Improved biological oxidation based on pretreatment using combined Fenton and ultrasound in
presence of stirring as the best approach and use of modified activated sludge was demonstrated for the
treatment of wastewater containing benzene, toluene, naphthalene and o-xylene. The optimum
pretreatment conditions were observed as initial pH of 3–3.5, Fe2+ dosage of 2.0 g L–1 and H2O2 dosage of
1.0 g L–1 giving about 80–95% reduction in the chemical oxygen demand (COD) and favorable BOD5/COD
value for the biological oxidation. Use of modified prepared activated sludge gave about 20–30% higher
extent of degradation as compared to the conventional sludge types.
2015 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights
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