Physico-chemical treatment for the depuration of wine distillery wastewaters (vinasses).

In the present work, an integrated Fenton-coagulation/flocculation process was applied for the depuration of wine distillery wastewaters, commonly known as "vinasses". This study evaluates the Fenton process (H2O2/Fe2+), involving oxidation--in a first stage and coagulation/flocculation (using Ca(OH)2 as base-precipitant)--in a second stage for the removal of chemical oxygen demand (COD). The experimental variables studied were the dosages of hydrogen peroxide and iron salts, the molar ratio [H2O2]o: [Fe2+]o, the effluent dilution and the manner in which the reagents were added (splitting the reagent dose of hydrogen peroxide and ferrous salt into different fractions). The optimal operating conditions of the integrated process were: [H2O2]o = 0.5 mol/L using an optimal concentration ratio [H2O2]o: [Fe2+]o= 15 mol/mol. Under these conditions, the COD removal was 74%.