New (old) RO I am trying to figure out.

[NW Ohio]

I recently came across an old RO from a car wash that I figured could be used for maple sap. Problem is I don't know anything about running an RO so I am asking for your help.

Here's what I think I have: a prefilter (looks like a whole house filter) which appears to be a 20" long filter with an absolute filtration rating of 5 microns (0.6 nominal rating). The RO membrane that came with the unit is a Filmtec TW30-2540 (850 GPD). I take that to be a tapwater filter that is 2.5 inches by 40 inches. The tag on the side of the RO indicates the following flow rates: Permeate 0.63 GPM, Concentrate 0.47 GPM. There is a single housing for one RO membrane.

My questions: Is this RO going to be useful for sap concentration? Do I use the prefilter? There is not a 2.5" RO membrane from Dow that they list for use with maple (it appears most of you are using at least a 4" membrane) , does something like the TW30-2540 (for tapwater?) or the BW30-2540 (for brackish water?) work just as well? Are the flow rates listed real, with sap can I really expect this thing to spit out almost a half gallon of concentrate per minute?

Just FYI: Ours is a very small hobby operation. This past season we had about 50 taps and produced about 9.5 gallons of syrup. We enjoy the process but I am trying to shorten the boils a little.

Thanks for any input!

787678777878

[mapleack]

There's no reason this won't work for you, just don't expect it to be fast. Yes you use the prefilter, it keeps the membrane from plugging as fast. You'd be fine with either XLE, NF90, or NF270 membranes. With the low pressure of your machine you'd probably be better with the XLE or NF270, just be aware that you cannot concentrate much above 12% with the NF270's or they supposedly pass sugar. Good luck.

[Amber Gold]

Contact 3% Solution about membranes. I think he has two 2.5" membranes on his homemade RO.

[NH Maplemaker]

Yes, 3% has two 2.5" membranes on his home made RO. He got them from Joe at Atlantic RO. 910-457-9336 or www.AtlanticRO.com

[NW Ohio]

Is the reason for 2 membranes to speed up the process?

What if I had a 4040 membrane instead of a 2540? What would the benefit be?

Also, you say not to expect it to be fast. What should I expect in terms of gpm or gph?

[bowhunter]

A second membrane won't help you much unless you change the pump, but what you have should be fine for your operation. I just built an RO with one 2.5 x 40 NF-90 membrane. I haven't operated it yet, but I have quite a bit of design information from Dow. Without some pump information it's difficult to say exactly what your unit will do, but it should be plenty for your operation. You might be able to get 5-6 gallons per hour of concentrate once through if the pump is adequate. At this pressure (~200 psi) 8-10% is probably the practical limit for the concentrate. If you can find the tag on the pump include that information on your post and I'll try to estimate the performance of your system. See if it has one pump or two. Also try to see if it has a recycle back to the pump inlet.

[maple flats]

The .63 gpm permeate and .47 gpm concentrate are not what you will get. My guess is that is for water, since this was for cleaning water. You will get significantly less but how much is anybody's guess. Not knowing the history of the membrane I'd get a new one and be very thorough cleaning the housing as well as all the plumbing and the pump innards. Then run a test with water and get the concentrate tested for potability by a lab that runs water tests. If that passes great, if not clean everything even better and repeat the test.

[bowhunter]

I looked at your pictures again. The pump's rated at 5.5 amps which means it's probably about a 1/3 hp and pumping maybe 100 gallon per hour. The concentrate is preset and that could be a limitation to getting the sugar content up once through. If you get everything working you should be able to recycle back to the sap tank until you get the sugar content up to the desired level, but probably not more than 8-10%.

[NW Ohio]

I made a nice schematic in Microsoft Word I was going to post here but it says the file size is to large so I'll try explaining it.

The pump is a Procon 102A100R11BB on a 1/3 hp motor. There is a second pump, however, I don't believe it is part of the RO system but instead appears to be what sent the RO water to the car wash bays. That pump looks to be larger, also a Procon but the only numbers I could see on it were 692 2503x 170 PSI and is on a 1 hp motor.

Bowhunter, there is a line coming from the RO vessel and going back to the water inlet. Why does that matter?

I don't know how well this system operates but I can tell that there has been "maintenance" to it. I am going to re-plumb this at minimum and would listen to suggestions on how to improve it.

[bowhunter]

I'll send you a couple of links with information on Procon pumps and RO's in general. The Procon pump model number tells a lot about the pump if you have their model numbering key which I'm attaching. For example I can tell that's it's rated at 100 GPH, it's brass and it's not food grade. You can buy this pump online for about $90 which is rated food grade. You're right about the other pump. The RO most likely feeds into a tank and the 1 hp pump pumped water to the washing system from the permeate storage tank.

The line from the RO concentrate outlet to the water inlet is a recycle line and there should be a needle valve in that line. The needle valve is used to adjust the pressure on the RO unit. You have to adjust the system pressure up and down to get the permeate flow you want. The position of the needle valve would not be adjusted very much for a car wash .... only as the membrane starts to foul over time.

Try to use stainless steel or high pressure plastic fittings and tubing that meet food grade spec's. You can use some brass, but no galvanized fittings. Brass is fine in potable water, but the maple syrup industry usually tries to minimize the use of brass.

Here are a few links that should be helpful. The first one is to procon pumps, the second is an online RO design site Dow has and the third is a link to Fresh Water systems. They sell procon pumps, membranes, housings and a lot of things you might need to rebuild your system. They also sell a Watts RO system that is almost identical to the one you have. I believe you can access the Watts system operating manual from Fresh Water's site.
http://www.proconpumps.com/
http://www.dowwaterandprocess.com/support_training/literature_manuals/lm_techinfo/designstps_balance.htm
http://www.freshwatersystems.com/