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Stage 2 Disinfectants and Disinfection Byproducts Rule Bruce Macler USEPA Region 9 415 972-3569 macler.bruce@epa.gov

Stage 2 Disinfectants and Disinfection Byproducts Rule Bruce Macler USEPA Region 9 415 972-3569 macler.bruce@epa.gov. H. Cl. Br. Cl. Bromodichloromethane. Stage 2 DBPR. Will ultimately require TTHM and HAA5 MCL compliance at each monitoring point in distribution system

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Stage 2 Disinfectants and Disinfection Byproducts Rule Bruce Macler USEPA Region 9 415 972-3569 macler.bruce@epa.gov

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  1. Stage 2 Disinfectants and Disinfection Byproducts RuleBruce MaclerUSEPA Region 9415 972-3569macler.bruce@epa.gov H Cl Br Cl Bromodichloromethane

  2. Stage 2 DBPR • Will ultimately require TTHM and HAA5 MCL compliance at each monitoring point in distribution system • No averaging across distribution • Goal to control for DBP "hot spots“ • More linkage between wholesalers and retailers • Initial Distribution System Evaluation • Monitoring requirement to determine compliance points • Proposed August 18, 2003 • Federal Register v.68, n.159, pp49547-49596 • Final Rule expected December 15, 2005*

  3. *Regulatory Schedule • S2 DBPR expected to be signed by EPA Administrator on December 15, 2006 • At same time as LT2 ESWTR • Publication in Federal Register is official “promulgation” date- January? • 60-day Congressional review hold • Rounded to beginning of following month for “effective” date • April 1, 2006 starts the ball rolling

  4. Purpose of the Stage 2 DBPR • Purpose is to provide additional protection from disinfection byproducts of concern • Supplements existing S1 D/DBPR by focusing on parts of distribution system with higher risks

  5. Significant Changes from Proposal • Proposed Interim “Stage 2A” MCLs to apply before final “Stage 2B” locational MCLs • Deleted these as too complex • Proposed early implementation dates • Now will be staggered • Proposed system-based monitoring • Now will be based on population served • Added criteria and details on “Significant Excursions”

  6. Systems Affected bythe Stage 2 DBPR Applies to all CWSs and NTNCWSs that add a disinfectant other than UV, or deliver water that has been treated with a disinfectant other than UV • Systems using surface water • Systems using ground water under the influence of surface water • Ground water systems • Consecutive systems Consecutive systems are defined in the Stage 2 Rule as public water systems that buy or otherwise receive some or all of their finished water from one or more wholesale systems for at least 60 days per year.

  7. Why Are Consecutive Systems an Issue? • Wholesalers’ MCL requirements end at turnouts… • Some regulated contaminants increase in the distribution system • TTHMs • Coliform bacteria • States have taken varying approaches to regulating DBPs in consecutive systems

  8. Definitions • Consecutive systemis a public water system that buys or otherwise receives some or all of its finished water from one or more wholesale system(s), for at least 60 days per year • Finished water is water that is introduced into the distribution system of a public water system and is intended for distribution without further treatment, except that necessary to maintain water quality • Wholesale system is a public water system that treats source water and then sells or otherwise delivers finished water to another public water system for at least 60 days per year. Delivery may be through a direct connection or through the distribution system of one or more consecutive systems • Combined distribution system is the interconnected distribution system consisting of the distribution systems of wholesale systems and of the consecutive systems that receive finished water from those wholesale systems

  9. Stage 2 DBPR Components • Initial Distribution System Evaluation (IDSE) • New compliance monitoring locations • Sites chosen from IDSE and/or Stage 1 DBPR sites • Locational Running Annual Average • Operational Evaluations • Inclusion of consecutive systems • Population based compliance • Revisions to Stage 1 DBPR • Reduced monitoring based on TOC • Bromate reduced monitoring

  10. Source Water TOC Reduced DBP Monitoring • Stage 1 DBPR • Systems with • TTHM < 0.040 mg/L, HAA5 < 0.030 mg/L, and TOC < 4.0 mg/L as a running annual average can qualify for reduced monitoring of TTHM and HAA5 • No timeframe specified • Stage 2 DBPR • Timeframe added • To qualify for reduced monitoring sample every 30 days • To stay on reduced monitoring sample every 90 days

  11. Reduced Monitoring for Bromate • Stage 1 DBPR • Systems that use ozone monitor for bromate at the entry point to the distribution system. • Reduced monitoring if bromide in source water is < 0.05 mg/L • Stays in effect until December 31, 2008 • Stage 2 DBPR • Reduced monitoring if bromate is < 0.0025 mg/L RAA at entry point to the distribution system • New analytical method for bromate with lower detection limit • System must have 12 months of data utilizing new method • Goes into effect January 1, 2009

  12. Consecutive Systems • Must comply with IDSE requirements • Must conduct TTHM and HAA5 compliance monitoring • Must comply with the Stage 1 DBPR requirements for chlorine and chloramines • Daily monitoring • MCLs (4.0 mg/L)

  13. Challenges for Consecutive Systems • If receiving treated water • Likely to contain DBPs already • May contain high levels of precursors and disinfectants that make more DBPs over time • Upstream treatment changes may substantially affect downstream water quality • Long-term • Variable or episodic

  14. MCL Compliance Challenges for Consecutive Systems • S1 DBPR controlled DBP precursors • Not an option for consecutive systems • S2 DBPR introduces new BATs for consecutive systems • Chloramination (>10,000 only) • Management of flow and storage • These may not work • May need locational treatment in distribution system Stora ge

  15. Population-Based Monitoring and Scheduling • Stage 1 DBPR • Scheduling based on source water type and population served • Monitoring based on source water type, population served, and number of plants • Stage 2 DBPR • Scheduling based on source water type, population served, and population of systems in combined distribution system • Monitoring based on source water type and population served

  16. Combined Distribution Systems (CDS) • All systems in a CDS (i.e., wholesalers, consecutive systems) must comply with Stage 2 DBPR requirements on the same schedule • Compliance date is based on the largest system in the CDS  • Largest system is not necessarily the wholesaler • State has discretion to determine CDS • Emergency or seasonal connections

  17. Combined Distribution Systems Consecutive System Wholesale System Consecutive System Treatment Plant System A System B System C R i v e r Combined Distribution System

  18. Combined Distribution System Example All 3 systems must comply based on the schedule of System B (Schedule 2) System A System serving 12,000 System C System serving 500 Sells water to. . . Who treats and sells water to. . . System B System serving 60,000

  19. Violations Monitoring and MCL violations are attributed to the PWS where the violation occurred Example System A sells to System B and a violation occurs in System B B A System B is in violation because it has the legal responsibility for complying with the MCL System B may set up a contract with System A that details water quality delivery specifications

  20. Public Notice and Consumer Confidence Reports • Responsibility of individual system • Wholesale system is responsible for notifying the consecutive system of analytical results and violations related to monitoring • Consecutive system must include the wholesale system’s monitoring results in the consumer confidence report • Consecutive system must conduct appropriate public notification upon a violation (whether in the wholesale or consecutive system)

  21. Initial Distribution System Evaluation (IDSE) • Studies conducted by water systems to identify distribution system locations that represent high TTHM and HAA5 levels • Results of the IDSE are used to select Stage 2 compliance monitoring sites • Not required for NTNCWSs serving fewer than 10,000 people • In addition to current regulatory monitoring

  22. Initial Distribution System Evaluation Options • Standard monitoring • One-year study of TTHM and HAA levels in distribution system using protocol • System-specific study using models and data • Must accomplish same goal as standard approach • “40/30 Monitoring Waiver” • ALL existing data are <40 ug/L for TTHM and <30 ug/L for HAA • Very small systems waiver • <500 people and existing monitoring site representative

  23. IDSE Options (cont.) Very Small System Waiver • Systems serving < 500 people • Can be granted by the State, if the State determines that the Stage 1 site represents both high TTHM and HAA5 concentrations Waiver 40/30 Certification • All Stage 1 compliance monitoring results (not just LRAAs) are under 40 g/L TTHM and 30 g/L HAA5 • Monitoring periods are specified in rule

  24. IDSE Options (cont.) System Specific Study (SSS) • The system must evaluate DBP concentrations throughout the distribution system using existing data source or combination of data sources (e.g., historical data, hydraulic monitoring results) • Report must be submitted to the State • System must conduct 1 year of distribution system monitoring for TTHM and HAA5 • Report must be submitted to the State Standard Monitoring Program (SMP)

  25. Compliance Spread Over Time • Systems >100,000 plus consecutives start first • 257 SW+ 22 GW systems in R9 • Systems 50-100K plus consecutives • Start six months after first group • 69 SW + 33 GW systems in next group • Systems 10-50K plus consecutives • Start six months after second group • 86 SW + 181 GW • Systems <10K • Start six months after third group • 535 SW + 3516 GW

  26. IDSE Schedule Schedule for systems in a combined distribution system is based on that of the largest system in the combined distribution system

  27. IDSE Challenges for Consecutive Systems • No previous DBP monitoring requirements • May lack data to determine appropriate monitoring locations for Stage 2 DBPR • May not be eligible for VSS Waiver or 40/30 Certification under IDSE • Must work with wholesaler, maybe others • Work together to find or get data • Samples may have been taken in consecutive system’s distribution system

  28. Standard Monitoring • One of four options for compliance with IDSE requirements • Most systems that need to complete an IDSE will use this option- hopefully! • Process is set by U.S. EPA • Frequency, number, and location of samples

  29. Standard Monitoring IDSE Steps • Select locations for Standard Monitoring • Prepare and submit Standard Monitoring plan • Primacy Agency must approve or modify the plan • Conduct Standard Monitoring • 12 months of monitoring for TTHM and HAA5 • Select Stage 2 DBPR compliance monitoring locations • Prepare and submit IDSE report

  30. Required Components of Standard Monitoring Plan • Distribution system schematic • Entry points and sources • Locations and dates of proposed Standard Monitoring sites • Locations and dates of Stage 1 DBPR monitoring sites • Population served • Source water type • Justification of Standard Monitoring sites • Must include data used to justify selection of Standard Monitoring sites

  31. Sampling Requirements • What, where, and how often do I sample? • Samples Collected • Dual sample set (both TTHM and HAA5) collected at all locations • Sample Locations • High TTHM levels • High HAA5 levels • Average Residence Time • Near Entry Points • Number of sites • Based on system type • Sample Frequency • 1, 4 or 6 samples during the year at each location • Number based on population served and source type

  32. Standard Monitoring Requirements • When do I sample? • Sample months • Peak historical month • Peak TTHM levels or • Peak HAA5 levels or • Month of warmest water temperature • Subsequent sample months every 60 days or every 90 days from peak historical month

  33. TTHM and HAA5 Standard Monitoring(1) • For GW systems or systems that purchase GW (1) A dual sample set (i.e., a TTHM and an HAA5 sample) must be taken at each monitoring location during each monitoring period. (2) Taken during peak historical month. The peak historical month is the month with the highest TTHM or HAA5 levels or the warmest water temperature. (3) You must monitor at or near the entry point if you are a consecutive system. If you are not a consecutive system, you must monitor at a high HAA5 location.

  34. TTHM and HAA5 Standard Monitoring • For Surface and GWUDI systems and systems that purchase surface or GWUDI

  35. Standard Monitoring Site Selection – Justification • Plan must include a justification for the selection of sites to be sampled during Standard Monitoring • Data sources and tools • Distribution system maps • Water quality data • Distribution system operating data

  36. Factors Affecting DBP Formation • Precursor concentration • Disinfectant - type and dose • Water chemistry • Water temperature • Water age • Biodegradation of HAAs

  37. TTHM Formation High TTHM concentration Organics Disinfection

  38. HAA5 Formation High HAA5 concentration Organics Disinfection

  39. Data Sources and Tools for Site Selection • Distribution system maps • Pipes • Dead ends • Length and diameter • Age and material • Land use • Highly and lightly developed areas • Major users • Entry points and sources • Key components • Tanks, pump stations, booster chlorination

  40. Data Sources and Tools for Site Selection • Water quality data • Source water quality • DBP data • Can use Stage 1 DBPR data for information • Cannot use Stage 1 DBPR sites for Standard Monitoring sites • Disinfectant residual data • Can be indicative of water age • May indicate biodegradation of HAA5

  41. Data Sources and Tools for Site Selection • Distribution system operating data • Understanding water flow • Pump run times • Metered flows between pressure zones • Billing records for major users • Advanced tools (hydraulic modeling or tracer studies) • Impact of tanks • Tank level records and tank configurations • Impact of booster chlorination

  42. Selecting Near Entry Point Sites • Tools • Distribution system map • Location • After treatment • Before first customer (not required) • If fewer entry points than needed • Replace with high TTHM and HAA5 sites • Alternate, starting with TTHM

  43. x Monitoring Location Selecting Near Entry Point Sites– Example • System needs 1 location near entry point • System has 2 surface water treatment plants and 1 well = 3 entry points • System considers flows from each source • WTP 1 – 5 MGD • WTP 2 – 3 MGD • Well 1 – 0.75 MGD • Locate site near entry point for WTP 1 WTP 1: 5 MGD WTP 2: 3 MGD Well 1: 0.75 MGD

  44. Selecting Average Residence Time Sites • Determination • Flow weighted calculation • Population weighted calculation • Tools • Distribution system map • Distribution system operational data • Hydraulic modeling or tracer study • Pump run times, metered flow • Distribution system water quality data • Average Disinfectant Residual

  45. Selecting High TTHM Sites • TTHM formation • Advanced water age is primary factor • Good TTHM sites • Downstream of tanks • Dead ends, but prior to last customer • Hydraulic dead ends and mixing zones • Downstream of booster chlorination • Sites with difficulty maintaining residual • Areas with low water use • Areas of high historic levels

  46. HAA5 formation Water age, but also consider biodegradation Avoid Areas with known biofilm growth Areas with difficulty maintaining a residual Good HAA5 sites Downstream of booster chlorination Sites with low but detectable residual Areas of high historic levels Downstream of tanks Hydraulic dead ends and mixing zones Areas with low water use Selecting High HAA5 Sites

  47. Standard Monitoring Site Selection Data Sources and Tools • Preliminary data will present many “candidate sites” from which the system can choose “selected sites” Disinfectant residual, maps, models, etc. Select Candidate Sites Select Standard Monitoring Sites Narrow Down Selection

  48. Final “Selected” Sites • Some site selection will be obvious • Near entry point • Others will require professional judgment • Consider geographic representation • Consider hydraulic representation • Consider areas fed by sources with higher DBPs • Use sites that “multi-task” • Consider accessibility

  49. Submitting Standard Monitoring Plan • Once the system has collected and analyzed its information, it must prepare the plan and submit it to the Primacy Agency • Must include required information

  50. Primacy Agency Review of Standard Monitoring Plan • Primacy Agency will review the monitoring plan submitted by the system • Verify that it contains required elements • Review Standard Monitoring site selection and justification • Primacy Agency may approve or modify plan If the Primacy Agency does not take action within 12 months from the date when the Plan was due, the system can consider the plan approved

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