Emissions of chlorinated aromatics during sludge combustion

The emissions of the toxic chlorinated dioxins and furans during the combus tion of sewage sludge and their distribution to the gas/solid phase were ex amined in this work. Sewage sludge samples were collected from two municipa l and one industrial wastewater treatment plant, and were incinerated in a lab scale reactor at 1000 degreesC. High PCDD/F emissions, about 300 ng I-T EQ/kg of fuel were observed during the combustion of the industrial sewage sludge due to the high chlorine and copper content in this sample. Go-combu stion of the industrial sludge with coal resulted in reduced toxic emission s reaching up to 158 ng/kg fuel. Almost similar PCDD/F concentrations were measured in the solid particles removed at the quartz wool filter and in th e gas phase. The examination of the homologue patterns revealed the dominat ion of furans over dioxins in both the gas and the solid phase. The tetrach lorinated congeners prevailed over the other isomers in the gas phase, whit e in the solid phase the lower chlorinated isomers with four and five chlor ine atoms dominated.