Rapid and efficient activated sludge treatment by electro-Fenton oxidation

Area of Science:

• Environmental Engineering
• Water Treatment Technologies
• Advanced Oxidation Processes

Background:

• Activated sludge dewatering and digestion efficiency are critical in wastewater treatment.
• Advanced oxidation processes (AOPs) offer potential for sludge treatment enhancement.
• Electro-Fenton (EF) is an AOP with potential for sludge pretreatment.

Purpose of the Study:

• To investigate electro-Fenton (EF) as a pretreatment method for activated sludge.
• To evaluate EF's impact on sludge dewatering and disintegration.
• To understand the mechanisms behind EF-induced sludge changes.

Main Methods:

• Sludge dewatering was assessed using specific resistance to filtration.
• Sludge disintegration was measured by volatile suspended solids (VSS) removal and soluble organic release.
• Sludge floc morphology and extracellular polymeric substance (EPS) properties were analyzed.

Main Results:

• EF treatment (40-60 min) effectively improved activated sludge dewaterability.
• EF reduced sludge floc size, increased zeta potential towards zero, and coarsened floc structure.
• EF enhanced sludge disintegration, releasing proteins and polysaccharides and promoting humification.

Conclusions:

• Electro-Fenton is a rapid and efficient method for improving activated sludge dewaterability.
• EF treatment alters sludge floc structure and EPS composition, facilitating disintegration.
• The study demonstrates EF's potential as a viable solution for sludge management.