so there are 2 things you need:

- a cool polluted water geyser (you could cool polluted water but why would you need ice then and would make it to expensive power wise)

- a gulp (200g/s conversion)

make a reservoir of cold polluted water and keep it at around -10 just pipe the geyser output through it you need to move it anyway. keep one or multiple gulps in there and as they turn polluted water into normal water it instantly freezes and sinks to the bottom. don't know if it's common knowledge so you tough I'd mention it.

Edit: mainly early mid game use for over couldown in combination with temp shift plats. Also reduces the pipe cooling mess a bit early game.