Their not running that stuff through the filtration or chiller. If you're boiling additions like that it stays in the boil kettle. If you're adding it during the fermentation you'd want to , in most cases, add it to a secondary fermenter. You can do both the boil and fermenter if you feel its warranted. Some folks don't secondary and may actually add their additives into primary. If your adding something into the fermenter there are options. If your not worried about infection from say the orange peel and coriander, you could put them in a hop sack/ muslin bag and stick it into the fermenter. I prefer to give them, or any additive for that matter, a soak in vodka, rum, bourbon, or whiskey depending on the recipe and additive to sanitize them. Vodka is a good one because its flavor is relatively neutral, however something like Oak cubes going into a stout or porter for instance do really well in bourbon. If you start trying to run these additives through chillers or filters it's eventually going to lead to problems, I.e. stoppages. Plus you've already boiled it, the flavor, kinda like a tea bag has been depleted so if you feel more of the flavor is warranted why not add some fresh flavor via fresh ingredients into the fermenter. I know that was long winded, but I hope it helps,
Troy