This is a post from 2014, please check if it still applies, at the time of writing bumblebee was relatively new.
I had some problems with bumblebee and optirun command --- it just suddenly stopped working.
So here is how to switch your computer to use nvidia on debian, and use nvidia proprietary drivers
Install Nvidia proprietary drives (https://wiki.debian.org/NvidiaGraphicsDrivers).
Remember to configure xorg.conf precisely as in the instructions.
Restart. Go to bios and switch off integrated graphics card.
If you restart your computer before step 3, most probably your X will not be usable.