I once did consulting for a battery recycling company. It depends on what's in them and what price they're going to the recycler for. Battery recyclers jump through a lot of hoops due to the chemicals in them so if tesla makes the costs right it will be handled between manufacture/reseller and an industrial recycler.

Consumers are a different story. Not sure who's going to take it directly from the consumer. Maybe auto shops or auto retail chains? Some of them will recycle normal car batteries so it may fall under that category.