I have a Reverse Osmosis (RO) filtration system for brewing because I have extremely hard water off my 90 year old hand dug well. I generally do ten gallon batches and mix the strike water 50/50 between "tap" and RO, and then fill the HLT back up with RO for the sparge. So I go through quite a bit of RO for a brewday, and I brew lot.
I'm not sure what the exact ratio of pure RO water produced to mineral-rich waste water is at 50 or so psi, but it seems to be quite a bit. 4 gallons waste to 1 gallon usable water maybe?
I'd like to reuse the water for irrigation- I would plan to simply reroute the waste line from my drain to a 55 gallon rain barrel and then use that to drip-irrigate my garden. Does any one else do this?
The waste water will obviously be pretty alkaline, but I'm not on city water so there is no chlorine or chemicals or anything. Watchall think?