Unfortunately for you, I’ve got a hot plate and it gets pretty darn hot.

It’s okay, you’re both off by at least an order of magnitude anyways. :)

Just elemental silver.

Yeah I meant mass, but that’s a fair question. I updated the title.

Changing things up by finding the most unattractive anime girl for my background instead.

At that point you might as well just send it as text.

Unfortunately most QR readers don’t recognize an image regardless of the data format.

Depends on what you consider readable, but I got it down to 2842 bytes by downscaling it and using an absolutely atrocious quality setting:

That’s just small enough to fit inside a QR code, so I did that! (You probably can’t scan it with a typical QR reader; you need something like zbar that supports reading binary data).

I don’t see how looking like me would help them get CCTV footage, unless it’s through some sort of supernatural means. And even if they could find footage of me entering a password, they’d be hard-pressed to extract individual keystrokes from a typical CCTV quality recording. Perhaps it’s technically possible, but it’s certainly not trivial.

Same as I do now, passwords. Unless they inherited my memories, in which case who’s to say I’m not the doppelganger?

If you’re going to stick to the rules in the future I wouldn’t worry about it; the main reason ban evasion isn’t allowed is to keep out repeat offenders. (And you have no obligation to tell anyone that you were banned on a different account).

Don’t be too afraid, breathing in a bit of HF never hurt anybody.

I see three.

More of a reverse supernova I’d think. You’re starting with the very heavy elements and fissioning them into lighter ones.

I’ve never heard a nuclear bombing described as a supernova, but you do you?

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.

I would bring a list of supernovas that occured in my past, but in the future of the time I traveled to. A couple matching observations will provide indisputable proof that I have information from the future.

Well… The Large Hadron Collider can smash lead nuclei together at nearly the speed of light, which turns them into something that is definitely no longer lead.

Yes; this is something that has been studied. However as other commenters have said it requires a lot of energy, and is better suited for processing smaller quantities of water with a high level of PFAS contamination than massive quantities of water with an extremely low level of PFAS. It’s also not a standalone solution, as plenty of harmful chemicals survive heating past 400/500C (heavy metals like cadmium, lead, and mercury do not break down at any temperature).

I don’t think life has any kind of inherent meaning; it simply arose from random physical processes when the conditions were right and took off from there. I keep living mostly because it’s kind of the default, and because I don’t want to hurt others with my death.