Our waterways are becoming more and more polluted due to PFAS, plastics, medicines, drugs, and new chemicals made by companies that just hand over the responsibility of cleaning to plants paid for by public moneys. Detecting the different chemicals and filtering them out if getting harder and harder. Could the simple solution of heating up past a point where even PFAS/forever chemicals decomposes (400C for PFAS, 500C to be more sure about other stuff) be alright?
Always good to do a quick search of the literature to make sure your intuition about something is actually correct; I too thought “no way” when I first saw your question.
I don’t think only heating water to 500C would remove more harmful chemicals than a typical full treatment process, as they have a lot of steps to filter various things out, but I don’t have a source for that.
Even if it did, there’s still the issue of heating up the water taking an enormous amount of energy, which is probably a dealbreaker. My local wastewater plant treats 40 million gallons a day, which by a quick calculation would take 150 GWh to heat, 83% the daily energy consumption of the whole of Minnesota. That can be reduced significantly with heat exchangers but even 1% of that would be far too expensive.