Acid Wash

[Amber Gold]

I think I have 4 years on my membrane and wanted to do an acid wash to "freshen" it up. Can someone tell me what the proper procedures are for an acid wash? I know if you don't do it right, the membrane can open up too much and pass sugar...bad.

Since I will not have any permeate water after doing the wash/rinse/wash/rinse cycles, how can I test the membrane to see if it's back at 100% after the acid wash? I understand it's OK to rinse with well water, but not to concentrate it to generate permeate.

Should I just send the membrane out to get professionally cleaned? Is one company better than another? Approximate cost?

Thanks for the help.

[maple flats]

Are you saying you have never done an acid wash in 4 years? What membranes do you have? I could give you my acid wash proceedure but I think it would be better to get the info based on what membrane you have, who made it, what size, what number is it and how many. Then someone can give you specifics based on that info.

[Amber Gold]

I have never done an acid wash in any RO I've owned.

H2O Innovation Econox 600...single H2O factory 8" membrane.

Their owners manual does not have directions for an acid wash.

Is there a pH I'm looking for? A quantity of citric acid I should use?

[JoeJ]

Have you bench marked your membrane? If you do not have a benchmark how are you going to know when the membrane is any where near original output.

If you want to do the acid wash, you need to first soap wash, rinse then do the acid wash. You let the acid stay in the membrane for a couple days, then rinse, soap wash, rinse then do a bench mark to see if you raised the output. If you don't want to ruin your newly acid washed membrane, you must use soft water low in iron and manganese. Other wise, if you use hard water high in iron and manganese, you just re plug your membrane.

Much simpler to take it to a CDL or Lapierre dealer and have it washed for about $165.00

[Russell Lampron]

To get the right acid and instructions for your membrane you should buy it from an H20 dealer. It will take a lot of permeate so if you don't think that you have enough don't try it. You are looking for a ph number and for mine it's 2 if I remember right.

[Amber Gold]

Thanks for the responses.

Since I didn't benchmark it from the start, I guess I'd establish a new benchmark.

Can the maple companies do that much better of a wash job for $165 that I can't do for $15 in citric acid? Just curious. I guess they'd give me a benchmark to shoot for moving forward.

From the catalogs I've checked, I think they all use citric acid. pH range for my membrane is 2-12.

[dlclark_76]

I have never done an acid wash in any RO I've owned.

H2O Innovation Econox 600...single H2O factory 8" membrane.

Their owners manual does not have directions for an acid wash.

Is there a pH I'm looking for? A quantity of citric acid I should use?

Take your ph to around 3.5 and wash up to 70 degrees. Shouldn't go over that. Then rinse and see what your flows are if they aren't up to where you think they should be then do it again and you can let it sit with acid for a few weeks if needed

[WESTVIRGINIAMAPLER]

We normally use One cup of Citric Acid to 25 gallons of water and a normal 8" post holds about 5 gallon so add that to however much you normally put in your wash tank and this will get you around PH 2. We let it do a full wash cycle with citric acid which goes to 110 degrees and usually sits overnight like a normal wash cycle. Then rinse the next day with at least 100 gallons per 8" membrane then do a soap wash and rinse with at least 100 gallons per 8" membrane. If you can store membrane in machine or in a storage canister, if you can store it in 100% permeate with membrane fully submerged, that will help dissolve any remaining minerals and help bring membrane performance back up.

[Haynes Forest Products]

For the amount of money my Membrane saves me spending the $225.00 to get it cleaned and stored for the winter and then get a report on it condition and get it back with a new O ring is a steal. Criminy guys I cant believe you would treat it that way. Now I run most things I have like I stole them but I would at least check the oil in a stolen get way car.

[wiam]

For the amount of money my Membrane saves me spending the $225.00 to get it cleaned and stored for the winter and then get a report on it condition and get it back with a new O ring is a steal. Criminy guys I cant believe you would treat it that way. Now I run most things I have like I stole them but I would at least check the oil in a stolen get way car.

You can check the flow while it is still in the machine. I can soap/acid/soap wash. Why take the membrane out if I don’t have to. My membranes have not been out of the vessels in 3 years.

[Haynes Forest Products]

I'm also a big proponent of if you know your machine and what your doing by all means do your own end of year final cleaning. I for one will admit I do't have a clue as to how to check for this or make sure you do that when it comes to the nuances of the RO. But I do know that you cant rinse or clean it enough so I error on the side of clean clean clean. I RO a fellow producers sap because he got a simple to use hard to clean machine and so after the first year it was all fouled up and he bought new membranes and they are shot also.

[Amber Gold]

I checked with CDL Lancaster and it's $165 per membrane. I drop it off and they take care of the rest. This summer, I'll have a construction project in the North Country and will be making weekly trips through Lancaster, so I may just go this route to be on the safe side, and I'll get a benchmark report.

How come the benchmark tests are different between the maple companies. For H2O, you set the pressure valve, so the pressure is at 150psi and you take a permeate reading. For Lapierre, you set the concentrate to 3gpm and pressure at 225 and take a permeate reading.

For what it's worth, after the first wash cycle, my membrane tested at a corrected 6.12gpm. Does this sound about right for an 8" membrane?

[wiam]

You can use whatever pressure you want as long as it is the same as your first benchmark on that membrane in that machine. From what I understand concentrate flow is irrelevant to benchmark. One thing I did not realize until recently is different membranes have different temperature correction charts.

[Amber Gold]

I checked the Lapierre and H2O owners manuals and they have the same correction charts.

If I send the membrane out to get cleaned/benchmarked, don't I want to use the same benchmark method they used or won't I get different perm. flows?

[wiam]

Saw an MES chart the other day and it seemed way different than Lapierre.