Tips on Increasing RO Output

[Bubbles Galore]

As many of you know, I am getting ready to put in an automatic. My spot free system has been more than sufficient up to this point with the self serve bays, but I am concerned that the auto will take me out of my daily production range (hopefully ).

My production pump is a small 1/2 hp motor with a procon pump. I have one charcoal filter, one 5 micron filter(20"), and one RO membrane (40").

What can I do to "up" production? I don't think increasing motor size without adding to the spot free components I already have will do anything, so do I just add 1 of everything?

One good thing is that I have increased storage by replacing my (1) 100 gallon tank with (3) 55 gallon drums plumbed inline which is a 30% increase in storage.

Any and all tips are appreciated!

 

[MEP001]

You'll definitely have to increase the pump and add a second membrane. One large booster pump like this one is sufficient for two membranes.

Be sure to plumb the system to recirculate some of the reject back into the pump so you're only rejecting 1:1. It saves on water and actually improves on the production of RO.

 

[cleaning up mud]

I have two differant systems, one with one membrane and another with three! The one membrane works just as well as the other on an IBA and 3 self serves!

 

[MEP001]

I have two differant systems, one with one membrane and another with three! The one membrane works just as well as the other on an IBA and 3 self serves!

That's because your 1-membrane system is set up like I described to recirculate some of the reject to improve the production, and you have a 300-gallon storage tank.

 

[Kirb]

Be sure to plumb the system to recirculate some of the reject back into the pump so you're only rejecting 1:1. It saves on water and actually improves on the production of RO.

MEP,
I would also like to up production. Should the reject from the first membrane be the incoming water for the second or should the reject for the first be teed to the fresh incoming water to the second.
Thanks,
Kirb

 

[MEP001]

I've seen it both ways. It's easier to plumb all the water through both membranes, then split the output from the second one between the drain and the recirc valve. It seems like the speed of the water through the membranes is what increases production, and running all the water through both membranes achieves that.

 

[my2cents]

I am an R.O. novice but I have heard that these systems like to work instead of sit idle. If storage was increased only with the same amount of membranes and pump size, would that work too? or would the single membrane not keep up with production regardless of storage? The R.O can make water all night if necessary can't it?

 

[Mr. Clean]

Please tell me more about recirculating RO reject water. What does the recirc and final reject configuration look like? I can see back into the supply side, but how do you separate reject to be recirculated form that which is finally rejected?

I currently have two RO systems; a single 4X40 and a triple 4X80. We've just started recovering reject from the triple and haven't seen a water bill yet. If reject could be recirculated before recovery the reduction in water use should be phenomenal.

Thanks!

MC

 

[Bubbles Galore]

Thanks for the tips MEP...I'm sure once I get into the thick of it I will have more questions. I can't wait to get this auto in...

 

[cantbreak80]

What about converting membranes? Dow offers LP-4040 membranes that reportedly produce 2900gpd @ 145psi. Here's some info I've found.

 

[MEP001]

What does the recirc and final reject configuration look like?

It's a simple matter of something that can be adjusted to control flow. I've reconfigured a number of units using a bypass regulator and returning the bypass to the inlet of the pump and using a valve to control the reject. I've seen units that use a valve for both, but it's difficult to get it set up right because changing one valve affects all the flows and pressures, whereas once you set the system pressure with the bypass regulator you can adjust the reject flow to match the product flow without continually "steering" everything else.

 

[MEP001]

What about converting membranes? Dow offers LP-4040 membranes that reportedly produce 2900gpd @ 145psi.

Any idea how the product quality compares to standard TFC membranes?

 

[cantbreak80]

Uh...I wash hoping YOU knew.

 

[MEP001]

Uh...I wash hoping YOU knew.

I've never used them - they weren't common when I was still working full time in the industry. There are some numbers in the link you provided, but they don't mean much to me.

 

[Bubbles Galore]

So, looking into it a bit deeper, I should be able to go from my current 1/3 HP spot free production pump to a 3/4 HP Dayton booster pump with a second RO membrane should give me the production levels I need? Grainger seems really high price wise, anyone have a better place to buy that booster pump?

 

[Randy]

Multi-stage booster pumps are expensive because they are a industrial type pump. I bought a new Myers multi-stage pump on EBay a couple of years ago that I use for washing down the parking lot. http://www.femyers.com/pdf/pdf.ws/ws brochure/M9143WS_MPB.pdf

 

[Bubbles Galore]

Thanks Randy, I will look into one like that. A 3/4 HP, should be able to pump the spot free up to my loft where my storage barrels are, correct? My estimation is that it's about 16' of 3/4" line with a 10' rise in elevation.

 

[MEP001]

A 3/4 HP, should be able to pump the spot free up to my loft where my storage barrels are, correct? My estimation is that it's about 16' of 3/4" line with a 10' rise in elevation.

The issue is the volume of water being moved and the pressure. You'll need the 1 1/2 HP pump/motor I listed, or something equivalent, for two standard production membranes to achieve 200 PSI and maximize production.

A 3/4 HP unit is barely enough for a single 4x40" membrane - is yours currently a 2 1/2x40"?

 

[Bubbles Galore]

The issue is the volume of water being moved and the pressure. You'll need the 1 1/2 HP pump/motor I listed, or something equivalent, for two standard production membranes to achieve 200 PSI and maximize production.

A 3/4 HP unit is barely enough for a single 4x40" membrane - is yours currently a 2 1/2x40"?

Now that I actually start to think about it, I think I actually have a 2.5" membrane...crap...more stuff to buy...

 

[MEP001]

Kleen-Rite used to carry a membrane housing like this one for about $120. Maybe their direct price is similar.