Is there any sensor which could differentiate the biodegradable and non-biodegradable waste?

To common knowledge, there is no sensor that is capable of distinguishing waste. From a technological standpoint, this is quite the task, how do you create a mechanical eye that has a complex enough program to distinguish a piece of lumber that is covered in paint as "bio-degradable" and a piece of metal covered in food waste as "non-biodegradable" it is simply too hard to make a device that can sort trash effectively. Instead, many facilities that specialize in separating bio-waste from garbage do it BY HAND. Needless to say, this is an unsavory job, but it takes out a considerable amount of waste to be re-used in generating electricity. I know that an episode of "Dirty Jobs" features this job, but I can't be specific enough to tell you which episode (sorry).