Iowa Administrative Code › Agency 567 - Environmental Protection Commission › Title II - Air Quality › Division B › Chapter 43 - Water Supplies-design and Operation › Appendix C - Ct Tables for Virus Inactivation Under the Groundwater Rule, 567-41.7 (455B)

Current through Register Vol. 47, No. 3, July 24, 2024
TABLE 1: CT Values (mg-min/L) for Inactivation of Viruses
					 by Free Chlorine, pH 6.0-9.01
Inactivation Log Credit
Water Temperature, °C
1
2
3
4
5
6
7
8
9
2
5.8
5.3
4.9
4.4
4.0
3.8
3.6
3.4
3.2
3
8.7
8.0
7.3
6.7
6.0
5.6
5.2
4.8
4.4
4
11.6
10.7
9.8
8.9
8.0
7.6
7.2
6.8
6.4
1CT values provided in
								  the table are modified by linear interpolation between 0.5°C
								  increments.
Inactivation Log Credit
Water Temperature, °C
10
11
12
13
14
15
16
17
2
3.0
2.8
2.6
2.4
2.2
2.0
1.8
1.6
3
4.0
3.8
3.6
3.4
3.2
3.0
2.8
2.6
4
6.0
5.6
5.2
4.8
4.4
4.0
3.8
3.6
1CT values provided in
								  the table are modified by linear interpolation between 0.5°C
								  increments.
TABLE 2: CT Values (mg-min/L) for Inactivation of Viruses
					 by Free Chlorine, pH 9.1-10.0
Inactivation Log Credit
Water Temperature, °C
18
19
20
21
22
23
24
25
2
1.4
1.2
1.0
1.0
1.0
1.0
1.0
1.0
3
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
4
3.4
3.2
3.0
2.8
2.6
2.4
2.2
2.0
1CT values provided in
								  the table are modified by linear interpolation between 0.5°C
								  increments.
TABLE 3: CT Values (mg-min/L) for Inactivation of Viruses
					 by Chlorine Dioxide, pH 6.0-9.01
Inactivation Log Credit
Water Temperature, °C
0.5
5
10
15
20
25
2
45
30
22
15
11
7
3
66
44
33
22
16
11
4
90
60
45
30
22
15
Inactivation Log Credit
Water Temperature, °C
1
2
3
4
5
6
7
8
9
2
8.4
7.7
7.0
6.3
5.6
5.3
5.0
4.8
4.5
3
25.6
23.5
21.4
19.2
17.1
16.2
15.4
14.5
13.7
4
50.1
45.9
41.8
37.6
33.4
31.7
30.1
28.4
26.8
1CT values provided in
								  the table are modified by linear interpolation between 0.5°C
								  increments.
Inactivation Log Credit
Water Temperature, °C
10
11
12
13
14
15
16
17
2
4.2
3.9
3.6
3.4
3.1
2.8
2.7
2.5
3
12.8
12.0
11.1
10.3
9.4
8.6
8.2
7.7
4
25.1
23.4
21.7
20.1
18.4
16.7
15.9
15.0
1CT values provided in
								  the table are modified by linear interpolation between 0.5°C
								  increments.
Inactivation Log Credit
Water Temperature, °C
18
19
20
21
22
23
24
25
2
2.4
2.2
2.1
2.0
1.8
1.7
1.5
1.4
3
7.3
6.8
6.4
6.0
5.6
5.1
4.7
4.3
4
14.2
13.3
12.5
11.7
10.9
10.0
9.2
8.4
1CT values provided in
								  the table are modified by linear interpolation between 0.5°C
								  increments.
TABLE 4: CT Values (mg-min/L) for Inactivation of Viruses
					 by Ozone1
Inactivation Log Credit
Water Temperature, °C
1
2
3
4
5
6
7
8
9
2
0.90
0.83
0.75
0.68
0.60
0.58
0.56
0.54
0.52
3
1.40
1.28
1.15
1.03
0.90
0.88
0.86
0.84
0.82
4
1.80
1.65
1.50
1.35
1.20
1.16
1.12
1.08
1.04
1CT values provided in
								  the table are modified by linear interpolation between 0.5°C
								  increments.
Inactivation Log Credit
Water Temperature, °C
10
11
12
13
14
15
16
17
2
0.50
0.46
0.42
0.38
0.34
0.30
0.29
0.28
3
0.80
0.74
0.68
0.62
0.56
0.50
0.48
0.46
4
1.00
0.92
0.84
0.76
0.68
0.60
0.58
0.56
1CT values provided in
								  the table are modified by linear interpolation between 0.5°C
								  increments.
Inactivation Log Credit
Water Temperature, °C
18
19
20
21
22
23
24
25
2
0.27
0.26
0.25
0.23
0.21
0.19
0.17
0.15
3
0.44
0.42
0.40
0.37
0.34
0.31
0.28
0.25
4
0.54
0.52
0.50
0.46
0.42
0.38
0.34
0.30
1CT values provided in
								  the table are modified by linear interpolation between 0.5°C
								  increments.
No CT table is provided for chloramines or total chlorine
					 because the CT values would be prohibitively high for groundwater
					 systems.
Tables are from the EPA Groundwater Rule Implementation
					 Guidance, EPA 816-R-09-004, January 2009, pages 97-98.