Abstract

The colloidal index (CI) (Silt Density Index—SDI) is an important integral indicator of the quality of water prepared for reverse osmosis plants (ROP). To date, this is the only indicator that allows us to assess the likelihood of the membrane unit’s contamination with colloids and suspended solids contained in the source water. It is shown that the new method for measuring the colloidal index, in contrast to the standard one, makes it possible to eliminate the contribution of nonlinearities to the description of water quality and it has a smaller error in a wide range of concentrations of suspended particles, which provides a more accurate prediction of potential contamination of reverse osmosis plants. Based on the differential form of the CI, a generalization of the standard technique for measuring the colloidal index in the linear region of decreasing the water flow rate using more accurate measurement and automation methods is presented. For waters with a low content of suspended and colloidal particles, the water flow through the microfilter changes slowly; therefore, to notice a drop in its performance, a considerable observation time is required (approximately 15 min). Attempts to measure CI on water with a high content of colloidal particles and suspended solids show their practical impossibility. The data of experimental studies are presented, confirming the correctness and advantages of the methodology for measuring the colloidal index demonstrated in the article. Comparison of methods for calculating the generalized colloidal index presented in the article and the modified fouling index (MFI) is performed. It is shown that the colloidal index is proportional to the concentration of suspended particles, and the MFI additionally contains a normalization factor inversely proportional to the filtrate velocity. In practice, the results presented in the article are likely to make it possible to calculate the load on reverse osmosis plants and to reveal the correlation of the frequency of chemical purification. In the course of the experiments, the phenomenon of an initial sharp drop in the flow rate of the filtrate through the filter was discovered, which is still awaiting its explanation.

中文翻译：

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测量胶体指数的新方法

摘要

胶体指数 (CI)（淤泥密度指数 - SDI）是为反渗透设备 (ROP) 制备的水质量的重要综合指标。迄今为止，这是允许我们评估膜单元被源水中所含胶体和悬浮固体污染的可能性的唯一指标。结果表明，与标准方法相比，新的胶体指数测量方法可以消除非线性对水质描述的影响，并且在较宽的悬浮颗粒浓度范围内具有较小的误差。 ，它可以更准确地预测反渗透设备的潜在污染。基于CI的微分形式，介绍了使用更准确的测量和自动化方法在降低水流量的线性区域中测量胶体指数的标准技术的概括。对于悬浮颗粒和胶体颗粒含量低的水，通过微滤器的水流量变化缓慢；因此，要注意到其性能下降，需要相当长的观察时间（约 15 分钟）。尝试测量胶体颗粒和悬浮固体含量高的水的 CI 表明它们实际上是不可能的。提供了实验研究数据，证实了文章中展示的用于测量胶体指数的方法的正确性和优势。对文章中介绍的广义胶体指数和修正的污垢指数 (MFI) 的计算方法进行了比较。结果表明，胶体指数与悬浮颗粒的浓度成正比，MFI 还包含一个与滤液速度成反比的归一化因子。在实践中，文章中提供的结果可能可以计算反渗透设备的负载并揭示化学净化频率的相关性。在实验过程中，发现了滤液通过过滤器的流速开始急剧下降的现象，目前仍在等待其解释。结果表明，胶体指数与悬浮颗粒的浓度成正比，MFI 还包含一个与滤液速度成反比的归一化因子。在实践中，文章中提供的结果可能可以计算反渗透设备的负载并揭示化学净化频率的相关性。在实验过程中，发现了滤液通过过滤器的流速开始急剧下降的现象，目前仍在等待其解释。结果表明，胶体指数与悬浮颗粒的浓度成正比，MFI 还包含一个与滤液速度成反比的归一化因子。在实践中，文章中提供的结果可能可以计算反渗透设备的负载并揭示化学净化频率的相关性。在实验过程中，发现了滤液通过过滤器的流速开始急剧下降的现象，目前仍在等待其解释。文章中提供的结果可能有助于计算反渗透设备的负载并揭示化学净化频率的相关性。在实验过程中，发现了滤液通过过滤器的流速开始急剧下降的现象，目前仍在等待其解释。文章中提供的结果可能有助于计算反渗透设备的负载并揭示化学净化频率的相关性。在实验过程中，发现了滤液通过过滤器的流速开始急剧下降的现象，目前仍在等待其解释。