We have prototype waste incinerators working at very high temps, to eliminate/reduce the toxic ash probs.
Gas emmissions are a major factor to consider, all gases will have to be dealt with, they cannot be released to the atmosphere, unless of course they are "green " . For example there will be quite a lot of methane, which of course is of great value, and can be used for generation or for water distillation plant etc. But some gases are quite nasty such as Dioxins etc. You will need a specialist company to deal with this huge problem. It certainly has to be addressed but the cost will be very high. The ultimate is to collect and re-use or sell the gases.