ro waste water ( not a typical question)

[Ooulophilia]

You mentioned that the permeate pumps will do little when used with a pressurized tank. If you are just filling a trash can with no lid, from what I understand the permeate pump would have no effect at all, right?
If you are running RO units in line, installing a permeate pump in between each one should boost the ratio of product/waste, right, as the RO unit itself is pressurised?
Sorry for the basic questions, I am trying to get my head around these units, and if they will be cost effective for me.

 

[goda]

pump will help if oyu haev low pressure or want more GPD at the cost of higher tds ( increasing the psi by 25 could yield alot more water.. i was getting 130 gpd from 90 gallon membrains but the tds was elevated slightly

 

[jdieck]

<a href=showthread.php?s=&postid=8264932#post8264932 target=_blank>Originally posted</a> by Ooulophilia
If you are just filling a trash can with no lid, from what I understand the permeate pump would have no effect at all, right?

That is right..

If you are running RO units in line, installing a permeate pump in between each one should boost the ratio of product/waste, right, as the RO unit itself is pressurised?
Sorry for the basic questions, I am trying to get my head around these units, and if they will be cost effective for me.

I am not really sure what will be the end result of using a permeate pum in between membranes. In theory it may increase the inlet pressure of the second membrane thus increasing it's ouput flow but I am not sure if it will be the same waste flow or if it will work better with either increaserd or reduced restriction. Also it might not be clear what will be the effect on the first membrane as it will see a reduction in pressure at the waste side as if it had a less restrictive restrictor.
Finally I shall assume that if the second membrane is producing more than the first membrane then the overall purity will be lowered for the mix as the second membrane is the one that produces higher TDS due to the higher TDS on the inlet.
So in summary I think that although we can hypotherize to death we will need to test to really find out.

 

[Thefilterguys]

Anyone I have come across with a permeate pump bought it for the wrong reason and was unhappy. Most didn't realize it needed a pressure tank to operate first off. I consider them more of a drinking water system pump and for aquariums we make to much water volume. I would be interested to hear if someone pipes up with a successful application. This is something I don't have on hand to run a test on.

Jim

 

[Thefilterguys]

<a href=showthread.php?s=&postid=8264079#post8264079 target=_blank>Originally posted</a> by goda
well if one probe says 0a nd the other says 9. then somthing is wrong besides air temp.. i know there are only good for comparing in to out

Is that what your readings are with the probe corrected and now in flow. Are your membranes in Series for that reading?

Jim

 

[goda]

ok well were talking about 2 different systems. the one at home ( where im getting a reading of 2 post di and 0 pre di) and at work. where i am getting weird readings in general because of the them being run in seris

now as for booster pumps. we use one at work for our ro system that does not have apressure storage tank. with out hte pump the psi is at 40 so the pump helps there.

at home i use a pressure tank and no pump. i get a reading of 4 post ro and 0 post 1st di and 2 post 2nd di