Home built small scale RO

[MapleMark753]

After looking at the commercial guys' RO for 7k to 15k, I researched, designed, built, and used my own this year. It isn't really efficient, but works, and I only take out about 7 gallons of water from about 30 gallons of raw sap. Just used readily available off the shelf parts, ie., membranes, filter, pumps, pressure gauge, hoses, connections etc... And its portable. Just pick up the small cabinet by the handle, take it where it needs to be and go. At night I just put it in a thermal blanket or carry it indoors so it stays at room temp. Next year I'm adding another pump and membrane. We will see how it goes then. So, I'm wondering if other non-engineer types have done similar and what your successes/failures have been. I've seen that it works, is cheap compared to commercial brands, but is not nearly as efficient as the commercial ones. Mine is more for hobby users, or pretty small producers. Opinions?

[Diesel Pro]

Check out the Homemade Equipment forum.

[MapleMark753]

Hey-- Yeah, did that. Some good info there, but I thought this thread was where to post. After research and actually building one, I thought people would really be interested in an RO that is about one tenth the cost of larger machines, takes out about 24 percent (more possible depending on operating pressure and time) of the water before boiling, is portable, upgradable, and costs pennies to operate. Truthfully, you could build 10 of the type I have for the cost of one of the small commercial ones. Could be good for those who regularly use multiple sap collecting and storage tanks too. Learned a lot on these threads, hope to learn more. Good luck all. Mark

[packrat]

Very interesting. Pics would be very good.

[MapleMark753]

Like some of us, I get going on something and don't take pictures, just do it. I took the RO apart to examine and clean and store it for the summer and fall. I plan on fall tapping (trees that are not tapped in early spring just to test sap production, percent brix of sap, syrup quality, etc. as compared to early spring tapping) so will be putting it back together for that and will make sure to take a few phone pics then and post them then. But its mounted on about a 2 feet square piece of plywood with a handle on top and 2 by 4 base to keep it stable, 3 horizontal membranes, two pumps (one will work but it doesn't like it much), an overpressure automatic off switch, and a pressure gauge. It runs at 50 to 85 PSI, best output is the higher figure. The pumps are adjustable as to pressure output. They are also centrifigal (sp?) and self priming. I adjust the first which picks up the sap from the sap tank to mimic household water pressure, around 40 psi, and the second I try to get up to 80-85 psi. Yes, I know this is very low compared to any commercial RO system. I ran it with filter and without filter, it seemed to run and output better with no filter so went with that for most of the season. The membranes didn't foul, crack, melt or anything like that. I flushed it with RO water before and after using it, and cleaned it at season end. I screen and filter the sap prior to the RO going in. I usually recirculate until the amount of water I want to take out is there. I think I'm at about 750.00 total cost for it. Hope it lasts, but it looks like it will. Don't know how long the membranes will last but at last boil they still put out just about zero sugar in the RO water when I tested it on the refractometer.

[not_for_sale]

Like some of us, I get going on something and don't take pictures, just do it. I took the RO apart to examine and clean and store it for the summer and fall. I plan on fall tapping (trees that are not tapped in early spring just to test sap production, percent brix of sap, syrup quality, etc. as compared to early spring tapping) so will be putting it back together for that and will make sure to take a few phone pics then and post them then. But its mounted on about a 2 feet square piece of plywood with a handle on top and 2 by 4 base to keep it stable, 3 horizontal membranes, two pumps (one will work but it doesn't like it much), an overpressure automatic off switch, and a pressure gauge. It runs at 50 to 85 PSI, best output is the higher figure. The pumps are adjustable as to pressure output. They are also centrifigal (sp?) and self priming. I adjust the first which picks up the sap from the sap tank to mimic household water pressure, around 40 psi, and the second I try to get up to 80-85 psi. Yes, I know this is very low compared to any commercial RO system. I ran it with filter and without filter, it seemed to run and output better with no filter so went with that for most of the season. The membranes didn't foul, crack, melt or anything like that. I flushed it with RO water before and after using it, and cleaned it at season end. I screen and filter the sap prior to the RO going in. I usually recirculate until the amount of water I want to take out is there. I think I'm at about 750.00 total cost for it. Hope it lasts, but it looks like it will. Don't know how long the membranes will last but at last boil they still put out just about zero sugar in the RO water when I tested it on the refractometer.

If you spent $750 on it and having the performance issues you are talking about you didn't read much before you built it. I have $300 in parts in mine and take about half the water out easily and 70-75% of the water over night.

[MapleMark753]

Good to hear of your less expense and 70-75 percent of the water being taken out overnight. I have not done overnight yet, I stop when I need to start to boil for the day. As a first year RO effort, and at the time without the benefit of maple trader forums and information, I was just glad mine worked period and appears durable. Do I have more to learn? Sure. My intent here was not to promote my effort, just to give some small encouragement to others who may not be technically inclined or deep pocketed that they can do it if I can do it. Also, to see others experience and efforts, like yours. And, learn more.

[mustanger]

I am not being critical, but I think you could improve your the performance of your RO and that folks on this list would be happy to help you do it. I built an RO and it easily takes out 75% of the water in one pass. I think yours could possibly do this as well. Tell us what you used for membranes and how you are set up and maybe someone can give you some helpful hints. I got lots of help here building mine and I am sure the same folks would be happy to share their knowledge with you.

[MapleMark753]

Thank you for the offer of help! I am glad there are practical minded experienced people who will " lend a hand". I don't mind criticism of what I did at all. Its the only way to get better. Now, after seeing all the info available and searchable here, its obvious many many people have already been where I am and have done better. Being the RO is apart now, I think I will read as much as I can here and elsewhere, then in the fall when I'm setting up to do the 50 or so experimental taps I'll ask for improvement advice. It only took a couple days to build the thing (well, waiting for parts not included), so I figure that If I get it together a couple weeks in advance and get some advice then and tweak it, (or hit it with the sledge and start over) that should be good. I have aquatech pumps (8852 I think), and filmtech residential type membranes. That isn't precise I know, but I'll get the exact models, brands, and part numbers in the fall and have that ready with a few pics. thanks again.

[mustanger]

Frankly, I would not wait till fall. I would search out the issues now while the system is more fresh in the memory. I tend to forget the bad stuff and remember the good and make the same mistakes over, but that's me. I built a system with the residential type membranes and ran it. I didn't like the production rate I got and sold the whole shebang to a neighbor that admired it. I then built a system with one 4x40 membrane (XLE4040). I ran it with a procon pump and it kept up for me. It processed about 80 gph cold sap. I got equal amounts of permeate and concentrate (about 42 gph each) and was getting 4% concentrate from 2% sap. I recirculated and got it up to 10%. When I did the recirculation, it was toward the end of the season and I didn't have enough liquid left to do a decent boil. I just started the evaporator and shut it down an hour later. I like the short boils and frequent draws that the RO provided. I'm all set to run well next year with a few modifications, like more storage and better plumbing (3-way valves etc.) You learn as you go I think.
I was lucky in that I had studied both types and had the knowledge and some good parts sources to build from. I lost some good tap time goofing around with the two systems, but learned a lot. I ended up with about 900 in the single membrane RO and now have a system that run faster than my evaporator. I think that is important as you get to cook your sap as soon as it is concentrated and don't get as much chance of deterioration of sap quality.

I am pretty sure you can improve the rate of your system by running it closer to the membrane max pressure. I think the household membranes are rated at about 120, so running at 100 with a pressure relief set to bypass above that will get you a lot more through your membranes. It helped me to run at the higher pressure. I could have benefited if I had a pump that supplied my primary pressure pump with sap instead of using a gravity feed. Sounds like you were doing something like that.

Whatever you decide to do, I hope you have good luck with it and don't be afraid to ask folks for help, there is plenty of it here.