Polychlorinated biphenyl concentration changes in sewage sludge and organic municipal waste mixtures during composting and anaerobic digestion

• The PCBs degradation under anaerobic and aerobic conditions was investigated.
• During composting the loss of PCBs depended on their chlorination level.
• During anaerobic digestion the PCBs loss did not depend on the chlorination level.
• The PCBs degradation without PCB 28 was described by a first-order kinetic model.
• The second-order kinetic model described the loss of the PCB 28 contents.

We determined the changes in polychlorinated biphenyl (PCB) concentrations in a mixture of sewage sludge and the organic fraction of municipal waste during composting and during anaerobic digestion. The processes were carried out on a laboratory scale. The PCBs were analyzed in the waste samples using gas chromatography–mass spectrometry. We evaluated the rates at which the PCB concentrations decreased during composting and during anaerobic digestion and compared the PCB degradation kinetics during these processes. The most important conclusion of this work is that anaerobic digestion is much more effective than composting at removing PCBs from a mixture of sewage sludge and the organic fraction of municipal waste.