提供给南达科他州Watertown的大部分饮用水在8号处理站进行处理 每天百万加仑（MGD）城镇水处理厂（WTP），该厂雇佣 常规地下水处理系统，包括曝气、石灰软化、再碳化、， 介质过滤和消毒。该工厂经历了几次水平升高 分配水中消毒副产物（DBPs）的浓度，总浓度 高达120µg/L的三卤甲烷（TTHM）。建议使用纳滤膜系统 对现有软化水进行强化处理。NF膜处理的目的 该系统用于进一步处理软化水流，以降低水的浓度 消毒副产物（DBP）前体。NF渗透液将与剩余的软化水混合，而软化水不是 通过NF系统布线，以及从新的常规 地下水软化厂。最终混合的饮用水总量为12 MGD 满足D/DBP规则的第一阶段和第二阶段。 该项目的主要挑战之一是选择能够提供 最经济的解决方案，同时满足几个相互竞争的目标:高TOC拒绝率以减少 DBP前体水平；低钙和低碱度去除，避免最终混合 稳定治疗；而且，浓缩水中的无机物截留率低，成本效益高 处置NF膜的选择基于中试研究项目的结果 由三部分组成。首先，用一个4“ 飞行员分队。这使得快速有效地筛选六种候选NF膜成为可能 方式筛选标准为高TOC去除率、低模拟分配系统（SDS）- 产品水和混合物中DBP的形成，以及通过的低总溶解固体（TDS） 费率。在没有优先顺序的情况下，选择的膜是科赫TFC-SR3、Trisep XN45和 液压传动ESNA1-LF。 这些膜进行了第二阶段的测试，测试分两个阶段进行 试验装置，模拟全尺寸工厂设计，刚刚完成。 一片薄膜就可以了 根据运行性能参数以及产品水质量（TOC， SDS-DBP、TDS、碱度和钙）。试点的第三个也是最后一个阶段将集中在 污垢和清洁要求，将于2009年1月开始。这项初步研究的结果 不仅可以为该应用选择最合适的NF膜，还可以 为全尺寸NF膜装置的设计提供一套水力参数。这 本文重点介绍了试点前两个阶段的结果和选择过程 程序包括表格、数字。

The majority of the drinking water provided to Watertown, South Dakota, is treated at the 8 million gallons per day (MGD) Town Water Treatment Plant (WTP), which employs a conventional groundwater treatment system, comprised of aeration, lime softening, recarbonation, media filtration and disinfection. The plant has experienced a few occurrences of elevated levels of disinfection byproducts (DBPs) in the distributed water, with concentrations of Total Trihalomethanes (TTHM) up to 120 µg/L. A nanofiltration membrane system is proposed as enhanced treatment for the existing softened water. The purpose of the NF membrane treatment system is to further treat a stream of the softened water in order to reduce the concentration of disinfection byproduct (DBP) precursors. The NF permeate will be blended with the remaining softened water, which is not routed through the NF system, as well as with additional 4 MGD from a new conventional groundwater softening plant. Final blend will represent a total of 12 MGD of drinking water meeting Stage 1 and Stage 2 of D/DBP Rules. One of the main challenges of this project is selecting the NF membrane which can provide the most economical solution while satisfying several competing goals: high TOC rejection to reduce the level of DBP precursors; low calcium and alkalinity removal to avoid the need for final blend stabilization treatment; and, low inorganic rejection in the concentrate water for cost-effective local disposal. Selection of the NF membrane is performed based on the results of a pilot study program composed of three segments. First, a membrane screening study was performed with a single 4" element pilot unit. This allowed screening of six candidate NF membranes in a quick but effective manner. The screening criteria were high TOC removal, low simulated distribution system (SDS)- DBP formation in the product water and in the blend, and low total dissolved solids (TDS) passing rates. In no preferred order, the selected membranes were Koch TFC-SR3, Trisep XN45, and Hydranautics ESNA1-LF. These membranes underwent a second phase of testing which was performed with a two stage pilot unit, modeling the full scale plant design, and which was just completed. One membrane will be selected based on operating performance parameters as well as quality of product water (TOC, SDS-DBP, TDS, alkalinity and calcium). A third and last phase of the piloting will focus on fouling and cleaning requirements and will begin in January 2009. The results of this pilot study will not only allow selection of the most suitable NF membrane for this application but will also provide a set of hydraulic parameters for the design of the full scale NF membrane plant. This paper focuses on the results and the selection process for the first two phases of the piloting program. Includes tables, figures.