On-line ultrasound on fouling control of membrane bioreactor

A novel on-line ultrasound assisted membrane bioreactor (US-MBR) was proposed to control membrane pollution. The changes of trans-membrane pressure and fouled membrane surface under the condition of different ultrasound interval time in US-MBR were analyzed. At ultrasound time 2min and membrane flux 12.0L/(h·m2), under the condition that ultrasound interval times were 8, 12 and 16h respectively, the operation period of US-MBR was prolonged about 17, 13 and 5d respectively compared with common membrane bioreactor of not adding ultrasound. On-line ultrasound effectively controlled the gel layer fouling induced from organic matters in the supernatant liquor and thus reduced the gel layer resistance. SEM-EDS was applied to analyze the membrane fouling, also revealing that ultrasonic irradiation could effectively reduce adhesion of organic matters on the membrane surface. Through comparative test using US-MBR and control-MBR, it was demonstrated that the effluent quality was not deteriorated by on-line ultrasonic irradiation.