digging in basement for waste pipes

I'm working on re-plumbing my basement bathroom. It basically had only one vent for the sink and none for the other fixtures.

The vent pipes will run inside a 2x4 framed wall on the outside wall of the basement....therefore, I'll need to dig out the concrete in a couple of spaces relatively close to the foundation walls--about 2 inches off the wall.

Is it OK to notch out the concrete in a couple of places that close to the foundation walls?