Bio-diesel from waste food?

Sustainability in business is a big things nowadays. It can mean many things from saving energy, reducing waste and altering product design. Going one better of course is to completely re-use waste to make a new product. I read a great example recently in the Telegraph [London]. The article mentioned a UK company called Greenergy. The company has invested £50m in a plant to make bio-diesel from used cooking oil, which in itself is a great [if not new] idea. But this company has taken things a little further. In partnership with another company called Brocklesby, the company is now processing waste food into bio-diesel. Apparently, fatty foods like crisps, pies and junk food are great candidates as they are full of fatty oils. While the company has started this new process on a small scale, it seems like a great way to make money out of waste. It ticks so many boxes on the sustainable/environmental side too – it reduces waste to land fill, reduces fossil fuel dependency and may even in the future reduce land use e.g. rape seed grown for vegetable oil.