On the one hand, maybe due to the very low concentrations of them in dissolved,
(possible) oxidation by ferrate or flocculation/adsorption by Fe(OH)3 cannot occur accompanied with the competitive effect among various pollutants. On the other hand, the
fraction remaining in the treated wastewater, unexpectedly high for hydrophobic compounds, could be explained by possible adsorption of PCBs onto nonsettleable solids, which remain in the wastewater stream due to the lack of chemical
coagulation