Application of ultrasonic system for enhanced sewage sludge disintegration: A comparative study of single- and dual- frequency

This work focused primarily upon the effects of ultrasonic pretreatment of both single frequency and dual frequency ultrasonic on the characteristics of sewage sludge disintegration. Quantifications of individual single frequency ultrasonic effects, as well as those of combined dual frequency ultrasonic were determined. This study also investigated and discussed the effects of ultrasonic power density and ultrasonic time. The reported results showed that the sludge solubilization rates increased as the ultrasonic time and ultrasonic power density increased. In terms of the degree of disintegration, the SCOD/TCOD ratio, the SCOD extraction rates, and the solubilization rates, dual-frequency ultrasonic at 28+40 kHz was more effective than single-frequency ultrasonic at 28 kHz or 40 kHz. Sewage treatment plants facing problems with the treatment and disposal of sludge can benefit significantly from the application of dual frequency ultrasonic to the process of sludge pretreatment.