Abstract:

The disk-tube nanofiltration membrane was used for advanced treatment of the domestic water, while the effects of various operating conditions on the component separation performance and outflow water quality were evaluated. The optimal operating conditions were found at 1MPa operating pressure, inlet water temperature above 25℃, and minimum concentrated water flow of 300L/h. The analysis of the raw water quality can effectively predict the pollutant composition and membrane fouling. The design of the pretreatment system and the selection of a suitable cleaning scheme were proposed. The experiment data were analyzed by scanning electron microscopy, EDS, infrared and three-dimensional fluorescence spectroscopy. As shown in the results, the membrane pollution from the inlet to the outlet end was gradually aggravated, in which the pollutant components were mainly organic pollution and contained inorganic impurities precipitated and crystallized by insoluble salts and a certain degree of biological pollution. Therefore, the study on the membrane fouling characteristics of the disk-tube nanofiltration membrane in domestic water treatment by analyzing the causes of pollution found that the insoluble salt precipitates on the membrane surface with the increase of concentration to form inorganic scale, a large number of organic substances adsorb on the membrane surface to form organic sludge layer, and the microorganisms or bacteria in water breed on the membrane surface to cause biological pollution. The order of pollution formation was that organic pollution would first form on the surface of the membrane, followed by the formation of inorganic fouling, and interaction would occur, resulting in a decrease in membrane flux and a deterioration in water quality. This research explored the contamination characteristics of disk-tube nanofiltration membrane components by means of pilot tests, providing a basis for the efficient use of this novel membrane elements and effective control of membrane fouling in real application.

Key words: nanofiltration, membranes, disk-tube membrane, domestic water, membrane fouling, deposition

摘要：

采用碟管式纳滤膜对生活用水进行深度处理，研究了不同操作条件对元件分离性能及产水水质的影响，得到最佳运行条件为运行压力1MPa、进水温度为25℃以上、最小浓水流量300L/h。对原水水质进行分析，有效预测了污染物成分及膜污染情况，提出了预处理系统的设计及清洗方案。运用扫描电镜、EDS能谱、红外光谱及三维荧光光谱分析出，从进水端至出水端膜污染逐渐加剧，污染物成分主要以有机污染为主，并且含有难溶盐析出结晶的无机污垢及一定程度的生物污染。对碟管式纳滤膜在生活用水处理中膜污染特性的研究，分析污染成因为难溶盐随浓度增加在膜表面析出形成无机结垢，大量有机物在膜表面吸附形成有机污泥层，而水中微生物或细菌等在膜表面滋生造成生物污染，污染形成顺序为有机污染率先在膜表面形成，随后形成无机污垢，并且会发生相互作用，其结果导致膜通量下降、产水水质变差。本研究借助中试试验探究了碟管式纳滤膜元件的污染特性，为这种新型膜元件在实际生产中如何高效使用及有效控制纳滤膜污染提供依据。

关键词: 纳滤, 膜, 碟管式膜, 生活用水, 膜污染, 沉积物