Advanced anaerobic processes to enhance waste activated sludge stabilization

Area of Science:

• Environmental Engineering
• Waste Management
• Microbiology

Background:

• Growing demand for stable, pathogen-free sewage sludge for agricultural reuse presents waste management challenges.
• Innovative solutions are needed to enhance sludge quality and biological stability within the waste hierarchy.
• The Routes European project focuses on novel processing routes for effective sewage sludge management.

Purpose of the Study:

• To assess innovative sludge stabilization processes for improved quality and biological stability.
• To investigate the effects of sequential anaerobic/aerobic processes and thermophilic digestion on sludge properties.
• To evaluate the impact of thermal hydrolysis pre-treatment on anaerobic digestion performance.

Main Methods:

• Investigated sequential anaerobic/aerobic digestion and thermophilic digestion.
• Assessed the integration of thermal hydrolysis pre-treatment.
• Utilized Fluorescence in situ hybridization (FISH) for methanogen quantification.

Main Results:

• Thermal pre-treatment increased volatile solids reduction and biogas production.
• Digestate dewaterability decreased after thermal pre-treatment.
• Aerobic post-treatment improved sludge dewaterability and stability, despite reduced energy recovery.

Conclusions:

• Thermal hydrolysis pre-treatment enhances anaerobic digestion but negatively impacts dewaterability.
• Aerobic post-treatment offers benefits for sludge stability and dewaterability.
• Optimizing sludge stabilization requires balancing pathogen reduction, dewaterability, and energy recovery.