No, if a high pH RO cleaning solution is mixed with RO brine, it would result in severe scaling. Always consult with your hydrogeologist before sending any solution to the deep injection well.
See also:
What is the procedure for cleaning RO membranes? What CIP chemicals should be used?
Can we send our CIP solution direct to the waste water treatment plant after cleaning our Reverse Osmosis System?
We recently installed new RO membranes in our system and observed that the permeate water tested positive for coliform bacteria. Is it possible in your experience that RO membranes could be damaged during installation and cause contamination of the water distribution system by bacteria and pathogens?
Our RO plant doesn’t have a neutralization tank for our spent CIP solution. Can we just neutralize while circulating through the membrane system?