3745-81-72 Disinfection of water from surface water sources.

"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, 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. 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 paragraph (N) of rule 3745-81-68 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 it 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, which ever 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 its 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 its 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; and

(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 its 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; and

(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 their 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 its 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; or

(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 CT99.9 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(s), T, shall be determined during peak hourly flow.

(d) The residual disinfectant concentration(s), 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 requirements of paragraph (E)(5)(a) or (E)(5)(b) of this rule.

(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(s) 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 specified in paragraphs (E)(6)(a) to (E)(6)(c) of this rule.

(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/CT99.9) before or at the first customer during peak hourly flow.

(ii) Determine successive CTcalc/CT99.9 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 ([SIGAM] (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 ([SIGAM] (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

  

pH<=6 ..............................................................

pH= 6.5 ................................................................

pH= 7.0 ................................................................

Chlorine Concentration

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

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

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

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

  

pH= 9.0 or pH> 9.0 ..............................................................

Chlorine Concentration

Log Inactivations .............................................................

(mg/L)

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 Concentrati

Log Inactivations on .............................................................

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 Concentrati

Log Inactivations on .............................................................

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 Concentration

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 Concentrati

Log Inactivations on

.............................................................

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

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 Concentrati

Log Inactivations on .............................................................

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

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 Concentrati

Log Inactivations on .............................................................

(mg/L)

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 Concentrati

Log Inactivations on .............................................................

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

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 Concentrati

Log Inactivations on .............................................................

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

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 Concentrati

Log Inactivations on .............................................................

(mg/L)

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 Concentrati

Log Inactivations on .............................................................

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

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 Concentrati

Log Inactivations on .............................................................

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

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 Concentrati

Log Inactivations .............................................................

(mg/L)

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 Concentrati

Log Inactivations on .............................................................

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 Concentrati

Log Inactivations on .............................................................

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 Concentrati

Log Inactivations .............................................................

(mg/L)

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

1.43

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

>=25

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 Chloramine1

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

1These 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.

image: oh/admin/2014/3745-81-72_PH_FF_A_RU_20130925_1030-1.jpg

Click to view Appendix

Effective: 10/05/2013
R.C. 119.032 review dates: 07/16/2013 and 10/05/2018
Promulgated Under: 119.03
Statutory Authority: 6109.04
Rule Amplifies: 6109.03 , 6109.04
Prior Effective Dates: 01/01/05, 01/08/10, 10/31/10