I know that at least one person doing 3D printing was making it a point of picking up old projection TVs and recycling the ABS housing to make new filament using a Filastruder.
Theoritically some filaments are recyclable, and the main one (PLA) is even advertised as biodegradable. However in practice this is not the case, both for material reasons (PLA needs actually to be processed to decompose) and logistic reasons (there is no recycling center for 3d prints and you'll need to print only a single filament type)
You can mostly recycle ABS but unsure of the others. In the case of ABS Plastic it isn't infinity recyclable and you can get maybe 2 or 3 uses from it before it degrades. Personally, I would prefer we design for minimizing plastics.
I know that at least one person doing 3D printing was making it a point of picking up old projection TVs and recycling the ABS housing to make new filament using a Filastruder.