check with your local DNR
in missouri, the rules are different depending on the size of the compost area.
If you are using 3 acres or more you need to have a septic system for all runoff of water. The guideline for 1 acre or less is very minimal.
You can usually get a grant (free money) however the state will want their name on the deed of land for a few years to make sure your not doing some thing stupid with the money.
I have thought of that myself. It can be successful if you have the machine to till/aerate the pile when needed and enough water. To have a commercially viable product you must ensure that it 'cooked' well enough to kill weed seeds and disease organisms. When the pile cools, stir and add water if not done.