Question:
Does chametz that belonged to a Jew over Pesach need to be burnt afterwards or is it enough to throw it away…
Answer:
It is sufficient to throw it away.
The entire concept of burning applies to chametz before Pesach (according to Rabbi Yehudah), and to a number of Torah mandated prohibitions.
It does not apply to this rabbinic prohibition.
See Shulchan Aruch 548:3 and Mishnah Berurah (where the idea of burning is not mentioned).
Best wishes.