与南加州长滩（LBWD）相似 公用事业公司一直面临饮用水供应减少的问题。因为它的 地理位置优越，长滩市地理位置优越，可以充分利用海水淡化的优势 海水作为饮用水的来源。然而，海水的主要屏障 与其他可用水相比，海水淡化的成本相对较高 消息来源。降低海水淡化运行成本的一种方法是 LBWD提出的是一种双级纳滤（NF）膜工艺， 这有可能降低所需的总能量。在这种配置中， 来自第一阶段的渗透液由第二阶段膜处理，以 生产饮用水。本文介绍了从最初的试点中获得的数据 LBWD进行的测试。包括10个参考文献、表格和图表。

The Long Beach Water Department (LBWD), similar to many Southern California utilities, has been facing the issue of decreased potable water supplies. Because of its location, the City of Long Beach is ideally situated to take advantage of desalinated seawater as a source of drinking water. However, the primary barrier to seawater desalination has been its relatively high cost as compared to other available water sources. One method of reducing the operational cost for seawater desalination being proposed by LBWD is through a dual-staged nanofiltration (NF) membrane process, which has the potential of lowering the overall energy required. In this configuration, permeate from the first stage is treated by the second stage membranes in order to produce potable water. This paper presents the data derived from the initial pilotscale tests conducted by LBWD. Includes 10 references, tables, figures.