To get rid of ants that are nesting in the ground is pretty easy. The fastest approach is to drench them with some Cypermethrin. This will kill them on contact and requires very little material to be effective. More details can be read about in our Fireant Control article. Fireant mound drenching is very effective and quick so that's the preferred method of treatment for that species. But any species of ant can be treated the same way so I'm sure it will work for your problem too. If you take care of all the ones you see now chances are high they won't be nearly as active for the rest of this year. Treat early next season and you'll find controlling them to be a lot easier in the long run.