RO build options - 4" vs 8" membrane

[gmc8757]

Hey guys. I'm planning on building a RO machine for next year. I've bothered a few guys on this board way too much already so figured I'd ask my question here! (thank you guys who have helped tremendously already!)

My goal is to get about 35 gallons of 8% concentrate an hour. I'd love to do this in one pass so I can fire up the RO and evaporator at the same time. I'm between either a 3 post 4" membrane setup or a 1 post 8" setup.

I have a procon series 6 pump which is rated for 250psi, 660gph. This should work fine for a 3 post 4" setup as it should keep the flow going pretty good over the membranes.

Would this same procon 660gph 250psi pump work for an 8" setup? I "think" an 8" RO is meant to run at higher pressures. If a 250psi pump would not work for an 8" setup, do you know of another model that would work?

[madmapler]

You can do 250 psi with an 8" membrane, no problem. Use an xle (extra low energy) or comparable. It's more the flow rate that you need to pay attn. to. Various membranes require different flow rates but I "think" that pump would suffice for an xle type membrane. I don't think you'll get enough squeeze to get 8% on the first pass though.

[gmc8757]

I was thinking of using the MES membrane no matter whether I choose to go 4" or 8" but I'm not against the xle or NF270

Is it possible to get 35 gallons of 8% sap in one pass using one 8" post running at only 200-250psi?



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[bowhunter]

Yes. Think I've answered this before, but the 8" will work at 200-250 psi. Any membrane will produce 8% concentrate on one pass if you use recirculation to keep the recovery down so the membrane doesn't foul too quickly.

[gmc8757]

Sorry Dave. I don't think I ever asked you if running that psi would work or not. I was thinking of asking you but didn't want to wear out my welcome (not sure how I haven't already!)




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