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Protozoa in open reservoirs
Author(s) -
LeChevallier Mark W.,
Norton William D.,
Atherholt Thomas B.
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.tb08291.x
Subject(s) - effluent , turbidity , cryptosporidium , fecal coliform , environmental science , water quality , giardia , inlet , indicator bacteria , microorganism , contamination , disinfectant , biology , environmental engineering , pulp and paper industry , bacteria , feces , ecology , microbiology and biotechnology , chemistry , mechanical engineering , genetics , organic chemistry , engineering
Open finished water reservoirs are vulnerable to microbial contamination, but current analytical techniques do not permit assessment of the organisms' viability. The impact of storage of potable water in open reservoirs was assessed by examining inlet and effluent water samples from six open finished water reservoirs used by four New Jersey utilities. Water quality parameters investigated included Giardia cysts, Cryptosporidium oocysts, total and fecal coliforms, bacteriophage, heterotrophic plate count bacteria, turbidity, particle counts, chlorine residuals and other parameters. Fifteen percent of inlet samples and 25 percent of effluent samples contained the organisms. When data for cysts and oocysts were combined, the difference in concentrations between the inlet and effluent was statistically significant, even when results were adjusted for analytical recovery efficiency. Although the concentration of protozoa increased following open reservoir storage, the analytical method used does not permit assessment of the organisms' public health significance. Nearly all of the cysts and oocysts were empty or contained undiscernible internal structures, suggesting the health risk is low. The implication of these findings for watershed control programs is discussed.