Fouling potentials of biopolymers isolated from surface water and supernatants of a membrane bioreactor

Abstract

 Membrane fouling is strongly influenced by biopolymers, which are characterized by their high molecular weights and hydrophilic nature in application of membrane technology to both drinking water treatment and wastewater treatment. However, there is little knowledge about the differences between biopolymers present in drinking water sources and wastewater, mainly because of the unavailability of isolated biopolymer samples. In this study, biopolymers were isolated from surface water and MBR supernatants, and their membrane fouling potentials and physicochemical properties were investigated. Biopolymers isolated from MBR supernatants exhibited much more severe membrane fouling than biopolymers isolated from surface water. Affinities between biopolymers and a membrane polymer (i.e., PVDF) assessed by QCM were consistent with the results obtained in the filtration tests. LC-OCD/UVD/OND and FT-IR analyses revealed clear differences in physical/chemical properties of the biopolymers isolated from the surface water and the MBR supernatants. It is suggested that amino sugars and/or lipopolysaccharide-like components in biopolymers can cause severe membrane fouling.