Effect of coagulation pretreatment on the fouling of ultrafiltration membrane.

The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter (NOM). A relatively higher molecular weight (MW) of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux.

[Effect of coagulation on preventing membrane from fouling].

In this experiment, the effects on improve of flux and prevention of membrane from fouling is studied. The results demonstrate that after backwashing, the flux was completely recovered by addition of 4mg/L and l0mg/L(as Al), while the flux was only 40% of initial flux without coagulation pretreatment. It is also observed that whether or not prevention of fouling by coagulation are depended on the characteristics of cake layer formed on membrane surface during membrane filtration.