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以受污染地表水为处理对象,通过与单独膜生物反应器(MBR)工艺的对比,考察了臭氧预氧化/膜生物反应器(O3/MBR)工艺的除污效果及膜污染情况。两个系统均稳定运行了55d,其中预氧化工艺的臭氧投量为1.5 mg/L,臭氧反应柱的接触时间为15 min。结果表明,臭氧预氧化不仅能够有效提高对有机污染物的去除效率,而且显著降低了膜污染。三维荧光光谱分析结果显示,臭氧预氧化能够以不同方式缓解膜表面及膜孔内污染物质的积累,从而减轻了膜污染。采用凝胶色谱对水中溶解性有机物(DOM)的分子质量分布进行了研究,结果显示:在254 nm波长处,O3/MBR工艺混合液中DOM的吸收强度明显低于MBR的,尤其是分子质量为500～2 000 u的有机污染物,说明臭氧预氧化能够减轻这类物质引起的膜污染。运行结束后,通过扫描电镜观察发现,臭氧预氧化能够有效降低膜孔的堵塞,从而有助于控制不可逆污染对膜过滤过程的影响。
Taking polluted surface water as object of treatment, the decontamination effect and membrane fouling of ozone pre-oxidation / membrane bioreactor (O3 / MBR) process were investigated by comparison with single membrane bioreactor (MBR) process. Both systems operated stably for 55 days, with a pre-oxidation ozone dose of 1.5 mg / L and an ozone column contact time of 15 min. The results show that ozone pre-oxidation can not only effectively improve the removal efficiency of organic pollutants, but also significantly reduce membrane fouling. The results of three-dimensional fluorescence spectroscopy showed that pre-oxidation of ozone could mitigate the pollution of membrane in different ways by alleviating the accumulation of pollutants in membrane surface and membrane pores. The molecular mass distribution of dissolved organic compounds (DOM) in water was investigated by gel permeation chromatography (GPC). The results showed that the absorption intensity of DOM in O3 / MBR mixture was significantly lower than that of MBR at 254 nm, especially the molecular mass 500 ~ 2 000 u organic pollutants, indicating that ozone pre-oxidation can reduce such substances caused by membrane fouling. After the operation was finished, the results of scanning electron microscopy showed that ozone preoxidation can effectively reduce the clogging of membrane pores and thus help to control the influence of irreversible pollution on membrane filtration process.