Solar photoreactor: application in the recalcitrance and toxicity reduction of old leachate by photo-Fenton

Abstract

This research evaluated the applicability of a solar photoreator using the photo-Fenton process to reduce the old leachate recalcitrance from the biological treatment system of the Metropolitan Sanitary Landfill of João Pessoa, Brazil. The operational variables, such as flow rate and reaction time were initially investigated in the photoreactor. Then, the test was carried out under defined conditions: pH (2.8), [Fe2+] (0.257 g.L-1), [H2O2] (9.42 g.L-1), volumetric flow rate (35 L.s-1) and reaction time (60 minutes). The results showed high colour removal (94.4%), COD (81.7%), aromatic compounds, in terms of absorbance at 254 nm (87.1%) and 280 nm (87.74%), as well as a threefold increase in biodegradability (BOD5/COD) of the phototreated effluent. The phytotoxicity of the leachate in the Lactuca sativa (lettuce), in terms of median effective concentration (EC50) was reduced by 76%. It can be concluded that photoreactor was efficient using the solar photo-Fenton process, being available alternative for the leachate post-treatment.