Section Env-Ws 380.24 - Disinfection Profiling for Systems Which Serve at Least 10,000 People(a) The owner of a public water system subject to the requirements of Env-Ws 380.23 and which serves at least 10,000 people shall comply with the requirements in this section and Env-Ws 380.26.(b) The system owner shall determine: (1) The TTHM annual average using the procedure specified in (c) below; and(2) The HAA5 annual average using the procedure specified in (d) below.(c) The TTHM annual average shall be calculated during the same period as the HAA5 annual average and be based on the following:(1) A system owner collecting data under the provisions of 40 CFR 141 Subpart M, July 1, 2000 edition shall use the results of the samples collected during the last 4 quarters of required monitoring;(2) A system owner using HAA5 occurrence data that meet the provisions of (d)(2) below, shall use TTHM data collected at the same time under the requirements of Env-Ws 317.70 and Env-Ws 327.70; and(3) A system owner using HAA5 occurrence data that meet the provisions of (e)(1) or (2) below, shall use TTHM data collected at the same time under the provisions of Env-Ws 317.70 and Env-Ws 327.70.(d) The HAA5 annual average shall be: (1) The annual average during the same period as the TTHM annual average; and(2) Based on the following:a. A system owner collecting data under the provisions of 40 CFR 141 Subpart M, July 1, 2000 edition, shall use the results of the samples collected during the last 4 quarters of required monitoring; andb. A system owner collecting 4 quarters of HAA5 occurrence data that meets the routine monitoring sample number and location requirements for TTHM set forth in Env-Ws 317.70 and Env-Ws 327.70, and the handling and analytical method requirements of Env-Ws 382.06, shall use those data to determine whether the requirements of this section apply.(e) A system owner who fails to collect the HAA5 data specified in (d) above shall: (1) Conduct monitoring for HAA5 that meets the routine monitoring sample number and location requirements for TTHM set forth in Env-Ws 317.70 and Env-Ws 327.70 and the handling and analytical method requirements of Env-Ws 382.06 to determine the HAA5 annual average and whether the requirements of (l) below apply; or(2) Comply with all other provisions of this section as if the HAA5 monitoring had been conducted and the results required compliance with (l) below.(f) If the department determines that the data set determined under (c) or (d) above is not representative, the department shall require that a system owner use a more representative annual data set for the purpose of determining applicability of the requirements of this section. The determination that a more representative data set is needed shall be based on the following criteria.(1) Water quality reported to the department pursuant to administrative rules Env-Ws 380 shall be reviewed to determine a divergence in treated water quality during the period represented by the data set from the norm.(2) The location of the sampling points in the data set shall be reviewed to determine whether the points are uniformly distributed throughout the water delivery system.(g) The department shall approve the data set offered in place of the data set determined under (c) or (d) above if it determines that the data set is more representative of actual system performance and is equivalent to the data set collected under the criteria specified in (c) or (d) above.(h) A system owner shall submit the following data to the department: (1) A system owner collecting TTHM and HAA5 data under the provisions of 40 CFR 141 Subpart M, July 1, 2000 edition, as required by (c)(1) and (d)(1) above, shall submit the results of the samples collected during the last 12 months of required monitoring;(2) A system owner collecting 4 consecutive quarters of HAA5 occurrence data that meet the routine monitoring sample number and location for TTHM in Env-Ws 317.70 and Env-Ws 327.70 and the handling and analytical method requirements of Env-Ws 382.06 as allowed by (c)(2) and (d)(1) above, shall submit that data; and(3) A system owner conducting monitoring for HAA5 using the monitoring requirements specified by (c)(3) and (e)(1) above shall submit TTHM and HAA5 data.(i) A system owner electing to comply with all other provisions of this section as if the HAA5 monitoring had been conducted and the results required compliance with this section, as allowed under (e)(2) above, shall notify the department in writing of the election.(j) Until the department has approved the data identified in (i) above, the system owner shall conduct monitoring for HAA5 using the monitoring requirements specified under (d) above.(k) A system having either a TTHM annual average greater than or equal to 0.064 mg/L or an HAA5 annual average greater than or equal to 0.048 mg/L during the same monitoring period specified in (c) above shall conduct disinfection profiling as follows: (1) A system owner shall develop a disinfection profile of its disinfection practice for a period of up to 3 years;(2) A system owner shall monitor daily for a period of 12 consecutive calendar months to determine the total logs of inactivation, expressed as log inactivation, for each day of operation, based on the CT99.9 values specified in Tables 380-2 through 380-9 as appropriate, through the entire treatment plant;(3) A system owner shall conduct the monitoring required in (2), above as follows: a. A system with a single point of disinfectant application prior to entrance to the distribution system shall conduct the monitoring in (4) a. through d. below; andb. A system with more than one point of disinfectant application shall conduct the monitoring in paragraphs (4) a. through d. below for each disinfection segment;(4) A system owner shall monitor the parameters necessary to determine the total inactivation ratio, using analytical methods described in Env-Ws 380.13, as follows: a. The temperature of the disinfected water shall be measured at least once per day at each residual disinfectant concentration sampling point during peak hourly flow;b. If the system uses chlorine, the pH of the disinfected water shall be measured at least once per day at each chlorine residual disinfectant concentration sampling point during peak hourly flow;c. The disinfectant contact time(s) (T) shall be determined for each day during peak hourly flow; andd. The residual disinfectant concentration(s) (C) of the water before or at the first customer and prior to each additional point of disinfection shall be measured each day during peak hourly flow.(l) A system owner may submit a written request to the department to use existing operational data in lieu of the monitoring conducted under the provisions of (k)(2) above.(m) The written request shall include the following:(1) The water system name;(2) The water system EPA number;(3) The most recent operational data for the past 3 years; and(4) A profile generated using the operational data specified in (3) above.(n) The data offered pursuant to (l) above shall be representative of giardia lamblia inactivation through the entire treatment plant and not just of certain treatment segments.(o) The department shall accept the data offered under (l), above, if the operational data is substantially equivalent to data collected under the provisions of (k)(2).(p) Until the department approves the request submitted pursuant to (l) above, the system owner shall conduct monitoring under the provisions of (k)(2), above.(q) In addition to the monitoring conducted under the provisions of (k)(2) above, to develop the disinfection profile, the system owner may elect to meet the following: (1) In addition to the disinfection profile generated under (k)(2) above, the owner of a public water system that has existing operational data may use the data to develop a disinfection profile for additional years;(2) A system owner may use the additional yearly disinfection profiles to develop a benchmark under the provisions of Env-Ws 380.26; and(3) The data shall be representative of inactivation through the entire treatment plant and not just of certain treatment segments.(r) A system owner shall calculate the total inactivation ratio as follows: (1) If a system uses only one point of disinfectant application, the system owner shall determine the total inactivation ratio for the disinfection segment by: a. Determining one CTcalc/CT99.9 (inactivation ratio) before or at the first customer during peak hourly flow; orb. Determining successive sequential inactivation ratios, between the point of disinfectant application and a point before or at the first customer during peak hourly flow;(2) Under b. above, a system owner shall calculate the [SIGMA] CTcalc/CT99.9 (total inactivation ratio) by determining the inactivation ratios for each sequence and then adding the inactivation ratio values together to determine the total inactivation ratio;(3) If a system uses more than one point of disinfectant application before the first customer, the system owner 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 and the inactivation ratio value of each segment and the total inactivation ratio shall be calculated using the method in (1) and (2) above; and(4) The system owner shall determine the total logs of inactivation by multiplying the value calculated in (1) or (3) above by 3.0.(s) The owner of a system that uses either chloramines or ozone for primary disinfection shall calculate the logs of inactivation for viruses based on methods accepted by the department. Methods accepted by the department shall be based on tables for log inactivation based on published, peer-reviewed and reproducible research.(t) The system owner shall retain disinfection profile data in the form of a graph or as a spreadsheet and have the data available when the department conducts a sanitary survey pursuant to Env-Ws 306.N.H. Code Admin. R. Env-Ws 380.24
#5098, eff 3-18-91, EXPIRED 3-18-97
New. #6521, eff 6-4-97 (See Revision Note at chapter heading for Env-Ws 300); ss by #8352, eff 5-14-05 (formerly part of Env-Ws 380.28 )