Help...

OK.  So we've had ants since we've been here and we temporarily got rid of them with the powder stuff.  But...they have come back.  What do we do?

(We have a food bin in the kitchen because of the recycling mission round here and obviously that just adds an issue to the said problem, but that's also unavoidable really because I don't want to have to keep going outside every time I have rubbish!!!!!)