The preliminary study investigated the effect of pre-ozonation of synthetic raw water (bentonite and humic acid) on membrane fouling. The results showed that humic acid, not bentonite, was the dominant factor in membrane fouling. When the synthetic raw water was pre-treated using ozone and activated carbon, stable operation was possible at twice the flux of membrane filtration without pre-treatment. Thus, ozone and activated carbon reduced the concentration of organic matter (humic acid), leading to an increase in flux.
Secondly, an MF membrane filtration device with ozone tolerance was attached downstream of the ozone reactor so that residual ozone could reach the membrane surface. When water was treated with MF membrane filtration in the presence of ozone, the flux was stable at 4 m/d. The membrane filtration resistance increased when ozone was not injected, and decreased when it was injected. This phenomenon was repeatable. In the presence of ozone, organic matter that could accelerate fouling as decomposed and converted to less fouled materials, resulting in a suppression of fouling as well as facilitating removal of the fouling layer during back washing.