与宾夕法尼亚州环境保护部（对匹兹堡水和污水管理局（PWSA）负有监管责任的州机构）的讨论表明，该机构认为未覆盖成品水库中的水相当于未经处理的地表水。任何用于替代覆盖的后处理过程都必须保证四个对数去除或灭活病毒，三个对数去除或灭活贾第虫囊肿，以及至少两个对数去除或灭活隐孢子虫卵囊。本文报告了PWSA通过使用Highland水库#1的水进行中试研究，对膜过滤的可能用途进行的调查。选择该方案是基于其去除小（直径5微米）耐氯隐孢子虫卵囊的能力。 使用灭活贾第虫和隐孢子虫进行膜激发研究，将其悬浮在成品水中，并通过5种不同的中试膜过滤系统。先导膜系统位于一个分配系统泵站。试验中使用的水在Highland水库#1中储存后流入电站，平均滞留时间为4天。所有膜挑战试验均在冬季进行，以评估在严格低温条件下的去除效率。包括9个参考文献和表格。

Discussions with the Pennsylvania Department of Environmental Protection (the state agency with regulatory responsibility over Pittsburgh Water and Sewer Authority, PWSA) have indicated that water in an uncovered finished water reservoir is considered by the agency to be the equivalent of untreated surface water. Any post treatment process used in lieu of covering would have to guarantee four-log removal or inactivation of viruses, three-log for Giardia cysts, and at least two-log removal or inactivation of Cryptosporidium oocysts. This paper reports on an investigation by PWSA into the possible use of membrane filtration, through pilot-scale studies using water from Highland Reservoir #1. This option was selected for consideration based on its documented ability to remove the small (5 um diameter), chlorine resistant Cryptosporidium oocyst. Membrane challenge studies were conducted using inactivated Giardia and Cryptosporidium, suspended in finished water, and passed through 5 different pilot membrane filter systems. The pilot membrane systems were located at a distribution system pumping station. The water used in the trials flowed into the station after storage in the Highland Reservoir #1 for an average detention time of 4 days. All membrane challenge experiments were conducted during winter months to evaluate removal efficiency under rigorous low temperature conditions. Includes 9 references, tables.