RO back into same tank?

[StephensMountainVermont]

Does anyone just recerculate back into the same tank? Small scale 250- 600 GPH RO

[Bricklayer]

You can do that. Lots of people do. But my theory on that is you are constantly diluting concentrated sap.
I have done this method. It does work in the end.
And I do recirculate my concentrate in my head tank once I'm done concentrating.
But the best way is to do multiple passes first.
Run all the sap through the RO into a seperate tank.
Then run it from that tank through the RO to the head tank. You can do 3 passes if you wish. But I find after 2 it's usually around 8-9 %.
Once it's in head tank and your running evaporator you can plumb it so that the RO is recirculating the concentrate in head tank through the RO.
I find that running it through on lower pressure works best with the 8-10% stuff on my RO cause it plugs up membrane fast if cranked right down. And it's still taking permeate off. Once it slows right down on permeate output I turn it off and rinse it.

[BreezyHill]

We use an old memtek RO back when you ran 500 psi. 2 4x40s in series and I batch until I need to fill the head tank. Then I turn a valve to open and close the valve to the tank I'm batching in. I too run to 8-12% in the past.

I am always supportive of the operator that's stays within budget and keeps costs in check. That being said there are numerous producers on here that have built or modified their ROs.

One place I suggest you visit is MES website and DOWs site for parameters for the membranes you will be using. The more you read up on them the more you will get out of an RO.

[Haynes Forest Products]

To simplify my operation I fill my 800 gallon bulk sap tank and RO back into itself until it hits 18% then off to the holding tank and then its the next 800. I start the evap and off to the head tank it goes and I start cooking. I have a CDL 600 and I run it like I stole it. I have the membrane cleaned at my dealer and it comes back better every year. I rinse often and wash every night.

[wnybassman]

Getting an RO mid season this year was not in my plans so I was not really set up with extra tanks and space, but to quickly get up and running I just recirculate in my tank. I added a splitter in the concentrate output, and when that reaches 8% I shoot it up to my head tank. It was recommended that if it was run this way to flush the membrane every 30 minutes for 1 minute by opening the needle valve fully, then cranking it back down to operating pressure. I will probably continue to run this way as it seems to work out pretty good. Mine is a smaller 50gph RO though.

[Russell Lampron]

I used to recirculate back into my raw sap tank but had to keep diluting it when I had big runs and no place else to put the sap. I now have a dedicated sweet tank. I do recirculate back into that until I get it to 14% and then send it to the head tank. I'm a small guy too and like to concentrate in batches of about 300 gallons to keep my flow rates up. I can do that with the sweet tank.

[ronintank]

I recirulate right back into the ro system after the filter and before the HP pump. this way the concentrated sap does not have to run through the filter again.

[Daryl]

I believe that if you use one tank, you should pull the sap for the RO from the top of the tank. The higher concentrate is in the bottom of the tank. You will concentrate much faster.
The way that I do is to go from (A) tank then to (B) tank then the head tank at 11 - 14%

[wiam]

I believe that if you use one tank, you should pull the sap for the RO from the top of the tank. The higher concentrate is in the bottom of the tank. You will concentrate much faster.
The way that I do is to go from (A) tank then to (B) tank then the head tank at 11 - 14%

I feel this helps. Before I had enough tanks I had a stand pipe I could drop into the drain in my tank that had openings about half the tank height. The pipe was tall enough to reach top of tank. The other neat part of this was the RO would shut down at half a tank if I was not right there to switch it over.

[VT_K9]

We run a CDL Hobby 250. We RO from a larger holding tank which holds sap pumped from the woods. We do a first pass into a 230 gallon tank. If the sap is not at 4% we often recirculate until it hits 4% (most of our sap is around 1.75%). The one thing to remember when recirculating is you can go too far. We keep our suction a few inches from the top and the output on the bottom. We also stir the tank prior to checking the sugar content. It easiest to go from tank to tank, but running the RO is quicker than boiling on our 2x6.

Mike

[Haynes Forest Products]

ronintank what is the harm in having clean concentrate going thru your pre filter?

[ronintank]

I look at it as why re-filter what has already been run through the membrane.
to each his own on the operation of the ro.
My ro fits my evap perfect as a small producer. My sap has been running at 1-1.25 percent when i have it all set on the recirulating valve i am feeding at my evap rate of 15 gph and boiling 5.5-6.5 percent sap.
I am running the big blue filter and have not seen more than a 5 psi differential pressure through the filter after running 1200 gallons of sap through it so far this season.

[Haynes Forest Products]

Tim I in no way want to change your operating procedures I'm trying to understand the hows and whys so bear with me. Your not really running anything thru the membrane a second time as far as sugars or minerals but just the water/permeate out of the sap so its only once thru Correct.

[ronintank]

No i have 2 needle valves. at the concentrate exit on the membrane. 1 of the needle valves runs the control of the gph of concentrate that goes to the evap. pan. the other needle valve can be opened to allow flow of concentrate back into the system after the filter before the hp pump. so i recirculate right in the system.
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