Chlorine input and chlorophenol emission in the lab-scale combustion of municipal solid waste

Incineration of municipal solid waste (MSW) yields a variety of chlorinated aromatics such as chlorophenols. In this study, regular and modified samples of MSW have been processed in a micromodel reactor mimicking the primary combustion chamber of a practical MSW incinerator. To understand the relationships between the origin of chlorine in the feed and the formation of products of incomplete combustion (PICs) and HCl, emitted chlorophenols (CPs) and HCl have been measured. With humidified air as the carrier gas, the chlorine load of regular MSW (ca. 50% due to inorganic chloride, ca. 45% due to PVC) entailed a net CP production of ca. 110 mu g/kg wet MSW. With an (up to 8-fold) increase of the PVC load in the MSW, only a slight increase of this CP emission level has been observed. Also, in replacing the compostables and the other important chlorine carrying fractions-including PVC-by cellulose and NaCl, the level of CP emission does not change. Enrichment of the combustion air with HCl leads to twice as high CP levels. Removal of 70% of the PVC a nd 80% of the compostables results in a reduction of the CP production by a factor of 2.