[Extracellular polymeric substances disintegration by Fenton oxidation of excess sludge]

Fenton oxidation was used to disintegrate extracellular polymeric substances (EPS) of excess sludge with its strong oxidation ability. The concentration of polysaccharide, protein and the change of soluble chemical oxygen demand (SCOD) disintegrated from EPS represent the EPS disintegration degree. The objective of this study is to optimize the operational conditions for EPS disintegration with Fenton oxidation. It is shown that the optimal operational condition is as following: pH = 2.5, reaction time = 90 min, H2O2/Fe2+ (weight dosage ratio) = 8:1 and reaction temperature is about 65-70 degrees C. Under this condition after the Fenton oxidation, SCOD, concentration of polysaccharide, protein in the supernate increase from 45.88, 10.96 and 11.99 mg x L(-1) to 684.93, 382.17 and 302.62 mg x L(-1), respectively; the average diameter and the median diameter of sludge particulates reduce from 838.89 microm and 859.20 microm to 137.22 microm and 148.69 microm, respectively. As a result, EPS is effectively disintegrated by Fenton oxidation and the sludge is greatly mineralized, which benefits the further sludge reduction and utilization.