I'd rather see the leftover food go to something like this than just become part of the giant hill of a landfill. As for the poo, well, why not use it as well? As long as they don't expect me to start bagging it.
I have to admit though, I scanned a headline about this bus and I pictured it running off of the poo that was deposited in the bathroom of the bus. This isn't JUST poo, but I like that everyone's billing it as a poo-powered bus.