Giardia and virus monitoring of sewage effluent in the state of Arizona

J. B. Rose, R. De Leon, C. P. Gerba

Research output: Contribution to journalConference articlepeer-review

10 Scopus citations


Virus and Giardia monitoring of wastewater used for irrigation has been initiated as a means for controlling the public's exposure to these pathogens. Treatment facilities must produce wastewater with no detectable Giardia cysts and one virus plaque forming unit (pfu) per 40 liters (L) for unrestricted reuse. For restricted reuse, 125 pfu/40 L is allowed. Methods based on filtration were used to monitor facilities at monthly, quarterly or biannual frequencies. Results after two years of monitoring are presented. All 11 treatment facilities produced water meeting the virus standard of 125 pfu/40 L. Only plants which used sand filtration and disinfection achieved consistent levels of virus below 1 pfu/40 L. Out of 70 samples, 74% contained no detectable viruses. Giardia was detected in 29 to 50% of the samples. Most plants would need to upgrade their treatment in order to meet standards for unrestricted irrigation.

Original languageEnglish (US)
Pages (from-to)43-47
Number of pages5
JournalWater Science and Technology
Issue number3
StatePublished - 1989
EventHealth-Related Water Microbiology 1988 - Brighton, Engl
Duration: Jul 19 1988Jul 21 1988

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology


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