Development of the Stage 2 Disinfectants and Disinfection Byproducts Rule Tom Grubbs, USEPA November 1, 2007

1. Development of the Stage 2 Disinfectants and Disinfection Byproducts Rule  Tom Grubbs, USEPA November 1, 2007

2. 2 Overview DBP regulatory history Stage 2 DBPR background information Stage 2 DBPR requirements Schedule IDSE MCLs and monitoring Compliance and treatment options Available resources

3. 3 1979 TTHM Rule TTHM MCL of 0.10 mg/L Compliance based on running annual average Requirements applied to systems serving at least 10,000 people Systems <10,000 were not included due to concerns about their ability to simultaneously control TTHM and pathogens There were no specified requirements for pathogen treatment other than turbidity standards

4. 4 1998 Stage 1 DBPR Lower MCL for TTHM, new MCLs for HAA5, bromate, chlorite MRDLs for chlorine, chloramine, chlorine dioxide Extended compliance requirements to systems serving <10,000 Subpart H systems with conventional filtration treatment had to meet TOC removal treatment technique Staggered compliance schedule

5. 5 Stage 2 DBPR Background EPA required by 1996 SDWAA to develop Stage 2 Things learned through ICR data analysis, implementation, etc. DBP formation in the distribution system more complex than previously thought Consecutive systems not adequately protected Treatment plant-based monitoring inadequate EPA chartered a federal advisory committee (FAC) to develop recommendations to regulate DBPs and pathogens as needed Beyond Stage 1 and IESWTR/LT1ESWTR Supported by a technical workgroup IDSE will help identify appropriate monitoring locations LRAA will provide equivalent protection throughout individual systems Specific inclusion of Consecutive systems will provide equivalent protection to systems that have been subject to varying state requirements. Based on public comments, new data on occurrence and health effects of disinfection byproducts, and costs and potential impacts on public water systems, the Stage 2 Disinfectants and Disinfection Byproducts Rule (Stage 2 DBPR) was developed to build upon the Stage 1 DBPR and further reduce potential risks of cancer and reproductive and developmental health effects from DBPs. In conjunction with the Long Term 1 Enhanced Surface Water Treatment Rule (LT1ESWTR), the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR), and the Stage 1 DBPR, the Stage 2 DBPR will improve control of microbial contaminants and reduce public exposure to DBPs, while maintaining a strong level of protection against other contaminants. The regulatory changes required by the Stage 2 DBPR will provide more equal levels of protection against DBP exposure across entire distribution systems. To improve public health, the Stage 2 DBPR requires systems to conduct initial distribution system evaluations (IDSEs) that identify the high TTHM and HAA5 locations throughout the distribution system. The Stage 2 DBPR also requires systems to use locational running annual averages (LRAAs) to calculate compliance to ensure that customers at every location in the distribution system are equally protected from high levels of DBPs. *Schedule based on largest system in CDS.*IDSE will help identify appropriate monitoring locations LRAA will provide equivalent protection throughout individual systems Specific inclusion of Consecutive systems will provide equivalent protection to systems that have been subject to varying state requirements. Based on public comments, new data on occurrence and health effects of disinfection byproducts, and costs and potential impacts on public water systems, the Stage 2 Disinfectants and Disinfection Byproducts Rule (Stage 2 DBPR) was developed to build upon the Stage 1 DBPR and further reduce potential risks of cancer and reproductive and developmental health effects from DBPs. In conjunction with the Long Term 1 Enhanced Surface Water Treatment Rule (LT1ESWTR), the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR), and the Stage 1 DBPR, the Stage 2 DBPR will improve control of microbial contaminants and reduce public exposure to DBPs, while maintaining a strong level of protection against other contaminants. The regulatory changes required by the Stage 2 DBPR will provide more equal levels of protection against DBP exposure across entire distribution systems. To improve public health, the Stage 2 DBPR requires systems to conduct initial distribution system evaluations (IDSEs) that identify the high TTHM and HAA5 locations throughout the distribution system. The Stage 2 DBPR also requires systems to use locational running annual averages (LRAAs) to calculate compliance to ensure that customers at every location in the distribution system are equally protected from high levels of DBPs. *Schedule based on largest system in CDS.*

6. 6 Stage 2 DBPR Background (cont.) FAC signed Agreement in Principle in September 2000 Final rule consistent with FAC recommendations, public comments Builds on existing rules in M-DBP Suite Provides greater public health protection and equity through risk targeting Initial distribution system evaluations (IDSE) to identify compliance monitoring locations with high DBPs Basing compliance on Locational Running Annual Averages (LRAAs) and population-based monitoring Specifying requirements for consecutive systems IDSE will help identify appropriate monitoring locations LRAA will provide equivalent protection throughout individual systems Specific inclusion of Consecutive systems will provide equivalent protection to systems that have been subject to varying state requirements. Based on public comments, new data on occurrence and health effects of disinfection byproducts, and costs and potential impacts on public water systems, the Stage 2 Disinfectants and Disinfection Byproducts Rule (Stage 2 DBPR) was developed to build upon the Stage 1 DBPR and further reduce potential risks of cancer and reproductive and developmental health effects from DBPs. In conjunction with the Long Term 1 Enhanced Surface Water Treatment Rule (LT1ESWTR), the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR), and the Stage 1 DBPR, the Stage 2 DBPR will improve control of microbial contaminants and reduce public exposure to DBPs, while maintaining a strong level of protection against other contaminants. The regulatory changes required by the Stage 2 DBPR will provide more equal levels of protection against DBP exposure across entire distribution systems. To improve public health, the Stage 2 DBPR requires systems to conduct initial distribution system evaluations (IDSEs) that identify the high TTHM and HAA5 locations throughout the distribution system. The Stage 2 DBPR also requires systems to use locational running annual averages (LRAAs) to calculate compliance to ensure that customers at every location in the distribution system are equally protected from high levels of DBPs. *Schedule based on largest system in CDS.*IDSE will help identify appropriate monitoring locations LRAA will provide equivalent protection throughout individual systems Specific inclusion of Consecutive systems will provide equivalent protection to systems that have been subject to varying state requirements. Based on public comments, new data on occurrence and health effects of disinfection byproducts, and costs and potential impacts on public water systems, the Stage 2 Disinfectants and Disinfection Byproducts Rule (Stage 2 DBPR) was developed to build upon the Stage 1 DBPR and further reduce potential risks of cancer and reproductive and developmental health effects from DBPs. In conjunction with the Long Term 1 Enhanced Surface Water Treatment Rule (LT1ESWTR), the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR), and the Stage 1 DBPR, the Stage 2 DBPR will improve control of microbial contaminants and reduce public exposure to DBPs, while maintaining a strong level of protection against other contaminants. The regulatory changes required by the Stage 2 DBPR will provide more equal levels of protection against DBP exposure across entire distribution systems. To improve public health, the Stage 2 DBPR requires systems to conduct initial distribution system evaluations (IDSEs) that identify the high TTHM and HAA5 locations throughout the distribution system. The Stage 2 DBPR also requires systems to use locational running annual averages (LRAAs) to calculate compliance to ensure that customers at every location in the distribution system are equally protected from high levels of DBPs. *Schedule based on largest system in CDS.*

7. 7 Stage 2 DBPR Definitions Combined distribution system (CDS) � Interconnected distribution system consisting of the distribution system of wholesale systems and consecutive systems that receive finished water. Consecutive system � PWS that receives some or all of its finished water from one or more wholesale systems. Finished water � Water introduced into the distribution system of a PWS intended for distribution and consumption without further treatment, except as necessary to maintain water quality in the distribution system. Wholesale system � PWS that treats source water as necessary to produce finished water and then delivers some or all of that finished water to another PWS. Combined distribution system (CDS): Interconnected distribution system consisting of the distribution systems of wholesale systems and consecutive systems that receive finished water. Consecutive system: PWS that receives some or all of its finished water from one or more wholesale systems. Dual sample set: Set of two samples collected at the same time and location, with one sample analyzed for TTHM and the other analyzed for HAA5. Finished water: Water introduced into the distribution system of a PWS intended for distribution and consumption without further treatment, except as necessary to maintain water quality in the distribution system. GAC10: Granular activated carbon filter beds with an empty-bed contact time of 10 minutes based on average daily flow and a carbon reactivation frequency of every 180 days, except that the reactivation frequency for GAC10 used as a BAT for compliance with Stage 2 DBPR MCLs under 141.64(b)(2) shall be 120 days. GAC20: granular activated carbon filter beds with an empty-bed contact time of 20 minutes based on average daily flow and a carbon reactivation frequency of every 240 days. Locational running annual average (LRAA): Average of sample analytical results for samples taken at a particular monitoring location during the previous four calendar quarters. Wholesale system: PWS that treats source water as necessary to produce finished water and then delivers some or all of that finished water to another PWS. Combined distribution system (CDS): Interconnected distribution system consisting of the distribution systems of wholesale systems and consecutive systems that receive finished water. Consecutive system: PWS that receives some or all of its finished water from one or more wholesale systems. Dual sample set: Set of two samples collected at the same time and location, with one sample analyzed for TTHM and the other analyzed for HAA5. Finished water: Water introduced into the distribution system of a PWS intended for distribution and consumption without further treatment, except as necessary to maintain water quality in the distribution system. GAC10: Granular activated carbon filter beds with an empty-bed contact time of 10 minutes based on average daily flow and a carbon reactivation frequency of every 180 days, except that the reactivation frequency for GAC10 used as a BAT for compliance with Stage 2 DBPR MCLs under 141.64(b)(2) shall be 120 days. GAC20: granular activated carbon filter beds with an empty-bed contact time of 20 minutes based on average daily flow and a carbon reactivation frequency of every 240 days. Locational running annual average (LRAA): Average of sample analytical results for samples taken at a particular monitoring location during the previous four calendar quarters. Wholesale system: PWS that treats source water as necessary to produce finished water and then delivers some or all of that finished water to another PWS.

8. 8 MCLs for DBPs TTHM and HAA5 MCLs remain the same Calculating compliance changes: Stage 1 RAA vs. Stage 2 LRAA Point out that these have not changed from Stage 1Point out that these have not changed from Stage 1

9. 9 RAA vs. LRAA

10. 10 Population Based Monitoring Required for both IDSE and Compliance Monitoring Based on system population/source water type Targets DBP problem areas based on better understanding of DBP occurrence and formation Easier to implement for systems and states Greater equity of public health protection Addresses issues associated with part-time treatment plants and sources, multiple wells, consecutive systems, too few or too many samples to characterize DBP occurrence

11. 11 Stage 2 DBPR Schedules

12. 12 systems that are part of a combined distribution system (I.e. interconnected) will comply based on the schedule of the LARGEST system in the combined distribution systemsystems that are part of a combined distribution system (I.e. interconnected) will comply based on the schedule of the LARGEST system in the combined distribution system

13. 13 IDSE General Requirements Purpose: Determine locations of high TTHM and HAA5 concentrations throughout distribution system Results are used in conjunction with Stage 1 DBPR compliance monitoring to identify and select Stage 2 DBPR compliance monitoring locations Applicability CWS (and NTNCWS serving 10,000+) that uses or delivers water that has been treated with a primary or residual disinfectant other than UV light To comply with Stage 2 DBPR IDSE Requirements, all CWSs and all NTNCWSs serving at least 10,000 persons that treat their water with a primary or residual disinfectant other than UV or deliver water that has been treated with a primary or residual disinfectant other than UV must qualify for a Very Small System (VSS) Waiver, apply for 40/30 Certification, conduct Standard Monitoring and develop a report, or conduct a System Specific Study and develop a report.To comply with Stage 2 DBPR IDSE Requirements, all CWSs and all NTNCWSs serving at least 10,000 persons that treat their water with a primary or residual disinfectant other than UV or deliver water that has been treated with a primary or residual disinfectant other than UV must qualify for a Very Small System (VSS) Waiver, apply for 40/30 Certification, conduct Standard Monitoring and develop a report, or conduct a System Specific Study and develop a report.

14. 14 Standard Monitoring Standard monitoring sampling locations: Must be different from existing Stage 1 monitoring locations Must be distributed throughout distribution system Distribution System Schematics are not CBI and therefore are subject to the Freedom of Information Act (FOIA). System will continue to conduct compliance monitoring at existing Stage 1 DBPR locations Near entry point locations: If the number of entry points to the distribution system is less than the specified number of entry point monitoring locations, excess samples must be replaced equally by high TTHM or high HAA5 locations. An odd extra location must be a high TTHM location. If the number of entry points to the distribution system is greater than the specified number of entry points monitoring locations, then samples must be taken at the entry points having the highest annual water flow. Point out that systems in a combined distribution system must each conduct IDSE. They cannot monitor as one combined distribution systemNear entry point locations: If the number of entry points to the distribution system is less than the specified number of entry point monitoring locations, excess samples must be replaced equally by high TTHM or high HAA5 locations. An odd extra location must be a high TTHM location. If the number of entry points to the distribution system is greater than the specified number of entry points monitoring locations, then samples must be taken at the entry points having the highest annual water flow. Point out that systems in a combined distribution system must each conduct IDSE. They cannot monitor as one combined distribution system

15. 15 System Specific Study Existing Monitoring Existing Monitoring Results Based on samples collected and analyzed according to analytical requirements Minimum Requirements: Collected no earlier than 5 years prior to study plan submission date Each location must be sampled once during month of highest TTHM/HAA5 or highest water temperature for each 12 months of data submitted Must include all Stage 1 DBPR compliance monitoring results plus additional results as necessary to meet minimum number of sample requirements Point out that system cannot choose the data they want to submit. They have to submit all compliance as well as operational or special purpose samples collected from the date of the earliest result submitted.Point out that system cannot choose the data they want to submit. They have to submit all compliance as well as operational or special purpose samples collected from the date of the earliest result submitted.

16. 16 System Specific Study Hydraulic Modeling Extended period simulation hydraulic model Simulate 24 hour variation in demand; show consistently repeating 24 hour pattern of residence time Must represent key distribution system components Model must: Be calibrated or have calibration plans for the current configuration of the distribution system during the period of high TTHM formation potential Evaluate all storage facilities Calibration completed NLT 12 months after SSS plan submission System must conduct one round of TTHM/HAA5 monitoring during that period

17. 17 40/30 Certification Eligibility All required Stage 1 DBPR (Subpart L) compliance samples have been taken No individual sample exceeded 0.040 mg/L for TTHM No individual sample exceeded 0.030 mg/L for HAA5 No TTHM or HAA5 monitoring violations Based on recent two-year window 40/30 is individual sample, not RAA or LRAA.40/30 is individual sample, not RAA or LRAA.

18. 18 VSS Waivers Eligibility Systems serving < 500 persons Must have taken TTHM and HAA5 samples Stage 2 Compliance Monitor at Stage 1 DBPR compliance monitoring locations for Stage 2 DBPR compliance monitoring

19. 19 Stage 2 DBPR Compliance Monitoring Location Surface water and GWUDI systems and systems that purchase surface or GWUDI Footnotes: 1 � All systems must take at least one dual sample set during month of highest DBP concentrations. Systems on quarterly monitoring must take dual sample sets every 90 days 2 � System is required to take individual TTHM and HAA5 samples (instead of a dual sample set) at the locations with the highest TTHM and HAA5 concentrations, respectively. Only on location with a dual sample set per monitoring period is needed if highest TTHM and HAA5 concentrations occur at the same location Number of samples based on system�s own population and source water Not based on size of systems in CDSFootnotes: 1 � All systems must take at least one dual sample set during month of highest DBP concentrations. Systems on quarterly monitoring must take dual sample sets every 90 days 2 � System is required to take individual TTHM and HAA5 samples (instead of a dual sample set) at the locations with the highest TTHM and HAA5 concentrations, respectively. Only on location with a dual sample set per monitoring period is needed if highest TTHM and HAA5 concentrations occur at the same location Number of samples based on system�s own population and source water Not based on size of systems in CDS

20. 20 Stage 2 DBPR Compliance Monitoring Location Ground water systems and systems that purchase ground water Footnotes: 1 � All systems must take at least one dual sample set during month of highest DBP concentrations. Systems on quarterly monitoring must take dual sample sets every 90 days 2 � System is required to take individual TTHM and HAA5 samples (instead of a dual sample set) at the locations with the highest TTHM and HAA5 concentrations, respectively. Only on location with a dual sample set per monitoring period is needed if highest TTHM and HAA5 concentrations occur at the same location Number of samples based on system�s own population and source water Not based on size of systems in CDSFootnotes: 1 � All systems must take at least one dual sample set during month of highest DBP concentrations. Systems on quarterly monitoring must take dual sample sets every 90 days 2 � System is required to take individual TTHM and HAA5 samples (instead of a dual sample set) at the locations with the highest TTHM and HAA5 concentrations, respectively. Only on location with a dual sample set per monitoring period is needed if highest TTHM and HAA5 concentrations occur at the same location Number of samples based on system�s own population and source water Not based on size of systems in CDS

21. 21 Stage 2 DBPR Monitoring Plan Monitoring Plan must include: Monitoring locations & dates Compliance calculation procedures Monitoring plans for any other systems in the CDS if the state has modified monitoring requirements Complete no later than date you must conduct initial monitoring. Revise as needed to reflect changes in treatment, distribution system operations, layout, or other factors that could affect TTHM or HAA5 formation in consultation with State Plan must be kept on file for State and public review. State can consider systems in a combined distribution system as one combined system but each individual system must have at least one site total number of sites cannot be less than the total they would have based on the total population Point out that systems that prepared an IDSE report will rely heavily on that for their Stage 2 MPState can consider systems in a combined distribution system as one combined system but each individual system must have at least one site total number of sites cannot be less than the total they would have based on the total population Point out that systems that prepared an IDSE report will rely heavily on that for their Stage 2 MP

22. 22 Schedule 1 The state may grant up to an additional 24 months for compliance if you require capital improvements to comply with an MCL. 1 The state may grant up to an additional 24 months for compliance if you require capital improvements to comply with an MCL.

23. 23 Other Stage 2 Provisions Modifies eligibility for reduced bromate monitoring Clarifies eligibility for reduced DBP monitoring for subpart H systems without conventional filtration Requires disinfectant residual monitoring by consecutive systems Requires operational evaluations by systems with high DBP levels prior to violation Updates PN and CCR requirements

24. 24 Compliance Approaches System, in consultation with the State, chooses the compliance approach Take into account magnitude/nature of the problem, existing treatment, source water characteristics, costs, technical capabilities, co-occurring contaminants This is a site-specific decision THERE IS NO SILVER BULLET Optimize or modify current operations Move point of disinfection or change predisinfectant Improve precursor removal through EC/ES Modify distribution system operations to reduce water age, add booster chlorination

25. 25 Compliance Approaches (cont.) Change primary or secondary disinfectant Primary � switch to ozone, chlorine dioxide, UV Secondary � switch to chloramine Improve precursor removal Membranes, GAC Miscellaneous Change source water, consolidate with other systems Keep simultaneous compliance issues in mind � check before you change

26. 26 Stage 2 Resources Guidance manuals Initial Distribution System Evaluation (IDSE) Guidance Manual IDSE Guide for Systems Serving < 10,000* Operational Evaluation Guidance Manual Stage 2 DBPR Implementation Guidance Stage 2/ LT2 Simultaneous Compliance Guidance Stage 2 DBPR Small System Compliance Document Consecutive System Guidance Manual

27. 27 Stage 2 Resources (cont.) Factsheets IDSE Standard Monitoring IDSE System Specific Study IDSE Very Small System Waiver & 40/30 Certifications IDSE Tool Designed to help systems determine their IDSE requirements and prepare & submit sampling plans & reports

28. 28 Stage 2 Resources (cont.) Stage 2 DBPR Website: http://www.epa.gov/safewater/disinfection Final Rule & Preamble Guidances, Manuals, & Fact Sheets Link to the IDSE Tool, DCTS Contact List by State Searchable Q&A LT2ESWTR/Stage 2 DBPR Implementation Team Stage2mdbp@epa.gov