Quantification and risks associated with bacterial aerosols near domestic greywater-treatment systems

Maya Benami, Allison Busgang, Osnat Gillor, Amit Gross

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

Abstract

Greywater (GW) reuse can alleviate water stress by lowering freshwater consumption. However, GW contains pathogens that may compromise public health. During the GW-treatment process, bioaerosols can be produced and may be hazardous to human health if inhaled, ingested, or come in contact with skin. Using air-particle monitoring, BioSampler®, and settle plates we sampled bioaerosols emitted from recirculating vertical flow constructed wetlands (RVFCW) - a domestic GW-treatment system. An array of pathogens and indicators were monitored using settle plates and by culturing the BioSampler® liquid. Further enumeration of viable pathogens in the BioSampler® liquid utilized a newer method combining the benefits of enrichment with molecular detection (MPN-qPCR). Additionally, quantitative microbial risk assessment (QMRA) was applied to assess risks of infection from a representative skin pathogen, Staphylococcus aureus.According to the settle-plate technique, low amounts (0-9.7 × 104 CFU m-2 h-1) of heterotrophic bacteria, Staphylococcus spp., Pseudomonas spp., Klebsiella pneumoniae, Enterococcus spp., and Escherichia coli were found to aerosolize up to 1 m away from the GW systems. At the 5 m distance amounts of these bacteria were not statistically different (p > 0.05) from background concentrations tested over 50 m away from the systems. Using the BioSampler®, no bacteria were detected before enrichment of the GW-aerosols. However, after enrichment, using an MPN-qPCR technique, viable indicators and pathogens were occasionally detected. Consequently, the QMRA results were below the critical disability-adjusted life year (DALY) safety limits, a measure of overall disease burden, for S. aureus under the tested exposure scenarios. Our study suggests that health risks from aerosolizing pathogens near RVFCW GW-treatment systems are likely low. This study also emphasizes the growing need for standardization of bioaerosol-evaluation techniques to provide more accurate quantification of small amounts of viable, aerosolized bacterial pathogens.

Original languageEnglish
Pages (from-to)344-352
Number of pages9
JournalScience of the Total Environment
Volume562
DOIs
StatePublished - 15 Aug 2016

Keywords

  • Aerosols
  • Enrichment
  • Greywater
  • MPN-qPCR
  • Pathogens
  • QMRA

ASJC Scopus subject areas

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

Fingerprint

Dive into the research topics of 'Quantification and risks associated with bacterial aerosols near domestic greywater-treatment systems'. Together they form a unique fingerprint.

Cite this