Combination of Coagulation-Flocculation-Decantation with Sulfate Radicals for Agro-Industrial Wastewater Treatment †

Abstract

In this work, the effect of the combined coagulation–flocculation–decantation (CFD) with the sulfate radical oxidation process on the treatment of two winery wastewaters (WW1 and WW2) was investigated. The oxidation process was optimized by the application of a Box–Behnken design of the Response Surface Methodology. Under the best CFD conditions: [potassium caseinate] = 0.4 g/L, [bentonite] = [PVPP] = 0.1 g/L, pH = 3.0, rapid mix (rpm/min) = 150/3, slow mix (rpm/min) = 20/20, sedimentation time = 12 h, and oxidation conditions: [sodium persulfate (SPS)] = 51.9 mM, [Fe2+] = 0.90 mM, pH = 3.0, radiation UV-A (365 nm), time = 300 min, a total organic carbon (TOC) and a chemical oxygen demand (COD) of 38.9 and 45.3%, respectively, were achieved for WW 1, and 51.2 and 73.3%, respectively, for WW2. The combined process shows a good potential for WW treatment.