Vapor-induced transfer of bacteria in the absence of mechanical disturbances

Ayoub, George M.; Dahdah, Lamia; Alameddine, Ibrahim M.; Malaeb, Lilian

Vapor-induced transfer of bacteria in the absence of mechanical disturbances

Type

Article

Authors

Ayoub, George M.
Dahdah, Lamia
Alameddine, Ibrahim M.
Malaeb, Lilian

KAUST Department

Biological and Environmental Sciences and Engineering (BESE) Division
Water Desalination and Reuse Research Center (WDRC)

Date

2014-09

Abstract

Transfer of bacteria through water vapor generated at moderate temperatures (30-50. °C) in passive solar stills, has scarcely been reported. The objective of this research was to investigate whether bacteria in highly humid atmospheres can get transferred through water vapor in the absence of other transfer media to find their way to the distillate. To achieve this objective, passive solar reactors were chosen as the medium for experimentation, and distillation experiments were conducted by spiking a pure bacterial culture (Escherichia coli, Klebsiella pneumonia or Enterococcus faecalis) in low mineralized water vs. highly mineralized water in the dark under moderate temperatures ranges (30-35. °C, 40-45. °C and 50-55. °C). Results showed that bacteria indeed get transferred with the vapor in stills when not exposed to solar U.V. radiation. The trends observed were adequately explained by a zero-modified Hurdle-Poisson model. The numbers of cultivable bacterial colonies transferred were bacterial size, water type and temperature dependent with highest transfers occurring in E. faecalis>. E. coli>. K. pneumonia at the 40. °C range in low mineralized water. Proper management strategies are recommended to achieve complete disinfection in solar stills. © 2014 Elsevier B.V.

Citation

Ayoub, G. M., Dahdah, L., Alameddine, I., & Malaeb, L. (2014). Vapor-induced transfer of bacteria in the absence of mechanical disturbances. Journal of Hazardous Materials, 280, 279–287. doi:10.1016/j.jhazmat.2014.08.003

Acknowledgements

The study was made possible by funding from the Lebanese National Council for Scientific Research (NCSR). Any views, findings or conclusions expressed are those of the authors and do not necessarily reflect the views of the NCSR. The authors extend their appreciation to Professor George Araj, Director of Clinical Microbiology, for extending his help and advice.