投加HCPA对UF-MBR处理低温高色高氨氮水源水效能与膜污染控制的影响

The effect of dosing HCPA on decontamination efficiency and membrane fouling control for UF-MBR treating high color and high ammonia nitrogen source water at low temperature

采用高浓度纯化凹凸棒土-超滤膜生物反应器(HCPA-UF-MBR)耦合工艺处理低温高色高氨氮水源水,考察HCPA对UF-MBR系统除污效能与膜污染控制的影响.基于污泥混合液粒径分布、Zeta电位、有机物相对分子质量分布、傅里叶红外光谱与三维荧光光谱分析探究HCPA投加后UF-MBR中污泥混合液性能的变化,研究清洗前后膜的微观性貌、洗脱液的物质成分,明确HCPA在减缓膜污染方面发挥的作用.结果表明:HCPA-UF-MBR工艺对色度、COD_(Mn)、TOC、NH_4^+-N、浊度等的去除效果优于UF-MBR工艺的1.02~3.9倍,HCPA-UF-MBR中TMP始终大于UF-MBR.投加HCPA后,UF-MBR内污泥絮体平均粒径变小、趋于均匀,易使膜通量降低,HCPA通过吸附、生物载体降解有机物与降低污泥混合液粘度作用控制膜污染,使系统除污效能未降返增;污泥混合液的|Zeta|电位降低11%~26%,利于污泥沉降;系统对UF膜难以截留的3~10kD小分子有机物的去除效能增强,污泥混合液与相应膜表面滤饼层中有机物种类与含量明显减少,系统对蛋白质类、溶解性微生物代谢产物去除效果显著.膜表面主要污染物为无机物Ca、Fe、Mg、Mn、Si与有机物,同样运行条件下膜HCPA-UF-MBR的污染程度比膜UF-MBR轻,污染物少;污染膜HCPA-UF-MBR表面的有机物易被水清洗但效果甚微,碱清洗膜效果最佳;该研究为凹凸棒土在MBR中的应用提供技术支撑.

The coupling process of high concentration of purified attapulgite(HCPA)and ultra-filtration membrane bioreactor(UF-MBR)was used to treat high color and ammonia nitrogen from source water at low temperature.The effect of HCPA on the decontamination efficiency and membrane fouling control in UF-MBR was examined.Based on the analysis of particle size distribution of sludge mixture,Zeta potential,relative molecular weight distribution of organics,flourier infrared spectroscopy and three-dimensional fluorescence spectra,the changes in properties of sludgemixture after adding HCPA into UF-MBR were explored.The micrographs of membrane before and after cleaning,and the material composition of the eluted liquid were studied,furthermore,the effect of HCPA on reducing membrane fouling was defined.The results show that,the removal effect of chroma,CODMn,TOC,NH4+-N,turbidity and so on for HCPA-UF-MBR was better1.02~3.9times than that for UF-MBR.TMP in HCPA-UF-MBR was always greater than in UF-MBR.After HCPA dosing,the average particle size of sludge flocculation in UF-MBR was small and tended to be uniform,which would cause the membrane flux reduce.Membrane fouling was controlled by HCPA through adsorption,carrying more organisms to degrade organics and reducing the viscosity of sludge mixture,so the decontamination efficiency in UF-MBR was not reduced but increased.For HCPA-UF-MBR,the potential of sludge mixture was decreased by11%~26%,it would help sludge settling.The removal efficiency of organics was improved,especially for a relative molecular weight ranging from3kD to10kD which was hard to be entrapped by UF membrane.The type and content of organics in sludge mixture and corresponding cake layer on the membrane surface were significantly decreased.The removal efficiency of protein and soluble microorganism metabolites was significant.The main pollutants of the membrane surface were inorganic substances such as Ca,Fe,Mg,Mn,Si and organic matters.Under the same operating conditions,compared with the membrane in UF-MBR,the membrane in HCPA-UF-MBR was with lower pollutant,more easily to be cleaned by water for organics on the surface.The effect of alkali cleaning membrane from MBR was the best.The study provides technical support for attapulgite application in MBR.