Influence of combustion conditions on the PCDD/F-, PCB-, PCBz- and PAH-concentrations in the post-combustion chamber of a waste incineration pilot plant

Experiments at a pilot scale waste incinerator (0.5 MW thermal power) showe d that the conditions in the postcombustion chamber (650-900 degrees C) are strongly influencing the formation of chlorinated and non-chlorinated arom atics. Non-optimal combustion conditions resulted in increased concentratio ns of mono- to trichlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF ) and polycyclic aromatic hydrocarbons (PAH), while chlorinated benzenes (P CBz), polychlorinated biphenyls (PCB) and the higher chlorinated PCDD/F are only weakly affected or even decrease. The changes in concentration of the compounds investigated over a time span of hours gave hints on 'memory eff ects' in this combustion zone. For mono- and dichlorinated benzenes, a high correlation (r(2) = 0.80) with the international toxicity equivalent (I-TE Q) value of PCDD/F was observed. As recently has been demonstrated, this co rrelation can be utilized for an indirect on-line measurement of the I-TEQ by a novel laser mass spectrometric technique (REMPI-TO-FMS). (C) 2000 Else vier Science Ltd. All rights reserved.