Dishwater

Here in California dishwater is considered black water. Even if you use natural soap. I know its not black, but the people who utilize relentlessly abrasive soaps ruin it for the rest of us. What can i do with my dishwater to make it real clear for the city? I'm thinking of putting it in a tank, letting it settle, then running it through a filter into a plant.  I know this is more than fine, but I want to take every precaution to avoid trouble with the authorities :X .  Any ideas to deal with the kitchen runoff cleanly?