[invernomut0]

You're forgetting dioxins and other pollutants resulting from burning various materials, especially plastic.

[londons_explore]

By having a 'loop' in the process, anything that is incompletely burned and results in dioxins (and anything with a boiling point under ~1500C, which cannot be vitrified) will end up not passing the fractional distillation stage and will be put back into the start of the process to have a 2nd go at breaking down.

[pwarner]

Burning above 1000°C supposedly destroys the dioxins. https://www.who.int/news-room/fact-sheets/detail/dioxins-and...