When the Millipore system processes it has a batch of water that is not purified and rejects. So when the purified water is utilized the tank simultaneously starts the rejection of the non-purified water.
The rejected water is flowing back into the same sink at the same time of the final rinse, not an acceptable practice.
The correct facet head should be a
spray nozzle for rinsing.
The drain for the rejected water needs to be tied into the
floor drain and not discharge back into the sink.