Summary of pathogen and indicator log10 reduction in properly 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-Waste Stabilization Ponds

F/M (3)

F/M1/M2 (2)

F/M1/M2/M3 (1)

A/F/M (2)

UASB/F2 (2)

UASB/F2/M1/M2 (1)

Bacteria

Fecal Coliforms

NR

4.89 to 5.14

3.00

NR

2.45

NR

E. coli 3.02 to 4.84 NR NR 2.90 to 5.00 NR 5.74
Vibrio cholerae 01 NR 4.26 NR NR NR NR
Salmonella NR NR 1.24 NR NR NR

WHO (2006)

1 to 6

1 to 6

1 to 6

1 to 6

≥1.5b

1 to 6

Protozoa

E. coli, E. histolytica, Giardia

NR

NR

NR

>1.74

NR

NR

Giardia NR NR NR 1.57 NR NR
Cryptosporidium NR NR NR 1.98 NR NR
WHO (2006)

1 to 4

1 to 4

1 to 4

1 to 4

≥1.0b

1 to 4

Helminths

Helminth eggs

NR

>1.41

2.48

>2.89

>1.79 − 2.55

NR

WHO (2006)

1 to 3

1 to 3

1 to 3

1 to 3

0.5 to >1b

1 to 3

aProperly functioning in terms of design, loading rates, or operation and maintenance; bEstimated from WHO (2006) data for only one pond following a UASB.

Table caption: 

Table 8a. Summary of pathogen and indicator log10 reduction in properly 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 comparison. It is assumed all treatment produced sludges contain concentrations of pathogens potentially posing health risks.

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