20世纪90年代初设计和建造的一座20米高的水处理设施计划投入使用 水力显著膨胀至42 mgd。该设计将按照长期2强化地表水处理规则执行 （LT2）即将出现的需求。业主希望在 同时整合新的工艺元素，确保符合最坏情况 LT2的隐孢子虫灭活/去除要求。 考虑采用两条工艺路线进行膨胀、常规澄清/紫外线过滤（UV） 消毒与传统的膜过滤澄清。这两种选择都能实现 满足4仓水源水消毒要求，要求5.5 log 隐孢子虫去除/灭活值（如有必要）。 澄清/膜过滤工艺的选择基于相对成本比较，即现场 有利于更小占地面积和为后续扩建保留空间的考虑，以及 考虑到高效的去除能力比特定的目标微生物更可取 灭活过程。 本文描述了对膜过滤集成至关重要的选择和采购考虑 进入现有的工艺序列。文中给出了设计方案。包括表格、数字。

A 20 MGD water treatment facility, designed and constructed in the early 1990s was slated for a significant hydraulic expansion to 42 mgd. The design was to be executed with the Long Term 2 Enhanced Surface Water Treatment Rule (LT2) requirements looming on the horizon. The Owner desired to provide the expansion facilities while simultaneously integrating new process elements capable of assuring compliance with the worst case Cryptosporidium inactivation/removal requirements of LT2. Two process trains were considered for expansion, conventional clarification/filtration with ultraviolet (UV) disinfection versus conventional clarification with membrane filtration. Both options would be capable of meeting the disinfection requirements of source water classified in Bin 4 and requiring 5.5 log Cryptosporidium removal/inactivation value, if necessary. The clarification/membrane filtration process was selected based on a relative cost comparison, site considerations favoring a smaller footprint and preservation of space for subsequent expansions, and consideration that a highly effective removal capability was preferable to a specific microbe targeted inactivation process. This paper describes selection and procurement considerations critical to integration of membrane filtration into the existing process train. The proposed design is illustrated. Includes tables, figures.