Behaviour of pathogenic and indicator bacteria during urban wastewater treatment and sludge composting, as revealed by quantitative PCR.
Two enteric pathogens, Salmonella spp. and Campylobacter jejuni, and two bacteria commonly used as indicators, Escherichia coli and Clostridium perfringens, were monitored using quantitative real-time PCR during municipal wastewater treatment and sludge composting. The results were compared with those obtained using standard culture methods. A reduction of all bacteria was observed during wastewater treatment and during the thermophilic phase of composting. However, the bacterial groups studied behaved differently during the process, and the main differences were observed during biological treatment in activated sludge basins. In particular, Salmonella spp. and C. jejuni survived better during activated sludge treatment than E. coli. C. jejuni was the most resistant to wastewater treatment among the four bacterial groups. Overall, differences in survival were observed for all bacteria studied, when submitted to the same environmental pressure. This holds both for differences between indicators and pathogenic bacteria and between pathogenic bacteria. These results show the difficulty in defining reliable indicators.
Wéry
Nathalie
N
INRA, UR050, Laboratoire de Biotechnologie de l'Environnement, Avenue des Etangs, Narbonne F-11100, France. weryn@supagro.inra.fr
Lhoutellier
Claire
C
Ducray
Florence
F
Delgenès
Jean-Philippe
JP
Godon
Jean-Jacques
JJ
D001419:Bacteria / Q000235:genetics* / Q000302:isolation & purification; D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000032:analysis; D004275:DNA, Ribosomal / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D005798:Genes, Bacterial / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012722:Sewage / Q000382:microbiology*; D012987:Soil; D014865:Waste Disposal, Fluid; D014871:Water Microbiology; D014873:Water Pollutants / Q000302:isolation & purification
D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012722:Sewage; D012987:Soil; D014873:Water Pollutants