Anybody reuse RO water waste?
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Stauffbier
Well-Known Member
Doesn't the waste get trapped in filters and filter media?
I am reading that up to 9 gallons is wasted for every 1 gallon you use. It apparently just goes down your drain. I don't care if it's pennies, I don't like to see that much waste. The minerals should help my plants too.
BBL_Brewer
Well-Known Member
The wastewater will have more dissolved solids, but you might be able to get away with it for outside plants. I wouldn't use it for potted plants.
No. RO units waste between 8-12 gallons of water to produce 1 gallon of RO water. It's a pressure thing. Only so much water can pass through the RO membrane at household pressure, the rest runs down the drain. I've been thinking about getting one, but I don't like how ineffeicient they are.
Stauffbier
Well-Known Member
Ahhh! I've never had a RO system, and I had no idea of that.. Then in that case I would want to harvest it and use it too if I could..
depending on your water source and how you water plants can suffer form a buildup of salts in the soil. using the effluent form an ro system would just make the problem worse.
on the radio there is a call in show with a garden guy early sunday morning that regularly deal with this problem. any potted and acid loving plants are most supseptable but any plants that require a certain ph of the soil can be affected.
all that being said if you are really bothered by it you can always use it for other brewery or house hold uses. do you freeze water to keep fermentation temps low or for cooling wort? hose off a driveway? it just depends on how hard your water is.
just remember that the effluent has concentrated mineral content.
on the radio there is a call in show with a garden guy early sunday morning that regularly deal with this problem. any potted and acid loving plants are most supseptable but any plants that require a certain ph of the soil can be affected.
all that being said if you are really bothered by it you can always use it for other brewery or house hold uses. do you freeze water to keep fermentation temps low or for cooling wort? hose off a driveway? it just depends on how hard your water is.
just remember that the effluent has concentrated mineral content.
Hermit
fuddle
The concentration isn't going to be that much higher if it is 'wasting' 9 to 1 is it?
Modern RO units don't waste anything like 8 - 12 gallons for every gallon produced. It is more like 3 or 4 for the inexpensive systems and more like 1 or 2 for the fancier ones. This is good news in terms of conservation of water but bad in the sense that the higher the recovery the higher the mineral content in the concentrate. If you know what your recovery rate is (and the manual that comes with the unit will tell you this) it's a pretty simple matter to determine an approximate concentrations in the brine from assumed rejection. Of course you need to know what's in the feed.
Assuming, for example, 25% recovery (1 gal RO water, 3 gal brine) 100 mg/L of some ion in the feed and 95% rejection ratio for that ion we'd have 400 mg entering the system in 4 liters. Ninety five percent of that, 380 mg, would go out with the 3 liters of brine for a concentration of 380/3 = 127 mg/L. You'll have to decide for yourself whether that's too much for whatever purpose you have in mind.
Assuming, for example, 25% recovery (1 gal RO water, 3 gal brine) 100 mg/L of some ion in the feed and 95% rejection ratio for that ion we'd have 400 mg entering the system in 4 liters. Ninety five percent of that, 380 mg, would go out with the 3 liters of brine for a concentration of 380/3 = 127 mg/L. You'll have to decide for yourself whether that's too much for whatever purpose you have in mind.
Airplanedoc
Well-Known Member
I suppose you could flush your toilet with it. You are currently using potable water to discard waste. You could just collect the waste water, then pour into toilet instead of flushing.
A permeate pump dramatically cuts down on waste water as well as reducing regeneration time. I have these on all my ro systems:
http://www.airwaterice.com/product/PAM1000/Permeate-Pump-With-Clips.html
http://www.airwaterice.com/product/PAM1000/Permeate-Pump-With-Clips.html
My RO system produces around 5 gallons of "waste" for every gallon of RO water. But to call it waste is silly - it's in fact carbon filtered, delicious water that has a slightly higher mineral content than the source. I use it for everything from making tea to watering plants without any issues at all. Water is cheap (.5 cents per gallon here in MN), so I can make a gallon of RO water for 2.5 cents. Compare that to what grocery stores charge and you will see why getting an RO system makes so much sense for those of you with difficult water to brew with.
Do you have a jug under your sink to collect it?
The better solution would be to run the discharge outside and collect it in a big barrel for when it's time to water plants, lawn, etc.
The reason they cut down on waste is because systems that use pressure tanks with out booster pumps are poorly designed WRT recovery. They are usually small systems from which a few GPD is the maximum that is likely to be demanded. If you have such a system you can increase recovery by running the permeate to an atmospheric rather than a pressure tank. Your HLT could be that tank. Eliminating the pressure tank may lead to other inconveniences however. Efficient systems collect to an atmospheric tank and then pump from the atmospheric tank to a pressure tank if pressurized water is needed. Needed or not it certainly is handy.
But the essence of high recovery is the feed booster pump and concentrate line restriction. By restricting the flow of concentrate one forces the pressure across the membrane higher for more permeate at the same time cutting down on what goes to the drain. Many systems have an adjustable needle valve as the concentrate restriction device. By adjusting this one can set up for a wide range of recoveries. I run my system at 50%, for example i.e. 1L of concentrate for each liter of permeate.
It is possible to go even higher recovery by recirculating a portion of the concentrate back to the pump inlet. This is, of course, at the cost of lower system rejection.
aiptasia
Well-Known Member
I got tired of using R/O with my saltwater aquariums. Our area has tap water that is very high in phosphates and silicates which are notorious for NOT BEING REMOVED by standard R/O membranes. To remove them, you need a special type of membrane that produces on average about five gallons more wastewater to product water than standard R/O membranes. If you don't use them, your aquarium will very quickly be overgrown by problem algaes.
So, after looking around, I went with a Kent Marine Deion 200-R unit. It uses a 1 micron carbon post pre-filter and a large cation and then anion resin chambers to produce virtually pure water WITH NO WASTEWATER whatsoever. It's so pure that it measures 0 TDS on my lab calibrated TDS meter (professional digital TDS meter, not a pen). It's so pure that you would have to add minerals back to it to make it potable (drinkable). Without reconstituting the water for drinking, the pH would shift wildly in any direction depending on what interacts with the water.
Here's a link to it: http://www.kentmarine.com/products/kent-deion-200r.htm
The resins are re-chargeable and color change as they get used up. I've had mine for years and it wastes no water. 100% of the water flowing into the unit is cleaned and 100% of it is useable. The flow through the unit is very fast at normal household pressures.
I also like the Kold Ster il units that poly bio marine has. It works in a similar fashion and their technology was originally developed for hospitals as a pre-filter for water used in dialysis machines. I've seen a lot of professional breweries use this type of filtration set up, too. It doesn't remove as much from the water as the kent marine unit but it does make some pretty pure water without having to add anything back to it to reconstitute it (doesn't filter out all of the minerals).
Here's a link to it: http://www.marinedepot.com/Kold_Ste...r_Systems-Poly_Bio_Marine-PB1211-FIRO-vi.html
So, after looking around, I went with a Kent Marine Deion 200-R unit. It uses a 1 micron carbon post pre-filter and a large cation and then anion resin chambers to produce virtually pure water WITH NO WASTEWATER whatsoever. It's so pure that it measures 0 TDS on my lab calibrated TDS meter (professional digital TDS meter, not a pen). It's so pure that you would have to add minerals back to it to make it potable (drinkable). Without reconstituting the water for drinking, the pH would shift wildly in any direction depending on what interacts with the water.
Here's a link to it: http://www.kentmarine.com/products/kent-deion-200r.htm
The resins are re-chargeable and color change as they get used up. I've had mine for years and it wastes no water. 100% of the water flowing into the unit is cleaned and 100% of it is useable. The flow through the unit is very fast at normal household pressures.
I also like the Kold Ster il units that poly bio marine has. It works in a similar fashion and their technology was originally developed for hospitals as a pre-filter for water used in dialysis machines. I've seen a lot of professional breweries use this type of filtration set up, too. It doesn't remove as much from the water as the kent marine unit but it does make some pretty pure water without having to add anything back to it to reconstitute it (doesn't filter out all of the minerals).
Here's a link to it: http://www.marinedepot.com/Kold_Ste...r_Systems-Poly_Bio_Marine-PB1211-FIRO-vi.html
AJ,
Thanks for the information. To clarify, my 2 systems and the others I've installed are all 75 gpd systems running the permeate pump from AWI. All use the DOW Filmtec membrane and all seem to be right in line with the listed rejection rate (97% IIRC). I have no problem running off 21 gallons of water in a few hours for a brew in addition to my regular demands (drinking, ice).
A friend has a 20G pressure tank in his garage and an 8G tank inside. He uses the larger for brewing and the smaller for drinking / ice.
Logzor
Well-Known Member
A lot of people use their waste water for washing clothes, it should be perfectly fine for this application, I've done it in the past. I pump about 25+ gallons of RO/DI water per week for my aquarium.
To reduce waste and increase the rate at which I can produce water, I installed a booster pump and a second RO membrane, this brought my original 75 gpd system up to at least 150 or 175. The waste water is cut in half, at least.
I use tap for brewing, Cincinnati has pretty decent water, tastes great.
To reduce waste and increase the rate at which I can produce water, I installed a booster pump and a second RO membrane, this brought my original 75 gpd system up to at least 150 or 175. The waste water is cut in half, at least.
I use tap for brewing, Cincinnati has pretty decent water, tastes great.
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