Tests on the effect of ultrasonic treatment on two different activated sludge waste

The effect of ultrasonic treatment on two different waste activated sludges (WAS1 and WAS2) was compared by batch tests. WAS1 was taken from an industrial WWTP that treats pulp and paper wastewater, WAS2 was obtained from a traditional municipal WWTP. Physical and chemical characterization of sludges and supernatants was performed at various specific energy inputs. Upon increasing specific energy input, sludge structure changed, particle size decreased and organic and nitrogen release increased. A different release of organic matter and nitrogen compound related to the sludge origin was observed. The study is a preliminary assay of the potential of sonication treatment to enhance biogas production in anaerobic digestion.