What you do for an island is you must provide a vent with the drain line or it may not drain at all regardless of the dishwasher. I don;t have a picture handy but it is fairly easy to visualize. The drain's vent line runs right under the floor from the outside wall to the island and the drain line itself runs beneath it. Then they both go up and connect right under counter height in the island. Now that that's done you can hook up to the drain line just like any other drain line. Air gap/check valve thing or a small sink and disposal will do - I would do the small sink myself.