short wash and for 6 to 12 hours for a long wash. Alternate between the circulation cycle and the rest cycle. During the rest period, the recirculation pump is not running, but the feed pump is still running, this is so that the machine does not go below 90 degrees. Your trying to maintain the temp around 100 degrees and not more than 120 degrees. Maybe your machine has an auto temperature shut down anyway, as mine will shut down if the temp gets over 115 degrees. If you're doing a short wash, the cycle is 15 minutes circulation, 15 minutes rest circulation. If your doing a long wash cycle, it's 30 minutes circulation and 30 minutes rest cycle, then 30 minutes circulation, then 3 to 6hours rest cycle, then 30 minutes circulation, then 3 to 6 hours rest cycle. Wash time depends on how dirty the membrane is. If you would like a copy of my instructions, let me know and I will send you the info.
Hope this helps.

[DrTimPerkins]

.... using bleach as the wash solution.

Bleach should NOT be used with most modern RO membranes. It will destroy them. Even chlorinated tap water is not good for them.

[DrTimPerkins]

....Circulate this solution through the membrane with the high pressure off for 1 1/2 hours for a short wash and for 6 to 12 hours for a long wash. Alternate between the circulation cycle and the rest cycle. ...

And after every wash cycle, it is CRITICAL that there be a sufficient RINSE cycle to avoid contamination of sap with these harsh chemicals.

[white mt]

And after every wash cycle, it is CRITICAL that there be a sufficient RINSE cycle to avoid contamination of sap with these harsh chemicals.

Q Could you give a number of Gallons for a sufficiant Rinse cycle for a 600 size RO.The number seems to very from one guy to the next.

[DrTimPerkins]

Q Could you give a number of Gallons for a sufficiant Rinse cycle for a 600 size RO.The number seems to very from one guy to the next.

The general rule for the machines we've used (Springtech) is that a rinse cycle should be done with about half the rated gph of the machine. So a 600 gph machine should be rinsed with 300 gallons of permeate, which should take about a half hour. Each soap wash or acid/oxidizer wash is followed by a rinse between each step. So to do an acid wash, you'd first rinse, then acid wash, then rinse, then soap wash, then rinse. But again, a caution that your system may very well be different.

[sapman]

Seems like my Airablo goes through 20-30 gpm of rinse water, making a 300 gal. rinse get done in 10-15 minutes. Does this sound wrong? I thought the PVD 1 used a chlorine based soap?

[DrTimPerkins]

Seems like my Airablo goes through 20-30 gpm of rinse water, making a 300 gal. rinse get done in 10-15 minutes. Does this sound wrong? I thought the PVD 1 used a chlorine based soap?

I don't know specifically abou the PVD1. Many membranes are very sensitive to chlorine.

If your machine is doing 30 gpm, you'd need to do a 900 gal (half-hour) rinse.

This is exactly why you need to get the SPECIFIC recommendations for your setup (RO and membrane) from the manufacturer/supplier.

[Brent]

Dr Tim is right.
My Airablo has (had ) PVD-1's and the factory instructions said not to use chlorinated tap water ... not to mention stronger solutions that you could call "cleaners".

An Airablo dealer will give you the correct soap, a strong basic solution, to clean the bio-slime. And they can also give you the correct acid, which you need less often, but it is to clear out the minerals. It's not that expensive.
But, if you've been pumping chlorine through them, they're likely finished. Bad news.

[Brent]

After some poking around on the DOW web site I found a good looking document on cleaning the XLE family of membranes.

There is a link to it at the bottom of this page on our web site.
http://www.duffyslanemaple.ca/syrup-equipment/syrup-equip.html

Note in particular the graph showing the difference in cleaning effectiveness at Ph 11 and Ph 12 .... WOW !!!