Prediction of PCDD and PCDF emissions from municipal solid waste (MSW) incinerators

A procedure has been developed for predicting PCDD/F formation in and emission from incinerator off-gas plant. Calculations are based on rates of static and in-flight formation, and take account of electrostatic enhancement and phase redistribution in electrostatic precipitators. Application to operating data from two incinerators gave good estimates of PCDD levels within an order of magnitude, while PCDF levels were overestimated by a considerable margin. The discrepancy is believed to arise mainly from the use of an overestimated in-flight formation rate, and homologue distribution data that over-represents the proportion of furans. The results suggest different formation routes for dioxins and furans, and underline the need for more reliable data as a basis for prediction.