The persistence and removal of enteric pathogens in constructed wetlands

Mohammad R. Karim, Faezeh D. Manshadi, Martin M. Karpiscak, Charles P. Gerba

Research output: Contribution to journalArticle

135 Scopus citations

Abstract

Sedimentation is thought to be one of the mechanisms of microbial reduction from wetlands used for wastewater treatment. This study compared the occurrence and survival of enteric indicator microorganisms and pathogens in the water column and sediments of two constructed surface flow wetlands in Arizona. On a volume/wet weight basis the concentration of fecal coliforms and coliphage in the water column and sediment was similar. However, on a volume/ dry weight basis the numbers were one to two orders of magnitude higher in the sediment. Giardia cyst and Cryptosporidium oocyst concentrations were one to three orders of magnitude greater in the sediment compared to the water column. The die-off rates of all the bacteria and coliphage were greater in the water column than the sediment. The die-off rates of fecal coliforms in the water and sediment were 0.256log10day-1 and 0.151log 10day-1, respectively. The die-off rates of Salmonella typhimurium in the water and sediment were 0.345log10day -1 and 0.312log10day-1, respectively. The die-off rates of naturally occurring coliphage in water column and sediment were 0.397log10day-1 and 0.107log10day -1, respectively, and the die-off rates of and PRD-1 in water and sediment were 0.198log10day-1 and 0.054log 10day-1, respectively. In contrast Giardia die-off in the sediment was greater compared to the water column. The die-off rates of Giardia in water and sediment were 0.029log10day-1 and 0.37log10day-1, respectively. Coliphage survived the longest of any group of organisms in the sediment and the least in the water column. In contrast Giardia survived best in the water column and least in the sediment.

Original languageEnglish (US)
Pages (from-to)1831-1837
Number of pages7
JournalWater research
Volume38
Issue number7
DOIs
StatePublished - Apr 2004

Keywords

  • Constructed wetland
  • Cryptosporidium
  • Fecal coliforms
  • Giardia
  • PRD-1
  • S. typhimurium

ASJC Scopus subject areas

  • Ecological Modeling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

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