There exist a Flemish document stating that only a grate incinerator with selective catalytic reduction of NOx is a state to the art incinerator.  A selective catalytic reduction filter of NOx reduce de emissions of NOx to about 70 mg/m.
As I saw in the environment state impact of the projects of the INDAVER waste incinerators in Ireland, there was even not a Denox filter foreseen.
People of INDAVER Belgium has cooperated on the development of this study.  The study was done last year (2001) by VITO (the Flemish Institute for Technological Research).
You can download a summery of the study in English.  By aware because the first part of the document is in Dutch, the second part is the English translation. 


Belgian Platform Environment and Health