Excess secondary sludge reuse by H₂O₂ thermal dehydration.

Area of Science:

• Environmental Engineering
• Water Treatment Technologies
• Waste Management

Background:

• Municipal wastewater treatment generates significant excess activated sludge.
• High water content complicates sludge transport, disposal, and management.
• Developing efficient sludge dewatering methods is crucial for sustainability.

Purpose of the Study:

• To investigate the dehydration of excess activated sludge using combined temperature and hydrogen peroxide treatment.
• To optimize operating variables for improved sludge dewaterability and filterability.
• To explore the potential of dehydrated sludge as a sustainable biosorbent.

Main Methods:

• A Box Behnken experimental design with 15 runs was employed.
• Key variables studied included temperature (120-180°C), hydrogen peroxide dose (0.01-0.03 M), and treatment time (20-60 min).
• Sludge dewaterability, filterability, and characteristics like water content and extracellular polymeric substances were monitored.

Main Results:

• Temperature was identified as the most influential parameter for achieving dehydrated sludge with desirable management characteristics.
• Optimized conditions yielded reduced sludge volume and improved filterability.
• The dehydrated sludge, when carbonized and activated, showed potential as a biosorbent for removing phenol, ofloxacin, and diuron from water.

Conclusions:

• Combined heat and hydrogen peroxide treatment effectively dewaters activated sludge.
• Temperature plays a critical role in enhancing sludge dewaterability and filterability.
• Further research is needed to optimize the synthesis of biosorbents from treated sludge for enhanced water purification efficacy.