Disintegration of waste activated sludge with composite ferrate solution: Sludge reduction and settleability

Area of Science:

• Environmental Science
• Water Treatment Engineering
• Chemical Engineering

Background:

• Waste activated sludge (WAS) treatment faces challenges with sludge reduction.
• Effective sludge disintegration is crucial for optimizing wastewater treatment processes.

Purpose of the Study:

• To investigate the efficacy of composite ferrate solution (CFS) for waste activated sludge (WAS) disintegration.
• To analyze the sludge reduction efficiency and changes in sludge properties.

Main Methods:

• Disintegration of WAS using CFS.
• Analysis of released intracellular matter (SCOD, cations, organic acids).
• Monitoring sludge reduction, settleability (SV, SVI) over a 24-hour period.

Main Results:

• CFS effectively disrupted sludge flocs and cells, releasing intracellular matter.
• The sludge disintegration process exhibited a rapid (0-2h) and a slow (2-24h) reaction stage.
• Optimal conditions (50 mg Fe/g SS, 24h) yielded 55.4% sludge reduction and significant decreases in SV and SVI.
• Fe(VI), ClO-, and OH- in CFS contributed to decomposition without synergistic effects.
• In situ formed Fe3+ and released Ca2+ improved sludge settleability.

Conclusions:

• CFS is a viable agent for effective WAS disintegration and sludge reduction.
• The study elucidates the mechanism of CFS-induced sludge disintegration and its impact on sludge properties.
• The findings suggest potential for improved wastewater treatment efficiency through enhanced sludge management.