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Protozoa in river water: sources, occurrence, and treatment
Author(s) -
States Stanley,
Stadterman Kathleen,
Ammon Louis,
Vogel Paul,
Baldizar Julie,
Wright Denise,
Conley Louis,
Sykora Jan
Publication year - 1997
Publication title -
journal ‐ american water works association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.466
H-Index - 74
eISSN - 1551-8833
pISSN - 0003-150X
DOI - 10.1002/j.1551-8833.1997.tb08290.x
Subject(s) - cryptosporidium , raw water , effluent , sewage , environmental science , water treatment , giardia , filtration (mathematics) , sewage treatment , protozoa , water quality , environmental engineering , slow sand filter , water source , biology , ecology , water resource management , feces , microbiology and biotechnology , statistics , mathematics
A dairy farm, sewage plant, and backwash water were among sources of protozoa in the raw water treated by the Pittsburgh, Pa., water utility. Giardia and Cryptosporidium were monitored monthly for two years to determine their occurrence in the Allegheny and Youghiogheny rivers, their source, and the efficiency of their removal by the Pittsburgh Drinking Water Treatment Plant. Sources investigated included a dairy farm stream, treated effluent from a sewage plant, and several samples from combined sewer overflows, all of which regularly contribute parasites to rivers. Raw, settled, filtered, and filter backwash waters were also sampled. Clarification and filtration generally control passage of protozoa into the drinking water, but small numbers of Cryptosporidium occasionally pass through even in the absence of treatment difficulties. Cysts and oocysts are also reintroduced into the drinking water plant via recycling of backwash water.