Section 11-20-46 - Filtration and disinfection (Surface Water Treatment Rule)(a) General requirements This section, also known as the Surface Water Treatment Rule (SWTR), establishes criteria under which filtration is required as treatment for public water systems supplied by either a surface water source or by a ground water source under the direct influence of surface water (GWUDI). In addition, these rules establish treatment requirements in lieu of MCLs for the following contaminants: Giardia lamblia, viruses, heterotrophic plate count (HPC) bacteria, Legionella, and turbidity.
(1) Each public water system with a surface water source or a GWUDI source shall provide treatment of that source water by installing and properly operating water treatment processes which reliably achieve at least: (A) A total of 99.9 per cent (3-log) removal and/or inactivation of Giardia lamblia cysts between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer; and (B) A total of 99.99 per cent (4-log) removal and/or inactivation of viruses between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer. (2) A public water system using a surface water source or a GWUDI source shall meet the requirements of this section if it meets the disinfection requirements in subsection (b) and the filtration requirements in subsection (c).(3) Each public water system using a surface water source or a GWUDI source shall be operated by qualified personnel who meet the requirements specified by the director to minimize risk to human health or welfare.(4) Water purveyors with a surface water or GWUDI source shall implement the requirements of the 'Surface Water Treatment Rule Administrative Manual" dated January 1, 2002. Copies of the administrative manual are available upon request from the safe drinking water branch office in Honolulu, or the district health offices on Kauai, Maui, and Hawaii.(5) In addition to complying with the requirements in this section, systems must also comply with the requirements in section 11-20-46.1.(b) Disinfection. A public water system that uses a surface water source or a GWUDI source shall comply, before filtration is installed, with any interim disinfection requirements the director deems necessary to protect human health and welfare. A system that uses a surface water source or a GWUDI source shall provide the disinfection treatment specified in this subsection beginning June 29, 1993, or beginning when filtration is installed, whichever is later. Each public water system that provides filtration treatment shall provide disinfection treatment as follows: (1) The disinfection treatment shall be sufficient to ensure that the total treatment processes of that system achieve at least a total of 99.9 per cent (3-log) inactivation of Giardia lamblia cysts and at least a total of 99.99 per cent (4-log) inactivation of viruses, as determined by the director. Each public water system shall prove that it is meeting the previous disinfection criteria by determining CTs and total inactivation ratios of 1.0 or greater and reporting these data to the director on a monthly basis;(2) The residual disinfectant concentration in the water entering the distribution system, measured as specified in subsections (d)(1)(B) and (d)(2)(B)(ii), cannot be less than 0.2 mg/l for more than four hours; and(3) The residual disinfectant concentration in the distribution system, measured as total chlorine, combined chlorine, or chlorine dioxide, as specified in subsection (d)(1)(B), cannot be undetectable in more than five per cent of the samples each month, for any two consecutive months that the system serves water to the public. Water in the distribution system with a heterotrophic bacteria concentration greater than 500/ml, measured as HPC as specified in subsection (d)(1)(A), is deemed to have an undetectable disinfectant residual for purposes of determining compliance with this requirement. Thus, the value "v" in the formula given in subsection (e)(2)(B)(iv) cannot exceed five per cent in one month, for any two consecutive months. (c) Filtration. A public water system that uses a surface water source or a GWUDI source shall provide treatment consisting of both disinfection, as specified in subsection (b), and filtration treatment which complies with the requirements of paragraphs (1) and (2) by June 29, 1993. (1) Except where specified in section 11-20-46.1(c), the turbidity level of representative samples of a system's filtered water shall at no time exceed 5 NTU, measured as specified in subsections (d)(1)(A) and (d)(2)(B)(i).(2) The turbidity level of representative samples of a system's filtered water shall be less than or equal to the following values in at least ninety-five per cent of the measurements taken each month as specified in subsections (d)(1)(A) and (d)(2)(B)(i). (A) Conventional filtration treatment or direct filtration. 0.5 NTU, measured as specified in subsections (d)(1)(A) and (d)(2)(B)(i). (i) Beginning January 1, 2002, systems serving at least 10,000 people must meet the turbidity requirements in section 11-20-46.1(c)(1). (ii) Beginning January 1, 2005, systems serving fewer than 10,000 people must meet the turbidity requirements in section 11-20-46.1(c)(1).(B) Slow sand filtration. 1 NTU.(C) Diatomaceous earth filtration. 1 NTU.(D) Other filtration technologies. A public water system may use a filtration technology not listed in subparagraphs (A) to (C) if the supplier demonstrates to the director, using pilot plant studies or other means, that the alternative filtration technology, in combination with disinfection treatment meeting the requirements of subsection (b), consistently achieves at least a total of 99.9 per cent removal and/or inactivation of Giardia lamblia cysts and at least a total of 99.99 per cent removal and/or inactivation of viruses. For a system that makes this demonstration, the requirements for subparagraph A apply. Beginning January 1, 2002, systems serving at least 10,000 people must meet the requirements for other filtration technologies in section 11-20-46.1(c)(2). Beginning January 1, 2005, systems serving fewer than 10,000 people must meet the requirements for other filtration technologies in section 11-20-46.1(c)(2). (d) Analytical and monitoring requirements. (1) Analytical requirements. Only the analytical method(s) specified in this paragraph, or otherwise approved by EPA, may be used to demonstrate compliance with the requirements of subsections (b) and (c). Measurements for pH, temperature, turbidity, and residual disinfectant concentrations shall be conducted by a party approved by the director. Measurements for total coliforms, fecal coliforms or E. coli, and HPC shall be conducted by a laboratory certified by the director or EPA to do such analysis. Until laboratory certification criteria are developed for the analysis of HPC and fecal coliforms or E. coli, any laboratory certified for total coliform analysis by EPA is deemed certified for HPC and fecal coliform or E. coli analysis. The following procedures shall be performed in accordance with the publications listed in the following subparagraphs. (A) Public water systems must conduct analysis of pH and temperature in accordance with one of the methods listed in 40 C.F.R. § 141.23(k)(1). Public water systems must conduct analyses of total coliforms, fecal coliforms or E. coli, heterotrophic bacteria, and turbidity in accordance with the analytical methods in 40 C.F.R. § 141.74(a)(1) or alternative methods listed in Appendix A to Title 40 Code of Federal Regulations, Part 141, Subpart C, and by using analytical test procedures contained in Technical Notes on Drinking Water Methods, EPA-600/R-94-173, October 1994. This document is available from the National Service Center for Environmental Publications (NSCEP), P.O. Box 42419, Cincinnati, Ohio 45242-0419 or http://www.epa.gov/nscep/.(B) Public water systems must measure residual disinfectant concentrations with one of the analytical methods in 40 C.F.R. § 141.74(a)(2) or alternative methods listed in Appendix A to Title 40 Code of Federal Regulations, Part 141, Subpart C. If approved by the director, residual disinfectant concentrations for free chlorine and combined chlorine also may be measured by using DPD colorimetric test kits. Free and total chlorine residuals may be measured continuously by adapting a specified chlorine residual method for use with a continuous monitoring instrument provided the chemistry, accuracy, and precision remain the same. Instruments used for continuous monitoring must be calibrated with a grab sample measurement at least every five days, or with a protocol approved by the director. (2) Monitoring requirements. (A) A public water system that uses a surface water source or a GWUDI source shall comply with any interim reporting requirements, as specified by the director to minimize risk to human health or welfare, until filtration is in place.(B) A public water system that uses a surface water source or a GWUDI source and provides filtration treatment shall monitor in accordance with this paragraph beginning June 29, 1993, or when filtration is installed, whichever is later.(i) Turbidity measurements as required by subsection (c) shall be performed on representative samples of the system's filtered water at least every four hours that the system serves water to the public. A supplier may substitute continuous turbidity monitoring for grab sample monitoring if the supplier validates the continuous measurement for accuracy on a regular basis using a protocol approved by the director. (ii) The residual disinfectant concentration of the water entering the distribution system shall be monitored continuously, and the lowest value shall be recorded each day, except that if there is a failure in the continuous monitoring equipment, grab sampling every four hours may be conducted in lieu of continuous monitoring, but for no more than five working days following the failure of the equipment. If at any time the residual disinfectant concentration falls below 0.2 mg/l in a system using grab sampling in lieu of continuous monitoring, the supplier shall take a grab sample every four hours until the residual disinfectant concentration is equal to or greater than 0.2 mg/l. (iii) Beginning April 1, 2016, HPC must be measured at least at the same points in the distribution system and at the same time as total coliforms are sampled, as specified in sections 11-20-9.1(d) and (e). The director may allow a public water system which uses both a surface water source or a GWUDI source, and a ground water source to take HPC samples at points other than the total coliform sampling points if the director determines that such points are more representative of treated (disinfected) water quality within the distribution system. Residual disinfectant concentration should also be measured for operational control. (e) Reporting and recordkeeping requirements. (1) A public water system that uses a surface water source or a GWUDI source shall comply with any interim reporting requirements, as specified by the director to minimize risk to human health and welfare, until filtration is in place.(2) When a public water system that uses a surface water source or a GWUDI source and provides filtration treatment, the supplier shall report monthly to the director the information specified in this paragraph beginning June 29, 1993, or when filtration is installed, whichever is later. (A) Turbidity measurements as required by subsection (d)(2)(B)(i) shall be reported within ten days after the end of each month the system serves water to the public. Information that shall be reported includes: (i) The total number of filtered water turbidity measurements taken during the month. (ii) The number and percentage of filtered water turbidity measurements taken during the month which are less than or equal to the turbidity limits specified in subsection (c) for the filtration technology being used. (iii) The date and value of any turbidity measurements taken during the month which exceed 5 NTU. (B) Disinfection information specified in subsection (d)(2) shall be reported to the director within ten days after the end of each month the system serves water to the public. Information that shall be reported includes: (i) For each day, the lowest measured residual disinfectant concentration in mg/l in water entering the distribution system. (ii) The date and duration of each period when the residual disinfectant concentration in water entering the distribution system fell below 0.2 mg/l and when the director was notified of the occurrence.(iii) The following information on the samples taken in the distribution system in conjunction with total coliform monitoring pursuant to subsection (b): the number of routine total coliform samples collected and the number of instances in which HPC is more than 500 per milliliter.(iv) For the current and previous month the system serves water to the public, the value of "V" in the following formula: V = b X 100 / a
where
a = the number of routine total coliform samples collected,
b = the number of instances in which HPC is more than 500 per milliliter.
(C)(i) Each supplier, upon discovering that a waterborne disease outbreak potentially attributable to that water system has occurred, must report that occurrence to the director as soon as possible, but no later than by the end of the next business day.(ii) If at any time the turbidity exceeds 5 NTU, the system must consult with the State as soon as practical, but no later than 24 hours after the exceedance is known, in accordance with the public notification requirements under section 11-20-18(c)(2)(C).(iii) If at any time the disinfectant residual falls below 0.2 mg/l in the water entering the distribution system, the supplier must notify the director as soon as possible, but no later than by the end of the next business day. The supplier also must notify the director by the end of the next business day whether or not the residual was restored to at least 0.2 mg/l within four hours. (f) Recycle provisions. (1) Applicability. All public water systems supplied by a surface water source or a GWUDI source that employ conventional filtration or direct filtration treatment and that recycle spent filter backwash water, thickener supernatant, or liquids from dewatering processes must meet the requirements in paragraphs (2) through (4).(2) Reporting. A system must notify the director in writing by December 8, 2003, if the system recycles spent filter backwash water, thickener supernatant, or liquids from dewatering processes. New plants shall be given 15 months from the startup date approved by the director to report the information required under this subsection. This notification must include, at a minimum, the information specified in subparagraphs (A) and (B). (A) A plant schematic showing the origin of all flows which are recycled (including, but not limited to, spent filter backwash water, thickener supernatant, and liquids from dewatering processes), the hydraulic conveyance used to transport them, and the location where they are reintroduced back into the treatment plant. (B) Typical recycle flow in gallons per minute (gpm), the highest observed plant flow experienced in the previous year (gpm), design flow for the treatment plant (gpm), and State-approved operating capacity for the plant where the director has made such determinations. (3) Treatment technique requirement. Any system that recycles spent filter backwash water, thickener supernatant, or liquids from dewatering processes must return these flows through the processes of a system's existing conventional or direct filtration system as defined in section 11-20-2 or at an alternate location approved by the director by June 8, 2004. If capital improvements are required to modify the recycle location to meet this requirement, all capital improvements must be completed no later than June 8, 2006. New plants shall return these recycle flows through the processes of a system's conventional or direct filtration system or at an alternate location approved by the director.(4) Recordkeeping. The system must collect and retain on file recycle flow information specified in subparagraphs (A) through (F) for review and evaluation by the director beginning June 8, 2004. (A) Copy of the recycle notification and information submitted to the director under paragraph (2).(B) List of all recycle flows and the frequency with which they are returned.(C) Average and maximum backwash flow rate through the filters and the average and maximum duration of the filter backwash process in minutes. (D) Typical filter run length and a written summary of how filter run length is determined.(E) The type of treatment provided for the recycle flow.(F) Data on the physical dimensions of the equalization and/or treatment units, typical and maximum hydraulic loading rates, type of chemicals used and average dose and frequency of use, and frequency at which solids are removed, if applicable. [Eff and comp 1/2/93; am and comp 12/15/94; am and comp 10/13/97; comp 9/7/99; am and comp 11/30/02; am and comp 12/16/05; am and comp 11/28/11; comp MAY 02 2014 ] (Auth: HRS §§ 340E-2, 340E-9) (Imp: HRS §§ 340E-2, 340E-9; 42 U.S.C. §§300 f, 300g-1, 300g-2, 300g-3, 300g-4, 300g-5, 300g-6, 300j-4, and 300j-9; 40 C.F.R. §§141.70, § 141.72, § 141.73, § 141.74, and § 141.75 )