Ultrasonic Dispersal of Activated Sludge Floes

Summary. A novel device which could be used for the disruption of activated sludge flocs, using a transversely oscillating wire, is discussed. The acoustic microstreaming generated around the wire produced hydrodynamic shear forces sufficiently strong to break up sludge flocs, without causing a loss in viability of the component cells. A 20-fold increase in total heterotrophs and Thiobacillus-type organisms was observed. Electron micrographs provided visual evidence for the disruption of flocs.