Research status of ultrasonic sludge process reduction and discussion on combined measures with new biological nitrogen removal process.

The increasing production of excess sludge has become a serious problem that plagues the development of Chinese sewage treatment industry. Ultrasonic technology (high-intensity ultrasound) has attracted the attention of researchers because of its advantage of reducing sludge production from the source. The principle and main influencing factors of ultrasonic sludge process reduction technology are introduced. The current research status of improving the sludge process-reduction rate and reducing energy consumption was reviewed, including the combination of ultrasound and physicochemical method or traditional sewage biological treatment process. There is a contradiction between the sludge reduction and deterioration of effluent quality in the combination of ultrasound and traditional wastewater biological treatment process. Combining the advantages of low-intensity ultrasound to increase the biological activity of sludge and promote the shortcut nitrification process, a method of new wastewater biological treatment process (partial nitrification-denitrification (PND) and partial nitrification/partial denitrification-anammox (PN/PD-A)) coupled with different intensity ultrasound was summarized and its technical advantages were discussed. [ABSTRACT FROM AUTHOR]