The use of Fenton's system in the yeast industry wastewater treatment.

The paper presents the results of the research conducted with the use of hydrogen peroxide and iron (II) sulfate or chloride in the chemical pretreatment of Saccharomyces cerevisae yeast industry wastewater. It was found that the use of Fenton's system permitted a high reduction of sugar-like substances and total decolorizing of non-sugar compounds. The level of COD reduction depended on the amount and mutual proportions of COD:Fe(II):H2O2, as well as a type of the applied salt Fe(II). For iron concentrations: 1000-4000 mg l(-1) with molar excess [H2O2]:[Fe(II)] - 2-14:1 and reaction pH - 3.1-3.4, very high reproducibility of results and the COD reduction exceeding 75% were obtained. For this range of the reagent concentrations, the distribution of COD reduction values correlated with the equation: COD = - Ax4 + Bx3 - Cx2 + Dx - E (where: x = [H2O2]:[Fe(II)]). Additional neutralization with the use of lime milk made the secondary reduction of CODr(CaO) value possible, which resulted in the reduction of the total CODT above 90%. The method enabled us to consider the possibility of the preliminary chemical elimination of the wastewater load, which might increase the effectiveness of working wastewater treatment plants, especially in cases of continuous and occasional overloads above the level assumed by the project.