If your system * * * | Your system must determine * * * |
(a) Uses only one point of disinfectant application | (1) One inactivation ratio (CTcalc/CT9 9.9) before or at the first customer during peak hourly flow or |
(2) 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, your 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 (<<SIGMA>>CTcalc/CT99.9). | |
(b) Uses more than one point of disinfectant application before the first customer | The (CTcalc/CT99.9) 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 using the procedure specified in paragraph (a)(2) of this section. |
To calculate a disinfection benchmark your system must perform the following steps | |
Step 1: | Using the data your system collected to develop the Disinfection Profile, determine the average Giardia lamblia inactivation for each calendar month by dividing the sum of all Giardia lamblia inactivations for that month by the number of values calculated for that month. |
Step 2: | Determine the lowest monthly average value out of the twelve (12) values. This value becomes the disinfection benchmark. |
If your system consists of * * * | Your 95th percentile turbidity value is * * * |
(1) Conventional Filtration or Direct Filtration ............ | 0.3 NTU |
(2) All other 'Alternative' Filtration ................... | A value determined by the Department (not to exceed 1 NTU) based on the demonstration described in paragraph (6)(c)of this section. |
If your system consists of * * * | Your maximum turbidity value is * * * |
(1) Conventional Filtration or Direct Filtration............. | 1 NTU |
(2) All other 'Alternative' Filtration ................... | A value determined by the Department (not to exceed 5 NTU) based on the demonstration as described in paragraph (6)(c) of this section. |
If * * * | Your system must * * * |
(a) The turbidity of an individual filter (or the turbidity of combined filter effluent (CFE) for systems with 2 filters that monitor CFE in lieu of individual filters) exceeds 1.0 NTU in two consecutive recordings 15 minutes apart. | Report to the Department by the 10th of the following month and include the filter number(s), corresponding date(s), turbidity value(s) which exceeded 1.0 NTU, and the cause (if known) for the exceedance(s). |
If a system was required to report to the Department * * * | Your system must * * * |
(b) For three months in a row and turbidity exceeded 1.0 NTU in two consecutive recordings 15 minutes apart at the same filter (or CFE for systems with 2 filters that monitor CFE in lieu of individual filters). | Conduct a self-assessment of the filter(s) within 14 days of the day the filter exceeded 1.0 NTU in two consecutive measurements for the third straight month unless a CPE as specified in paragraph (c) of this section was required. Systems with 2 filters that monitor CFE in lieu of individual filters must conduct a self-assessment on both filters. The self-assessment must consist of at least the following components: assessment of filter performance; development of a filter profile; identification and prioritization of factors limiting filter performance; assessment of the applicability of corrections; and preparation of a filter self-assessment report. |
(c) For two months in a row and turbidity exceeded 2.0 NTU in 2 consecutive recordings 15 minutes apart at the same filter (or CFE for systems with 2 filters that monitor CFE in lieu of individual filters). | Arrange to have a comprehensive performance evaluation (CPE) conducted by the Department or a third party approved by the Department not later than 60 days following the day the filter exceeded 2.0 NTU in two consecutive measurements for the second straight month. If a CPE has been completed by the Department or a third party approved by the Department within the 12 prior months or the system and the Department are jointly participating in an ongoing Comprehensive Technical Assistance (CTA) project at the system, a new CPE is not required. If conducted, a CPE must be completed and submitted to the Department no later than 120 days following the day the filter exceeded 2.0 NTU in two consecutive measurements for the second straight month. |
Corresponding requirement | Description of information to report | Frequency |
(a) Combined Filter Effluent Requirements. (paragraphs (6)(a) through (d) of this section). | (1) The total number of filtered water turbidity measurements taken during the month. | By the 10th of the following month. |
(2) The number and percentage of filtered water turbidity measurements taken during the month which are less than or equal to your system's required 95th percentile limit. | By the 10th of the following month. | |
(3) The date and value of any turbidity measurements taken during the month which exceed the maximum turbidity value for your filtration system. | By the 10th of the following month | |
(b) Individual Turbidity Requirements. (paragraph (7)(a) through (e) of this section). | (1) That your system conducted individual filter turbidity monitoring during the month. | By the 10th of the following month. |
(2) The filter number(s), corresponding date(s), and the turbidity value(s) which exceeded 1.0 NTU during the month, and cause (if known) for the exceedance(s), but only if 2 consecutive measurements exceeded 1.0 NTU. | By the 10th of the following month. | |
(3) If a self-assessment is required, the date that it was triggered and the date that it was completed. | By the 10th of the following month (or 14 days after the self-assessment was triggered only if the self-assessment was triggered during the last four days of the month) | |
(4) If a CPE is required, that the CPE is required and the date that it was triggered. | By the 10th of the following month. | |
(5) Copy of completed CPE report........ | Within 120 days after the CPE was triggered. | |
(c) Disinfection Profiling..... (paragraphs (4)(a) through (g) of this section) | (1) Results of optional monitoring which show TTHM levels 0.064 mg/L and HAA5 levels 0.048 mg/L (only if your system wishes to forgo profiling) or that your system has begun disinfection profiling. | (i) For systems serving 500-9,999 by July 1, 2003; (ii) For systems serving fewer than 500 by January 1, 2004. |
(d) Disinfection Benchmarking (paragraph (5)(a) through (e) of this section) | (1) A description of the proposed change in disinfection, your system's disinfection profile for Giardia lamblia (and, if necessary, viruses) and disinfection benchmark, and an analysis of how the proposed change will affect the current levels of disinfection. | Anytime your system is considering a significant change to its disinfection practice. |
Corresponding requirement | Description of necessary records | Duration of time records must be kept |
(a) Individual Filter Turbidity Requirements (paragraphs (7)(a) through (e) of this section) ........................ | Results of individual filter monitoring ..... | At least 3 years. |
(b) Disinfection Profiling (paragraphs (4)(a) through (g) of this section) ........................ | Results of Profile (including raw data and analysis) ......... | Indefinitely-y. |
(c) Disinfection Benchmarking (paragraphs (5)(a) through (e) of this section) ........................ | Benchmark (including raw data and analysis) .... | Indefinitely-y. |
S.C. Code Regs. 61-58.10.I