RO question

[yards1520]

If I run 2% sap to 8% in one pass and then I run that sap through one more pass what would that bring my sugar content to? 16%? or does it not work like that? Also how much sap would I have left to boil after bringing 1,000 gals to 16%? just trying to figure out what I need for tanks/sizes

[batsofbedlam]

If you pass the 8% sap through with the same RO settings, you should end up with a 32% concentrate.

[PATheron]

If you take a 1000 gallons of two percent sap to 8 percent that would be 250 gallons of concentrate. Youd be removing 75% of the water. If you go to 16 Percent youd have I believe 125 gallons of concentrate. Once its to 8 percent what you get running it through again will depend on how much you pinch off the concentrate output and what pressure you run at. You might want to run it through the first time more open flow to like 5% then run it through again and pinch it down to what you want. If its a one post machine maybe run it to 2 gallons a minute of concentrate and it probly will be pretty high. Theron

[Thad Blaisdell]

If you pass the 8% sap through with the same RO settings, you should end up with a 32% concentrate.

When you figure out how to do this you will be quite rich, as no one else has figured it out yet.

I can tell you that with a 3 post machine, it takes about as much out of the machine to go from 2-10 as it does to then go from 10-20%. 8-16 is more likely possible. It will all depend on the RO capabilities. Theron is right on with the quantities that he posted.

[Thompson's Tree Farm]

Therons got it right on

[delivron]

It is highly recommended that you do not double pass your Concentrate.
Reasons:
1. You heat you sap with each pass and the heat will increase bacteria in you sap as the sap awaits the second pass.
2. You will foul you membrane as a result of increased bacteria and warmer sap.

But as many know producers routinely disregard the recommendations of leading RO builders.

[yards1520]

Is it really that bad for the membrane to do a double pass? If so, what are the reasons? My D&G dealer where I bought the RO was actually the one who suggested that I double pass my sap

[nymapleguy607]

It is highly recommended that you do not double pass your Concentrate.
Reasons:
1. You heat you sap with each pass and the heat will increase bacteria in you sap as the sap awaits the second pass.
2. You will foul you membrane as a result of increased bacteria and warmer sap.

But as many know producers routinely disregard the recommendations of leading RO builders.

You're right about sap heating as you run multiple passes however its better to do multiple passes for higher concentration, you keep higher flow rates and lower pressures on the membrane reducing the chances for fouling. Recirculating sap is not nearly as hard on a membrane as trying to concentrate on a single pass. If you concentrate back into an open topped feed tank the sap can cool some before going back thru the ro.