Yeah, the rod did nothing. I also think it would be odd to assume that this thing is single-phase.

As other have suggested, compaction is potentially needed to transport waste from the deeper parts. But there are several security considerations of just ejecting trash as-is from a high security area. I imagine a trash compactor is also a way to destroy the trash to prevent the old “spy tosses a data device into the prisoner cell block waste chute and have his allies follow the death star to pick it up during ejection”.