ChenLei,LiNing,LiZhijian,et al.Effects of PFS and CaO Conditioning on Vertical High-pressure Filter Press Dewatering of Sludge[J].China Water & Wastewater,2026,42(15):104-110.
Effects of PFS and CaO Conditioning on Vertical High-pressure Filter Press Dewatering of Sludge
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第42卷
Number:
第15期
Page:
104-110
Column:
Date of publication:
2026-08-01
- Keywords:
- deep dewatering; sludge conditioning; high-pressure filtration; moisture distribution; sludge structure
- Abstract:
- Two representative inorganic conditioners—polyferric sulfate (PFS) and quicklime (CaO)—which operate via distinct mechanisms (acidification-coagulation and skeleton-building effects, respectively), were selected to compare their effects on the dewatering performance of municipal sludge during vertical high-pressure filtration. Meanwhile, the changes in pH, Zeta potential, and particle size distribution of sludge before and after conditioning were analyzed. Advanced analytical techniques including low-field nuclear magnetic resonance (LF-NMR) spectroscopy and scanning electron microscopy (SEM) were employed to investigate the evolution patterns of water states and microstructural characteristics in sludge during the conditioning process. The results demonstrated that both PFS and CaO conditioning significantly improved the dewatering performance of sludge under vertical high-pressure filtration, with the optimal dosages determined to be 5 mg/g and 20 mg/g, respectively. Following conditioning and high-pressure treatment, the sludge moisture content decreased from 80.13% to 51.34% for PFS-conditioned samples and to 49.33% for CaO-conditioned samples. PFS and CaO neutralized the negative surface charges of sludge through Fe3+ and Ca2+, respectively, thereby increasing the Zeta potential and reducing electrostatic repulsion between sludge particles. The acidic environment generated by PFS induced hydrolysis of extracellular polymeric substances (EPS), while CaO disrupted the sludge floc structure via calcium hydroxide formation and binding interactions with bioflocs; both conditioners promoted the release of strongly bound water in sludge. Furthermore, sludge conditioned with PFS and CaO exhibited a rougher surface, increased porosity, and reduced particle size, facilitating the release of water from the sludge.
Last Update:
2026-08-01