LEACHING OF POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS IN FLY-ASH FROM MUNICIPAL SOLID-WASTE INCINERATORS TO A WATER-SYSTEM

In order to predict how much polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/Fs) are leached from fly ash by rain water when fly ash is disposed, leaching of PCDDs/Fs from a fly ash obtained from a municipal solid waste incinerator (MSWI) was investigated by packing the ash in a column and eluting with water. In the beginning of the elution, PCDDs/Fs associated with water-soluble particulates in the ash were eluted, whereas in the latter half, those associated with water slightly soluble particles were eluted, judging from the comparison of PCDDs/Fs in eluate fractions with those transferred to solutions from the original ash by stepwise batch methods with water and 2N hydrochloric acid. The amounts of PCDDs/Fs eluted from the ash column were 2.9% and 1.7% of those extracted from the original ash, respectively, while large amounts of PCDDs/Fs were contained in the fly ash in the column after the elution, suggesting that PCDDs/Fs in water-insoluble particulates of the ash would not be eluted by water.