Occurrence of Cryptosporidium, Giardia, and Cyclospora in influent and effluent water at wastewater treatment plants in Arizona

Masaaki Kitajima, Eiji Haramoto, Brandon C. Iker, Charles P. Gerba

Research output: Contribution to journalArticle

56 Scopus citations

Abstract

We investigated the occurrence of Cryptosporidium, Giardia, and Cyclospora at two wastewater treatment plants (WWTPs) in Arizona over a 12-month period, from August 2011 to July 2012. Influent and effluent wastewater samples were collected monthly, and protozoan (oo)cysts were concentrated using an electronegative filter, followed by the detection of protozoa using fluorescent microscopy (Cryptosporidium oocysts and Giardia cysts) and PCR-based methods (Cryptosporidium spp., Giardia intestinalis, and Cyclospora cayetanensis). The concentration of Giardia cysts in the influent was always higher than that of Cryptosporidium oocysts (mean concentration of 4.8-6.4×103 versus 7.4×101-1.0×102(oo)cysts/l) with no clear seasonality, and log10 reduction of Giardia cysts was significantly higher than that of Cryptosporidium oocysts for both WWTPs (P<0.05). Log10 reduction of Giardia cysts at the WWTP utilizing activated sludge was significantly higher than the other WWTP using trickling filter (P=0.014), while no statistically significant difference between the two WWTPs was observed for the log10 reduction of Cryptosporidium oocysts (P=0.207). Phylogenetic analysis revealed that G. intestinalis strains identified in wastewater belonged to two assemblages, AII and B, which are potentially infectious to humans. C. cayetanensis was also detected from both influent and effluent using a newly developed quantitative PCR, with the highest influent concentration of 1.2×104copies/l. Our results demonstrated that these protozoan pathogens are prevalent in the study area and that efficacy of the conventional wastewater treatment processes at physically removing (oo)cysts is limited.

Original languageEnglish (US)
Pages (from-to)129-136
Number of pages8
JournalScience of the Total Environment
Volume484
Issue number1
DOIs
StatePublished - Jun 15 2014

Keywords

  • PCR
  • Phylogenetic analysis
  • Protozoa
  • Removal
  • SYBR Green
  • Wastewater

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

Fingerprint Dive into the research topics of 'Occurrence of Cryptosporidium, Giardia, and Cyclospora in influent and effluent water at wastewater treatment plants in Arizona'. Together they form a unique fingerprint.

  • Cite this