I don't know how much you know about water filtration plants, but in the real world everything is a series of filters, each more fine-grained than the one befor

I don't know how much you know about water filtration plants, but in the real world everything is a series of filters, each more fine-grained than the one before it. You would never use this on unfiltered ocean or waste water - it would be yet-another-stage in the filtration pipeline, after many of the others and possibly before a few more.