ENHANCED BIODEGRADABILITY OF AZO DYES THROUGH PRETREATMENT WITH ELEMENTAL IRON

摘要

The objective of this research is to evaluate an integrated system coupling zero-valentiron (Fe0) and aerobic biological oxidation for treatment of azo dye wastewater. Zerovalentiron can be used to reduce the azo bond, cleaving dye molecules into products thatare more amenable for mineralization by bacteria in aerobic biological treatmentprocesses. Azo dye reduction products, including aniline and sulfanilic acid, have beenshown to be readily biodegradable at concentrations up to approximately 25 mg/L. Thisbatch reduction and biodegradation data has been used to support an integrated ironpretreatment/activated sludge process for the treatment of the azo dyes orange G andorange I. The integrated system was able to decolorize dye solutions and yield effluentswith lower total organic carbon concentrations than control systems without ironpretreatment. The success of the bench-scale integrated system demonstrates that ironpretreatment technology is a feasible option for treatment of dye-containing wastewaters.