* Burn it hot.
* Take the exhaust from the burnt waste and fractionally distill it to extract the Nitrogen, CO2, water and other safe gasses.
* Take the ash and extract things that are worth money (metals), then vitrify the rest (turn it into glass)
* Take everything else and stick it back into the input, letting it go round again and becoming something safe this time.
1 ton of household waste probably only makes 5kg of vitrified glass - turns out nearly everything in your house is carbon, hydrogen and oxygen.
I suspect the energy in all the waste makes this process "free" from an energy standpoint. But obviously the capital cost of a plant big enough for the worlds waste is huge, and unless laws are written to ban landfills and regular incineration, it would never make financial sense.