Ultrasonic pre-treatment of biological sludge: consequences for disintegration, anaerobic biodegradability, and filterability

BACKGROUND: Disintegration was developed as a pretreatment process for sludge to accelerate the digestion processes. Ultrasonic treatment may be a good alternative for sludge disintegration. In this study, different specific energy inputs ranged between 0 and 15 880 kJ kg(-1) and very low ultrasonic densities ranged between 0.04 and 0.1 W mL(-1) were applied to biological sludge for disintegration purposes. The potential for improving anaerobic digestion through ultrasonic pre-treatment and the effect of ultrasonic pre-treatment on the filterability characteristics of sludge were also investigated.