KWR Watercycle Research Institute, P.O. Box 1072, 3430 BB Nieuwegein, The Netherlands.
Water Res. 2010 May;44(10):3283-93. doi: 10.1016/j.watres.2010.03.007. Epub 2010 Mar 15.
Anionic Fluidized Ion Exchange (FIX) is used to improve the performance of downstream Nanofiltration (NF). The research is divided in three parts: (i) NOM removal by FIX, (ii) the effect of FIX treatment on NF fouling and (iii) FIX treatment in relation to biological stability. Pre-treated anaerobic groundwater was (i) fed directly to a 4-inch membrane element and (ii) fed to another 4-inch membrane element after anionic FIX treatment. The operational parameters of the membrane set-up were monitored during 42 days, followed by a membrane autopsy study in which accumulated biological, organic and inorganic fouling was determined. Parallel to this experiment, two small ion exchange (IEX) resin and glass beads filled columns were operated to study the effect of FIX on the biomass concentration of the feed water. FIX operated satisfactory and selectively removed humic substances (>90%) and hydrophobic organic carbon (HOC) (>80%) from the feed water. Furthermore, iron was substantially removed (71%) which was explained by complexation with humic substances. Removal of NOM by FIX did not reduce membrane fouling problems; the Membrane Transport Coefficient (MTC) decreased and the Normalized Pressure Drop (NPD) increased more rapidly for the NF membrane after FIX compared to the membrane without FIX pre-treatment. NOM removal by FIX did not reduce adsorption of organic matter onto the downstream membrane element, since predominantly humic substances were removed which did not adsorb to the membrane surface. FIX treatment resulted in higher biomass densities (400%) and slightly less iron deposition (20%) onto the membrane surface. Fouling of the membrane element after FIX treatment was dominated by biofouling and fouling of the reference membrane element experienced more colloidal iron fouling compared to the membrane element after FIX, both resulting in an increase in NPD. The microbiological water quality deteriorated after anionic FIX treatment, as was observed by an increase in ATP content. Growth of biomass onto the IEX resins was observed which was caused by both IEX materials and feed water components, such as NOM fractions.
阴离子型流化离子交换（FIX）用于改善下游纳滤（NF）的性能。研究分为三部分：（i）FIX 去除 NOM，（ii）FIX 处理对 NF 结垢的影响，（iii）FIX 处理与生物稳定性的关系。预处理的厌氧地下水（i）直接进料至 4 英寸膜元件，（ii）在阴离子 FIX 处理后进料至另一 4 英寸膜元件。在 42 天的时间里监测膜组件的操作参数，然后进行膜剖析研究，确定累积的生物、有机和无机结垢。与此平行，运行了两个小型离子交换（IEX）树脂和玻璃珠填充柱，以研究 FIX 对进水生物量浓度的影响。FIX 运行良好，可选择性地从进水去除腐殖质（>90%）和疏水性有机碳（HOC）（>80%）。此外，铁的去除量显著增加（71%），这是由于腐殖质的络合作用。FIX 去除 NOM 并未减少膜结垢问题；与未进行 FIX 预处理的 NF 膜相比，FIX 后 NF 膜的膜传输系数（MTC）降低，归一化压力降（NPD）增加更快。FIX 去除 NOM 并未减少有机物在下游膜元件上的吸附，因为主要去除的腐殖质不会吸附到膜表面。FIX 处理导致膜表面的生物量密度增加（400%），铁沉积量略有减少（20%）。FIX 处理后膜元件的结垢主要由生物垢引起，而参考膜元件的结垢比 FIX 后膜元件经历更多的胶体铁垢，这两种情况都导致 NPD 增加。阴离子 FIX 处理后，水中的微生物质量恶化，通过增加 ATP 含量观察到。IEX 树脂上观察到生物量的生长，这是由 IEX 材料和进水成分（如 NOM 分数）引起的。
