Application of biological oxidation and solar driven advanced oxidation processes to remediation of winery wastewater

Biological oxidation and solar driven advanced oxidation processes (AOPs) applied as a single stages were tested at a pilot plant equipped with an immobilized biological reactor (IBR) and a photocatalytic system with compound parabolic collectors (CPCs) for the remediation of a winery wastewater (DOCaverage = 882 mg L-1; pH 4.1). Due to the variable nature of winery wastewater composition and quantity, the application of AOPs as a single or as preliminary stage can be an effective alternative to only conventional biological treatment. Regarding the AOPs systems tested (TiO2/H2O2/UV and Fe2+/H2O2/UV), the solar photo-Fenton reaction (optimized at pH 2.8 and 55 mg Fe2+ L-1) showed the highest efficiency, being necessary an UV dose of 100 kJUV L-1 and 338 mM H2O2 (15 mg H2O2 mg C-1) to achieve a COD value lower than 150 mg O-2 L-1, which is agreement with the discharge limits into receiving waters imposed by the Portuguese Legislation (Decree-law n. 236/98). To achieve the same COD target value using only the IBR system or the combination of solar-photo-Fenton (22 kJUV L- (1); 80 mM H2O2 consumed) and biological systems, approximately 10 and 6 days (time necessary for the biological oxidation) are required. The efficiency of the AOPs in the treatment of simulated and real winery wastewaters was also compared. (C) 2012 Elsevier B.V. All rights reserved.