all you got to do is ki9ll the ants with something like nippon or propper ant powder then it will just be a bump in the lawn . when there gone carefully cut a slit about an inch deep and across the bump about a foot further than the bump each side . then slice it so you can get a spade under the turf and roll it back revealing the bump . dig it out and get it flat and tread it down flat . roll your turf back and water it well and it should be fine.