Operational Evaluation Level Stage 2 D/DBP

Rule Compliance

Michael W. DealCompliance Assurance SectionCentral OfficeDivision 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  + B  +  (2∗C ¿¿ ¿𝟒  =𝐃

A = TTHM or HAA5 result for the quarter before the previous quarterB = TTHM or HAA5 result for the previous quarterC = TTHM or HAA5 result for current quarterD = Current Operational Evaluation Level Value

ExampleLocation “X” (DS201)

TTHM Results

Current Quarter Value (3rd Qtr 2013) ……………………...(114.0 µg/L) 2Previous Quarter Value (2rd Qtr 2013)……………….....…….61.3 µg/LQuarter Before Previous (1st Qtr 2013)….............………..45.1 µg/L

334.4 µg/L

4

OEL = 83.6 µg/L

83.6 > MCL of 80.0 µg/L for TTHMResult 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

1. Receive call from OEPA to determine scope

2. Receive letter from OEPA with report template

3. Complete OEL report (Form 5031)

45 Total 84%3rd Quarter

62%Purchased SW

6 Repeat

18 13

29

3

OEL Exceedances (Since Aug. 2012)

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

OEL 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 1 – Source Water and Treatment

Section 2 – Distribution System Operations

Section 2 – Distribution System OperationsNoteworthy Events or Changes to the Distribution System:

Hydrant flushing Line breaks Rerouted flow Significant demands

Section 3 – Storage Tank Operations

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

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

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

Questions