Disintegration of sewage sludge with bifrequency ultrasonic treatment

摘要

A bifrequency ultrasonic generating trough was used to improve disintegration of sewage sludgenfrom thickener tanks. Ultrasonic operating parameters such as frequency, power, and time werenoptimized. Ultrasonic treatment successfully disintegrated the floc structure of sewage sludgenand promoted the release of organic matter and metal ions such as Ca2+ and Mg2+. Afternultrasonic treatment, soluble chemical oxygen demand (SCOD) in the sludge solution increasedn11.28–49.06%, while the concentrations of Ca2+ and Mg2+ rose 5.5–25.0% and 2.7–19.0%,nrespectively. The ultrasonic frequency of 25 kHz was most effective in disintegrating sludge,nand high energy densities and longer treatment time increased SCOD and metal ion release.nThe optimal parameters that promoted the increase SCOD were 25 kHz, 75 W/L and 60 s.nUnder these conditions, double-frequency ultrasonication was more effective than singlefrequencynultrasonication.