I had a similiar problem with fruit flies. Are you sure these aren't the (fruit) flies that feed and breed on fermenting waste?
Regardless, what I found out is that you've got to find the source where they are feeding and reproducing. Taking out the fresh garbage like you're doing is the best place to start. They need a moist environment, so the next place to inspect is all your drains. Plugging them when not in use would be a good measure. A careful inspection of your environment will reveal other possible sources.
What I did to finally get rid of the very last of them was to create a trap by rolling a sheet of paper into a cone, fastening it with a paper clip at the top to hold the roll, and sticking it into the mouth of a mason jar so that the sides of the paper cone were snug up against the mouth of the jar. The bottom end of the cone will be about 1/2 to 2/3's of the way into the mason jar, which is fine. The most important thing is that the paper cone/jar mouth seal have no gaps that will allow the flys to escape. Inside the jar I placed a juicy slice of peach, but banana works just as well. It took about three days, emptying the jar once a day of 2 to 4 flies, but finally I did not see anymore. I learned my lesson about taking the trash out on a daily basis.