EPA Tables
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About
CT values in mg·min/L, from EPA 815-R-99-013/Surface Water Treatment Rule Guidance Manual.
Disinfectant
Free chlorine
Chlorine dioxide
Chloramine
Ozone
Pathogen
Giardia
Viruses
Temperature (°C)
0.5
5
10
15
20
25
Logs of inactivation
0.5
1
1.5
2
2.5
3
mg/L ↓ pH →
6
6.5
7
7.5
8
8.5
9
0.4
23
27
33
40
46
55
65
0.6
24
28
33
40
48
57
68
0.8
24
29
34
41
49
59
70
1.0
25
29
35
42
51
61
73
1.2
25
30
36
43
52
63
75
1.4
26
31
37
44
54
65
77
1.6
26
32
38
46
55
66
80
1.8
27
32
39
47
56
68
82
2.0
28
33
39
48
55
70
83
2.2
28
34
40
50
59
71
85
2.4
29
34
41
50
60
73
87
2.6
29
35
42
51
61
74
89
2.8
30
36
43
52
63
75
91
3.0
30
36
44
53
64
77
92