Treatment of Antibiotic Fermentation Wastewater Using the Combined Polyferric Sulfate Coagulation with Fenton-Like Oxidation

The combined polyferric sulfate (PT-S) coagulation with Fenton-like was investigated for treating nondegradable antibiotic fermentation wastewater. The experimental results indicated that 62.2% of chemical oxygen demand (COD) and 66.7% of color were removed, under the optimum conditions of coagulant dosage 200 mg/L, stirring time 12 min, and settling time 1 h. From the PFS characterization by means of Fourier transform infrared, X-ray diffraction, scanning electron microscope, and transmission electron microscope, it was believed that PFS coagulation was a mechanism including adsorption, neutralization of charged particles, and bridging between colloid particles. In addition, optimal conditions of Fenton-like process were determined to be H2O2 dosage of 150 mg/L and oxalic acid of 45 mg/L. With effluents of Fenton-like being controlled atpH 7.0, the pollutants could be coagulated further. The hydroxyl radicals measurement by means of electron paramagnetic resonance showed that Fenton-like system could produce more HO center dot than did photo-Fenton system. The total removal efficiencies of COD and color could reach 93.5 and 96.7%, respectively. (C) 2009 American Institute of Chemical Engineers Environ Prog, 29: 42-51, 2010