Air-borne ultrasound could improve the convective drying behavior of sewage sludge.
The drying time required with the ultrasound-assist was shortened by about 60 min.
There was maximum increasing rate for the Deff at 30 W as growing the temperature.
Activation energy with ultrasound-assist was less than that for convective alone.
Midilli model was the best one to predict the moisture content in the sewage sludge.