Zero Excess Sludge Production in a Thermophilic MBR System: Performance and Energy Consumption Evaluation

Area of Science:

• Environmental Engineering
• Biotechnology
• Water Treatment

Background:

• Increasing operational and regulatory challenges in managing sewage sludge.
• Need for creative solutions to lower sludge output while maintaining process dependability and environmental compliance.

Purpose of the Study:

• To present the first full-scale implementation of a thermophilic pure-oxygen biological process integrated with ceramic ultrafiltration (UF) membranes in Europe.
• To evaluate the system's effectiveness in minimizing sludge output and its overall sustainability.

Main Methods:

• Treating thickened municipal sludge under thermophilic conditions (50°C-55°C).
• Utilizing ceramic ultrafiltration (UF) membranes for complete biomass retention.
• Long-term monitoring of biodegradation performance, sludge yields, and COD removal efficiencies.

Main Results:

• Achieved high biodegradation performance with VS removal exceeding 85%.
• Demonstrated very low biomass yields (0.01 kg VS kg^-1 COD_removed).
• Identified membrane hydraulic performance as a key factor influencing process efficiency, with fouling and permeability decline requiring maintenance.

Conclusions:

• The thermophilic UF-based system offers substantial sludge reduction and recovery of soluble COD, making it economically competitive.
• The process is robust and sustainable, providing a strategic solution for modern wastewater treatment plants seeking resilient, circular, and regulation-proof sludge management pathways.