This article is about 10 years old, but contains some good facts about people coming to Florence to help with the clean up and restoration:

On arriving in Florence, he was astounded by the immensity of the task. Something like a million books from the BNC alone, including hundreds of thousands of old and rare books, had been damaged by the flood. Although all the books had been dried by early 1967, he estimated that it would take a staff of about 100 working on book restoration for another 20 years at the Library just to undo the worst of what the Arno River had done in minutes.

That was a conservative estimate, as they are still restoring books 40 years later!