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Ohio Administrative Code (Last Updated: January 12, 2021) |
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3745 Ohio Environmental Protection Agency |
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Chapter3745-81. Primary Drinking Water Rules |
3745-81-72. Disinfection of water from surface water sources
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"Disinfection practice" means the application of a disinfectant to the treatment flow for the purpose of meeting CT requirements of this rule. Significant changes to disinfection practice include any change which will affect the ability of a system to meet the CT requirements of this rule.
(A) A public water system that uses a surface water source, in whole or in part, shall provide the disinfection treatment specified in paragraph (B) of this rule. Failure to meet any requirement of this rule, excluding paragraph (E) of this rule, is a treatment technique violation for which public notification is required under rule 3745-81-32 of the Administrative Code. Failure to meet any requirement of paragraph (E) of this rule is a monitoring violation for which public notification is required under rule 3745-81-32 of the Administrative Code. A public water system that uses a surface water source, in whole or in part, and does not already provide filtration treatment shall comply with any interim disinfection requirements established by the director before filtration is installed.
(B) Each public water system that uses a surface water source, in whole or in part, shall provide disinfection treatment of the water as follows:
(1) The disinfection treatment shall be considered sufficient if the total treatment processes of that public water system would consistently and reliably achieve at least 99.9 per cent (3 log) inactivation and/or removal of Giardia lamblia cysts and at least 99.99 per cent (4 log) inactivation and/or removal of viruses, as determined from table A, and tables B-1 to B-13 of this rule or tables under paragraph (N) of rule 3745-81-68 of the Administrative Code. The inactivation by disinfection is calculated from the actual CT divided by the required CT during the peak hourly flow of each day that the public water system is in operation.
(2) Table A of this rule lists: the minimum requirement for inactivation and/or removal of Cryptosporidium, Giardia lamblia and viruses; the extent to which a properly operated conventional filtration treatment, direct filtration (once demonstrated in accordance with rule 3745-81-73 of the Administrative Code), and slow sand filtration are considered sufficient to remove Cryptosporidium, Giardia lamblia, and viruses; and the minimum disinfection needed to complete the required minimum inactivation and/or removal of Cryptosporidium, Giardia lamblia and viruses. Table A specifies the additional minimum log inactivation of Giardia lamblia and viruses by disinfection if filtration is properly operated and the turbidity treatment technique requirements of rule 3745-81-73 of the Administrative Code are satisfied. The filtration and disinfection treatment shall include disinfection that consistently and reliably achieves at least the minimum log inactivation by disinfection of Giardia lamblia and viruses as specified in table A.
(3) The residual disinfectant concentration in the water entering the distribution system shall not be less than 0.2 milligram per liter free chlorine or one milligram per liter combined chlorine for more than four consecutive hours.
(4) The residual disinfectant concentration in the distribution system shall not be less than 0.2 milligram per liter free chlorine or one milligram per liter combined chlorine in more than five per cent of the samples each month for any two consecutive months that the public water system serves water to the public.
(C) Disinfection treatment sufficiency determination.
(1) Paragraph (B)(1) of this rule requires a minimum percentage of inactivation and/or removal of Giardia lamblia and viruses in water obtained at least partly from a surface water source. Because of the difficulties in measuring the concentrations of viable Cryptosporidium, Giardia lamblia, and viruses, maximum contaminant levels are not practical and treatment technique requirements are used to ensure control of these contaminants in drinking water. For disinfectants other than UV, tables B-1 to B-13 of this rule shall be used to determine the sufficiency of disinfection. For disinfectants other than UV, this determination is made at the peak hourly flow rate of each day the water system is in operation. Systems using UV to comply with the inactivation requirements of this rule shall meet the following:
(a) Paragraph (N) of rule 3745-81-68 of the Administrative Code.
(b) The reporting and record-keeping requirements of rule 3745-81-69 of the Administrative Code.
(2) For disinfectants other than UV, the level of inactivation being provided by the system is determined by measuring actual CT values. The level of inactivation being provided by a system using UV is determined by the UV dosage. For systems using chlorine dioxide or ozone to comply with the additional Cryptosporidium treatment requirements in paragraph (E) of rule 3745-81-67 of the Administrative Code, unfiltered water flow may be used to achieve the additional treatment credit if approved by the director.
Only filtered water flow shall be used in the required CT calculations to meet the minimum log inactivation in table A of this rule, regardless of the disinfectant used.
Actual CT values are obtained by multiplying the residual disinfectant, C, by the disinfection contact time, T, giving the resultant, CT. The value of C in milligrams per liter is determined at a point before or at the first customer. The value of T in minutes is based on the time available for the disinfectant to work from the point at which the disinfectant is added to the water until the point at which C is measured. Values of T are determined based on the approved effective volume factor of the clearwell or contact tank. It may be appropriate to determine the value of C at more than one point of the water treatment flow, with the T associated with each C being estimated from the previous measurement point or the previous addition of disinfectant, whichever is closer. If more than one disinfectant concentration point is used, the products of each C and its associated T are added and the sum of these products is the actual CT value to compare with the appropriate value of the required minimum CT values for specified conditions and levels of inactivation in the following tables. Note that any disinfection after the last determination of C is not included in the actual CT value. Minimum required CT values for inactivation of Giardia lamblia and viruses by disinfection in relation to the disinfectant, the extent of inactivation, the disinfectant concentration, the pH, and the water temperature at the peak hourly flow rate for each day of operation are found in tables B-1 to B-13 of this rule. Applicable information for UV is found in paragraph (N) of rule 3745-81-68 of the Administrative Code.
(3) In tables B-1 to B-13 of this rule, the required CT between the indicated pH or residual disinfectant concentration may be determined by linear interpolation. The required CT between the indicated temperatures of different tables may be determined by linear interpolation.
If no interpolation is used, then the required CT shall be determined at the lower temperature, and at the higher pH, and at the higher residual disinfectant concentration. For Giardia lamblia inactivation at a pH greater than nine, the required CT shall be the same as the required CT at a pH equal to nine. For virus inactivation at a pH greater than nine, the required CT shall be the same as the required CT at a pH equal to ten.
(4) On each day when the actual CT value meets or exceeds the required minimum CT value in or linearly interpolated from tables B-1 to B-13 of this rule for chlorine, chlorine dioxide, ozone, or chloramines, or the table in paragraph (N) of rule 3745-81-68 of the Administrative Code for UV disinfection, then the water treatment plant is considered to be satisfying treatment technique requirements of this rule for disinfection of surface water sources. On each day when the actual CT value does not meet or exceed the required minimum CT value from tables B-1 to B-13 of this rule, then the water treatment plant is in violation of paragraph (B)(1) of this rule.
(5) For each clearwell, or contact tank, the approved effective volume factor shall be determined by the director based upon the design characteristics including: the average flow path length to channel width ratio; baffling; and the proximity of the outlet to the inlet using figures B-1 and B-2 of this rule. The approved effective volume factor shall be the preliminary effective volume factor obtained from figure B-1 of this rule multiplied by the reduction factor obtained from figure B-2 of this rule, rounded down to the nearest 0.05. A public water system may request that the director approve an effective volume factor that was determined by tracer studies, hydraulic analysis or modeling, or an equivalent demonstration. For a tracer study to be acceptable, the net advection of the tracer shall be within ten per cent of the change in the tracer chemical storage within the clearwell system. Net advection means the amount of tracer convected out of the clearwell system minus the amount of tracer convected into the clearwell system over the duration of the tracer study.
[Note: Refer to the appendix to this rule for more information on how to determine disinfection sufficiency.]
(D) A public water system that serves a population of at least ten thousand persons and was required to develop a disinfection profile or benchmark under 40 CFR 141.172 or 40 CFR 141.170(d), or a community or nontransient noncommunity public water system that serves a population of less than ten thousand persons and was required to develop a disinfection profile or benchmark under 40 CFR 141.530, shall follow these requirements:
(1) Prior to making a significant change in the disinfection practice, the public water system shall submit the disinfection profile to the director for review and consultation. Such changes may require approval if determined substantial by the director as specified by rule 3745-91-02 of the Administrative Code. Significant changes to disinfection practice include any of the following:
(a) Changes to the point of disinfection.
(b) Changes to the disinfectant used in the treatment plant.
(c) Changes to the disinfection process.
(d) Any other modification identified by the director, including those identified and proposed in a general plan required by paragraph (A)(7) of rule 3745-81-24 of the Administrative Code.
[Comment: The 40 CFR 141.172, 40 CFR 141.170(d), and 40 CFR 141.530 refer to the "Code of Federal Regulations" published on July 1, 2012. At the effective date of this rule, a copy may be obtained from the "Superintendent of Documents, PO Box 371954, Pittsburgh, PA 15250-7954," (866) 512-1800, or http://bookstore.gpo.gov. This document is available for review at "Ohio EPA, Lazarus Government Center, 50 West Town Street, Columbus, OH, 43215-3425."]
(2) The public water system shall calculate the disinfection benchmark using the following procedure:
(a) The disinfection benchmark is the lowest monthly average value (for public water systems with one year of profiling data) or average of lowest monthly average values (for public water systems with more than one year of profiling data) of the monthly logs of Giardia lamblia inactivation in each year of profiling data.
(b) For each year of profiling data collected and calculated, the public water system shall determine the lowest average monthly Giardia lamblia inactivation in each year of profiling data. The average Giardia lamblia inactivation shall be determined by dividing the sum of Giardia lamblia inactivation values by the number of values calculated for that month. For public water systems with a combined population of at least ten thousand persons, daily values shall be used. For public water systems with a combined population less than ten thousand persons, weekly values may be used. Values for each calendar month for each year of profiling data shall be used in the calculation.
(3) A public water system that uses chloramines, chlorine dioxide, or ozone for primary disinfection shall also calculate the disinfection benchmark for viruses using a method acceptable to the director.
(4) Prior to making a significant change, the public water system shall submit the following information for review by the director:
(a) A description of the proposed change.
(b) The disinfection profile for Giardia lamblia (and, if necessary, viruses) and disinfection benchmark.
(c) An analysis of how the proposed change will affect the current levels of disinfection.
(5) The public water system shall retain the disinfection profile data in graphic form, as a spreadsheet, or in some other format acceptable to the director for review as part of a sanitary survey. The disinfection profile, disinfection benchmark, and all data and analysis used to complete the disinfection profile shall be retained by the public water system indefinitely.
(E) Disinfection profiling and benchmarking requirements for any system making a significant change to the disinfection practice.
(1) Following the completion of initial source water monitoring in accordance with paragraph (A) of rule 3745-81-65 of the Administrative Code, a system that plans to make a significant change to the disinfection practice, as defined in paragraph (E)(2) of this rule, shall develop disinfection profiles and calculate disinfection benchmarks for Giardia lamblia and viruses as described in paragraphs (E)(3) to (E)(7) of this rule. Prior to changing the disinfection practice, the system shall notify the director and shall include in this notice the following information:
(a) A completed disinfection profile and disinfection benchmark for Giardia lamblia and viruses as described in paragraphs (E)(3) to (E)(7) of this rule.
(b) A description of the proposed change in disinfection practice.
(c) An analysis of how the proposed change will affect the current level of disinfection.
(2) Significant changes to disinfection practices include any of the following:
(a) Changes to the point of disinfection.
(b) Changes to the disinfectant used in the treatment plant.
(c) Changes to the disinfection process.
(d) Any other modification identified by the director as a significant change to disinfection practice.
(3) Systems required to develop disinfection profiles in accordance with paragraphs (E)(1) and (E)(2) of this rule shall monitor at least weekly for a period of twelve consecutive months to determine the total log inactivation for Giardia lamblia and viruses. If systems monitor more frequently, the monitoring frequency shall be evenly spaced. Systems that operate for fewer than twelve months per year shall monitor weekly during the period of operation. Systems shall determine log inactivation for Giardia lamblia and viruses through the entire plant, based on CT 99.9 values in tables B-1 to B-13 of this rule, as applicable. Systems shall determine log inactivation of viruses through the entire treatment plant based on a protocol accepted by the director.
(4) Systems with a single point of disinfectant application prior to the entrance to the distribution system shall conduct the monitoring in this paragraph. Systems with more than one point of disinfectant application shall conduct the monitoring in this paragraph for each disinfection segment. Systems shall monitor the parameters necessary to determine the total inactivation ratio, using analytical methods in accordance with paragraph (C) of rule 3745-81-27 of the Administrative Code.
(a) For systems using a disinfectant other than UV, the temperature of the disinfected water shall be measured at each residual disinfectant concentration sampling point during peak hourly flow or at an alternative location accepted by the director.
(b) For systems using chlorine, the pH of the disinfected water shall be measured at each chlorine residual disinfectant concentration sampling point during peak hourly flow or at an alternative location accepted by the director.
(c) The disinfectant contact time, T, shall be determined during peak hourly flow.
(d) The residual disinfectant concentration, C, of the water before or at the first customer and prior to each additional point of disinfectant application shall be measured during peak hourly flow.
(5) In lieu of conducting new monitoring under paragraph (E)(4) of this rule, systems may elect to meet the following:
(a) Systems that have at least one year of existing data that are substantially equivalent to data collected under the provisions of paragraph (E)(4) of this rule may use these data to develop disinfection profiles as specified in this rule if the system has neither made a significant change to the treatment practice nor changed sources since the data were collected. Systems may develop disinfection profiles using up to three years of existing data.
(b) Systems may use disinfection profile developed in accordance with paragraph (D) of this rule in lieu of developing a new profile if the system has neither made a significant change to the treatment practice nor changed sources since the profile was developed. Systems that have not developed a virus profile under paragraph (D) of this rule shall develop a virus profile using the same monitoring data on which the Giardia lamblia profile is based.
(6) Systems shall calculate the total inactivation ratio for Giardia lamblia as follows:
(a) Systems using only one point of disinfectant application may determine the total inactivation ratio for the disinfection segment based on either of the following:
(i) Determine one inactivation ratio (CTcalc/CT 99.9 ) before or at the first customer during peak hourly flow.
(ii) Determine successive CTcalc/CT 99.9 values, representing sequential inactivation ratios, between the point of disinfectant application and a point before or at the first customer during peak hourly flow. The system shall calculate the total inactivation ratio by determining (CTcalc/CT99.9) for each sequence and then adding the (CTcalc/CT99.9) values together to determine ([SIGMA](CTcalc/CT99.9)).
(b) Systems using more than one point of disinfectant application before the first customer shall determine the CT value of each disinfection segment immediately prior to the next point of disinfectant application, or for the final segment, before or at the first customer, during peak hourly flow. The (CTcalc/CT99.9) value of each segment and ([SIGMA] (CTcalc/CT99.9)) shall be calculated using the method in paragraph (E)(6)(a)(ii) of this rule.
(c) The system shall determine the total logs of inactivation by multiplying the value calculated in paragraph (E)(6)(a) or (E)(6)(b) of this rule by 3.0.
(d) Systems shall calculate the log of inactivation for viruses using a protocol approved by the director.
(7) Systems shall use the following procedures to calculate a disinfection benchmark:
(a) For each year of profiling data collected and calculated under paragraphs (E)(3) to (E)(6) of this rule, systems shall determine the lowest average monthly level of both Giardia lamblia and virus inactivation. Systems shall determine the average Giardia lamblia and virus inactivation for each calendar month for each year of profiling data by dividing the sum of daily or weekly Giardia lamblia and virus log inactivation by the number of values calculated for that month.
(b) The disinfection benchmark is the lowest monthly average value (for systems with one year of profiling data) or the average of the lowest monthly average values (for systems with more than one year of profiling data) of Giardia lamblia and virus log inactivation in each year of profiling data.
Table A
Minimum Requirements For Inactivation Or Removal of Cryptosporidium, Giardia Lamblia, and Viruses
Type of Filtration
Required Minimum Log Removal/Inactivation
Expected Log Removal by Filtration
Minimum Log Inactivation by Disinfection
Cryptosporidium
(Log Removal
Only)
Giardia
Viruses
Cryptosporidium
Giardia
Viruses
Giardia
Viruses
Conventional
2
3
4
2
2.5
2.0
0.5
2.0
Direct
2
3
4
2
2.0
1.0
1.0
3.0
Slow Sand
2
3
4
2
2.0
2.0
1.0
2.0
Comment: Log removal and log inactivation refer to the negative logarithm of the quotient of the concentration of an impurity after treatment divided by the concentration before treatment. For instance, a 99.9 per cent decrease in viruses has a post treatment concentration 0.001 times the pretreatment concentration and a 3 log removal designation. Common conversions include:
Removal designation
Concentration decrease
Quotient after/before
0.5 log
70%
0.3
1 log
90%
0.1
1.5 log
97%
0.03
2 log
99%
0.01
2.5 log
99.7 %
0.003
3 log
99.9 %
0.001
4 log
99.99 %
0.0001
Table B-1
Required CT For Inactivation
Of Giardia Cysts By Free Chlorine
At 0.5 ° Celsius Or Less
Chlorine Concentration (mg/L)
pH<=6
pH= 6.5
pH= 7.0
Log Inactivations
Log Inactivations
Log Inactivations
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
23
46
69
91
114
137
27
54
82
109
136
163
33
65
98
130
163
195
0.6
24
47
71
94
118
141
28
56
84
112
140
168
33
67
100
133
167
200
0.8
24
48
73
97
121
145
29
57
86
115
143
172
34
68
103
137
171
205
1
25
49
74
99
123
148
29
59
88
117
147
176
35
70
105
140
175
210
1.2
25
51
76
101
127
152
30
60
90
120
150
180
36
72
108
143
179
215
1.4
26
52
78
103
129
155
31
61
92
123
153
184
37
74
111
147
184
221
1.6
26
52
79
105
131
157
32
63
95
126
158
189
38
75
113
151
188
226
1.8
27
54
81
108
135
162
32
64
97
129
161
193
39
77
116
154
193
231
2
28
55
83
110
138
165
33
66
99
131
164
197
39
79
118
157
197
236
2.2
28
56
85
113
141
169
34
67
101
134
168
201
40
81
121
161
202
242
2.4
29
57
86
115
143
172
34
68
103
137
171
205
41
82
124
165
206
247
2.6
29
58
88
117
146
175
35
70
105
139
174
209
42
84
126
168
210
252
2.8
30
59
89
119
148
178
36
71
107
142
178
213
43
86
129
171
214
257
3
30
60
91
121
151
181
36
72
109
145
181
217
44
87
131
174
218
261
pH= 7.5
pH= 8.0
pH= 8.5
Chlorine Concentration (mg/L)
Log Inactivations
Log Inactivations
Log Inactivations
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
40
79
119
158
198
237
46
92
139
185
231
277
55
110
165
219
274
329
0.6
40
80
120
159
199
239
48
95
143
191
238
286
57
114
171
228
285
342
0.8
41
82
123
164
205
246
49
98
148
197
246
295
59
118
177
236
295
354
1
42
84
127
169
211
253
51
101
152
203
253
304
61
122
183
243
304
365
1.2
43
86
130
173
216
259
52
104
157
209
261
313
63
125
188
251
313
376
1.4
44
89
133
177
222
266
54
107
161
214
268
321
65
129
194
258
323
387
1.6
46
91
137
182
228
273
55
110
165
219
274
329
66
132
199
265
331
397
1.8
47
93
140
186
233
279
56
113
169
225
282
338
68
136
204
271
339
407
2
48
95
143
191
238
286
58
115
173
231
288
346
70
139
209
278
348
417
2.2
50
99
149
198
248
297
59
118
177
235
294
353
71
142
213
284
355
426
2.4
50
99
149
199
248
298
60
120
181
241
301
361
73
145
218
290
363
435
2.6
51
101
152
203
253
304
61
123
184
245
307
368
74
148
222
296
370
444
2.8
52
103
155
207
258
310
63
125
188
250
313
375
75
151
226
301
377
452
3
53
105
158
211
263
316
64
127
191
255
318
382
77
153
230
307
383
460
Chlorine Concentration (mg/L)
pH= 9.0 or pH> 9.0
Log Inactivations
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
65
130
195
260
325
390
0.6
68
136
204
271
339
407
0.8
70
141
211
281
352
422
1
73
146
219
291
364
437
1.2
75
150
226
301
376
451
1.4
77
155
232
309
387
464
1.6
80
159
239
318
398
477
1.8
82
163
245
326
408
489
2
83
167
250
333
417
500
2.2
85
170
256
341
426
511
2.4
87
174
261
348
435
522
2.6
89
178
267
355
444
533
2.8
91
181
272
362
453
543
3
92
184
276
368
460
552
[Comment: CT99.9 = CT for 3 log inactivation.]
Table B-2
Required CT For Inactivation Of Giardia Cysts By Free Chlorine At 5° Celsius
pH<=6
pH= 6.5
pH= 7.0
Chlorine
Log Inactivations
Log Inactivations
Log Inactivations
(mg/L)
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
16
32
49
65
81
97
20
39
59
78
98
117
23
46
70
93
116
139
0.6
17
33
50
67
83
100
20
40
60
80
100
120
24
48
72
95
119
143
0.8
17
34
52
69
86
103
20
41
61
81
102
122
24
49
73
97
122
146
1
18
35
53
70
88
105
21
42
63
83
104
125
25
50
75
99
124
149
1.2
18
36
54
71
89
107
21
42
64
85
106
127
25
51
76
101
127
152
1.4
18
36
55
73
91
109
22
43
65
87
108
130
26
52
78
103
129
155
1.6
19
37
56
74
93
111
22
44
66
88
110
132
26
53
79
105
132
158
1.8
19
38
57
76
95
114
23
45
68
90
113
135
27
54
81
108
135
162
2
19
39
58
77
97
116
23
46
69
92
115
138
28
55
83
110
138
165
2.2
20
39
59
79
98
118
23
47
70
93
117
140
28
56
85
113
141
169
2.4
20
40
60
80
100
120
24
48
72
95
119
143
29
57
86
115
143
172
2.6
20
41
61
81
102
122
24
49
73
97
122
146
29
58
88
117
146
175
2.8
21
41
62
83
103
124
25
49
74
99
123
148
30
59
89
119
148
178
3
21
42
63
84
105
126
25
50
76
101
126
151
30
61
91
121
152
182
pH= 7.5
pH= 8.0
pH= 8.5
Chlorine
Log Inactivations
Log Inactivations
Log Inactivations
(mg/L)
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
28
55
83
111
138
166
33
66
99
132
165
198
39
79
118
157
197
236
0.6
29
57
86
114
143
171
34
68
102
136
170
204
41
81
122
163
203
244
0.8
29
58
88
117
146
175
35
70
105
140
175
210
42
84
126
168
210
252
1
30
60
90
119
149
179
36
72
108
144
180
216
43
87
130
173
217
260
1.2
31
61
92
122
153
183
37
74
111
147
184
221
45
89
134
178
223
267
1.4
31
62
94
125
156
187
38
76
114
151
189
227
46
91
137
183
228
274
1.6
32
64
96
128
160
192
39
77
116
155
193
232
47
94
141
187
234
281
1.8
33
65
98
131
163
196
40
79
119
159
198
238
48
96
144
191
239
287
2
33
67
100
133
167
200
41
81
122
162
203
243
49
98
147
196
245
294
2.2
34
68
102
136
170
204
41
83
124
165
207
248
50
100
150
200
250
300
2.4
35
70
105
139
174
209
42
84
127
169
211
253
51
102
153
204
255
306
2.6
36
71
107
142
178
213
43
86
129
172
215
258
52
104
156
208
260
312
2.8
36
72
109
145
181
217
44
88
132
175
219
263
53
106
159
212
265
318
3
37
74
111
147
184
221
45
89
134
179
223
268
54
108
162
216
270
324
pH= 9.0 or pH> 9.0
Chlorine
Log Inactivations
(mg/L)
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
47
93
140
186
233
279
0.6
49
97
146
194
243
291
0.8
50
100
151
201
251
301
1
52
104
156
208
260
312
1.2
53
107
160
213
267
320
1.4
55
110
165
219
274
329
1.6
56
112
169
225
281
337
1.8
58
115
173
230
288
345
2
59
118
177
235
294
353
2.2
60
120
181
241
301
361
2.4
61
123
184
245
307
368
2.6
63
125
188
250
313
375
2.8
64
127
191
255
318
382
3
65
130
195
259
324
389
[Comment: CT99.9 = CT for 3 log inactivation.]
Table B-3
Required CT For Inactivation Of Giardia Cysts By Free Chlorine At 10° Celsius
pH<=6
pH= 6.5
pH= 7.0
Chlorine Concentration (mg/L)
Log Inactivations
Log Inactivations
Log Inactivations
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
12
24
37
49
61
73
15
29
44
59
73
88
17
35
52
69
87
104
0.6
13
25
38
50
63
75
15
30
45
60
75
90
18
36
54
71
89
107
0.8
13
26
39
52
65
78
15
31
46
61
77
92
18
37
55
73
92
110
1
13
26
40
53
66
79
16
31
47
63
78
94
19
37
56
75
93
112
1.2
13
27
40
53
67
80
16
32
48
63
79
95
19
38
57
76
95
114
1.4
14
27
41
55
68
82
16
33
49
65
82
98
19
39
58
77
97
116
1.6
14
28
42
55
69
83
17
33
50
66
83
99
20
40
60
79
99
119
1.8
14
29
43
57
72
86
17
34
51
67
84
101
20
41
61
81
102
122
2
15
29
44
58
73
87
17
35
52
69
87
104
21
41
62
83
103
124
2.2
15
30
45
59
74
89
18
35
53
70
88
105
21
42
64
85
106
127
2.4
15
30
45
60
75
90
18
36
54
71
89
107
22
43
65
86
108
129
2.6
15
31
46
61
77
92
18
37
55
73
92
110
22
44
66
87
109
131
2.8
16
31
47
62
78
93
19
37
56
74
93
111
22
45
67
89
112
134
3
16
32
48
63
79
95
19
38
57
75
94
113
23
46
69
91
114
137
pH= 7.5
pH= 8.0
pH= 8.5
Chlorine Concentration (mg/L)
Log Inactivations
Log Inactivations
Log Inactivations
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
21
42
63
83
104
125
25
50
75
99
124
149
30
59
89
118
148
177
0.6
21
43
64
85
107
128
26
51
77
102
128
153
31
61
92
122
153
183
0.8
22
44
66
87
109
131
26
53
79
105
132
158
32
63
95
126
158
189
1
22
45
67
89
112
134
27
54
81
108
135
162
33
65
98
130
163
195
1.2
23
46
69
91
114
137
28
55
83
111
138
166
33
67
100
133
167
200
1.4
23
47
70
93
117
140
28
57
85
113
142
170
34
69
103
137
172
206
1.6
24
48
72
96
120
144
29
58
87
116
145
174
35
70
106
141
176
211
1.8
25
49
74
98
123
147
30
60
90
119
149
179
36
72
108
143
179
215
2
25
50
75
100
125
150
30
61
91
121
152
182
37
74
111
147
184
221
2.2
26
51
77
102
128
153
31
62
93
124
155
186
38
75
113
150
188
225
2.4
26
52
79
105
131
157
32
63
95
127
158
190
38
77
115
153
192
230
2.6
27
53
80
107
133
160
32
65
97
129
162
194
39
78
117
156
195
234
2.8
27
54
82
109
136
163
33
66
99
131
164
197
40
80
120
159
199
239
3
28
55
83
111
138
166
34
67
101
134
168
201
41
81
122
162
203
243
pH= 9.0 or pH> 9.0
Chlorine
Concentration
(mg/L)
Log Inactivations
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
35
70
105
139
174
209
0.6
36
73
109
145
182
218
0.8
38
75
113
151
188
226
1
39
78
117
156
195
234
1.2
40
80
120
160
200
240
1.4
41
82
124
165
206
247
1.6
42
84
127
169
211
253
1.8
43
86
130
173
216
259
2
44
88
133
177
221
265
2.2
45
90
136
181
226
271
2.4
46
92
138
184
230
276
2.6
47
94
141
187
234
281
2.8
48
96
144
191
239
287
3
49
97
146
195
243
292
[Comment: CT99.9 = CT for 3 log inactivation.]
Table B-4
Required CT For Inactivation Of Giardia Cysts By Free Chlorine At 15° Celsius
pH<=6
pH= 6.5
pH= 7.0
Chlorine Concentration (mg/L)
Log Inactivations
Log Inactivations
Log Inactivations
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
8
16
25
33
41
49
10
20
30
39
49
59
12
23
35
47
58
70
0.6
8
17
25
33
42
50
10
20
30
40
50
60
12
24
36
48
60
72
0.8
9
17
26
35
43
52
10
20
31
41
51
61
12
24
37
49
61
73
1
9
18
27
35
44
53
11
21
32
42
53
63
13
25
38
50
63
75
1.2
9
18
27
36
45
54
11
21
32
43
53
64
13
25
38
51
63
76
1.4
9
18
28
37
46
55
11
22
33
43
54
65
13
26
39
52
65
78
1.6
9
19
28
37
47
56
11
22
33
44
55
66
13
26
40
53
66
79
1.8
10
19
29
38
48
57
11
23
34
45
57
68
14
27
41
54
68
81
2
10
19
29
39
48
58
12
23
35
46
58
69
14
28
42
55
69
83
2.2
10
20
30
39
49
59
12
23
35
47
58
70
14
28
43
57
71
85
2.4
10
20
30
40
50
60
12
24
36
48
60
72
14
29
43
57
72
86
2.6
10
20
31
41
51
61
12
24
37
49
61
73
15
29
44
59
73
88
2.8
10
21
31
41
52
62
12
25
37
49
62
74
15
30
45
59
74
89
3
11
21
32
42
53
63
13
25
38
51
63
76
15
30
46
61
76
91
pH= 7.5
pH= 8.0
pH= 8.5
Chlorine Concentration (mg/L)
Log Inactivations
Log Inactivations
Log Inactivations
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
14
28
42
55
69
83
17
33
50
66
83
99
20
39
59
79
98
118
0.6
14
29
43
57
72
86
17
34
51
68
85
102
20
41
61
81
102
122
0.8
15
29
44
59
73
88
18
35
53
70
88
105
21
42
63
84
105
126
1
15
30
45
60
75
90
18
36
54
72
90
108
22
43
65
87
108
130
1.2
15
31
46
61
77
92
19
37
56
74
93
111
22
45
67
89
112
134
1.4
16
31
47
63
78
94
19
38
57
76
95
114
23
46
69
91
114
137
1.6
16
32
48
64
80
96
19
39
58
77
97
116
24
47
71
94
118
141
1.8
16
33
49
65
82
98
20
40
60
79
99
119
24
48
72
96
120
144
2
17
33
50
67
83
100
20
41
61
81
102
122
25
49
74
98
123
147
2.2
17
34
51
68
85
102
21
41
62
83
103
124
25
50
75
100
125
150
2.4
18
35
53
70
88
105
21
42
64
85
106
127
26
51
77
102
128
153
2.6
18
36
54
71
89
107
22
43
65
86
108
129
26
52
78
104
130
156
2.8
18
36
55
73
91
109
22
44
66
88
110
132
27
53
80
106
133
159
3
19
37
56
74
93
111
22
45
67
89
112
134
27
54
81
108
135
162
pH= 9.0 or pH> 9.0
Chlorine
Concentration
(mg/L)
Log Inactivations
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
23
47
70
93
117
140
0.6
24
49
73
97
122
146
0.8
25
50
76
101
126
151
1
26
52
78
104
130
156
1.2
27
53
80
107
133
160
1.4
28
55
83
110
138
165
1.6
28
56
85
113
141
169
1.8
29
58
87
115
144
173
2
30
59
89
118
148
177
2.2
30
60
91
121
151
181
2.4
31
61
92
123
153
184
2.6
31
63
94
125
157
188
2.8
32
64
96
127
159
191
3
33
65
98
130
163
195
[Comment: CT99.9 = CT for 3 log inactivation.]
Table B-5
Required CT For Inactivation Of Giardia Cysts By Free Chlorine At 20° Celsius
pH<=6
pH= 6.5
pH= 7.0
Chlorine Concentration (mg/L)
Log Inactivations
Log Inactivations
Log Inactivations
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
6
12
18
24
30
36
7
15
22
29
37
44
9
17
26
35
43
52
0.6
6
13
19
25
32
38
8
15
23
30
38
45
9
18
27
36
45
54
0.8
7
13
20
26
33
39
8
15
23
31
38
46
9
18
28
37
46
55
1
7
13
20
26
33
39
8
16
24
31
39
47
9
19
28
37
47
56
1.2
7
13
20
27
33
40
8
16
24
32
40
48
10
19
29
38
48
57
1.4
7
14
21
27
34
41
8
16
25
33
41
49
10
19
29
39
48
58
1.6
7
14
21
28
35
42
8
17
25
33
42
50
10
20
30
39
49
59
1.8
7
14
22
29
36
43
9
17
26
34
43
51
10
20
31
41
51
61
2
7
15
22
29
37
44
9
17
26
35
43
52
10
21
31
41
52
62
2.2
7
15
22
29
37
44
9
18
27
35
44
53
11
21
32
42
53
63
2.4
8
15
23
30
38
45
9
18
27
36
45
54
11
22
33
43
54
65
2.6
8
15
23
31
38
46
9
18
28
37
46
55
11
22
33
44
55
66
2.8
8
16
24
31
39
47
9
19
28
37
47
56
11
22
34
45
56
67
3
8
16
24
31
39
47
10
19
29
38
48
57
11
23
34
45
57
68
pH= 7.5
pH= 8.0
pH= 8.5
Chlorine Concentration (mg/L)
Log Inactivations
Log Inactivations
Log Inactivations
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
10
21
31
41
52
62
12
25
37
49
62
74
15
30
45
59
74
89
0.6
11
21
32
43
53
64
13
26
39
51
64
77
15
31
46
61
77
92
0.8
11
22
33
44
55
66
13
26
40
53
66
79
16
32
48
63
79
95
1
11
22
34
45
56
67
14
27
41
54
68
81
16
33
49
65
82
98
1.2
12
23
35
46
58
69
14
28
42
55
69
83
17
33
50
67
83
100
1.4
12
23
35
47
58
70
14
28
43
57
71
85
17
34
52
69
86
103
1.6
12
24
36
48
60
72
15
29
44
58
73
87
18
35
53
70
88
105
1.8
12
25
37
49
62
74
15
30
45
59
74
89
18
36
54
72
90
108
2
13
25
38
50
63
75
15
30
46
61
76
91
18
37
55
73
92
110
2.2
13
26
39
51
64
77
16
31
47
62
78
93
19
38
57
75
94
113
2.4
13
26
39
52
65
78
16
32
48
63
79
95
19
38
58
77
96
115
2.6
13
27
40
53
67
80
16
32
49
65
81
97
20
39
59
78
98
117
2.8
14
27
41
54
68
81
17
33
50
66
83
99
20
40
60
79
99
119
3
14
28
42
55
69
83
17
34
51
67
84
101
20
41
61
81
102
122
pH= 9.0 or pH> 9.0
Chlorine
Concentration
(mg/L)
Log Inactivations
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
18
35
53
70
88
105
0.6
18
36
55
73
91
109
0.8
19
38
57
75
94
113
1
20
39
59
78
98
117
1.2
20
40
60
80
100
120
1.4
21
41
62
82
103
123
1.6
21
42
63
84
105
126
1.8
22
43
65
86
108
129
2
22
44
66
88
110
132
2.2
23
45
68
90
113
135
2.4
23
46
69
92
115
138
2.6
24
47
71
94
118
141
2.8
24
48
72
95
119
143
3
24
49
73
97
122
146
[Comment: CT99.9 = CT for 3 log inactivation.]
Table B-6
Required CT For Inactivation Of Giardia Cysts By Free Chlorine At 25° Celsius And Greater
pH<=6
pH= 6.5
pH= 7.0
Chlorine
Log Inactivations
Log Inactivations
Log Inactivations
(mg/L)
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
4
8
12
16
20
24
5
10
15
19
24
29
6
12
18
23
29
35
0.6
4
8
13
17
21
25
5
10
15
20
25
30
6
12
18
24
30
36
0.8
4
9
13
17
22
26
5
10
16
21
26
31
6
12
19
25
31
37
1
4
9
13
17
22
26
5
10
16
21
26
31
6
12
19
25
31
37
1.2
5
9
14
18
23
27
5
11
16
21
27
32
6
13
19
25
32
38
1.4
5
9
14
18
23
27
6
11
17
22
28
33
7
13
20
26
33
39
1.6
5
9
14
19
23
28
6
11
17
22
28
33
7
13
20
27
33
40
1.8
5
10
15
19
24
29
6
11
17
23
28
34
7
14
21
27
34
41
2
5
10
15
19
24
29
6
12
18
23
29
35
7
14
21
27
34
41
2.2
5
10
15
20
25
30
6
12
18
23
29
35
7
14
21
28
35
42
2.4
5
10
15
20
25
30
6
12
18
24
30
36
7
14
22
29
36
43
2.6
5
10
16
21
26
31
6
12
19
25
31
37
7
15
22
29
37
44
2.8
5
10
16
21
26
31
6
12
19
25
31
37
8
15
23
30
38
45
3
5
11
16
21
27
32
6
13
19
25
32
38
8
15
23
31
38
46
pH= 7.5
pH= 8.0
pH= 8.5
Chlorine
Log Inactivations
Log Inactivations
Log Inactivations
(mg/L)
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
7
14
21
28
35
42
8
17
25
33
42
50
10
20
30
39
49
59
0.6
7
14
22
29
36
43
9
17
26
34
43
51
10
20
31
41
51
61
0.8
7
15
22
29
37
44
9
18
27
35
44
53
11
21
32
42
53
63
1
8
15
23
30
38
45
9
18
27
36
45
54
11
22
33
43
54
65
1.2
8
15
23
31
38
46
9
18
28
37
46
55
11
22
34
45
56
67
1.4
8
16
24
31
39
47
10
19
29
38
48
57
12
23
35
46
58
69
1.6
8
16
24
32
40
48
10
19
29
39
48
58
12
23
35
47
58
70
1.8
8
16
25
33
41
49
10
20
30
40
50
60
12
24
36
48
60
72
2
8
17
25
33
42
50
10
20
31
41
51
61
12
25
37
49
62
74
2.2
9
17
26
34
43
51
10
21
31
41
52
62
13
25
38
50
63
75
2.4
9
17
26
35
43
52
11
21
32
42
53
63
13
26
39
51
64
77
2.6
9
18
27
35
44
53
11
22
33
43
54
65
13
26
39
52
65
78
2.8
9
18
27
36
45
54
11
22
33
44
55
66
13
27
40
53
67
80
3
9
18
28
37
46
55
11
22
34
45
56
67
14
27
41
54
68
81
pH= 9.0 or pH> 9.0
Chlorine
Concentration
(mg/L)
Log Inactivations
0.5
1.0
1.5
2.0
2.5
3.0
<= 0.4
12
23
35
47
58
70
0.6
12
24
37
49
61
73
0.8
13
25
38
50
63
75
1
13
26
39
52
65
78
1.2
13
27
40
53
67
80
1.4
14
27
41
55
68
82
1.6
14
28
42
56
70
84
1.8
14
29
43
57
72
86
2
15
29
44
59
73
88
2.2
15
30
45
60
75
90
2.4
15
31
46
61
77
92
2.6
16
31
47
63
78
94
2.8
16
32
48
64
80
96
3
16
32
49
65
81
97
[Comment: CT99.9 = CT for 3 log inactivation.]
Table B-7
Required CT For Inactivation of Viruses by Free Chlorine
····························· Log Inactivation ·····························
2.0 Log
3.0 Log
4.0 Log
Temperature (Celsius)
pH 6-9
pH 10
pH 6-9
pH 10
pH 6-9
pH 10
0.5
6
45
9
66
12
90
5
4
30
6
44
8
60
10
3
22
4
33
6
45
15
2
15
3
22
4
30
20
1
11
2
16
3
22
25
1
7
1
11
2
15
Table B-8
CT Values for Inactivation of Giardia Cysts by Chlorine Dioxide pH 6-9
···························· Temperature (Celsius) ···························
Log Inactivation
<=1
5
10
15
20
>=25
0.5
10
4.3
4
3.2
2.5
2
1
21
8.7
7.7
6.3
5
3.7
1.5
32
13
12
10
7.5
5.5
2
42
17
15
13
10
7.3
2.5
52
22
19
16
13
9
3
63
26
23
19
15
11
Table B-9
CT Values for Inactivation of Viruses
By Chlorine Dioxide pH 6-9
··························· Temperature (Celsius) ····························
Log Inactivation
<=1
5
10
15
20
>=25
2
8.4
5.6
4.2
2.8
2.1
1.4
3
25.6
17.1
12.8
8.6
6.4
4.3
4
50.1
33.4
25.1
16.7
12.5
8.4
Table B-10
CT Values for Inactivation of Giardia Cysts
By Ozone pH 6-9
·························· Temperature (Celsius) ····························
Log Inactivation
<=1
5
10
15
20
>=25
0.5
0.48
0.32
0.23
0.16
0.12
0.08
1
0.97
0.63
0.48
0.32
0.24
0.16
1.5
1.5
0.95
0.72
0.48
0.36
0.24
2
1.9
1.3
0.95
0.63
0.48
0.32
2.5
2.4
1.6
1.2
0.79
0.60
0.40
3
2.9
1.9
0.95
0.72
0.48
Table B-11
CT Values for Inactivation of Viruses by Ozone
·························· Temperature (Celsius) ·······················
Log Inactivation
<=1
5
10
15
20
>=
2
0.9
0.6
0.5
0.3
0.25
0.15
3
1.4
0.9
0.8
0.5
0.4
0.25
4
1.8
1.2
1.0
0.6
0.5
0.3
Table B-12
Required CT Values for Inactivation of Giardia Cysts by Chloramine, pH 6.0 - 9.0
Temperature (Celsius)
Log Inactivation
<=1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
0.5
635
568
500
433
365
354
343
332
321
310
298
286
274
262
250
237
224
211
198
185
173
161
149
137
125
1
1270
1136
1003
869
735
711
687
663
639
615
592
569
546
523
500
474
448
422
396
370
346
322
298
274
250
1.5
1900
1700
1500
1300
1100
1066
1032
998
964
930
894
858
822
786
750
710
670
630
590
550
515
480
445
410
375
2
2535
2269
2003
1736
1470
1422
1374
1326
1278
1230
1184
1138
1092
1046
1000
947
894
841
788
735
688
641
594
547
500
2.5
3170
2835
2500
2165
1830
1772
1714
1656
1598
1540
1482
1424
1366
1308
1250
1183
1116
1049
982
915
857
799
741
683
625
3
3800
3400
3000
2600
2200
2130
2060
1990
1920
1850
1780
1710
1640
1570
1500
1420
1340
1260
1180
1100
1030
960
890
820
750
Table B-13
Required CT for Inactivation of Viruses by Chloramine
Temperature (Celsius)
Log Inactivation
<=1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
2
1243
1147
1050
954
857
814
771
729
686
643
600
557
514
471
428
407
385
364
342
321
300
278
257
235
214
3
2063
1903
1743
1583
1423
1352
1281
1209
1138
1067
996
925
854
783
712
676
641
605
570
534
498
463
427
392
356
4
2883
2659
2436
2212
1988
1889
1789
1690
1590
1491
1392
1292
1193
1093
994
944
895
845
796
746
696
646
597
547
497
These required CT may be assumed to achieve greater than 99.99 per cent inactivation of viruses only if chlorine is added and mixed in the water prior to the addition of ammonia. If this condition is not met, the public water system must demonstrate, based on onsite studies or other information, as approved by the director, that the public water system is achieving at least 99.99 per cent inactivation of viruses.
