R 325.10611m Enhanced treatment for Cryptosporidium; microbial toolbox; inactivation toolbox components.

Rule 611m. (1) Calculation of CT values is an inactivation toolbox component. All of the following apply to CT calculation of subpart H supplies that are subject to R 325.10611d: (a) CT is the product of the disinfectant contact time (T, in minutes) and disinfectant concentration (C, in milligrams per liter). Subpart H supplies with treatment credit for chlorine dioxide or ozone under subrule (2) or (3) of this rule shall calculate CT at least once each day, with both C and T measured during peak hourly flow as specified in R 325.10605. (b) Subpart H supplies with several disinfection segments in sequence may calculate CT for each segment, where a disinfection segment is defined as a treatment unit process with a measurable disinfectant residual level and a liquid volume. Under this approach, supplies shall add the Cryptosporidium CT values in each segment to determine the total CT for the treatment plant. (2) CT values for chlorine dioxide and ozone is an inactivation toolbox component. Both of the following apply to CT values: (a) Subpart H supplies receive the Cryptosporidium treatment credit listed in the following table by meeting the corresponding chlorine dioxide CT value for the applicable water temperature, as described in subrule (1) of this rule: CT Values in milligram-minutes per liter (mg-min/L) for Cryptosporidium Inactivation by Chlorine Dioxide * Log credit Water Temperature, in degrees Celsius less than or equal to 0.5 1 2 3 5 7 10 15 20 25 30 (i) 0.25 159 153 140 128 107 90 69 45 29 19 12 (ii) 0.5 319 305 279 256 214 180 138 89 58 38 24 (iii) 1.0 637 610 558 511 429 360 277 179 116 75 49 (iv) 1.5 956 915 838 767 643 539 415 268 174 113 73 (v) 2.0 1275 1220 1117 1023 858 719 553 357 232 150 98 Log credit Water Temperature, in degrees Celsius less than or equal to 0.5 1 2 3 5 7 10 15 20 25 30 (vi) 2.5 1594 1525 1396 1278 1072 899 691 447 289 188 122 (vii) 3.0 1912 1830 1675 1534 1286 1079 830 536 347 226 147 * Supplies may use this equation to determine log credit between the indicated values: Log credit = (0.001506 x (1.09116)Temp) x CT. (b) Subpart H supplies receive the Cryptosporidium treatment credit listed in the following table by meeting the corresponding ozone CT values for the applicable water temperature, as described in subrule (1) of this rule: CT Values in milligram-minutes per liter (mg-min/L) for Cryptosporidium Inactivation by Ozone * Log credit Water Temperature, in degrees Celsius less than or equal to 0.5 1 2 3 5 7 10 15 20 25 30 (i) 0.25 6.0 5.8 5.2 4.8 4.0 3.3 2.5 1.6 1.0 0.6 0.39 (ii) 0.5 12 12 10 9.5 7.9 6.5 4.9 3.1 2.0 1.2 0.78 (iii) 1.0 24 23 21 19 16 13 9.9 6.2 3.9 2.5 1.6 (iv) 1.5 36 35 31 29 24 20 15 9.3 5.9 3.7 2.4 (v) 2.0 48 46 42 38 32 26 20 12 7.8 4.9 3.1 (vi) 2.5 60 58 52 48 40 33 25 16 9.8 6.2 3.9 (vii) 3.0 72 69 63 57 47 39 30 19 12 7.4 4.7 * Supplies may use this equation to determine log credit between the indicated values: Log credit = (0.0397 x (1.09757)Temp) x CT. (3) Site-specific study is an inactivation toolbox component. The department may approve alternative chlorine dioxide or ozone CT values to those listed in subrule (2) of this rule on a site-specific basis. The department shall base this approval on a site-specific study a subpart H supply conducts that follows a department-approved protocol. (4) Ultraviolet light is an inactivation toolbox component. Subpart H supplies receive Cryptosporidium, Giardia lamblia, and virus treatment credits for ultraviolet (UV) light reactors by achieving the corresponding UV dose values shown in subdivision (a) of this subrule. Supplies shall validate and monitor UV reactors as described in subdivisions (b) and (c) of this subrule to demonstrate that they are achieving a particular UV dose value for treatment credit. All of the following apply to UV: (a) The following table is the UV dose table. The treatment credits listed in this table are for UV light at a wavelength of 254 nanometers as produced by a low pressure mercury vapor lamp. To receive treatment credit for other lamp types, subpart H supplies shall demonstrate an equivalent germicidal dose through reactor validation testing, as described in subdivision (b) of this subrule. The UV dose values in this table are applicable only to post-filter applications of UV in supplies. UV Dose Table for Cryptosporidium, Giardia lamblia, and Virus Inactivation Credit Log credit Cryptosporidium UV dose in milli-joule per centimeters squared (mJ/ cm2) Giardia lamblia UV dose (mJ/cm2) Virus UV dose (mJ/cm 2) (i) 0.5 1.6 1.5 39 (ii) 1.0 2.5 2.1 58 (iii) 1.5 3.9 3.0 79 (iv) 2.0 5.8 5.2 100 (v) 2.5 8.5 7.7 121 (vi) 3.0 12 11 143 (vii) 3.5 15 15 163 (viii) 4.0 22 22 186 (b) Subpart H supplies shall use UV reactors that have undergone validation testing to determine the operating conditions under which the reactor delivers the UV dose required in subdivision (a) of this subrule, that is, validated operating conditions. These operating conditions shall include flow rate, UV intensity as measured by a UV sensor, and UV lamp status. All of the following provisions apply to reactor validation testing: (i) When determining validated operating conditions, supplies shall account for all of the following factors: (A) UV absorbance of the water; lamp fouling and aging. (B) Measurement uncertainty of on-line sensors. (C) UV dose distributions arising from the velocity profiles through the reactor. (D) Failure of UV lamps or other critical system components. (E) Inlet and outlet piping or channel configurations of the UV reactor. (ii) Validation testing shall include both of the following: (A) Full scale testing of a reactor that conforms uniformly to the UV reactors used by the supply. (B) Inactivation of a test microorganism whose dose response characteristics have been quantified with a low pressure mercury vapor lamp. (iii) The department may approve an alternative approach to validation testing. (c) Both of the following provisions apply to reactor monitoring: (i) Supplies shall monitor their UV reactors to determine if the reactors are operating within validated conditions, as determined under subdivision (b) of this subrule. This monitoring shall include UV intensity as measured by a UV sensor, flow rate, lamp status, and other parameters the department designates based on UV reactor operation. Supplies shall verify the calibration of UV sensors and shall recalibrate sensors under a protocol the department approves. (ii) To receive treatment credit for UV light, supplies shall treat not less than 95% of the water delivered to the public during each month by UV reactors operating within validated conditions for the required UV dose, as described in subdivisions (a) and (b) of this subrule. Supplies shall demonstrate compliance with this condition by the monitoring required under paragraph (i) of this subdivision.