Not to sound pessimistic, but one problem that comes to mind is; what are people throwing out? We didgently separate our stuff, compostables get thrown in the green bin, cans and bottles in the blue bag, and everything else into the trash. It only takes a handful of those who don't care to throw everything into one container. Pigs and goats might have a hard time digesting old printers and computer parts.
Rick Mercer did a gig at a recycling facility and they showed him how much stuff was mixed in that shouldn't be. Sure they have sorters for that, but it only takes a few monkey wrenches to gum up the works.
Also, if someone has to pay $500 to dump their old roofing shingles at the landfill or risk a $250 fine for illegal dumping, guess which option is generally chosen? There needs to be some sort of incentive, at this end of the country it can be a real bother to some to comply with the many rules, and sometimes those who really try still don't get it right.