HAR §11-20-46.1. average ≥ 0

048 mg/L during the period identified in subparagraphs (A) and (B) must comply with paragraph (2). (2) Disinfection profiling. (A) Any system that meets the criteria in paragraph (1)(F) must develop a disinfection profile of its disinfection practice for a period of up to three years. (B) The system must monitor daily for a period of twelve consecutive calendar months to determine the total logs of inactivation for each day of operation, based on the CT99.9 values in Tables E-1 thru E-6, E-8, E-10, and E-12 of the Hawaii Surface Water Treatment Rule Administrative Manual, as appropriate, through the entire treatment plant. Public water systems with a surface water source or GWUDI source serving at least 10,000 people, must begin this monitoring not later than April 1, 2000. For a public water system with a surface water source or GWUDI source serving fewer than 10,000 people, monitoring must begin no later than July 1, 2003. New or substantially modified systems, as defined under sections 11-20-29 and 11-20-30 respectively, applying after April 1, 2000 shall begin monitoring not later than a date determined by the director. As a minimum, the system with a single point of disinfectant application prior to entrance to the distribution system must conduct the monitoring specified in this subparagraph. A system with more than one point of disinfectant application must conduct the monitoring in this subparagraph for each disinfection segment. The system must monitor the parameters necessary to 20-247 3376 §11-20-46.1 determine the total inactivation ratio, using analytical methods in section 11- 20-46(d)(1), as follows: (i) The temperature of the disinfected water must be measured once per day at each residual disinfectant concentration sampling point during peak hourly flow. (ii) If the system uses chlorine, the pH of the disinfected water must be measured once per day at each chlorine residual disinfectant concentration sampling point during peak hourly flow. (iii) The disinfectant contact time(s) ("T") must be determined for each day during peak hourly flow. (iv) The residual disinfectant concentration(s) ("C") of the water before or at the first customer and prior to each additional point of disinfection must be measured each day during peak hourly flow. (C) In lieu of the monitoring conducted under the provisions of subparagraph (B) to develop the disinfection profile, the system may elect to meet the requirements of clause (i). In addition to the monitoring conducted under the provisions of subparagraph (B) to develop the disinfection profile, the system may elect to meet the requirements of clause (ii). (i) A PWS that has three years of existing operational data may submit those data, a profile generated using those data, and a request that the director approve use of those data in lieu of monitoring under the provisions of subparagraph (B) not later than 20-248 3376 §11-20-46.1 March 31, 2000 for a public water system with a surface water source or GWUDI source serving at least 10,000 people, and July 1, 2003 for a public water system with a surface water source or GWUDI source serving fewer than 10,000 people. The director must determine whether these operational data are substantially equivalent to data collected under the provisions of subparagraph (B). These data must also be representative of Giardia lamblia inactivation through the entire treatment plant and not just of certain treatment segments. Until the director approves this request, the system is required to conduct monitoring under the provisions of subparagraph (B). (ii) In addition to the disinfection profile generated under subparagraph (B), a PWS that has existing operational data may use those data to develop a disinfection profile for additional years. Such systems may use these additional yearly disinfection profiles to develop a benchmark under the provisions of paragraph (3). The director must determine whether these operational data are substantially equivalent to data collected under the provisions of subparagraph (B). These data must also be representative of inactivation through the entire treatment plant and not just of certain treatment segments. 20-249 3376 §11-20-46.1 (D) The system must calculate the total inactivation ratio as follows: (i) If the system uses only one point of disinfectant application, the system may determine the total inactivation ratio for the disinfection segment based on either: determining one inactivation ratio (CTcalc/CT99.9) before or at the first customer during peak hourly flow, or determining 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. Under this alternative, the system must calculate the total inactivation ratio by determining (CTcalc/CT99.9) for each sequence and then adding the (CTcalc/CT99.9) values together to determine Σ(CTcalc/CT99.9). (ii) If the system uses more than one point of disinfectant application before the first customer, the system must 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 Σ(CTcalc/CT99.9) must be calculated using the method in clause (i). (iii) The system must determine the total logs of inactivation by multiplying the value calculated in clause (i) or (ii) by 3.0. 20-250 3376 §11-20-46.1 (E) A system that uses either chlorine dioxide, chloramines, or ozone for primary disinfection must also calculate the logs of inactivation for viruses and develop an additional disinfection profile for viruses using a method approved by the State. (F) The system must retain disinfection profile data in graphic form, as a spreadsheet, or in some other format acceptable to the director for review as part of sanitary surveys conducted by the State. (3) Disinfection benchmarking. (A) Any system required to develop a disinfection profile under the provisions of paragraphs (1) and (2) and that decides to make a significant change to its disinfection practice must consult with the director prior to making such change. Significant changes to disinfection practice are: (i) Changes to the point of disinfection; (ii) Changes to the disinfectant(s) used in the treatment plant; (iii) Changes to the disinfection process; and (iv) Any other modification identified by the State. (B) Any system that is modifying its disinfection practice must calculate its disinfection benchmark using the procedure specified in this subparagraph. (i) For each year of profiling data collected and calculated under paragraph (2), the system must determine the lowest average monthly Giardia lamblia inactivation in each year of profiling data. The system must 20-251 3376 §11-20-46.1 determine the average Giardia lamblia inactivation for each calendar month for each year of profiling data by dividing the sum of daily Giardia lamblia of inactivation by the number of values calculated for that month. (ii) The disinfection benchmark is the lowest monthly average value (for systems with one year of profiling data) or average of lowest monthly average values (for systems with more than one year of profiling data) of the monthly logs of Giardia lamblia inactivation in each year of profiling data. (C) A system that uses either chlorine dioxide, chloramines, or ozone for primary disinfection must also calculate the disinfection benchmark for viruses using a method approved by the State. (D) As part of its consultation process with the director, the system must submit the following information: (i) A description of the proposed change, including why the change is being proposed, a summary of alternatives considered with positive and negative impacts, and a final analysis of the selected alternative; (ii) The disinfection profile for Giardia lamblia (and, if necessary, viruses) under paragraph (2) and benchmark as required by paragraph (3)(B); (iii) An analysis of how the proposed change will affect the current levels of disinfection; and (iv) Any additional information requested by the director. 20-252 3376