How high will ro/di waste line push water?

goodtimes · Mar 5, 2014

I'm thinking of running my rodi waste line during the summer months outside to a storage tank and use the waste water for plants. It will need to go up 7-8' to accomplish this. I don't foresee any problems with it. Thoughts?

jl283467 · Mar 5, 2014

I have the booster pump on my system and I pump the water over 30 feet along the ceiling joists in my basement

MatteZ · Mar 5, 2014

I have the clean water pump from my basement to the first floor with no problems. So I m sure the waste water won't be an issue.

yudruln8 · Mar 5, 2014

I have mine going up from the ro system around a door frame about 9 feet high to a large 275 gal storage tank and have no issues btw I don't have a ooster pump

FF337 · Mar 5, 2014

The friction loss would be difficult to figure however this is based on incoming pressure from the source. I would assume several (30+) feet vertical.

EllisJuan · Mar 5, 2014

I agree, 7-8 foot would not be a problem at all. I would be curious to know that in extreme circumstance like having the waste water pushed 30-40 feet up how it would effect production of RODI.

goodtimes · Mar 5, 2014

Thanks for the input.

AZDesertRat · Mar 6, 2014

Lengthening or raising the waste line will change your waste ratio so ALWAYS measure the waste ratio when you make a change and adjust it back to the factory specs using a capillary tube flow restrictor you trim yourself using the new parameters.

Its not so much that it affects production, just that it lowers the waste so the membrane is not flushed as well when in use.

thejuggernaut · Mar 24, 2014

34' of water column is one atmosphere which is 14.7 psi. Most RODI shut-offs engage around 40 PSI. So 8' would be around 4.5 PSI. I bet you could push the water up over 60' before it shut off the RODI.

Regards,
Taylor

SaltyReefer · Mar 24, 2014

AZDesertRat said:
Lengthening or raising the waste line will change your waste ratio so ALWAYS measure the waste ratio when you make a change and adjust it back to the factory specs using a capillary tube flow restrictor you trim yourself using the new parameters.

Its not so much that it affects production, just that it lowers the waste so the membrane is not flushed as well when in use.

AZ, does it matter if the line run is up/down or parallel? or only if you are going up with the line?

thejuggernaut · Mar 24, 2014

Only vertical height will add to your head pressure. Friction from a very long length of tubing might increase back pressure a little bit, but I would imagine it is a very small amount because of the slow flow through the line. He is right though that back pressure on the waste water line will change the pressure differential between the two sides of the membrane. If you're really concerned about it you can put a pressure gauge on the outflow side before the flow restrictor. That will give you quantitative data on how much extra pressure you are creating.

Regards,
Taylor

thejuggernaut · Mar 24, 2014

Only vertical height will add to your head pressure. Friction from a very long length of tubing might increase back pressure a little bit, but I would imagine it is a very small amount because of the slow flow through the line. He is right though that back pressure on the waste water line will change the pressure differential between the two sides of the membrane. If you're really concerned about it you can put a pressure gauge on the outflow side before the flow restrictor. That will give you quantitative data on how much extra pressure you are creating. Or like he said, get a bucket and stop watch....
Regards,
Taylor

AZDesertRat · Mar 25, 2014

Any excessive length or elevation change does matter. The line is 1/4" and there is quite a bit of friction loss when you consider the velocity from the waste on a 75 GPD or larger membrane at 4:1 waste ratio. Same with the height since additional head will change the waste ratio and cause your membrane to fail since it is not being flushed as it should be during use.

Its not the total shutting off of the RO/DI you should be concerned with, which raising the waste wil not do since all the water would then come out of the treated line not the 4:1 it should be. It is the altering of the waste that is the concern and easy to correct with properly trimmed capillary tube flow restrictor.