MECHANISTIC INVESTIGATIONS IN ULTRASONIC PRETREATMENT AND ANAEROBIC DIGESTION OF LANDFILL LEACHATES

This study has attempted to gain mechanistic insight into ultrasound assisted pretreatment of landfill leachate (prior to anaerobic digestion) by coupling experimental results with simulations of cavitation bubble dynamics. Essentially, individual roles of physical and chemical effects induced by sonication in the process have been identified. Changes in properties of landfill leachate due to different ultrasound power levels were examined to establish a correlation with the efficiency of biogas production during subsequent anaerobic digestion. The findings reveal that low power ultrasound pretreatment enhances methanogenesis, resulting in a more effective biogas yield compared to high power sonication, which destabilizes leachate through the generation of oxidizing radicals. This approach provides a comprehensive understanding of how ultrasound affects the structural and chemical properties of leachate and underlines the significance of optimizing ultrasound treatment parameters to improve the overall effectiveness of anaerobic digestion processes.