Abstract
Application of membrane filtration processes in large-scale water treatment facilities has expanded in recent years. In particular, they are increasingly used for surface water treatment (river and lake waters) rather than for groundwater treatment. Generally, coagulation is used to remove colloidal and suspended particles in surface water, but the effects of coagulation, which is a pre-treatment process in membrane filtration, on membrane fouling are scarcely reported. In this research, we studied the effect of coagulation as a pretreatment process of the ceramic membrane filtration system, with the focus being concentrated on investigation of the effect of Gt value of coagulation through experiments of membrane filtration after precoagulation. The results indicate that; the difference in the increase rate of transmembrane pressure depends on the Gt-value of coagulation. The optimum Gt values seem to be existent in the range of 20,000-50,000. Optimization of the Gt-value contributes to suppression of the increase rate of the transmembrane pressure, reduction of the coagulant dosage and reduction of pH control chemicals.
