First off, between the four options: sanitization sanitizer sanitation sanitizing/
I prefer Sanitization.
Secondly, I believe that most of the time when people talk about Sterilization they actually mean sanitization. So I say a conditional merge into sanitization.
For Sterilization/Sterilisation there are four questions, one is mine and I think should keep the sterilization tag. (Other's should be the judge of it though, no hard feelings if it doesn't)
The second is a question about adding adjuncts to the fermenter, the third speaks of contamination in a batch and the fourth about "sterilizing" the hydrometer. In all these cases I believe the asker really means sanitization.
Thirdly, I support using the "z" version of the word sterilization (rather than sterilisation), this is merely because it's the way I spell them.