HOMEMADE R.O. Series VS parallel

[BIGMAPLEFARM]

I am about to cobble together a small r.o. for my hobby 75 taps on buckets operation. I have reasearched this enough to still be totally confused.
I am going with the aquatech pump, prefilter and 4 150gpd houshold membranes, am i better plumbing in parallel and runing it through a couple of times
or series and running it through once. The most sap I would get in a day is about 100 gallons, and I make between 15 and 20 gallons of syrup a year. I have a
Lapiere 18x60 junior evaporator that I run on a homemade propane arch. I am looking to save time, fuel and beer. I would like to thank all of you who posted diagrams,
photos and material lists it was all very helpfull. but like I said I am still confused.

Any and all opinions would be appreciated.

Thanks

Glenn

[bowhunter]

Here's my two cents worth. You really don't have a big enough pump to plumb the membranes in parallel, at least if you try to stay close to the manufacturers recommended minimum flows. If the flows are too low the membranes will foul very quickly. They will foul on sap even at the design minimum flows, but much more quickly with very low flows. I'm not sure you will get a lot of benefit out of the 4th membrane because the sugar content is pretty high by the time the sap gets through the first 3.

Even with the membranes in series you will need to run through the system more than once to get a significant reduction in water (50% removal). I think you should be able to process 100 gallons of sap in 8-9 hours using the membranes in series and just recycling back to the sap tank. I believe you can get a 50-70% volume reduction which will reduce your boiling time substantially.

[Clinkis]

I have used the exact setup you want to build for the past 3 years. I am currently in the process of upgrading to a larger RO as I am now up to 150 taps. I did a lot of experimenting with this RO and found in worked best in series. As Bowhunter stated, the 4th membrane does very little and 3 realistically is all you need. I was collecting 40-50 gallons of sap and processing it in about 12 hours and got it to 7-8%. That is about as high as they will go. As far as how much water it will remove depends a lot on what your starting sugar level is. My sap is usually around 3% so that meant about 60% water removal. If your sap is 1.5% then you are getting approx 75% water removal. These are a great little RO if you are around 75 taps or less and not in a hurry. I would collect one night, run RO over night and boil next day. There is a great website setup by one of the members on here that help me greatly to build the RO you are looking for. It has pictures and detailed instructions on how to build and operate it. I will attach the link. Good luck!
https://sites.google.com/site/mattatuckmadnessmaplesyrup/home/homemade-reverse-osmosis-system

[Pauly V]

Thanks for that link!

[Greenthumb]

I made the ro in the link above. I was able to take 2% sap to about 6%. Went a little higher at times but was worried about fouling. I'm not good at record keeping so can't give all the good data as others but I would run the ro a few hours and boil that down or run in the evening and boil the next day. I only used three membranes after reading some post last winter before building. I did use the permate often and rinse the membranes. I'm going to 75 taps year from 49 taps so we will see how,this,helps. I do have the 100 gpd menranes the 150 gpd membranes intrigue me. Will they fit in the same housing as the 100 gpd ones

[hodorskib]

I have run my system for several years starting with 3 100gpd membranes which was giving me between 5 and 6% concentrate. Last year I went to 4 150gpd membranes and I was able to bring the concentrate level up too 7-8%. I have tried all different combinations with the membranes:
Running parallel, running parallel then both into a final membrane and even recirculating, the best results have been in series. I do agree that three membranes will give you the results you are looking for but I found by adding the fourth I can achieve a higher flow rate. I know the math doesn't make sense and can't figure out why it worked but it did. The link provided below is to my website I hope it helps you out.