Study on Control of Membrane Fouling by Different Forms of Coagulation Pretreatment

Abstract-The influence of coagulants ferric chloride and aluminium sulfate on membrane fouling under different coagulation pretreatments was studied, and removal of organics in different molecular weight (MW) was also studied by two coagulants. The experimental results suggested that direct membrane filtration of coagulating liquid was more effective to alleviate membrane fouling than membrane filtration of supernatant after coagulation. Furthermore, when ferric chloride was used as a coagulant the membrane flux can be recovered to 95% of initial flux and a recovery rate of 77% could be achieved when aluminium sulfate was used. On the other hand, the experimental results also showed those organic pollutants whose molecular weight fractions were 100-30 kDa, 10-3 kDa, and 3-1 kDa could be obviously removed by direct membrane filtration of coagulating liquid.