Industrial waste
I wonder what happens to the lactose when they make lactose free milk. Is there just a pile of it out behind the Lactaid factory? If so, I wonder if there is something you could do with it. I'm reminded of the origins of rum, where plantation slaves in the 1600s correctly deduced that they could use molasses (which at the time was just a byproduct from sugar plantations) to brew a drink that would assist them in getting fucked up.