Yes it can/has been done, requires maintenance and bowser man.
Fuel removed can only go back in the same a/c or same companies other a/c. Or disposed of, the cost of which is picked up by the airline.
Done it several times, it can take a bit of organising, I understood that it was a requirement of the airports to have an empty bowser available, not sure if it still is.
I wouldn't imagine that it would take too long to get 5T off a 320.