Summary of pathogen and indicator log10 reduction in poorly functioninga natural wastewater treatment system configurations. Number of systems in parentheses. The range of pathogen group reduction (bacteria, viruses, protozoa, helminths) reported by WHO (

Table: 
Log10 Reduction
Pathogen
Group
Pathogen/Indicator Waste Stabilization Ponds UASB-WSP
F/M (4) F/M1/M2 (1) A/F/M (2) UASB/F2/M (1)
Bacteria E. coli 1.87 to 1.99 NR 0.7 to 1.1 NR
WHO (2006) 1 to 6 1 to 6 1 to 6 1 to 6
Viruses Enterovirus NR 3.06 NR 0.83
Norovirus GIb NR 0 NR 0
Rotavirusb NR 0 NR 1
WHO (2006) 1 to 4 1 to 4 1 to 4 1 to 4
Protozoa Giardia cysts NR 0.84 0.5 to 1.5 0.52
Cryptosporidium oocysts NR 0.18 0.7 to 0.8 0.16
WHO (2006) 1 to 4 1 to 4 1 to 4 1 to 4
Helminths Helminth eggs NR ≤1.82 0.5 to 0.6 NR
WHO (2006) 1 to 3 1 to 3 1 to 3 1 to 3

aPoorly functioning as a result of design, overloading or lack of operation and maintenance; bIt is assumed all treatment produced sludges contain concentrations of pathogens potentially posing health risks. cVirus concentrations were measured by the RT-qPCR molecular method and not by cell culture. The RT-qPCR method identifies specific viruses but they do not have to be intact or infective to be detected (Francy et al., 2011) and log10 reduction may be underestimated.

Table caption: 

Table 8b. Summary of pathogen and indicator log10 reduction in poorly functioninga natural wastewater treatment system configurations. Number of systems in parentheses. The range of pathogen group reduction (bacteria, viruses, protozoa, helminths) reported by WHO (2006) is shown for comparisonb.

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