sign guy
Active Member
Originally Posted by zeroc0o0l
http:///forum/post/2479308
Could you use the old water in fresh water tanks ?
no
http:///forum/post/2479308
Could you use the old water in fresh water tanks ?
no
Re-Cycling RO Waste
- Thread starter juice_1080
- Start date
sign guy
Active Member
Originally Posted by spanko
http:///forum/post/2479310
Has anyone run their waste water the a TDS test?
normally runs about 20% higer than original depending on age of filter
http:///forum/post/2479310
Has anyone run their waste water the a TDS test?
normally runs about 20% higer than original depending on age of filter
sign guy
Active Member
if you really dont want to waist water you can cap off your waist line but your filter would be shot to hell in a mater of weeks. I was in a huge thread a few months back about rodi wast water and finaly gave up and called dow corp. just to here that flush valves are bad and so is wast water your only use is for non living things
apos
Member
Originally Posted by sign guy
http:///forum/post/2481836
normally runs about 20% higer than original depending on age of filter
How is that possible unless the filter is adding TDS itself? The first stages can only remove TDS, so the water rejected from the membrane should have lower than normal TDS, and then the extra TDS from the pure water has to be diluted across many times its volume.
Also, while TDS should be higher, its not going to have chlorine or other REALLY bad things. It wouldn't be ideal, and I wouldn't use it, but what would be deadly about it?
http:///forum/post/2481836
normally runs about 20% higer than original depending on age of filter
How is that possible unless the filter is adding TDS itself? The first stages can only remove TDS, so the water rejected from the membrane should have lower than normal TDS, and then the extra TDS from the pure water has to be diluted across many times its volume.
Also, while TDS should be higher, its not going to have chlorine or other REALLY bad things. It wouldn't be ideal, and I wouldn't use it, but what would be deadly about it?
juice_1080
Member
From what I understand, maybe I am wrong though, the waste water picks up some of the TDS removed from the RO/DI water on its way out. I am not sure on this but thats what I think, which would mean that it is at a higher concentration. Which would make alot of sense with the 20% thing.
If your unit produces 4 Gallons of waste per 1 gallon of good that means that 100% of the TDS would be split between the 4 gallons and the filters, 20%x4=80% and then the other 20% stays in the filter. (This would change depending on how much of the DS is already trapped in the filter).
Also just because it is running through the filter to remove DS doesn't mean that it can't pick any up on the way out.
Maybe I am wrong though
If your unit produces 4 Gallons of waste per 1 gallon of good that means that 100% of the TDS would be split between the 4 gallons and the filters, 20%x4=80% and then the other 20% stays in the filter. (This would change depending on how much of the DS is already trapped in the filter).
Also just because it is running through the filter to remove DS doesn't mean that it can't pick any up on the way out.
Maybe I am wrong though
juice_1080
Member
My question still stands though for somebody that has maybe tried this or has some insight on it.
Can you hook a pump up to your RO/DI system and throw it in a bucket of rejected water and cycle it back through?
Would this just burn out the life of the filter before you got your money's worth of re filtered water or would it be economical?
It wouldn't be that hard to reduce a pump's outflow to a quick connect that connects to the RO/DI unit but the other trick would be matching/maintaining the proper pressure without burning out the pump. (65psi I think?)
Can you hook a pump up to your RO/DI system and throw it in a bucket of rejected water and cycle it back through?
Would this just burn out the life of the filter before you got your money's worth of re filtered water or would it be economical?
It wouldn't be that hard to reduce a pump's outflow to a quick connect that connects to the RO/DI unit but the other trick would be matching/maintaining the proper pressure without burning out the pump. (65psi I think?)
juice_1080
Member
The only real way to know is to test it with a TDS meter I guess and since I don't have one yet I can't give you solid proof whether it is or not. I guess it will just be something to check once I get one.
spanko
Active Member
Originally Posted by juice_1080
http:///forum/post/2482013
The only real way to know is to test it with a TDS meter I guess and since I don't have one yet I can't give you solid proof whether it is or not. I guess it will just be something to check once I get one.
This is too interesting. Doesn't someone with a RODI unit and a TDS meter already have the information on what the waste water TDS measures?
http:///forum/post/2482013
The only real way to know is to test it with a TDS meter I guess and since I don't have one yet I can't give you solid proof whether it is or not. I guess it will just be something to check once I get one.
This is too interesting. Doesn't someone with a RODI unit and a TDS meter already have the information on what the waste water TDS measures?
sign guy
Active Member
a tfc membrane filters by only acepting water the tds is left on the out side of the filter. the waste water then reverces back to pick up the tds left outside of the filter and carries it out. this meens that the waste water is more concentrated with tds than when it entered the unit
sign guy
Active Member
Originally Posted by spanko
http:///forum/post/2482093
This is too interesting. Doesn't someone with a RODI unit and a TDS meter already have the information on what the waste water TDS measures?
I cant remember where I posted the numbers but I tested with old filters and new and it came out the same each time. ill try to find them and repost
http:///forum/post/2482093
This is too interesting. Doesn't someone with a RODI unit and a TDS meter already have the information on what the waste water TDS measures?
I cant remember where I posted the numbers but I tested with old filters and new and it came out the same each time. ill try to find them and repost
juice_1080
Member
Originally Posted by juice_1080
http:///forum/post/2481970
My question still stands though for somebody that has maybe tried this or has some insight on it.
Can you hook a pump up to your RO/DI system and throw it in a bucket of rejected water and cycle it back through?
Would this just burn out the life of the filter before you got your money's worth of re filtered water or would it be economical?
It wouldn't be that hard to reduce a pump's outflow to a quick connect that connects to the RO/DI unit but the other trick would be matching/maintaining the proper pressure without burning out the pump. (65psi I think?)
????
http:///forum/post/2481970
My question still stands though for somebody that has maybe tried this or has some insight on it.
Can you hook a pump up to your RO/DI system and throw it in a bucket of rejected water and cycle it back through?
Would this just burn out the life of the filter before you got your money's worth of re filtered water or would it be economical?
It wouldn't be that hard to reduce a pump's outflow to a quick connect that connects to the RO/DI unit but the other trick would be matching/maintaining the proper pressure without burning out the pump. (65psi I think?)
????
apos
Member
Originally Posted by sign guy
http:///forum/post/2482112
a tfc membrane filters by only acepting water the tds is left on the out side of the filter. the waste water then reverces back to pick up the tds left outside of the filter and carries it out. this meens that the waste water is more concentrated with tds than when it entered the unit
The key word there is unit, and by unit, we mean the membrane, and NOT the RO/DI altogether. To get to the membrane, the water has to be filtered through the other stages first, which can't help but remove TDS.
So while it must be true that water rejected from the membrane must have a higher TDS than what went in, this factor can only be relative to the percentage of pure to waste water the unit produces. And whether it's more or less than tap water depends on how good a job the first three stages are doing in removing TDS. Of course, all of this could indeed be easily answered by someone with a handheld TDS meter.
http:///forum/post/2482112
a tfc membrane filters by only acepting water the tds is left on the out side of the filter. the waste water then reverces back to pick up the tds left outside of the filter and carries it out. this meens that the waste water is more concentrated with tds than when it entered the unit
The key word there is unit, and by unit, we mean the membrane, and NOT the RO/DI altogether. To get to the membrane, the water has to be filtered through the other stages first, which can't help but remove TDS.
So while it must be true that water rejected from the membrane must have a higher TDS than what went in, this factor can only be relative to the percentage of pure to waste water the unit produces. And whether it's more or less than tap water depends on how good a job the first three stages are doing in removing TDS. Of course, all of this could indeed be easily answered by someone with a handheld TDS meter.
sign guy
Active Member
Originally Posted by Apos http:///forum/post/2482403
The key word there is unit, and by unit, we mean the membrane, and NOT the RO/DI altogether. To get to the membrane, the water has to be filtered through the other stages first, which can't help but remove TDS.
So while it must be true that water rejected from the membrane must have a higher TDS than what went in, this factor can only be relative to the percentage of pure to waste water the unit produces. And whether it's more or less than tap water depends on how good a job the first three stages are doing in removing TDS. Of course, all of this could indeed be easily answered by someone with a handheld TDS meter.
understand your thinking because I thought the same way but look at it like this
start out with 5 gal of water with a ppm tds reading 50 then remove 5 ppms that are lost in the sed and even though the carbon dose not remove tds well go ahead and remove 5 more for that can as well. so entering the tfc you now have 5 gal of water with 40 ppms of tds. inside the tfc you seperate the water from the tds because the tds is too large to fit through the filter. as the water passes through the tfc the rejected water lets say 2 gal flows back over the outside of the tfc and picks up the tds that was left on the outside of the membrane. therefor 3 gal of water makes it through the filter and 2 gal now reads 40 ppms of tds in 2 gal insted of 50 in 5. this is a very quick summery of this thread
https://forums.saltwaterfish.com/t/299703/ro-waste-water-safe-to-drink
HTH
The key word there is unit, and by unit, we mean the membrane, and NOT the RO/DI altogether. To get to the membrane, the water has to be filtered through the other stages first, which can't help but remove TDS.
So while it must be true that water rejected from the membrane must have a higher TDS than what went in, this factor can only be relative to the percentage of pure to waste water the unit produces. And whether it's more or less than tap water depends on how good a job the first three stages are doing in removing TDS. Of course, all of this could indeed be easily answered by someone with a handheld TDS meter.
understand your thinking because I thought the same way but look at it like this
start out with 5 gal of water with a ppm tds reading 50 then remove 5 ppms that are lost in the sed and even though the carbon dose not remove tds well go ahead and remove 5 more for that can as well. so entering the tfc you now have 5 gal of water with 40 ppms of tds. inside the tfc you seperate the water from the tds because the tds is too large to fit through the filter. as the water passes through the tfc the rejected water lets say 2 gal flows back over the outside of the tfc and picks up the tds that was left on the outside of the membrane. therefor 3 gal of water makes it through the filter and 2 gal now reads 40 ppms of tds in 2 gal insted of 50 in 5. this is a very quick summery of this thread
https://forums.saltwaterfish.com/t/299703/ro-waste-water-safe-to-drink
HTH
robn70
Member
Originally Posted by T316
http:///forum/post/2481815
I'm not a tree hugger by any means (actually, I usually side on the other side of the fence), but I don't think it matters whether he's paying for the water or not. Waste is Waste. I'm finding this more important lately in regards to water. Here in NC we are under mandatory restrictions....no irrigation, no complimentary glass of water in restauraunts, it goes on and on due to our drought. None of this affects me, since I have my own well, but I applaud him for trying to be thinking of "what can I do with this stuff".
I'm also on a when but when the lakes, rivers, and streams dry up from a lack of rain so will the well eventually. The ground water has to come from somewhere..
http:///forum/post/2481815
I'm not a tree hugger by any means (actually, I usually side on the other side of the fence), but I don't think it matters whether he's paying for the water or not. Waste is Waste. I'm finding this more important lately in regards to water. Here in NC we are under mandatory restrictions....no irrigation, no complimentary glass of water in restauraunts, it goes on and on due to our drought. None of this affects me, since I have my own well, but I applaud him for trying to be thinking of "what can I do with this stuff".
I'm also on a when but when the lakes, rivers, and streams dry up from a lack of rain so will the well eventually. The ground water has to come from somewhere..
sign guy
Active Member
Originally Posted by RobN70
http:///forum/post/2483196
I wonder if you can loop the drain back to the water in connection with a wye connector to mix with the incomming water from your faucet. Just food for thought.
the water would become so high in tds that your filter would just clog up.
http:///forum/post/2483196
I wonder if you can loop the drain back to the water in connection with a wye connector to mix with the incomming water from your faucet. Just food for thought.
the water would become so high in tds that your filter would just clog up.
apos
Member
Ok, I demanded someone test, but then I got my unit and set it up to today, so I had to put my money where my mouth was.
And guess what?
I was wrong! sign guy wins.
My incoming TDS: 120-139
My outcoming TDS: 0
My wastewater TDS....... 145 !
Ok, so not a huge amount more, but apparently, the prefilters do not remove enough TDS prior to the membrane to compensate. Of course, the wastewater numbers will vary depending on the unit efficiency and so forth, but the overall picture seems clear. sign guy was right.
This doesn't answer some of the smaller questions though, such as exactly WHAT is making up that TDS. The concentration of TDS is slightly higher than drinking water, but for all we know, that could be all of the chlorine and copper removed... but double the mercury.
I'm not up to spending a zillon dollars testing everything with kits... but I know who is! The city gives away free drinking water tests, so I'll use one on the waste water and when I get the results back, let everyone know. Obviously drinking water contaminants vary from place to place, but we can compare the wastewater results to my city's published tap water results... as well as getting some more insight on the question of whether the wastewater is safe to drink.
And guess what?
I was wrong! sign guy wins.
My incoming TDS: 120-139
My outcoming TDS: 0
My wastewater TDS....... 145 !
Ok, so not a huge amount more, but apparently, the prefilters do not remove enough TDS prior to the membrane to compensate. Of course, the wastewater numbers will vary depending on the unit efficiency and so forth, but the overall picture seems clear. sign guy was right.
This doesn't answer some of the smaller questions though, such as exactly WHAT is making up that TDS. The concentration of TDS is slightly higher than drinking water, but for all we know, that could be all of the chlorine and copper removed... but double the mercury.
I'm not up to spending a zillon dollars testing everything with kits... but I know who is! The city gives away free drinking water tests, so I'll use one on the waste water and when I get the results back, let everyone know. Obviously drinking water contaminants vary from place to place, but we can compare the wastewater results to my city's published tap water results... as well as getting some more insight on the question of whether the wastewater is safe to drink.