Decolorization of a baker's yeast industry effluent by Fenton oxidation

Baker's yeast industry is an important industry in Turkey. Molasses is used as a raw material, which is an end product of sugar industry. Baker's yeast industry effluents contain various pollutants and are generally characterized with high chemical oxygen demand (COD), TKN, dark color and non-biodegradable organic pollutants. The objective of this study was to investigate the decolorization and the removal of non-biodegradable organic pollutants measured as mainly DOC, SUVA254, SUVA280 and COD parameters. Fenton oxidation was applied to biologically pre-treated effluent of full-scale wastewater treatment plant. Jar test method was used to determine the best operating conditions. The 600 mg/L H2O2/600 mg/L Fe2+ dosage was quite enough to obtain a high color removal efficiency of 97%. However, the best Fe2+/H2O2 dosage was 1200 mg/L Fe2+/800 mg/L H2O2 at pH 4 and in reaction time of 20 min for mineralization of DOC and COD. For these conditions, the maximum color removal efficiency was obtained as 99%, maximum DOC and COD removal efficiencies were obtained as 90 and 88%, respectively. Also, SUVA254 and SUVA280 values decreased.