FIVE YEAR EXPERIENCE WITH MEMBRANE PERFORMANCE ENHANCERS FOR MEMBRANE BIOREACTORS : FROM MECHANISTIC STUDIES TO FULL-SCALE IMPLEMENTATION

Membrane performance enhancer (MPE) technology has been developed to improve membrane performances in membrane bioreactors (MBR). This technology is based on modified polymers that coagulate soluble microbial products (SMP) and extra-cellular polymeric substances (EPS), thereby preventing membrane fouling. In full-scale municipal MBR plants, MPE has increased the average daily flux by 40–200% depending on the operating conditions. In general, the worse the sludge condition the better the flux improvement. It was found that MPE increased mixed liquor particle size and decreased SMP levels. The amount of deposited (cake) layer decreased and the cake layer was more porous. Due to the lower SMP level, the effluent COD also decreased by 30–70%. MPE did not affect nitrification and respiration rates