A Study on Polychlorinated Dibenzo-p-Dioxins, Polychlorinated Dibenzofurans, and Coplanar Polychlorinated Biphenyls formed from incineration of fallen leaves

Abstract

Three kinds of fallen leaves (keyaki: zelkova serrata, sudazii: castanopsis cuspidata, shirakashi: quercus myrsinaefolia) were incinerated using a domestic incinerator and formation factors were investigated.
Although dioxins concentrations in flue gas of zelkova leaves were high (TEQ value) compared with sudazii and shirakashi, dioxins concentrations in leaves, flue gas, and bottom ash showed little difference among the three kinds of leaves. It is thought that the high dioxins concentrations in flue gas of zelkova leaves are influenced by the chlorine contents in leaves. The chlorine contents of 14 kinds of leaves were investigated at parks and streets in Tokyo. It was shown that the chlorine contents in zelkova leaves were the heighest.
The equation
Y=308X^1.3 (R²=0.9485n=12)
demonstrated the relationship between dioxins concentrations (Y: ng-TEQ/m3N) in flue gas and the chlorine ratio (X:%) in combustible materials. From the equation, dioxins concentrations in flue gas increased 20 times when the ratio of chlorine contents (%) increased 10 times.
Flue gas of zelkova leaves with high chlorine contents contained many low-chlorinated-dioxins.