Ahh, the boogeyman.... This water containstraces of various contaminants. Most of which are substantial dimensionally. If you chose a dense ion exchange membran

Ahh, the boogeyman.... This water containstraces of various contaminants. Most of which are substantial dimensionally. If you chose a dense ion exchange membrane (sea water desalination membranes are low density to maximise water throughput) - this denser membrane will allow all the water to be stripped of contamination. You will get a clean stream and a dirty stream and with cascaded membranes you will separate the contaninated water into a releasable stream and a contaminated stream that is .001% of the volume of the clean stream. This contaminated stream is very small and can be stored for 1000+ years in less space than it now consumes. The clean stream is releasable.