Let's say a Torah has been in use for a temple's services for awhile. However the Torah was rendered incapable of use due to a disaster of some sort. Will the Torah (or what's left of it) meet a ritual end? Or will the congregation typically try and revive the Torah?
A scroll can be repaired by specially trained people, or, if it is beyond repair, it can be ritually stored/buried.
http://www.sofer.co.uk/html/repairing_a_scroll.html is a site for one person who explains some of hat he does (I am not affiliated with him and am not endorsing his services -- just using his website to illustrate some of the possibilities).
If the torah cannot be repaired, one can put it in a genizah.
The laws of fixing a Torah scroll are found in Shulchan Aruch YD 279. The Keset HaSofer, by Rabbi Shlomo Ganzfried, writes about them in Chapter 19. He writes that if 3 mistakes are found at once, then the whole scroll needs to be checked over as it has lost its assumption of being accurate. Similarly, if 85 mistakes were found (cf Sifrei Zuta 10:33), even at different times, then the entire scroll must be checked over. One cannot make more than 3 noticeable fixes in a single column, as this makes the scroll look ugly (מנומר). One must not leave an invalid Torah in their possession for 30 days without fixing it, based on Job 11:14.
If it cannot be fixed, the scroll is to be buried within 30 days, as above. It should be buried inside a earthenware vessel and alongside a Torah scholar (OC 154:5).
(See Igrot Moshe OC 4:38 regarding maintaining an unfixable Torah scroll in an honorary place in a synagogue instead of burying it.)