Have a plumber disconnect and seal the perimeter drain from the floor drain. Then add a sump pit and sump pump to the perimeter drain somewhere along the perimeter. The drain water froum around your foundation should not be connected to your sanitary drains. If you use a sealed sump pit and vent it properly, your odor problem should go away. Now, what causes your sanitary drains to back up? Hopefully, cleaning the drain has solved that problem.