Low-frequency and high-intensity ultrasonic treatment of biosolid is a good method for biosolid disintegration. So, as a pre-treatment method of anaerobic digestion, it may replace the hydrolysis. Thus, we studied the effect of ultrasonic disintegration of biosolid at different ultrasonic power densities. Results showed that the Soluble Chemical Oxygen Demand (SCOD), Total Nitrogen (TN), Total Phosphorus (TP), supernatant protein, polysaccharide and Deoxyribonucleic Acid (DNA) concentrations and biosolid mass reduction increased with the increase of sonication time and energy density. Ultrasonic treatment at 1.6 W/m for 30 min when the degree of biosolid disintegration (DDCOD) was 49.29% increased the SCOD, TN, TP, supernatant protein, polysaccharide and DNA concentrations by 3285, 150.13, 68.50, 1488.85, 531.66 and 123.35 mg/L, respectively, indicating that ultrasonic treatment can effectively disintegrate the biosolid. Higher energy ultrasound was more efficient than lower energy ultrasound for biosolid treatment.
Keywords: ultrasonic pretreatment, biosolids, anaerobic digestion, soluble chemical oxygen demand, total nitrogen, total phosphorus, supernatant protein, polysaccharide, deoxyribonucleic acid, DNA