hodorskib's Small Scale RO Build

My experience is consistent. With three membranes in series (low pressure pump feeding high pressure pump), I regularly process to 8% or above at the same rate as with in parallel and recirc. and lots of washing. It is much more efficient in series. Two nights ago I processed over 200-gallons of 1.6% sap to 8% concentrate in just over 12-hrs with one permeate rinse at about 5hrs in (before I went to bed!). The sap was relatively warm given the non-existence of early spring weather here in New England. In my experience, sap temperatures have much more impact on concentration rates than the arrangements of membranes in a small scale system. It also appears that I'm able to keep the syrup grades more "consistent" with the sap (e.g. lighter on average) than when I recirculated and had concentrate with multiple passes. I also feel that when I am able to bottle the syrup within 24-hrs of when it comes out of the tree, it makes a big difference no matter what method you use because there is less time for bacteria growth, impurity buildup and caramelization due to extended time on the fire.

what are your pump models, low to high?

The low pressure is a shell. Can't recall the high...I'll look when I get home. Both were supplied by Carl.

How does everyone cope with really ice cold sap? Its killing me watching it go so slow. I do not have a way to heat it up and just watching time go by...

SDdave

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Originally Posted by SDdave

How does everyone cope with really ice cold sap? Its killing me watching it go so slow. I do not have a way to heat it up and just watching time go by...

SDdave

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I use a bucket heater from Tractor Supply (https://www.tractorsupply.com/tsc/pr...r?cm_vc=-10015) to heat up a 5 gal bucket of sap and dump that into my tank. Repeat as necessary to get the tank temp up to 40F or more.

Great idea, thanks for sharing! I'm going to pick one of those up. It looks like it will fit through the 8" cap in my bulk tank so I can warm all of the sap as I process. That will make a huge difference.

Attachment 21260
First time user. 3 RO sessions over 5 days; outside porch temps 32-42*; 4)150 membranes serial; 8-9 gallons 2% sap concentrated to 5% @ 100 psi; 50/50 output has yielded 10 gallons concentrate; aiming for 18 at first boil this weekend.
4 hours in to third session, the Aquatec 8852 sounded an audible strain, and within seconds, all the third membrane hoses began leaking profusely, and I shut down. I opened the cap, but saw nothing wrong. Called it a day and came here.
What am I looking for tomorrow morning. I'll have another 8 gallons sap tomorrow; storage for 16.

If that is a 150-psi max pump, I'd dial it up to 8% concentrate. You'll save a ton of time and energy over 5% concentrate. Did the pressure spike before the leaks occurred? Have you rinsed/washed your system with permeate water after each RO session? You might consider keeping your sap until the night before you are going to boil, and then run it all through at once up to 8% or so.

Believe the pump is rated 120, and seems to run at 100 regardless of my needle valve setting. I've got it choked down to a dribble from both lines.
was standing there looking at it and saw no spike on the gauge. Did not rinse after the first run, as I thought I'd use it next day, but the trees shot down from a freeze, and I brought it inside and let it sit a day, then used it again before running the permeate through. It stayed above freezing. that night, so I left it out in the cold to see if it affected the gear, but yesterday noon it started right up; flow was as good as ever, but it does seems to fade as the hours pass. I had no idea the membranes were that touchy.

Thanks for the heads up. It sounds like I'd better run a rinse right away.

Thanks you again for the word to the wise: it's runnung the permeate fine; no leaks at 100psi. As a newbie, I'm pretty happy with the 5%, but will consider running it through twice. and happy to keep up with the rinse cycle now ;)