Enhanced Sludge Dewatering Efficiency and Mechanism of MnFe2O4/BC-Activated PMS
To enhance sludge dewatering efficiency, an MnFe2O4/BC/PMS system was constructed for sludge disintegration. Single-factor and multi-factor experiments were conducted to investigate the effects of MnFe2O4/BC (MFB) dosage, PMS dosage, and reaction time on sludge dewatering performance, establishing the optimal process parameters and the primary-secondary relationships among environmental factors. Active species identification in the MnFe2O4/BC/PMS system revealed the main free radicals responsible for sludge disintegration and the primary pathways of EPS breakdown. Results showed that the influence order of environmental factors on sludge moisture content (Wc) and total organic carbon (TOC) was MFB > PMS > reaction time, while the interaction effects followed MFB-PMS > PMS-reaction time > MFB-reaction time. Optimal dewatering occurred at MFB dosage of 132.99 mg/g DS, PMS dosage of 421.80 mg/g DS, and 18 min reaction time, achieving Wc of 45.8% and TOC of 489.2 mg/L. The ·OH and SO4−· radicals released from MnFe2O4/BC-activated PMS oxidized protein main chains, causing peptide chain breakage. This primarily reduced protein content in sludge from 174.6 mg/L to 75.7 mg/L, with TB-EPS protein content decreasing from 91.8 mg/L to 36.3 mg/L, thereby reducing EPS hydrophilicity and improving sludge dewatering efficiency.