[gbaygon]

Does anyone is familiar with the process they are using? The article says that it involve incinerators and it doesn't sound healthy to me.

[Gravityloss]

http://en.wikipedia.org/wiki/Gasification#Waste_disposal

The most modern technique is to gasify the waste before burning. That way it can even be used in a gas turbine for electricity, if desired.

[Maakuth]

They surely have strict limitations for the emissions. There is probably a load of filters and converters for the smoke before releasing it.