River water purification via a coagulation-porous ceramic membrane hybrid process

Membrane filtration technology combined with coagulation is widely used to purify river water. In this study, microfiltration (MF) and ultrafiltration (UF) ceramic membranes were combined with coagulation to treat local river water located at Xinghua, Jiangsu province, China. The operation parameters, fouling mechanism and pilot-scale tests were investigated. The results show that the pore size of membrane has small effect on the pseudo-steady flux for dead-end filtration, and the increase of flux in MF process is more than that in UF process for cross-flow filtration with the same increase of cross-flow velocity. The membrane pore size has little influence on the water quality. The analysis on membrane fouling mechanism shows that the cake filtration has significant influence on the pseudo-steady flux and water quality for the membrane with pore size of 50, 200 and 500 nm. For the membrane with pore size of 200 nm and backwashing employed in our pilot study, a constant flux of 150 L·m ^-2·h^-1 was reached during stable operation, with the removal efficiency of turbidity, total organic carbon (TOC) and UV254 higher than 99%, 45% and 48%, respectively. The study demonstrates that coagulation-porous ceramic membrane hybrid process is a reliable method for river water purification.