| Now it is necessary to develop efficient and healthy drinking water treatment process due to the pollution of surface water, the limitation of conventional water process and the gradually stringent water quality standard. In recent years, some reaches of Xiangjiang river usually couldn't meet the third grade of Environmental Quality Standards for Surface Water (GB3838-2002 ) because of its pollution, so the effluents of many water plants which supplies are from Xiangjiang river often contain many pollutants. This paper investigated the treatment of Xiangjiang source water by enhanced coagulation-ultrafiltration(UF) process, compared the effect of three kinds of coagulants, such as Al2(SO4)3·18H2O, FeCl3 and powdered activated carbon(PAC), on the pollutants removal of water and the filtration characters of UF membrane, and studied the long-run stability of the process. The experimental results were as follows: Al2(SO4)3·18H2O as coagulant was better than FeCl3 on the rejection of turbidity in the water, the addition of PAC to the water simultaneously couldn't change the removal of Al2(SO4)3·18H2O but reduced the rejection of FeCl3 on the turbidity; on the removal of organic matter in the water FeCl3 as coagulant was superior to Al2(SO4)3·18H2O, and it was apparent to removal organic matter with the combination of Al2(SO4)3·18H2O and PAC; Al2(SO4)3·18H2O as coagulant was better than FeCl3 on the removal of Fe in the water, and when PAC was added at the same time, the removal of Fe reduced; there was no difference on the removal of Mn whatever Al2(SO4)3·18H2O or FeCl3 was used; when the coagulant dose increased from 50mg/L to 100mg/L, the cake resistance(CR) rose subsequently, and when Al2(SO4)3·18H2O and PAC were added to the water together, the CR were on the decline with the increase of the Al2(SO4)3·18H2O dose, at the same dose the CR was less when PAC existed, but the effect on the CR was on the opposite with the combination FeCl3 and PAC; in one-month experiment, of the UF effluents the turbidities were fully rejected, the removal rates of TOC always reached above 50%, the removal rates of UV254, CODMn, Fe and Mn were 85.17%, 68.27%, 93.06% and 36.57% respectively on the average, bacterium haven't been determined, the UF effluent water quality met with Water quality standard for fine drinking water(CJ94-1999); during the operation of the process the recovery varied from 40%70% that showed coagulation as the pretreatment of UF is effective and the...
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