Study of Membrane Fouling Properties of Landfill Leachate Treatment by the SBAC-MBR Process

Landfill leachate was treated by a process involving use of sludge-based activated carbon (SBAC) combined with a membrane bioreactor (MBR), which reduced cost compared to traditional activated carbon. The MBR process was operated to compare the membrane fouling characteristics for exploring effects of the properties and amount of added SBAC on membrane fouling. Influences of extracellular polymeric substances (EPS) and soluble microbial products (SMP) on the transmembrane pressure (TMP) were illustrated based on the contents and components of EPS and SMP in sludge mixed liquor and on the membrane surface. Results showed that the EPS, SMP, proteins, and polysaccharides in sludge mixed liquor of the SBAC-MBR first increased and then decreased with the operation time, and accumulation of EPS, proteins, and polysaccharides on the membrane surface in the SBAC-MBR increased gradually with time during the operational cycle. TMP in the SBAC-MBR first increased gradually and then decreased exponentially during the operational cycle. Addition of SBAC to the MBR reduced the amounts and changed the compositions of EPS and SMP, which improved the properties and structure of the cake layer on the membrane surface and decreased membrane fouling. During the operational cycle, the period of slow increase of TMP in the reactor was prolonged by adding SBCA, which extended the cleaning cycle of the membrane module from 17 to 21 days.