Except ozonation, all other sludge disintegration methods have a potential to increase membrane fouling although there are not many references to cite. All the chemical methods such as alkaline/acid treatment, decoupling agents addition, etc.only increase the level of cell debris in mixed liquor, which are the major membrane foulants in MBR. Mechanical methods such as ball mill, ultrasound (Yoon, 2004), cavitation by venturi injector (Hwang, 2010a), homoginizer (Rabinowitz, 2006), plasma treatment, thermal treatment, etc. create fine particles, too.
The EPS concentrations with and without alkali-thermal treatment are compared in Fig. 1. EPS contents of mixed liquor are slightly higher in EMBR (treatment) than CMBR (control), but no significant differences were observed in membrane fouling tendencies measured by trans-membrane pressure (TMP).
Fig. 1. Extra-cellular polymeric substances (EPS) concentrations in the control MBR (CMBR) and the treatment MBR (EMBR) using alkaline and thermal treatment of excess biosolids (Banu, 2011).
© Seong Hoon Yoon