超滤膜处理净水厂沉淀池出水的中试研究

采用中试规模的内压式超滤膜系统处理水厂沉淀池出水,考察超滤膜系统长期运行的出水水质情况。结果表明,超滤膜系统在处理不同水质期沉淀池出水时具有较高的除浊率,平均除浊率达到93.4%,且99.4%的出水浊度<0.1 NTU,去除效果明显优于同期传统的滤池工艺。超滤膜系统对沉淀池出水中有机物的去除效果有限,对CODMn和UV254的平均去除率分别为17.2%和8.2%,出水CODMn≤2.0 mg/L的保证率在98%以上,膜出水CODMn浓度受进水水质和运行条件的影响不大。膜进水中以小分子质量有机物为主,在MW<1 ku区间内的DOC和UV254占到整体有机物含量的57.3%和53.5%。超滤膜系统对微生物的去除效果良好,膜出水水质大部分时间无需经过消毒就能保证卫生要求,可降低后续消毒的加氯量,从而减少消毒副产物的生成量。

Treatment of Effluent from Sedimentation Tank of Waterworks by Ultrafiltration Membrane

A pilot-scale internal pressure ultrafiltration(UF) membrane system was used to treat effluent from sedimentation tank in a waterworks and the quality of produced water from UF membrane system was investigated for a long time.The results demonstrated that a high removal rate of turbidity was achieved in different water quality periods,with an average removal rate of 93.4%.The guarantee rate of turbidity below 0.1 NTU was 99.4%.The removal efficiency of UF membrane system was significantly better than that of conventional filter process.The removal efficiency of organic matters in the effluent from sedimentation tank by UF membrane system was limited.The average removal rates of CODMn and UV254 were 17.2% and 8.2%,respectively.The guarantee rate of CODMn≤2 mg/L was above 98%.The CODMn concentration in membrane effluent was little influenced by the influent quality and the operation condition.Organics with low molecular weight were dominant in membrane influent.DOC and UV254 with MW of less than 1 ku accounted for 57.3% and 53.5% of the total organics.Microorganisms could be effectively removed by UF membrane system,and the membrane effluent quality could meet the hygiene requirements without disinfection,which reduced the chlorine dosage for subsequent disinfection and the formation of disinfection byproducts.