cleaning issue

[Mason Meyer]

I have been having an issue where my first and second post, in our three post machine, slows down. I have tried cleaning it with every combination possible that has been suggested by other producers in our area as well as CDL. When we originally got the machine, the dealer we purchased it from told us to use one tablespoon of soap per membrane to wash. That did not seem to get the second or third membrane clean. So I talked to someone else who told me to keep the pH at 11. In doing this the next wash the membranes came back as if they were brand new again. I then continued to wash the membranes that way after every run. Each time I wash I noticed that the first post would start slowing down from what had previously done. What would normally be throwing away 8 gallons per minute of permeate. Was only throwing away 7 then 6 and at the end of the season was only throwing away 4. I then contacted CDL who told me to do a soap wash, acid wash, soap wash, oxysan wash, and another soap wash and see what happens. After doing that I saw no improvement in the membranes performance. While we did produce 5000 gallons syrup out of the 3 post machine last year. I am of the opinion that the new membranesshould of held up longer. The problem seemed to start after i I started washing with more soap. Especially concerning is the fact that the membrane seem to slow down more after I clean them than they were when they were working the previous day. I am looking for anyone who has any idea or any information that will help me determine what caused this and how I can prevent it from happening again this year with either new membranes or the membranes that we get back from CDL. We sent them up for testing and haven't heard back yet.

[maple flats]

I don't have a CDL, but on my Ray Gingerich RO, 2 post (4x40), I use 1/2 cup soap/membrane and it works well. Double check to see if your directions are correct. I use Leader's soap and it is possible the CDL's soap is more concentrated so don't just go by what I use. After 2 seasons I sent my membranes to Lappierre for cleaning and the report came back that they were at 100%, passing no sugar. I think in the future I might only send them in every 3-4 years unless I have a problem. I do have an extra set of membranes for backup, if needed.

[mellondome]

Key cleaning points: max temp, max ph, max gpm flow, max time. Check ph levels as the wash progresses. It will decline as it cleans and you may need to add more soap to keep it to the proper level.

A ph of 14 is ineffective if the water is 40 deg. and you are only pushing 5 gal/min across the membrane.
Find the manufacturers specs on the membrane they will list max ph and temps as well as max flow across the membrane.
If it is really bad, let it soak in cleaning solution over night after getting it up to temp. This holds true for acid wash as well.
If these membranes are in series, try switching post locations. Also make sure you are using a good prefilter. 5 micron will help keep membranes from fouling as fast as they do with 10micron.

[lew]

I agree with mellondome. Contact time, temperature and ph. The pH will drop during a wash cycle because it is getting "eaten" up by the wash process. I find that checking the pH during the wash cycle in early season does not require that much soap to be added to keep my pH at 11. However, late season wash cycles often take much more soap. It's not a set it and forget it when it comes to washing in the late season.

[OGDENS SUGAR BUSH]

mellondone has it dead to rights, everything has to be right

[Mathieu]

What brand is your RO? What type of membranes is in? Wow many gallons of permeate do you have to clean?

[claytski]

I wish CDL wouldn't suggest oxysan to be used with membranes. It works very well if used correctly, but very devastating if not. It is a peracetic acid solution and the membranes should be soaked to make it work correctly. However, this needs to be mixed with the wash water in a percent ratio not a pH ratio and this is where everyone goes wrong. I have a handful of new customers for my membranes this year because they used oxysan. Permanent damage generally occurs.

When I test and wash membranes I can get the membrane generally within 5% of being new unless the customer really trashed the membrane bad. And even then, I can get the membrane back substantially.

[lew]

I just another thought. Are you rinsing as often as long as the membranes need? If you try and push through that extra couple thousand gallons, or rinse with only a few hundred gallons of permeate, you may not be getting all of the residue off the membrane before you wash, ultimately eating up your soap prematurely and not getting the best wash possible. I know I have pushed through that last little load of sap because I got lazy and didn't want to rinse and start the machine all over again. Ended up taking way longer to get her rinsed out good. Thankfully I have a large permeate storage tank that holds more than called for. I'm a fan of long rinses before the wash cycle.

[Walling's Maple Syrup]

I just another thought. Are you rinsing as often as long as the membranes need? If you try and push through that extra couple thousand gallons, or rinse with only a few hundred gallons of permeate, you may not be getting all of the residue off the membrane before you wash, ultimately eating up your soap prematurely and not getting the best wash possible. I know I have pushed through that last little load of sap because I got lazy and didn't want to rinse and start the machine all over again. Ended up taking way longer to get her rinsed out good. Thankfully I have a large permeate storage tank that holds more than called for. I'm a fan of long rinses before the wash cycle.

I agree 100%. I usually run at least 1000 gallons of permeate through my 3 post machine before I start the wash cycle.
Neil

[mellondome]

Also make sure you use a seperate prefilter for washing...

[Mason Meyer]

The slow down occurred after a wash. As it got later in the season, the more soap I had to use. The more soap I used, the more of a decrease in flow I saw after I washed. To reiterate, I saw a decrease of flow after a wash than what I had before. Flushing plenty of water after and used new filter to wash.

[Mason Meyer]

CDL 3 post with NF70-400 (h2o) we have 2500 gallon tank for permeate. Washed per CDL recommendations at the end of the season. Saw no improvement in flow. Sent to CDL for them to clean. Haven't received them back yet at this time.

[Walling's Maple Syrup]

How many hi-pressure pumps on your machine and what size(7.5 and 5 hp)? Also, what are you getting for permeate flow out of each post after machine has been running for half an hour or so and what are you concentrating to? What are you running for pressure? I believe I have the same machine and I have the same membranes. Want to compare flow rates.

Neil

[mellondome]

Did you do Any acid washes? Or all soap washes?

[maplwrks]

How hot is your wash water? You need to allow the water to come up to temp for the soap to work properly. I would let it wash with just plan hot permeate to start, then add some soap and wash for about 6 hours or more.

[Amber Gold]

I agree with everything said. Temp and pH are critical to get a good cleaning. I have a 600, and I'll run a couple hundred gallons of permeate through it before I add soap. I use a 2oz sample cup to the wash tank and let it run for 10 minutes before I check it again. I keep doing this until the pH stabilizes around 11 and I don't need to add more soap. I'm using Lapierre's soap if it matters. I think all the soap's are about the same, so I don't think it matters much which we use, and you can't add too much soap. There's a buffer in it, so the pH will only go so high. On the directions, Lapierre I think recommends dumping half the container for a wash cycle...seems excessive so we don't, we just monitor the pH.

We're also using the h2o membranes.