Factors affecting critical flux of ultrafiltration membrane in drinking water treatment

No fouling or very little fouling would be caused by the filtration of ultrafiltration membrane under the critical flux.According to the factors affecting the critical flux of ultrafiltration membrane in drinking water treatment,the effects of aeration,filtration mode,coagulation sedimentation pretreatment and some other factors on the critical flux of the submerged ultrafiltration membrane in treatment of water from Songhua River were investigated.The results showed that,critical flux could be enhanced by 5 L/(m2·h) under continuous aeration with the intensity of 10 m3/(m2·h),and the same effect could also be obtained under intermittent aeration with the intensity of 40 m3/(m2·h),however,after that,the critical flux could no longer be increased by increasing aeration intensity.Intermittent filtration had no positive effect on critical flux,when the aeration intensity was 40 m3/(m2·h),intermittent filtration with intermittent aeration could enhance the critical flux by 5 L/(m2·h).Critical flux could be enhanced by 10 L/(m2·h) when using coagulation sedimentation pretreatment,and be enhanced by 15 L/(m2·h) when using combined process of coagulation-continuous aeration and coagulation-intermittent filtration and intermittent aeration.