You were not fined for doing the right thing, you were fined for not doing the right thing, i.e. leaving bottles around the bottle bank (admittedly it was your friend who did the actual dumping).
For example if I am walking through town and go to a bin to dispose of my chip wrapper and empty can, and the bin is full, is it all right to leave the rubbish beside the bin? I personally think not. If I arrive at the bottle bank and it is full, I just but the bottles back in the car for the next time.
If it were me, I'd be asking my friend for the €150
Maybe just talk to your friend and explain what happened? S/he may offer to pay it without you having to ask. I know I would if it were me (even if I would not leave bottles on the ground).
If s/he doesn't offer to pay it then mention that s/he was caught by CCTV. S/he might offer to pay it then.
If s/he still doesn't I would question what kind of friend would do that and maybe challenge the fine and put your "not-friend" on the spot (unless s/he has financial problems).