Is micro-scale RO viable?

[jludman]

I'm looking to produce about 2 gallons of syrup per year from my back yard. Was wondering if it was possible to build a tiny RO system cheaply, and thus save some energy. As little as 1 quart per hour would be fine. Maybe the extremely low rate allows the use of gravity instead of a pump?

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15 taps with milk jugs

[Kev]

then go get the cheapest home undercounter RO you can find. push your sap through it and save what would normaly go to the drain, thats your concentrate.
try it and let us know how it worked!

[jludman]

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[jludman]

Anybody else done this with success?

[Kev]

Anybody else done this with success?

there are several with homemade ROs
I am planning on trying house use membranes, 3 100 gpd @ 80 psi, in parallel
next year. the vessels that I am looking at are rated for 250 psi so I hope to push around 175-180 psi
in perfect conditions (those do not exist i understand) at 80 psi and 70 deg. they should flow 4.16 gal per hour of pure with a concentrate of 2-3 per 1 of pure. so I ought to be in the ball park of 25 gal of concentrate per hour off 3 of them. I assume the flow goes up some with increased pressure over the 80 psi
if prices hold steady it looks like I will have less than 200 in the rig. But then I have a pump that I can use for this project and that will save a substancial amount. I am thinking a 5 micron prefilter and a carbon block 2nd prefilter.
I am tempted to use needle valves instead of the stock flow restrictors.
I might be nuts, but hopefully if someone knows that they will pipe up :)

[metalhead62]

kev i have been doing alot of research but have not built anything yet look up brent and go to his site he did alot of work with the ge merlins i am sure he said in his work that the carbin filters were a big no no cut flow rate and clogged or something check his homesite he used to have a diary of his use of the merlins

[jrgagne99]

I am currently putting together a 2x100 GPD system (in parallel) that I plan to run at 80-100 psi. I'm hoping for 50 gallons of permeate i.e. "effective evaporation" per day. Check out my "Homemade RO" thread for updates in the next few days. I'll post pictures and results as I get them.

[jrgagne99]

Kev-

I'm starting out with the stock restrictor capillary tubes. I bought three different sizes (100GPD, 75 GPD, 50 GPD) and will try them in different combination to see what I can get. Needle valve is my second option. I would stay away from the carbon filters- Brent found them to foul terribly on his Merlin RO project.

[Kev]

thanks!
I have also considered the stock restrictors and a valve after that to pinch it more if I want a sweeter concentrate in one pass.
I know I have more to learn before next season!

[jludman]

Check out my "Homemade RO" thread for updates in the next few days. I'll post pictures and results as I get them.

Thanks for pointing it out, and good luck! Very interested to see how it turns out. I actually own a 70w and a 240w pump, so maybe I can make a single membrane system like yours for under $50 next season.

[Gary in NH]

Activated carbon filters remove organics by the process of absorption and adsorption. Activated carbon has an internal pore structure that draws in organic molecules as well as attracting organic molecules to the surface of the carbon. You don't want to remove the organic molecules from sap or syrup. Using an activated carbon filter for sap will foul the filter very quickly as Brent had discovered. Activated carbon filters are typically part of smaller home RO systems to de-chlorinate tap water prior to the RO membrane to prevent damage to the membrane. Thin-Film Composite (TFC) RO membranes have very little tolerance for chlorine. In addition to organic removal activated carbon also has the ability to reduce chlorine (sodium-hypocholite) to sodium chloride, or basically salt which is harmless to the RO membrane.

[Paul VT]

wondering if you would be willing to share info on how you built your RO? i have 50 taps and have plenty more i could tap and have been gathering info on building a RO. i got spoiled once this spring when i had more than i could keep up with and a friend swapped some raw sap for some 12%!!! sap. i know i can't concentrate that much but if if could get rid of some of the water that would help.

[DrTimPerkins]

You don't want to remove the organic molecules from sap or syrup. Using an activated carbon filter for sap will foul the filter very quickly as Brent had discovered.

Not to mention the fact that using a carbon filter with sap or syrup would be illegal (adulteration).

[BryanEx]

Not to mention the fact that using a carbon filter with sap or syrup would be illegal (adulteration).

Just so I understand... why would carbon filters adulterate the syrup? Do they add something to the sap they process?

- Bryan

[DrTimPerkins]

Just so I understand... why would carbon filters adulterate the syrup? Do they add something to the sap they process?

No, they take stuff out. That is illegal under U.S. and Canadian, as well as several state and provincial laws and/or regulations.

[BryanEx]

Ah... okay. I never thought of adulteration in terms of removing naturally occurring minerals. I guess that's partially why maple RO's are priced as they are. They are designed to remove water and only water. I love the stuff I learn from this web site.

- Bryan