It just sits there taking up 20 kilos of room and cant be removed because its a quest item, can you get rid of it? I've defeated Alduin so I dont really need it anymore

Did you finish everything for Septimus?

Ah thanks, I didnt think about going back to him

Once you've done everything for septimus , you can take it to the orc in the College of winterhold library and he gives 2000 gold for it.