Depending on how your septic is routed it may be in the pipe or the box before the septic tank. There's usually a port on the line between the house and the box or septic tank, too. You can disconnect and flush to get it out.

I didn't know the box before the septic tank existed before I had work done. Digging up the box, if you do have one on your system, is a several hundred dollar bill.

This crap, ha ha, adds up fast. A ring upgrade may be the thing.