--= how much water does a ro/di unit waste? =--

[J Crew]

just wondering how much these units waste? i was considering purchasing a unit that had an output of around 50-60 gpd. how much would a unit like this waste? i'm curious becuase i'm thinking if it waste alot, then my water bill will rocket up. so then wouldn't it be better to just buy ro water from my LFS. but if it doesn't waste very much then the unit would be worth it.

anyone know the ratio? meaning for example, every gallon ro water produced there are 3 gallons of waste water... 3:1 ratio.

peace

 

[golfish]

Depending on water quality.....most are around 4-1

 

[mtellin]

It also depends on your water pressure because my ratio is like 1:10 @ 36psi

Mike

 

[Mouse]

Most RO/DI filters work on a 99% rejection rate. Which means that by the time i've filled my 400 gallon tank its used up 39600 gallons. Thats a large swimming pool, oh what a rediculous hobby, i love it.

 

[Mac1]

I've heard optimum is 1:4... As mouse said, that's a lot of water. I'm actually trying to figure out a way to run my waste water line through the house and out the back to where I'm going to plant my Garden. I thought that it would make an excellent irrigation system, and have nutrient laden water the plants would no doubt just love. I just have to work out a few details in the pressure/plumbing area, and come up with the money to do it.
I hate to admit it, but simply flushing all that water back down the drain, is just terribly wasteful... recycle and re-use, and the world will be a better place, right? At least that's the argument I'm planning on using with the Wife when she see's the bill from the Hardware Store after I buy all the stuff ;-)

- Mac

 

[simonh]

I beleive it is partly dependent on the restrictor fited by the manufacturer to the unit and also on the PSI of the water. Adding a booster pump to my system so the water pressure is 80 PSI reduced my waste water significantly while also improving the quality of the product water from the unit.

Filling a 400 gallon tank will not waste anything like the amount Mouse stated. If it did my water bill on a water meter would be around £230 for one fill of the tank

Remember that the ions it is removing a small percent of are only a small part of the total water volume. Something like 1200 gallons waste to get 400 gallons of good water with my current R/O and booster pump and a more reasonable £10

[ November 09, 2001: Message edited by: simonh ]</p>

 

[Chucker]

Mouse's figures are way off. That 99% rejection figure he lists is for impurities, not for waste water. Again, the most common rejection ratio is 4 gallon of "waste" to 1 gallon "good" water, which would mean that you would use roughly 2000 gallons to fill up a 400 gallon container.

Also, please keep in mind that "waste" water is a semantics game- there is nothing wrong with using it for drinking, cooking, watering plants, bathing, washing your car... etc. In most cases it has already run through a sediment filter and carbon filter- the only "bad" thing about it is that the impurities that the RO membrane rejects from your "good" water are 25% more concentrated. Just because it's labelled "waste" doesn't mean is has to get run down the drain.

 

[MarkO1]

I agree with chucker. Waste water is still drinkable and usable (depending upon the original source). Fortunately for me, my water is included in my condo fee. But even if I waste 30 gal for 10 gal of RO/DI once every two weeks, it isn't much more than my g'friend showers (15 min x 2 gal/min = 30 gal... 2x daily = 60 gal x 14 days = 840 gal/2 weeks!) Ouch!!!
_________________
Honda SL90

 

[Mouse]

Oops sorry chaps, still i was only 30000 gallons out.

 

[EEreefer]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by mtellin:
<strong>It also depends on your water pressure because my ratio is like 1:10 @ 36psi
Mike</strong><hr></blockquote>

Even at the lower water pressure, you should recalibrate your flow restrictor for as close to 4:1 as possible. At 10:1 your water purity is only slightly better with a lot higher waste. A recent "problem" with my RO/DI led me to have a long conversation with the guys at Spectrapure and the deal is "calibrate for the ratio, not the GPD". In other words, at different pressures, temperatures and source water qualities, you will get highly varying amounts of good water from a x GPD system if the ratio is correct. JME.

 

[mtellin]

EEreefer - are you saying I should close the ball valve a little then until I get closer to a 1:4 ratio? I was actually wondering that awhile back but I dont pay for water so I didnt bother asking it

Mike

 

[EEreefer]

No. You should allow for full pressure into the system. Where is the ball valve your speaking of located? On most systems there is a flow restrictor device you can't see inside the waste water line exiting the system. Too large a ratio shows the restrictor is too short or missing. When the ratio is too large, like yours, you have to get a new one and cut it to calibrate.

 

[J Crew]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by Mac:
<strong>...I hate to admit it, but simply flushing all that water back down the drain, is just terribly wasteful... recycle and re-use, and the world will be a better place, right? At least that's the argument I'm planning on using with the Wife when she see's the bill from the Hardware Store after I buy all the stuff ;-)

- Mac</strong><hr></blockquote>

lmao... i hear ya on that one.

so waste water can still be drinken? anyone on this forum drink their waste water?
simonh... did you purchase that booster online or do you know where online i could get one? thanks everyone for the input, peace

 

[slojmn1]

None of my waste water is "wasted". I have not tried drinking it, I can barely get my partner to drink the RO water I make from my RO/DI kit sometimes. I have my waste line long enough to run it into the garden, to my washer(where the bulk of it goes) and into the potted plants on the patio. I just move it around, very simple. In the winter it definately stays near the washer. It takes me about 7 hours of running the kit to get enough waste water for a load of laundry. Works out great.

 

[Jan-Dman]

when i first got my ro unit, i didn't realize the faster flowing one was waste water and was using it in my 180G because the guy that i got it from had the blue hose hooked up to the wrong outlet.

 

[Chucker]

"Waste" water tastes fine- I use it to fill the Brita in the fridge.

 

[Minh Nguyen]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by Chucker:
<strong>"Waste" water tastes fine- I use it to fill the Brita in the fridge.</strong><hr></blockquote>
The waste water actually had lots of impurities filtered out by the sediment filter and carbon. It is better water than tap water but may have more diolved solutes. Everything that were rejected by the membrane