remodeling our kitchen we installed a new single bowl sink that is deeper then the original. House has a galvanized pipe wall drain into large copper drain and exhaust stack. The drain out of the disposl is now about 2-3 inches lower then the wall drain.
Is there anything I can do with the P trap so that water doesn't sit on the disposal side of the trap?

Why do you have a galvanized pipe (Ferrous metal) connected to a copper (non ferrous metal) system?

This will lead to more problems then just the drain height