Application of advanced oxidation processes for polycyclic aromatic hydrocarbons removal from municipal treatment sludge

Abstract

This study was carried out to investigate the removal of polycyclic aromatic hydrocarbons (PAHs) from municipal treatment sludge. The effects of temperature, sunlight, H2O2 and FeSO(4)7H(2)O concentrations on the PAH removal were determined. A UV apparatus was designed for the PAH removal experiments. All experiments were conducted in triplicate. The highest Sigma(11) PAH removal ratio (71%) was obtained with 4.9M H2O2 addition to sludge (without FeSO(4)7H(2)O addition) at 17 degrees C. It was concluded that ferrous (Fe2+) and ferric (Fe3+) addition was unnecessary because ferrous and ferric contents of the sludge acted as catalysts. Sigma(11) PAH concentration was reduced 23% with acid cracking. PAH removal efficiency reached about 63% using the Fenton process. Sixty percent PAH was removed from the sludge with using sunlight in ambient air applications. PAH removal was hindered due to an increase in average temperature (17-36 degrees C) during Fenton and Fenton-like processes. It was determined that 3-rings compounds were removed from sludge easier than the heavier compounds. It could also be seen that phenanthrene and anthracene (3-ring compounds) were removed from sludge with evaporation as 20 and 35%, respectively. It was concluded that the evaporation mechanism became more effective with increasing temperature.