Aplicação do processo foto-Fenton em pH neutro utilizando Fe(III)+EDTA/H 2 O 2 /UV no tratamento de lixiviado de aterro sanitário

Abstract

This work demonstrates the application at neutral pH of a photo-Fenton reaction mediated by Fe(III)+EDTA complex on the treatment of sanitary landfill leachate (SLL) under simulated solar irradiation. The formation of a Fe(III)+EDTA complex is justified due the inconvenient application of the conventional Fenton and photo-Fenton reactions, as the acid pH of the solution leading to a reduction of organic compounds. Using a lab-scale photoreactor, the main operating parameters such as pH of the solution, dissolved iron ion and EDTA concentrations, H 2 O 2 consumption and amount of UV energy required; they were evaluated to SLL decolourisation and absorbance at 254 nm reductions. The best results were obtained using: pH of the solution 6.0, 100 mg Fe(III):EDTA, consuming approximately 280 mM of H 2 O 2 and ≈ 8 kJ UV L -1 required leading a complete decolourisation and ≈ 80% of absorbance at 254 nm reduction. In such conditions, the efficiencies of organic contents reduction as: biochemical oxygen demand (BOD 5 ), chemical oxygen demand (COD), dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) were satisfactory and probably improving the treated in terms of SLL-biodegradability (BOD 5 /COD ratio).