R.O. discharge water

[cephalotus]

I hooked up my ro unit today ,and was amazed at how much waste water it used just to make ten gallons. So I was wondering what everyone does with their ro discharge water? I plan on collecting and using it on my garden and maybe some of my not so picky house plants.

[streetrodder007]

Down the drain .

[henry hill]

Alot of people put the waste line into the washing machine, but be careful not to forget about it and cause a flood!

[tankdude]

I already answered this on MR, so here I go again lol. I let mine go down the drain, never really thought about reusing it.

[ROGERWILCO357]

what is in the waste water? ever test it?

[Sir Patrick]

The waste water is cleaner than your tap water- it has been through all the chambers besides the membrane.

I use the waste water for water changes on my pond- or for water changes on my goldfish tank, depending on if they are inside or out.

[nate_newton]

Could I use the waste water for my red ear slider turtle?

[Sir Patrick]

^ Yup- the water will be cleaner than your tap water. Wont be extreamly clean, but cleaner than the source water fpr sure.

[nate_newton]

So at this point the chlorine is gone?

[AZDesertRat]

The waste is not cleaner than your tap water. Yes it has been through a sediment filter and carbon but it also contains the concentrated TDS removed from the treated water so is 20 to 25% higher in TDS than the tap was to begin with.
Carbon only removes organics like chlorine, pesticides and herbicides and the prefilter only removes large particles so little actual treatment has been done at this point, its the membarne that does 90-98% of the work.

I send mine down the drain since the local WWTP recycles it anyway. I did do my part by going with a Spectrapure MaxCap UHE 1:1 system though so only waste a little less than 1 gallon of water for every good gallon treated unlike the normal 4:1.

[ReeferRob]

Man I dream of one day picking up the 1:1 unit.....so jealous.

[AZDesertRat]

Its a chunk of change but my recordkeeping has shown its well on its way to paying for itself.

[fawkes]

You waste 4-5 gallons for every good gallon you produce. It depends on temperature, membrane, back pressure and other factors. The waste is high in minerals - remember this is what is washed off the backside of the membrane.

I once observed a lawn where the waste was going, and it was greener. That may have been due to more water, although it the minerals were not too high they could help.

[Bella127]

I used some waste water for my dog bowl water, cleaned up my tools after mudding the drywall, used some waste water for the plants outside , laundry, mix with vinegar to clean my powerheads and skimmer, use it for the base of my daughters basketball set-up, mix it up for my car wash solution , use it for water to take bird baths when we go camping where there is no shower available in 5 gallon jugs. Some does go down the drain , but I try not to.

[Sir Patrick]

Ha! I learn somthing new every day!!

When I tested my waste water, it was right after I changed all filters. Never took into consideration all the minerals getting swept of the membrane after some use.

[AZDesertRat]

The dissolved solids that are removed must go somewhere. This is why the 4:1 waste ratio is necessary, it provides the volume and velocity to carry the TDS away from the membrane fabric so it does not begin to adhere to the surface and foul the membrane. Once the solids start to build up due to lack of flushing its almost impossible to remove them short of major chemical treatments.
Pay attention to your waste ratio and make sure it is close to 4:1, especially if your tap TDS is much higher than 200 or so. A membrane can be fouled and irreversibly damaged very quickly. If your waste is not close to 4:1 you may need a new adjustable or capillary tube type flow restrictor so you can set it according to your specific water conditions.

[fishtal]

I use the waste water in my washing machine. Using a TDS meter, waste water tests at 370, RO/DI water tests at 4.

[AZDesertRat]

fishtal,
If your RO/DI is 4 TDS, you need to replace the DI resin.
If your system is running at the normal 4:1 waste ratio and your waste TDS is 370 then your tap water TDS is probably in the 300 range and your RO only TDS should be between 6 and 12. If you are getting 4 out of the DI, it is exhausted and is not doing much for you. It will soon be higher than the RO only TDS as it has started to release all the contaminants it has trapped.