[oxide]

>The whole reason permanganate is added in the first place is twofold: it oxidizes simple organics all the way to carbon dioxide (think nail polish remover, denatured alcohol), and it oxidizes soluble ferrous iron to insoluble ferric iron. The byproduct of the oxidation, manganese dioxide, is insoluble and if balanced correctly the treatment does not increase manganese levels in the water.

Whenever I learn something like this, I always appreciate chemistry a little more. That is absolutely fascinating IMO.

The first thing that comes to mind is what the person who came up with the idea was doing at the time. Sometimes when we are intending to do one thing, we invent a solution to another problem, maybe one we didn't even know we had, along the way.