Insight into sludge dewatering by periodate driven directly with Fe(Ⅱ): Extracellular polymeric substances...

Area of Science:

• Environmental Engineering
• Water Treatment Technologies
• Chemical Oxidation

Background:

• Growing global population increases waste activated sludge production.
• Effective sludge reduction strategies are crucial for sustainable wastewater management.
• Sludge pretreatment technologies are essential for improving dewatering efficiency.

Purpose of the Study:

• To investigate the efficacy of Fe2+-catalyzed periodate (Fe2+/PI) conditioning for deep sludge dewatering.
• To elucidate the underlying mechanisms of sludge dewatering induced by Fe2+/PI treatment.
• To provide insights for optimizing sludge management strategies.

Main Methods:

• Utilized Fe2+/PI conditioning for sludge pretreatment.
• Optimized Fe2+ and periodate dosages.
• Analyzed the generation of radical species (e.g., ·OH, FeIV).
• Evaluated sludge dewatering performance using capillary suction time.
• Investigated sludge properties including zeta potential, particle size, and surface morphology.

Main Results:

• Achieved a 48.27% reduction in capillary suction time under optimal Fe2+/PI dosages.
• Identified ·OH and FeIV as key radical species contributing to dewatering (49.79% and 47.76% contribution, respectively).
• Demonstrated synergistic effects of oxidation and flocculation, leading to mineralization and aggregation of extracellular polymeric substances.
• Observed increased exposure of hydrophobic groups and reduced protein-water interaction, enhancing dewaterability.
• Verified synergistic effects through changes in zeta potential, particle size, and surface morphology.

Conclusions:

• Fe2+/PI conditioning is a highly effective pretreatment method for deep sludge dewatering.
• The synergistic action of radical oxidation and iron flocculation drives sludge dewatering by altering sludge properties.
• This approach offers a promising solution for optimizing sludge management and reducing sludge volume.