See, now this is something nice. Some folks have figured out how to turn unsorted household waste into building materials, compost, and fill. Called Fluff, this slurry turned powder turned 2 x 4 uses standard garbage which is then treated to ensure it is pathogen-free. The folks commenting on the post make some good points about the feasibility of this—what about PCBs, metals, and other junk?—but the concept seems plausible.
I (heart) Fluff [WorldChanging]