recycling R/O waste water?

[saltysteven]

I was wondering if anybody has yet to come up with a way to reinvert the waste water line back into the r/o so there will
A: not be anywaste water
B: you wouldnt go there the filters as fast since a cleaner water is entering the r/o
C: maybe a possible gain in water pressure from the pull or push of water flow (maybe drop instead)
D: i cant think of a D

But i was thinking if the water was reused itd be great. Espeacialy for people in lets say Arizona where the water is very valuable. Looping the line through a pump might be the only way to get this done. I was thinking there might be a way of using some kind of eductor valve switched into the line to create the extra flow - im really kinda thinking as i go here but im going to try on working on this since it would be a great value to many. I really dont even need it since i have an endless and free supply of well water (lucky me :graucho but i thought reef keepers should try to protect our planet as much as possible so we can still enjoy our hobby

any thoughts?

[RWillieK]

The description above wouldn't work.........but you could run the waste water back through another RO membrane to purify it.

Expect the membrane life to be lessened though.

Robbie

[shyland83]

use it to water your plants. the waste water has all the stuff in it that your trying to filter out. so if you sent it into the filter again you would decrease the life of your filter drastically and possibly the quality of your water.

[saltysteven]

isnt the waste water the same as the the water going into the r/o from your tap? i thought itd be cleaner if anything-
please explain

[Roland Jacques]

An RO allows clean water though and rejects "waste". the rejected waste is flushed out as "waste water". So, it is dirtier.

You can modify your house plumbing from your RO to put your waste water back into your house water. BUT....

[shyland83]

the way i understand it, your water goes in with a certain amount of contaminants. the filtered water has none, so the waste water has the contaminants it originally had, plus the contaminants that were removed from the clean water.

[saltysteven]

maybe i was wrong but i thought the contaminants were trapped in the filter. im going to test this out when i get home by hooking up my tds to the waste line

[shyland83]

also if you kept running the waste water through the membrane again and again, it would get progressively dirtier because all the tds you have removed up until that point is in that water. your filter would eventually not be able to remove it all.

[shyland83]

the carbon filters and DI filter do trap some contaminants which is why they need to be replaced. but the RO membrane which is what creates the waste water doesn't hold any contaminants, it uses the waste water to flush them out.

[saltysteven]

okay i get it now-
makes sense, thanks

[Crazy4salth2o]

I use DI. I got tired of the waste and expensive filters. Too much to keep up with.

[chrismhaase]

Why don't you collect the waste water in a trash can/bucket or plumb it to a garden or pool?

[saltysteven]

im not worried about wasting the waste water- i would run into something like a pool or gardden but i live up north and it would freeze. i have it now run into the drain

[mayham72]

myself and neibor run the waste water into the hot tub to top off works great

[Turbo5oh]

u could always run the waste line to a holding tank that is higher the ur washing machine and plumb ur machine to the tank. had this set up at my old apartment

the tank (30 gal drum) had a over flow pipe that went to a utility sink so i didnt have to worry about over filling the tank

the chlorine removal from the carbon filters will help with colored clothes from fading also

[saltysteven]

turbo5oh- the only problem with running the waste water is it will put a back pressure on the DI. especialy if its going up a flight or 2

[shyland83]

the problem with running DI only is that you go through resin very quickly, when using RO first you get much longer life out of your DI filter.

[t3chtr0nic]

you just going to decrease the life of your membranes. All it does is seperate the parts into 2 differnet ones. purified water and waste water.

[jkriebel]

sometimes I run the waste into the washing machine. That way it is used.

[AZDesertRat]

What we refer to as "waste" is actually called brine or flush water. It carries the concentrated waste away from the RO membrane flushing its surface so the contaminants do not solidify on its surface plugging the microscopic pores. The reason we run a 4:1 waste to good ratio is to keep the expensive membrane clean and operable. If you reduce the waste flow or try to recycle it back into the process you shorten the lfe of the membrane.

If you have sufficient pressure you can run the waste stream through a second RO membrane or "piggyback" it and increase your production time. You don't really reduce theamount of waste but you can make twice as much water in the same amount of time. I do this myself using 90 GPD and 150 GPD membranes for a 240 GPD production rate at 99.23% efficiency or rejection.

[Turbo5oh]

Originally posted by saltysteven
turbo5oh- the only problem with running the waste water is it will put a back pressure on the DI. especialy if its going up a flight or 2

so the minimal amount of back pressure from a 1/4 waste water line would affect the di how? the waste line doesnt even go through the di resin. none the less the back pressure of the restrictor on the waste water line that actualy makes the a r.o. system work

i just see it a waste of sediment and chlorine free water just to go down a drain, plus the main cause of dark clothing fading is the amount of chlorine in tap water

[AZDesertRat]

Running the waste up a few stories would create additional head or pressure drop of 7 or 8 psi which could be compensated for with an adjustable flow restrictor or capillary tube type trimmed for an exact 4:1 waste ratio. The problem would be if you are borderline on pressure to begin with that 8 psi could make a big difference in output, especially in winter time with cold water that really cuts production rates already. Remember RO membranes are rated at 50-65 psi depending on the manufacturer and all at 77 degrees F. If either or both are lower then production drops off significantly.

[saltysteven]

ive decided to get a aquatec 8800- its really the only wat my r/o is going to work right. when my prssure is low its at 29 psi! high is 49 psi so i rather just get the pump and then i can run it up a flight and ill get more out of my filters.
turbo5oh- yes you are right and i really have no idea why i said that, i think i was mentally exhausted that night

[Turbo5oh]

ur right about this but its just never crossed my mind to run ro lines up 2 stories. my ro/di system is in the same room as my washer. drum siting about 1 ft above washer