New method on assessment of membrane fouling potential -UMFI

The critical flux was determined by flux-step method in this paper. Under different permeate flows and multiple cycle filtration, the regulation of united membrane fouling index (UMFI) and irreversible fouling UMFI (UMFI_ir) was studied. Both removal efficiency of dissolved organic matter (DOM) and UMFI accompanying with permeate flow were also discussed. The results showed that gradual fouling still existed under operation of sub-critical condition owing to the existence of local supra-critical flux. Besides, the tendency of UMFI increased gradually attributing to the outer and inner pore adsorption/clogging as well as cake layer formation; on the contrary, UMFI_ir decreased gently. The removal of DOM was improved with flux increasing because of cake layer being further compressed and becoming denser. The relationship between DOM transmission and UMFI was inverse ratio.