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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.

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Edition: Vol. - No. Published: 01/01/1999File Size: 1 file , 220 KB