As far as public lending right is concerned, it shouldn't matter how the book entered the library
Retweeting in case any of my followers with more detailed knowledge of libraries have things to add (but it certainly sounds like a great idea from my perspective!)
Gretchen McCulloch
Gretchen: I buy from my local bookstore, and ask my local library if they want a copy, so sometimes I buy two copies, or get just one and then borrow it. Do donated books pay the same as the ones they buy?