Great question with a simple answer. You can put your bin up on four legs and put each leg in a bowl of water and the ants will drown trying to get in or avoid the water altogether.
Another thing you can try is using diatomaceous earth outside the bin if you want to avoid the first step. Insects will generally avoid the DE as it is NOT bug friendly. It dries them out and kills them.
(See my pages on Diatomaceous Earth in the left nav panel under the FREE-HOW-TO section)