Anaerobic digestion assisted by ultrasonic energy

This study researches the use of ultrasound sludge hydrolysis to do digestion experiments. The data of biogas production, chemical oxygen demand (COD) change, pH value, and the original sludge concentration were recorded. It was found that COD of ultrasound sludge hydrolysis significantly increased, the digester alkaline pH became 7.6 (the general standard of 7.0–7.5), and the anaerobic digestion time was shortened to half of the original. Recommendations for future full-scale operating in the original sludge concentration which is related to ultrasonic-treated sludge should be more than 14.8% to have better digestion effect.