| With the drinking water resources deteriorate, the traditional treatment process can not meet the stringent increasingly requirement of the standard for the drinking water. Membrane technology is regarded as "water treatment technology in the 21st Century", and has got more attention at home and abroad. Microfiltration (MF) and ultrafiltration (UF) have good prospect due to lower operation pressure and effective removal of particles such as turbidity and bacteria.This is a pilot-scale study in which drinking water is produced with MF and UF from Luan River water. The main contents include intensifying the removal of organics, optimizing parameters, controlling membrane fouling, etc. Based on the pilot-scale study, an appropriate precept of membrane technology used for the treatment of micro-polluted source water will be formed, which provides reference for project of 5000m3/d.Results show that the turbidity of raw water has a large range, but the average turbidity of filtrate is 0.09NTU, and the frequency of≤0.1NTU can exceed 98%. The amount of granules that larger than 2μm in raw water is 11970 per milliliter, but only 15 in filtrate. According to the turbidity and the amount of granules, the removal of Giadia and Cryptosporidium is deemed effective. In the test, the molecular weight distribution of the dissolved organics in the raw water was measured, and found that organics less than 1000 daltons was mainly occupied, which made the removal rate of organics low with direct-filtration, no more than 30%. Coagulation (the dosage of FeCl3 is 4mg/L) made the removal rate of CODMn increase 10.5%, and the prechlorination (the dosage of chlorine is 2mg/L) further increased 9% of CODMn removal. The water quality of filtrate conforms to the requirements of Water Quality Standard for Drinking Water (GB5749-2006), and the turbidity and the amount of microorganism were far less than the limited value. Compared with the traditional treatment process, the filtrate of membrane has lower turbidity, organics, chloride and iron, but close ammonia nitrogen, protein nitrogen, nitrous acid nitrogen and rigidity.When optimizing the parameters, investigator found that both increasing the flux and prolonging the runtime could accelerate the membrane fouling. The permeability of membrane is well while the addition of FeCl3 is 4 mg/L and the agglutination reaction timed 6min. Polymeric aluminium chloride excels FeCl3 in improving the permeability. Prolonging the duration of reverse-flushing and increasing the flux during reverse-flushing can improve the process of reverse-flushing, but the effect is mild. The aeration plays an important role in the reverse-flushing. This device adapts to the change very well, because it can still function stably even though reverse-flushing drain is discharged every five cycle, and the water quality of filtrate is good. When reverse-flushing drain is discharged each cycle, the reclaim rate is 90.9%, when reverse-flushing drain is discharged every five cycles, the reclaim rate arrives to 98.0%.When the membrane fouling becomes serious, Offline chemistry purge must be performed. In the process of chemistry purge, the temperature, the duration, the concentration and the degree of membrane fouling decide the effect of the chemistry purge. In the process of chemistry purge, 2% HCl reacted for 3 hours, then 1.5%NaOH and 3500ppmNaClO for 8 hours,this method was proved to be effective. EFM (Enhanced Flux Maintenance) is an effective method for releasing the membrane fouling, which can restore the permeability of membrane in time, and postpone the period of chemistry purge.
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