Move It can delete full landfills if you don't want to wait for them to empty. If I remember right, so can the Better Bulldoze mod.
Make sure you have a nice big pagefile set up. I recommend a custom one at 32 GB. That should hopefully help with the crashing.
https://steamcommunity.com/sharedfiles/filedetails/?id=2114415052&searchtext=pagefile
Keep an eye out for that error though as it could indicate problems with your RAM. Hopefully it's just running out of virtual memory though, so setting up your pagefile will do the trick.