| Worsening micro-polluted problems in surface water used as sources of drinkingwater have provoked growing concern among the water treatment engineers. Theorganics and ammonia nitrogen removal in water treatment becomes an importantissue. In China, MBR (membrane bioreactor) has been studied for water treatment inrecent years. But up to now it has been mainly adopted in lab-scale experiment. Andmembrane fouling is still regarded as the major obstacle to the wide application ofMBR in drinking water treatment. In this paper, on the basis of former small-scale experiments, a pilot-scalemicro-filtration MBR for micro-polluted surface water treatment was studied. PAC(powdered activated carbon) was dosed into the reactor and performance of the MBRwas investigated. With the combined effects of biological treatment, PAC adsorptionand micro-filtration, organic and nitrogenous compounds were eliminated efficientlyin MBR. In 130 d experiment, raw water was synthetic micro-polluted surface waterwith CODMn of 8.08~27.26 mg/L, NH3-N of 2.48~17.79 mg/L and turbidity of3.5~51.6 NTU. During the steady state period, 84.8% of CODMn, 89.1% of UV254,99.8% of UV410, 99.7% of turbidity and 97.4% of NH3-N could be removed. Thetreated water can meet the Sanitary Standard for Drinking Water Quality (2001).Reduction of permeate flux with time was found in this process. A study wasconducted on characteristics of membrane-fouling matter and cleaning of fouledmembranes. Effectiveness of various physical and chemical techniques in membranecleaning was also examined in this study. Besides, a discussion was given on somephenomenon occurred during the MBR operation in this paper, such as how tomaintain the viability of biomass in the bioreactor when the raw water is in anoligotrophic condition and influence of MBR stable operation by the formation ofcake layer, etc. At the end of this paper, some suggestions were proposed to ensurebetter operation of MBR in further studies.
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