Effect of sulfate radical oxidation on disintegration of waste activated sludge

• Waste activated sludge was effectively disintegrated by sulfate radical oxidation.
• Indicators to estimate sludge disintegration were screened by correlation analysis.
• Aromatic and tryptophan protein-like substances were degraded at high PMS dosage.

The effects of sulfate radical oxidation pretreatment on the disintegration of waste activated sludge were investigated at different dosages of peroxymonosulfate (PMS). Indicators for estimating sludge disintegration were selected by analyzing concentrations of released substances and statistical analysis. Results indicated that COD and total phosphorus (TP) were unsuitable for estimating sludge disintegration by oxidants. Pearson correlation analysis indicated that total nitrogen (TN), total organic carbon (TOC), UV254 and polysaccharides had strong correlation with each other, thus suitable for sludge disintegration estimation. Chemical analysis and 3D-EEM fluorescence spectra showed that at high dosage, sulfate radical oxidation was effective for sludge disintegration by inducing aromatic and tryptophan protein-like substances degradation. At PMS dosage of 12 mg (g SS)−1, sludge disintegration degrees in TOC and TN were 24.8% and 29.9%, respectively.