You can use WVO to make BD, and it turns out fine. I think some people may be afraid of that, or just want to sell you new oil.
If you plan to set up a plant, there is a lot of red tape. Plan on lots of forms etc.
I suggest you start on a smaller scale first, like a processor made from a steel drum, or a electric water heater.
Check out the colaborative BD tutorial here:
http://biodieselcommunity.org/
It has lots of good info to help you get started.
Good luck with your project!