ro water saving idea

One option is to reduce the waste to product ratio to something more like 2.5 or 3:1 instead of 4:1 or more. I wouldn't recommend that here in the southwest but it would probably work out OK if you have pretty good water quality to begin with. I think Bryan at www.purelyh2o.com has been experimenting with this and is part of the reason he gets 100 GPD out of a 75 GPD Dow membrane.
 
one thing people can do to reduce the amount of waste water is by using multiple RO membranes, take the waste line from the first until and sending it to the second RO membrane and connect it's waste line to the third and so on, this will reduce the waste water ratio.

This is what I have done and it is working pretty good so far.
 
I have not opened mine but looking at it operate, it seems to use a memebrane that is pushed inward by the Mains water pressure, on the other side of this membrane the incoming water is squeezed into the Ro membrane by the force and then when all the water is pushed, a valve seems to open and the water in the Mains chamber seems to be released and the cycles start's again. This seperates the Mains pressure from the RO back pressure .
If somebody actually pulled theres apart they may be able to confirm what I see happening, but I am not pulling mine apart to verify it.

<a href=showthread.php?s=&postid=7547306#post7547306 target=_blank>Originally posted</a> by yourfishman
dose any one no how the permeate pump work?

it dose not make sence to me. dose it let waste water recirculate?
Click to expand...
 
Think about this for a moment. The water you drink from the tap has a high TDS. The waste water from the RO is already filtered through three prefilters. Would that waste water be cleaner than the original water going into it.

TGUNN: Are you still with this thread???????? Can you PM me and tell me more about this straight to the DI idea. Thanks.
 
The waste stream from the RO will have a 20% to 25% higher TDS than your tap water. Yes it goes through carbon and particulate filters but these are designed to take out chlorine, volatiles and suspended solids not dissolved solids. Dissolved solids are where the membrane comes in, don't confuse the two as they are very different. The waste is probably less of things like pesticides, herbicides, gasoline products from leaking underground storage tanks and large particles. You probably have done nothing for things like iron, calcium, nitrates, manganese etc.
 
right now i have the luxury of not paying a water bill (its included in my rent no matter how much i use). the only thing motivating me to save any of my waste water would be an effort to be a little less of a burden on the environment than i already am. it seems to me that the easiest and most efficient way to save your waste is collecting it and using it for other things as many have already said. i am going to start saving some of my WW in a container for my neighbor to water her house plants with. mine all died due to the reef tank so thats not a factor :D in the past i used it for my freshwater tanks with mixed results. besides saving some i guess i can always just take one less shower per week.

mother nature: 1 my girlfriend: 0

-nick
 
i dont use this unit to save money on waste water as it is way more expensive than most ro units and it only produces 20 to 25gpd.

but it is a true zero waste unit as it pumps waste water back into your hot water line. not for everyone but this is what i use.

a di system works great too (without the ro part) but recharging the resins are too much of a pain for me so i found that the zero waste unit is a better option for me.

zero waste ro unit
 
A zero waste setup is a good option if you have pretty good water to begin with. Here in the Southwest with TDS as high as 1000 or even higher I would hate to be dumping the concentrated waste stream back into my hot water heater and into my internal plumbing though.
 
Seams to me the simple solution is to collect the waste water high enough that you can use gravity to feed a toilette. it would be real simple and does not have to but your waste through you whole house plumbing.
 
you'd have to have a large storage tank or use the toilet a lot. at 1.6 gpf, you'd have to use the bathroom 4 times for every gallon of water. if you have an older toilet at something like 3 gpf, you'd still have to use the bathroom once for every gallon.

i've got a 125G tank and low consumption toilets. i know i don't use the bathroom 400 times in a month. atleast not at home.
 
<a href=showthread.php?s=&postid=7547373#post7547373 target=_blank>Originally posted</a> by northbay-reefer
one thing people can do to reduce the amount of waste water is by using multiple RO membranes, take the waste line from the first until and sending it to the second RO membrane and connect it's waste line to the third and so on, this will reduce the waste water ratio.

This is what I have done and it is working pretty good so far.
Click to expand...
sounds like you're doing the same kind of thing only alot defferent. :rolleyes:

my question with your set up is, what is your pressure 1st membrane 2nd membran 3rd ... and how do you keep the pressure high in the 3 membranes. do you rotate your membranes seeing that the last one would go bad first? also how much water to waste water do you produce? with my water quality this sound doable the 3rd membrane would be seeing water in the 90 tds range. i wonder how much flow the 1/4" hose can flow at 50 psi to keep with 3 membranes?
 
AZDesertRat
After reading what you said earlier, it just dawned on me that carbon block filter are probley not activated carbon, is that true? My current unit is 3stage carbon block then deion unit. But the DI was exhausting very fast, even though the water going into the DI was normaly less than 40 tds. Would a GAC filter after the carbon block help much to extend the life of my deion resin? I think that is what i had before when i had a service take care of my water.

scrager
you saved this topic from going down the toilet, good work. but then again laverda might just be full of Poopy. :lol:
 
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Carbon blocks are activated carbon but will not do much to extend the life of DI resin. Carbon blocks and prefilters are designed to trap suspended solids and volatile chemicals not dissolved solids. Remember DI resin is only designed to treat something like 3000 ppm total TDS per 16 oz of resin so if you are putting a TDS of 40 into it you will treat about 75 gallons per pound of resin. Some cartridges hold closer to 24 oz but you can still only expect to treat maybe 120 gallons at best.
 
AZDesertRat
Thanks, but why do ro units that remove chloramines use a GAC filter, in addition to the carbon block?

So I guess im back to picking a good RO set- up. This is what I understand at this point.
The only zero waste units complete ive seen only do about 25 gallon per day. The zero waste retro kit are about $250 and will work on about 100 gallons per day. The permeate pump only met their claims when used with a pressure tank that really just inhibit the RO performance in the first place. The permeate pump seem to be on per with a boost pump w/o using electricity.
 
Chloramine removing RO units use granular catalytic carbon for the chloramine removal and a carbon block to aid it in volatile organics removal. Lots of better RO/DI units use two carbons before the membrane anyway so you are only substituting one carbon block or GAC for a granular catalytic carbon cartridge. Its always preffered to have either a 1 micron or 0.6 micron carbon block or even another fine sized prefilter after any granular material to trap the fines they produce so it does not get passed on the the membrane and potentially plug or damage it.
Zero waste technology just isn't there yet with RO systems. Like you have found there are things that help but some are expensive and like the ones that put the waste stream back into your hot water heater you have just defeated the purpose by putting the contaminants back in to your homes hot water rather than cold water?
 
I was thinking of piping the "waste" water to a large garbage can with a faucet at the bottom, then attaching a "drip irrigation" line to that faucet and have a sprinkler timer water my outdoor plants. I guess in theory, the can is not even needed if the waste line (typically a 1/4" line) can be connected to the drip irrigation line directly.

Ironically, I bought a front loading washing machine to save water, but you can't add "waste" water to the tub like you can with a top loader!

Also, I agree that the "waste" water is actually fine drinking water, since it has been through X prefilters. And so what if the TDS is a bit higher? Consider that you have a 2 glasses of tap water. if you drink them both, you drink all the stuff that's in them. If you run it through an RO unit, you end up with (say) half a glass of pure water and one and a half glasses of the "rest" of the water. if you then drink the 1.5 glasses of "waste" water...you aren't drinking anymore DS than you did if you drank the 2 glasses of tap water. In fact you've drank even purer water! Who cares about concentration of something so miniscule, particularly if the water has already gone though municipal water purification!

V
 
Oh another (probably impractical) thought. If you have a freshwater tank, you could probably rig it up so that the waste water flows into the tank, and tank water overflows into a drain ... almost a constant water change! (sort of).

V
 
<a href=showthread.php?s=&postid=7550879#post7550879 target=_blank>Originally posted</a> by yourfishman
sounds like you're doing the same kind of thing only alot defferent. :rolleyes:

my question with your set up is, what is your pressure 1st membrane 2nd membran 3rd ... and how do you keep the pressure high in the 3 membranes. do you rotate your membranes seeing that the last one would go bad first? also how much water to waste water do you produce? with my water quality this sound doable the 3rd membrane would be seeing water in the 90 tds range. i wonder how much flow the 1/4" hose can flow at 50 psi to keep with 3 membranes?
Click to expand...

all of my membranes are 100 gal/day, and I increased the psi of my house water by adjusting the pressure regulator to 80 psi. If you own a newer house, at the main line that comes into your house should have a psi regulator, by turning the screw on this regulator clockwise until you hear a wooshhhh, you can increase the pressure of the water entering your house. So far (5 years now) the result have been good and no ill effect to any of the plumbing inside the house. As for having constant pressure on all three membranes, I think the presure reduces and degraded but I still get s good amount of RO water from the second and thirf membranes so I know this method works. Also I got the idea from someone on here that did the same thing a while back with good result too.
 
Dangit AZ

Dangit AZ

I never get to say anything when your around. Save some brainpower for me will ya.. ;)

Im watching this one too...lol

This is a good one!
 
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