Membrane fouling and control in algae-rich water treatment

Abstract

Microfiltration and ultrafiltration membrane technology has now become one of the important methods for algae-rich water treatment due to its better solid-liquid separation effect and microbial retention capacity, while the existence of membrane fouling has been restricting the full-scale promotion and application of low-pressure membrane technology. The main foulants causing membrane fouling in algal-rich water include algal cells, algal debris and algal organic matter AOM (EOM and IOM). In this paper, the mechanism of membrane fouling caused by algal foulants in MF/UF for high algal water treatment is analysed in terms of both individual and composite fouling. Both individual and composite effects of algal foulants can lead to severe membrane fouling, in which algal cells and algal debris mainly dominate the accumulation of filter cake, while AOM mainly leads to membrane pore blockage membrane fouling is exacerbated by compounding effects, with severe reversible and irreversible fouling caused by filter cake formation and membrane pore shrinkage. This paper also discusses several common membrane fouling control methods, including pretreatment (oxidation, coagulation, combined oxidation-coagulation and adsorption) and membrane modification, and it is found that these several membrane fouling control methods can achieve good results.