The Stage 2 Disinfection By-Products Rule

Transcription

1 The Stage 2 Disinfection By-Products Rule DoD/EPA State Conference Compliance Track Atlanta, GA June 21, 2007 Amy Newbold Environmental Engineer Drinking Water Section EPA Region 4

2 Review: What are Disinfection By- Products? Precursor in Water Natural Organic Matter (NOM) Bromide Added Disinfectant + Chlorine Chloramines Chlorine Dioxide Ozone = Total DBP Trihalomethanes (TTHM) Haloacetic Acids (HAA5) Chlorite Bromate

3 Health Risks of DBPs Public Notification DBPs, including trihalomethanes (THMs) and haloacetic acids (HAAs), have been shown to cause cancer in laboratory animals. DBPs have been shown to affect the liver and the nervous system, and cause reproductive or developmental effects in laboratory animals. Exposure to certain DBPs may produce similar effects in people. EPA has set standards to limit exposure to THMs, HAAs, and other DBPs

4 Stage 1 Disinfection By-Products Rule Published December 1998 Applies to all CWS and NTNCWS that treat their water with a chemical disinfectant for either primary or residual treatment TTHM MCL = mg/l HAA5 MCL = mg/l Monitoring depends on number of plants Multiple wells drawing from same aquifer may be considered one treatment t plant Sample at Max Residence Time (MRT) and Average Residence Time (ART) if taking more than 1 sample per r plant Compliance based on Running Annual Average of quarterly results

5 Stage 2 Disinfection By-Products Rule - NEW Published January 4, 2006 Applies to CWS & NTNCWS that add and/or deliver water that is treated with a primary or residual disinfectant other than UV. Consecutives Systems Required to Monitor under Stage 2. MCLs are the same Compliance based on Locational Running Annual Average instead of Running Annual Average. Monitoring based on population served instead of number of plants Has 2 Parts Initial Distribution System Evaluation (IDSE) and beyond - Compliance Monitoring Operational Evaluation Levels (2012 and beyond)

6 New Definitions Wholesale System - is a public water 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. Delivery may be through a direct connection or through the distribution system of one or more consecutive systems. Consecutive System - is a PWS that receives some or all of its finished water from one or more wholesale systems. Delivery may be through a direct connection or through the distribution system m of one or more consecutive systems. Combined Distribution System (CDS) - is the interconnected distribution system consisting of the distribution systems of wholesale systems and of the consecutive systems that receive finished water.

7 More New Definitions... Dual Sample Set - is a set of two samples collected at the same time and same location, with one sample analyzed for TTHM and the other sample analyzed for HAA5. Dual sample sets are collected ed for the purposes of conducting an IDSE (part1) and determining compliance with the TTHM and HAA5 MCLs (part 2). Locational Running Annual Average - is the average of sample analytical results for samples taken at a particular monitoring location during the previous 4 calendar quarters.

8 RAA vs. LRAA Calculation Stage 1 RAA (4 samples per plant example) (Samp1 + Samp2 + Samp3 + Samp4)/4 = Quarterly Average (Q1 + Q2 + Q3 + Q4)/4 = RAA Stage 2 IDSE and Compliance Monitoring (Site1 Q1 + Site1 Q2 + Site1 Q3 + Site1 Q4)/4 = LRAA for Site 1 (Site2 Q1 + Site2 Q2 + Site2 Q3 + Site2 Q4)/4 = LRAA for Site 2 (Site3 Q1 + Site3 Q2 + Site3 Q3 + Site3 Q4)/4 = LRAA for Site 3 (Site4 Q1 + Site4 Q2 + Site4 Q3 + Site4 Q4)/4 = LRAA for Site 4

9 Part 1 of the Stage 2 Rule - The Initial Distribution System Evaluation (IDSE)

10 Initial Distribution System Evaluation Applies to NTNCWS that serve > 10,000 and all CWS Purpose is to Identify best locations to monitor TTHMs and HAA5s. One-time Study 1 year of increased monitoring Use results from IDSE and Stage 1 data (part 1), to select compliance monitoring locations for the Stage 2 DBPR (part 2).

11 Stage 2 DBPR IDSE Options IDSE Options VSS Waiver 40/30 Certification System Specific Study Standard Monitoring (Most Common Option)

12 VSS Waivers Criteria Serve fewer than 500 people Have taken TTHM and HAA5 samples Waivers effective immediately No application necessary Systems must meet all criteria Primacy agency may deny waiver and require Standard Monitoring or o System Specific Study VSS Waiver is only a waiver from additional IDSE activities. No IDSE Report Continue compliance with Stage 1 DBPR until Stage 2 DBPR compliance begins & Revise Stage 1 DBPR monitoring plan for Stage e 2 DBPR

13 40/30 Eligibility Criteria Systems must have taken all required Stage 1 DBPR samples: Within specified 2-year 2 year eligibility period based on system size No individual sample can have exceeded: mg/l for TTHM (40 μg/l) mg/l for HAA5 (30 μg/l) No TTHM or HAA5 monitoring violations within specified time period Continue compliance with Stage 1 DBPR until Stage 2 DBPR compliance begins & Revise Stage 1 DBPR monitoring plan for Stage 2 DBPR Sch. Population Eligibility Period Beginning No Earlier Than*: Submit 40/30 Certification By: 1 >100,000 Oct. 1, ,000-99,999 January 2004 Apr. 1, ,000-49,999 January 2005 Oct. 1, <10,000 Apr. 1, 2008

14 System Specific Studies (HQ) 2 Types of SSS: Hydraulic Model Specific requirements laid out in IDSE Guidance Manual Chapter 6 Submit SSS plan HQ will review all hydraulic models in Region 4 If approved, conduct monitoring based on System Specific Study Plan P Existing Monitoring Results Samples must be collected no earlier than 5 years prior to the study s plan submission date. Submit SSS plan HQ will review most existing monitoring SSS unless State requested ed otherwise If Approved, continue to monitor according to Stage 1 until Stage e 2 Compliance period begins.

15 Most Common IDSE Submission Standard Monitoring Plan Standard Monitoring: One year of increased distribution system monitoring to find locations with high TTHMs an HAA5s. Stage 1 Monitoring Will Continue During IDSE Results from IDSE Standard Monitoring should not be used to determine compliance with Stage 1 MUST continue to monitor Stage 1 sites according to Stage 1 monitoring plan.

16 Standard Monitoring IDSE Steps 2 1 Select Standard Monitoring Locations Prepare and Submit Standard Monitoring Plan EPA or the state approves the Standard Monitoring Plan 3 Conduct Standard Monitoring If you haven t 4 Select Stage 2 DBPR compliance monitoring locations heard from EPA or State within 12 months of submitting SMP 5 Prepare and Submit IDSE report

17 How to Prepare a Standard Monitoring Plan (SMP) Use Form 6 of the IDSE Guidance Manual (Chapter 7) Submit by mail or to EPA to: stage2mdbp@epa.gov Mail to: Stage 2 DBPR US EPA IPMC PO Box 98 Dayton, OH Or Use the IDSE Tool on website: idse.html Submit Distribution Schematic Showing: Locations of Sources Entry Points Storage Facilities Standard Monitoring Locations Stage 1 Monitoring Locations

18 Standard Monitoring Requirements Ground Water Monitoring Requirements Based PWS population (dual sample sets) For Groundwater systems or systems that purchase GW Population Frequency Total Near EP ART High TTHM High HAA5 < 500 1/year (2) 2 1 (3) , ,000 99, (every 90 days) 100, , > 500,

19 Standard Monitoring Requirements Surface Water (CFR ) For Surface and GWUDI systems and systems that purchase surface or GWUDI Population Frequency Total Near EP ART High TTHM High HAA5 <500 1/year (2) 2 1 (3) , ,301-9,999 4 (every 90 days) ,000-49, , , , ,999 6 (every 60 days) ,000,000-4,999, > 5,000,

20 Good Site Selection Characteristics (Use Chapter 7 of Guidance Manual): Entry Points Disinfected Entry Points (excluding pure UV) Average Residence Time Sites Flow weighted or population weighted Tracer Study Disinfectant Residual Avg High TTHM Sites High Water Temp Increased Water Age Near Dead Ends (before last group of customers) Hydraulically downstream of storage tanks High HAA5 Sites High Water Temp Low Residuals Lower Water Age (if biodegradation is occurring) Increased Water Age (if no biodegradation)

21 Biodegradation Check Three Questions: Are the highest HAA5 values typically in the summer months? Are the highest HAA5 values at MRT? Do highest HAA5 values generally occur at same time of year as TTHMs? If Yes to all 3 unlikely that biodegradation is taking place If No to Any HAA compounds may be degrading due to biological activity.

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23 What s s Your Schedule? IDSE Schedule determined by the population served a PWS or by the largest population served by a PWS in your CDS. Schedule Sys Serving (or connected to a sys serving): Submit 40/30, SMP, or SSS By: Complete Standard Monitoring or SSS By: Submit IDSE Report By: 1 > 100,000 10/1/2006 9/30/2008 1/1/ ,000 99,999 4/1/2007 3/31/2009 7/1/ ,000 49,999 10/1/2007 9/30/2009 1/1/2010 < 10,000 4/1/2008 3/31/2010 7/1/2010

24 Review of Standard Monitoring Plan State or EPA(FL only) will review & and approve or ask system to modify their SMP. If the State or EPA(FL only) does not approve or contact the system to modify the SMP within 12 months from the date it was due, the system can consider the plan approved Conduct Standard Monitoring in accordance with the plan.

25 Next Steps after IDSE Plan Submittal Once SMP is Approved, Conduct 12 months of monitoring based on Standard Monitoring Plan Determine Stage 2 Compliance Monitoring Locations Use protocol in IDSE Guidance Manual (Chapter 7) From IDSE Results and Stage 1 Results during Standard Monitoring Prepare and submit IDSE Report Stage 2 Monitoring Plan Deadline depends on schedule (3 months from deadline for completion of IDSE monitoring) Begin Stage 2 Compliance Monitoring (start date based on system type and size)

26 Stage 2 Routine Compliance Monitoring

27 Determining Stage 2 Compliance Monitoring Sites (Worsheet 7.2)

28 Stage 2 Compliance Monitoring Site Selection Protocol (Exhibit 7.7)

29 How to Prepare a IDSE Report Use Form 7 of the IDSE Guidance Manual (Chapter 7) Submit by mail or to EPA to: stage2mdbp@epa.gov Mail to: Stage 2 DBPR US EPA IPMC PO Box 98 Dayton, OH Submit Updated Distribution Schematic Showing: Locations of Sources Entry Points Storage Facilities Stage 2 Compliance Monitoring Locations

30 System Recordkeeping Must keep a copy of their Standard Monitoring plan and IDSE report for 10 years after date of submittal and make available for review by the public CCR must include the range of sample results from the IDSE monitoring in same calendar year as sampling occurred

31 Complete Schedule

32 Part 2 of the Stage 2 Rule - Compliance Monitoring 2012 and Beyond

33 Stage 2 Compliance Monitoring (2012 and Beyond) MCL Compliance will be calculated based on LRAA Operational Evaluation Levels predicts whether you will have an MCL violation in the next monitoring period (a)

34 Operational Evaluation Levels (2012 and Beyond) Reg Language: (a) You have exceeded the OEL at any monitoring location where the sum s of the 2 previous quarters TTHM results plus twice the current quarter s TTHM result, divided by 4 to determine an average, exceeds mg/l, or where the sum of the 2 previous quarters HAA5 results plus twice the current quarter s s HAA5 result, divided by 4 to determine an average exceeds mg/l. Example (for TTHMs): current quarter = Q2 (Q4 +Q1) + 2*(Q2) 4 ( ) + 2*(0.100) = mg/l 4 OEL = mg/l OEL EXCEEDED!

35 If OEL Is Exceeded... Must conduct an Operational Evaluation and submit a written report of the evaluation to the State no later than 90 days after being notified of the analytical result that causes you to exceed the OEL. Examination of System Treatment and Distribution Operational Practices including: Excess Storage Capacity Distribution System Flushing Changes in Sources or Source Water Quality Treatment Changes or Problems that may contribute to TTHM and HAA5 Formation

36 Summary of Stage 2 Requirements Determine IDSE Option (VSS, 40/30, SSS, or SMP) Submit IDSE (40/30 Cert, SSS, or SMP) Once Approved VSS continue monitoring Stage 1(if applicable) 40/30 continue monitoring Stage 1(if applicable) SSS (model) conduct monitoring (continue Stage 1) SMP conduct monitoring (continue Stage 1) After monitoring is complete, select new monitoring locations (out of IDSE and Stage 1 sites) Put together Stage 2 Monitoring Plan (IDSE Report) Stage 2 Compliance Monitoring & OELs

37 Contact Info: Amy Newbold EPA Region 4 Drinking Water Section (404) Newbold.Amy@epa.gov or Region4Stage2@epa.gov