Ultrasonic Pretreatment for Performance in Aerobic/Anoxic Sludge Digestion

Effect of ultrasonic pretreatment on aerobic/anoxic sludge digestion was investigated. In the first part of this study, the ultrasonic conditions for sludge pretreatment was optimized with orthogonal experiment for achieving better biological activity and disintegration of sludge, then the influence of sonication on the aerobic/anoxic digestibility was studied. The results revealed that the optimal ultrasonic condition is 28kHz, 0.15W/mL for 10 min. The aerobic/anoxic digestion was improved by sonication, using ultrasonic irradiation with optimal parameters, the VSS removal efficiency at the optimal conditions was increased by 20.30%, and digestion time was shorten by 8 d, compared to the control.