An approach to enhance permeate flux of submerged ultra-filtration membrane system

Total experimental period was divided into two stages. At the first stage, two runs of experiments were carried out to obtain an understanding of the effect of activated sludge concentration and SCOD in membrane bioreactor (MBR) on ultra-filtration (UF) membrane permeate flux. It was found that in a reactor with an excellent biological treatment performance, the majority of the increasing resistance was attributed to cake resistance; while in an environment with high organics, the fouling resistance increased at a rate higher than the cake resistance did. On the basis of experimental investigations, a concept of "protection coating layer" was proposed to illustrate the phenomenon of UF membrane fouling. At the second experimental stage, powdered activated carbon (PAC) was applied to the test reactor to enhance the formation of "protection coating layer". During the operational period of 32 days, compared with the control system, test system obtained higher removals for COD, NH3-N, TN and TP by 1. 15%, 1.39%, 6.75% and 8.3% respectively, and fouling rate of the U F membrane in it was also alleviated.