Effect of residual ozone on membrane fouling reduction in ozone resisting microfiltration (MF) membrane system.

The effect of residual ozone on reducing the membrane fouling was investigated using ozone resisting microfiltration membrane. It was found out that the fouling was reduced effectively by maintaining residual ozone in the membrane module. To clarify the reason why the residual ozone reduces the membrane fouling, research was focused on the molecular degradation reaction and particle destabilization reaction induced by residual ozone. The major reason of membrane fouling reduction was attributed to the reduction of reversible resistance induced by the cake layer. The reversible resistance was reduced due to degradation of organic substances in the cake layer. In addition to degradation reaction, the increase of fouling particle size due to residual ozone in the cake layer is another important process for fouling reduction. This effect has been referred to as ozone-induced destabilization reaction. The calcium present in the raw water influenced this reaction. The increase of fouling particles size improves the filterability through the cake layer and backwashing efficiency.