Ultrasound parameters                                 Values Ultrasound frequency (kHz) 25 35 132 170 350 Ultrasound power (W) 120 640 350 3000 5000 Power density (W/mL) 0.1 2.14 0.9 1.65 1.9 Ultrasound intensity (W/cm2) 15.7 51.4 24.2 36.9 46.2 Specific energy (kWh/kg CODinfluent) 2.4 11.5 3.1 4.1 5.1 COD removal efficiency (%) 45 61 47 53 58

Table 2: Sonicational parameters and corresponding values of sonication process in this study at pH=5.4 after 150 min ultrasound time for maximum CODdis yields under ambient conditions (at 25°C).