What actually happens to batteries after you drop them off at local councils or super markets? I highly suspect that as with most, but not all plastics they go to landfill, just see where most "donated" clothes end up, on the streets and in the rivers of a once beautiful remote town in Ghana. I highly suspect similar disposal techniques to hazardous chemicals, landfill that is designed not to contaminate the water table, either that or they are shipped off to the middle of nowhere so they can be dismantled for a meagre income by means of unsafe rare earth material salvage. We often pop "recyclables" in the bin and forget about them, but until recently I never saw a branded bottle made from 100% recycled plastic and even now most are made from 50% recycled material, in fact aluminium cans where the only thing to fully reused afaik.