COMPARISON OF BIOFOULING CHARACTERISTICS OF DIFFERENT TYPE AND PORE SIZE OF SUBMERGED MICROFILTRATION MEMBRANES USING JET LOOP MEMBRANE BIOREACTOR (JLMBR) ACTIVATED SLUDGE

摘要

In this study, membrane biofouling mechanism was investigated in a lab-scale jet loop membrane bioreactor (JLMBR) integrated with a submerged flat-sheet membrane system. Influence of various membrane materials and pore size on fouling was explored. Polyethersulfone (PES), polycarbonate (PC), and nitrocellulose mixed ester (ME) with two different pore sizes (0.2 and 0.1 urn) were used in the experiments. The cake layers on membrane surfaces were analyzed and surface roughness of clean and fouled membranes were determined using AFM images. It was observed that the rate of initial decline in flux was different depending on membrane; however, steady state flux values were almost the same for all membranes. The initial flux values were found as 93.2 L/m~2h (PES 0.22), 166.3 L/m~2h (PC 0.20), 75.1 L/m~2h (ME 0.22), 215.1 L/m~2h (PES 0.10), 225.5 L/m~2h (PC 0.10) and 176.8 L/m~2h (ME 0.10). The steady state flux values varied from 6.7 to 10.7 L/m~2h for the membranes with pore size of 0.2 urn and from 5.4 to 5.8 L/m~2h for the membranes with pore size of 0.1 um. For both pore sizes, ME membranes had the highest steady state flux values. The soluble microbial products (SMP) and extracellular polymeric substances (EPS) were analyzed at the cake layers on membrane surfaces. Although all types of membranes were tested simultaneously at the same time by using same activated sludge medium, EPS and SMP concentrations on the cake layer of membranes were different.