home made, portable RO

[gbeneke]

I built a small RO this fall while knowing nothing about ROs. It has a Aquatec 8855 pump, 6-400 GPD membranes and 3/8 tubing. The first 2 membranes are in parallel, the remaining membranes are in series. All the knowledge
I had, came from this forum, the Mattatuck site and the RO Bucket site. I thank you all for allowing me the use all of your info. In fact, in deference to Carl at RO Bucket, I am sure it would have been cheaper and much less work and frustration
to have purchased a kit from him and added my own modifications.
I made this unit to be portable. It is 30 inches long and weighs 35 pounds. I have a small unheated shack and need to be able to take it into the house. Will have to wait till the sap runs to find my screw ups but no leaks at 60 PSI.
Thank you for your info sharing on the forum. I appreciate you criticisms and comments, I've got broad shoulders.
Merry Christmas20417204182041920420

[carls47807]

Looks awesome! Interested to see what your flow rates are. Thanks for posting the pics!

Carl


Sent from my iPhone using Tapatalk

[littleTapper]

Nice! Also interested in your rates as well. I've built a 4x400 (RB20 kit) all in series for this upcoming season but am not afraid to add a couple more membranes if there's data showing it could be worth it!

[gbeneke]

Thank you for your pioneering work and ideas. I think that the 1st membrane does most of the work and gets clogged sooner. The first membrane becomes the bottle neck of the system. By starting with two membranes in parallel, I could increase flow rates. All this is based on no experience or knowledge so we will have to find out. I am tempted to start tapping early 1 percent sap to test the unit.

[Bmeehan19]

I do agree the first membrane gets clogged quicker but it won’t bottleneck the system. The concentrate sides are all open to each other so flow should still move, you will just have less permeate coming out of the sap as an overall is how I understand it.

[gbeneke]

Bheehan19,
You are probably right but it seems dividing the load on the first membrane should increase concentrate flow. Remember though, you are talking to a RO challenged person. Thanks very much for your input.

[carls47807]

I have tested many configurations of these systems for hundreds of hours and my conclusion is plumbing in series works the best in the long run. Ultimately, the flow rate of the pump is the deciding factor on processing rate. A stand alone aquatic 8855 can process about half a gallon of sap a minute at 150 psi. No matter how many membranes you have with that pump, you won’t get over 25 gph. If you process at 90psi, the pump capacity will increase to ~ 40 gph, but won’t be able to concentrate as high (less restriction of the needle valve and a lower % concentrate). Open flow on an 8855 is around 100gph, but that isn’t going to produce any permeate. Running membranes in parallel, in my opinion, will favor more flux through a particular membrane, causing the one with less flux to foul out faster and not have as much permeate production. Perhaps the best reason to plumb in series is to aid in the flushing process. A single pass, series, system is much easier to flush than membranes in parallel (unless you can easily isolate the lead membranes and flush them separately).

Another benefit to series plumbing is an overall decrease in % recovery. This is calculated by taking permeate flow/total flow x100. Because every membrane gets the total flow of the system, this value goes down. The lower the value, the less likely insoluble contaminates will find their way onto your membranes. When 2 membranes are plumbed in parallel, total flow is divided by two, increasing the % recovery by a factor of 2. Large units get around this because their pumps aren’t as limiting as hobby sized ones and they can incorporate a recirculating loop.

Btw, I have never encountered a “plugged” membrane. Only ones that have low permeate production.

[gbeneke]

Thank you, Carl. Another reason to use the RO Bucket system is that you get Carl to walk you through your stupidity. I started with 6 in series and than changed to hybrid system. I plan on learning a lot by using the RO
but I sure as hell need advice from this forum. People like me who did not go the RO Bucket route should not be allowed to see Carl's post. A big thank you for sharing, Carl. Doc

[carls47807]

I think your parallel set up will work fine. You still have the series membranes keeping your flow rate up. Your issue might be that you need to close the needle valve down too much to create the necessary pressure, causing your flow rate to be really low. Time will tell and from the looks of your setup it will be easy to research and change if needed!

Carl


Sent from my iPhone using Tapatalk

[gbeneke]

Sat. And Sun, I had 350 gallons of sap so was able to try out the RO. It was warm but flow rate was 30 gals per hour at 6 percent concentrate. New membranes, warm day but I was happy with that performance.

[GramaCindy]

I'm looking to add RO this year.
75 taps
half on 3/16th on gravity
2x5 Smoky Lake drop flue
typical day sap of 50-75 gal.
I'd like to go with the RB 10, but looking into more efficient ROing, would it pay for me to purchase the RB15 kit? And most importantly, how difficult is it to assemble?

[ecolbeck]

The kits are great and easy to assemble. In terms of sizing, I think a key question is about your intended use. Will you be using it before you boil or while you boil? If it needs to keep up with your evaporator, then a larger model is necessary. If you intend to have it concentrating while you are at work or whatever, then a smaller model will do.

[gbeneke]

The larger 15 gallon unit will process faster and you can increase the concentrate to 7-8 percent if you have a big sap day. I'm running a 6 400gpd membranes. Carl's kits make it easy to assemble and new quick connects are simple. With the larger pumps in RB-15, you could just add membranes.

[gbeneke]

Looks awesome! Interested to see what your flow rates are. Thanks for posting the pics!

Carl


Sent from my iPhone using Tapatalk
Carl, Flow rates on the first 250 gals. were 30 gallons per hour of 6 percent sap 60 degree day. Sap percentage went up to 8 percent but took it to 6 to increase total sugar output. Doc

[gbeneke]

Nice! Also interested in your rates as well. I've built a 4x400 (RB20 kit) all in series for this upcoming season but am not afraid to add a couple more membranes if there's data showing it could be worth it!
got 30 gph at 60 degrees at 6 percent. 25 gph at 40 degrees, good luck with you new RO and hope you have a good year!! Doc Beneke