Hydrodynamic Cavitation as a Novel Approach for Municipal Sludge Pretreatment for Anaerobic Digester

One of the main limitations of anaerobic digestion process is slow rate organics hydrolysis. Different pretreatment methods were suggested to enhance sludge hydrolysis and anaerobic digester performance. Sludge pretreatment methods have resulted in cell wall disruption and release of intracellular enzymes to soluble phase which consequently enhance hydrolysis rate. Among pretreatment methods, hydrodynamic cavitation has been recognized as the most convenient method due to higher degradation efficiency and lower energy consumption for cell disruption. In present research effect of secondary sludge pretreatment with cavitational slit venturi was investigated experimentally. Solubility and Turbidity of sludge were increased from 1598 mg/L to 17042 mg/L and 376 NTU to 8300 NTU after 5 hours of pretreatment, respectively. In addition, degradation degree of sludge climbed to 90% after 5 hours of pretreatment. In this research it was recognized that concentration is an effective factor in degradation rate, and the higher concentration is, the higher degradation degree will be.

Keywords:

Activated Sludge , Cavitation , Digestion , Pretreatment , Venturi