.obj file imported on 2.82 doesn't consider separated meshes, while blender 2.79 does as the title says, version 2.82 sees the .obj file as a merged mesh, while if i open it with blender 2.79 it divides it correctly in the different meshes that compose the object and i can select each one of them. 
Is there a way, a parameter to set, in order to see the .obj divided structure also in 2.82? 
Or is it a not fixed bug?
Any suggestion is appreciated,
thank you very much.
If the imported object consists of disconnected mesh parts then you can use Mesh > Separate > By Loose Parts (P > By Loose Parts). In order to move the origin to each separated object use Object > Set Origin > Origin to Geometry.