TRACKING CHANGES OF SLUDGE COMPONENTS INVOLVED IN SLUDGE FILTERABILITY IN MBR

Abstract

 In this study, changes of sludge components involved in membrane fouling were continuously monitored (>300 days) at a pilot-scale MBR treating real municipal wastewater. It was found that concentrations of colloidal TOC, dissolved lipopolysaccharides (LPS) and biopolymers in the sludge supernatant are strongly correlated with sludge filterability. Size fractions affecting membrane fouling were also investigated, and the results suggested that colloidal matter ranging 0.45-1.0 m, and 5.0-11 µm has significant impact on MBR fouling. Futhermore, isolation of biopolymers from the MBR sludge supernatant was conducted, and their characteristics were compared with sodium alginate which is commonly used as a model biopolymer. Isolated biopolymers caused more severe membrane fouling than did sodium alginate. It was suggested that biopolymers in MBR supernatant have higher fouling potential than that previously estimated by sodium alginate.