Waste Wheelers

I know most of the actual trash that we put out goes to a landfill, but what happens to the yard waste? I see a potential gold mine (or green mine if you will) for the city to privatize the collection of yard waste, turn it into compost, and sell it back to consumers for personal or commercial fertilization. Does anyone know where it goes?

Many municipalities do exactly that. Some also separate out branches, run them through a chipper, and sell the chips as landscaping material.