Behavior of coplanar PCBs and PCNs in oxidative conditions of municipal waste incineration

Non-ortho PCBs and mono-ortho PCBs are formed during primary combustion of municipal solid waste under oxidative conditions. Concentrations of coplanar PCBs in starved-air condition (O-2 content of about 3%) are much higher than at O-2 of 9.6%. In the secondary combustion, much of coplanar PCBs are destroyed. PCDDs/PCDFs are also reduced in the secondary combustion. Coplanar PCBs formation is probably via dimerization of chlorobenzenes (CBs) in the starved atmosphere of primary combustion. De novo synthesis of coplanar PCBs is also observed. PCNs in the outlet of combustion chambers are detected at similar concentrations as the total PCDDs/PCDFs.