Operational Evaluation Level Stage 2 D/DBP Rule Compliance
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Operational Evaluation Level Stage 2 D/DBP Rule Compliance . Michael W. Deal Compliance Assurance Section Central Office Division of Drinking And Ground Waters. Overview. Ohio Administrative Code Goals of OEL Calculation OEL Exceedance OEL Form 5031 Take Home.
Operational Evaluation Level Stage 2 D/DBP Rule Compliance
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Operational Evaluation Level Stage 2 D/DBP Rule Compliance Michael W. Deal Compliance Assurance Section Central Office Division of Drinking And Ground Waters
Overview • Ohio Administrative Code • Goals of OEL • Calculation • OEL Exceedance • OEL Form 5031 • Take Home
Ohio Administrative Code • OAC 3745-81-24 (D) (21) • OEL calculated for DBPs at all monitoring locations • Exceedance of the MCL requires a report • OEL report due 90 days following notification • Publicly accessible upon request
Goals • Primary: to help prevent an MCL through advanced warning of increased DBP Locational Running Annual Averages (LRAA) for quarterly monitoring • Secondary: to cause PWSs to address locations or facilities with seasonal DBP issues
Calculation of OEL A = TTHM or HAA5 result for the quarter before the previous quarter B = TTHM or HAA5 result for the previous quarter C = TTHM or HAA5 result for current quarter D = Current Operational Evaluation Level Value
Example • Location “X” (DS201) • TTHM Results • Current Quarter Value (3rdQtr 2013) ……………………...(114.0 µg/L) 2 • Previous Quarter Value (2rdQtr 2013)……………….....…….61.3 µg/L • Quarter Before Previous (1stQtr 2013)….............………..45.1 µg/L • 334.4 µg/L • 4 • OEL = 83.6 µg/L • 83.6 > MCL of 80.0 µg/L for TTHM • Result is an OEL Exceedance
OEL Exceedance • Early warning • Not a violation • No public notice requirement • Can be at 1 or more monitoring location(s) • TTHM or HAA5
Following an Exceedance • Receive call from OEPA to determine scope • Receive letter from OEPA with report template • Complete OEL report (Form 5031)
OEL Exceedances (Since Aug. 2012) 18 13 9 2 3
Limited Scope • Limited scope OEL report if cause is known • High DBP levels result from a certain change in water quality, treatment or distribution
What’s the Point? • Begin dealing with DBP issues prior to NOV • Investigate areas of concern • Make adjustments to lower DBP levels • Document investigation on Form 5031
Section 1 – Source Water and Treatment Noteworthy Changes to Source Water: • Significant algal blooms • Uncharacteristic precipitation events • Alternative well usage • Distinctive change to purchased water Changes to Treatment: • Chemical feed increase or decrease • Chemical product changes
Section 2 – Distribution System Operations Noteworthy Events or Changes to the Distribution System: • Hydrant flushing • Line breaks • Rerouted flow • Significant demands
Section 3 – Storage Tank Operations Calculate Percent Daily Fluctuation • The difference between the high and low water levels for each drain/fill event • X 100%
Section 4 – Chlorine Residual Monitoring Disinfectant residual information; • Average residual can be found on your MOR • Number of distribution samples includes daily samples and samples collected with TC • Number of samples <0.2 mg/L for free or <1.0 mg/L for combined chlorine • Repeated for each month of the quarter
Section 5 – Additional Information • Additional monitoring information • Plans to comply with the MCL • Corrective actions taken from past OEL exceedances
Take Home • Early warning not a violation • OEPA will notify of an exceedance • Report covers treatment, storage and distribution • Failure to submit a report is a violation • Goal is to optimize control of DBPs and avoid MCL exceedances
More Information • www.epa.ohio.gov/ddagw • www.epa.gov/safewater/disinfection/stage2