Estimation of the dioxin emission (PCDD/FI-TEQ) from the concentration of low chlorinated aromatic compounds in the flue and stack gas of a hazardouswaste incinerator

The concentrations of hexa- and pentachlorobenzene in the flue gases of was te incinerators are known to be strongly correlated with the emission of po lychlorinated dibenzo-p-dioxins/furans PCDD/F, measured in international to xicity equivalents, I-TEQ. In this work it was investigated whether polychl orinated benzenes (PCBz) with a lower degree of chlorination and mono- and dichlorinated dibenzo-p-dioxins/furans can be used for estimation of the di oxin emission (I-TEQ) in the flue gases of hazardous waste incinerators (HW I). The HWI process consists of a primary oxidative pyrolysis step in a rot ary kiln followed by a post-combustion of the pyrolysis gases. The investig ation indicated, that lower chlorinated PCDD/F homologues are very weakly c orrelated with the dioxin emission (I-TEQ) and thus are probably not useful as indicator parameters. In contrast to this finding, mono- to trichlorobe nzenes are present in relatively high amounts in flue and stack gases and a re correlated with the PCDD/F I-TEQ value. The mono- to dichlorinated benze nes can be readily detected by a laser mass spectrometric technique (REMPI- TOFMS) and thus are candidates for a direct on-line measurement in the flue gas and a continuous, indirect monitoring of the dioxin emission. (C) 1999 Elsevier Science B.V. All rights reserved.