Microorganism

Chlorine concentration (mg/L)

Deactivation period (min)

Ct

E. coli

0.1

0.4

0.04

Poliovirus I

1.0

1.7

1.7

Entamoeba histolytica cysts

5.0

18

90

G. lamblia cysts

1.0

50

50

2.0

40

80

2.5

100

250

G. muris cysts

2.5

100

250