OK, I just messed around with this and found a couple of potential solutions for you to try.
Since we don't know if iPhoto is freezing because of the unimaginably large # of photos you want to dump or an internal problem, the first step would be to try to empty the iPhoto trash (which yes, is a separate trash) when booted into another user account on your Mac.
If that fails, then the next step would be to delete the iPhoto preferences file and try again to empty. The pref file for it can be be found at Users/yourusername/Library/Preferences/com.apple.iPhoto.plist
Last suggestion is that if you open the iPhoto trash by clicking the trashcan in the left hand pane of iPhoto it will show you all the items in the trash. Highlighting a boat load of them (click the first one to highlight, then scroll down quite a ways and then shift+click one which will select all between those two points) and then selecting the "Photos--->Restore to Photo Library" will remove those from the trash. Perhaps after a bunch were removed it might be able to empty, at which time you could re-trash the ones that were moved back to the Library and empty a second (or third or fourth....) time.
Realistically though, it might just be easier to export (File-->Export) the ones that you want to keep. With 30K being thrown away, I have to guess you would be keeping less than that. One they were exported you could just set up a new iPhoto library (by holding Option at the startup of iPhoto) and just reimport them to the new library. Then just delete the old library.
Oh - as always, back up everything before you start!