Schwertmannite-based heterogeneous Fenton for enhancing sludge dewaterability over a wide pH range

Area of Science:

• Environmental Engineering
• Water Treatment Technologies
• Materials Science

Background:

• Fe-based Fenton technology is vital for sludge dewaterability but necessitates pH neutralization, increasing chemical use.
• Developing efficient, low-chemical sludge treatment methods is crucial for sustainable wastewater management.

Purpose of the Study:

• To investigate the efficacy of schwertmannite-composited Fe3O4 (Sch/Fe3O4) as a heterogeneous Fenton catalyst for sludge dewatering.
• To evaluate the performance of Sch/Fe3O4 in enhancing sludge dewaterability without requiring pH adjustment.

Main Methods:

• Sludge dewaterability was assessed using Sch/Fe3O4 and H2O2 at neutral pH.
• Key parameters measured included specific resistance to filtration, moisture content, and bound water.
• The generation of reactive species and their impact on sludge properties were analyzed.

Main Results:

• Sch/Fe3O4 + H2O2 treatment achieved high reductions in specific resistance to filtration (94.4%), moisture content (11.4%), and bound water (45.5%) at pH 7.5.
• The system generated SO4(2-) and H+ ions, facilitating sludge cell lysis and providing optimal pH for Fenton reactions.
• Reactive species (•OH, •O2-, 1O2) effectively degraded sludge EPS, releasing bound water and improving sludge cake structure.

Conclusions:

• Sch/Fe3O4 serves as an effective heterogeneous Fenton catalyst for sludge dewatering without pH adjustment.
• The process improves sludge dewaterability by releasing bound water, enhancing cake permeability, and preserving organic matter.
• This approach offers a sustainable alternative to traditional Fenton methods, reducing chemical consumption and facilitating sludge disposal.