When we were living in the South we had a huge problem with fire ants! Nasty, nasty creatures that bite, sitings like, you guessed it, fire.
I took perverse pleasure in getting rid of the ones in my yard organically. You need 2 fast people and 2 shovels. Dig out a shovel full of dirt and ants from both hills at the same time and run and dump them in the other hill. It creates an ant war, they kill each other off. Works great.