Removal of Refractory Pollutants from Landfill Leachate Using Two-Phase System

The study focused on the problem of removing refractory substances from leachate treated by means of activated sludge method and advanced oxidation process. Biological treatment was conducted in sequencing batch biofilm reactor. Biologically treated leachate was subject to further chemical treatment with the use of Fenton reagent. The permanent dosage of H2O2 amounting to 2 mg.L-1 was applied. Fe(II):H2O2 ratio was 1:10, 1:5 and 1:3. Biological treatment allowed for removing 97% of benzene and only 20% of ethylbenzene. There was a 25% decrease in the concentration of volatile organochlorine compounds. The concentration of benzene in chemically treated leachate increased in comparison with the value found in biologically treated leachate and the growth coincided with the decreasing Fe(II):H2O2 ratio. An analysis of polycyclic aromatic hydrocarbons showed that leachate subjected to advanced oxidation contained the sum of polycyclic aromatic hydrocarbons that was lower than in biologically treated leachate, irrespective of Fe(II): H2O2 ratio.